The Warwick Agreement on femoroacetabular impingement syndrome (FAI syndrome): an international consensus statement

Femoral and acetabular features explain acetabular contact pressure sensitivity to hip internal rotation in persons with cam morphology: A finite element analysis

BACKGROUND

Femoroacetabular impingement is characterized by premature contact between the proximal femur and acetabulum. The loss of femoral head-neck concavity associated with cam morphology leads to mechanical impingement during hip flexion and internal rotation. Other femoral and acetabular features have been linked with mechanical impingement but have not been comprehensively investigated. This study sought to determine which bony features are most influential in contributing to mechanical impingement in persons with a cam morphology.

METHODS

Twenty individuals (10 female, 10 male) with a cam morphology participated. Finite element analyses incorporating subject-specific bony geometry derived from computed tomography scans were used to determine which femoral (alpha angle and femoral neck-shaft angle) and acetabular (anteversion angle, inclination angle, depth, and lateral center-edge angle) features accentuate acetabular contact pressure with increasing degrees of hip internal rotation with the hip flexed to 90°. To determine the best predictors of acetabular contact pressure sensitivity to internal rotation, all morphological variables were included in a stepwise regression with the final model subjected to a bootstrapping procedure.

FINDINGS

The stepwise regression revealed that femoral neck-shaft angle, acetabular anteversion angle, acetabular inclination angle, and acetabular depth were the best combination of variables to predict contact pressure sensitivity to internal rotation, explaining 55% of the variance. Results of the bootstrap analysis revealed that a median value of 65% [37%, 89%] variance in sensitivity could be explained by these morphological variables.

INTERPRETATION

Mechanical impingement and the concomitant acetabular contact pressure are modulated by multiple femoral and acetabular features in persons with a cam morphology.

A Genome-Wide Association Study Meta-Analysis of Alpha Angle Suggests Cam-Type Morphology May Be a Specific Feature of Hip Osteoarthritis in Older Adults

OBJECTIVE

To examine the genetic architecture of cam morphology using alpha angle (AA) as a proxy measure and conduct an AA genome-wide association study (GWAS) followed by Mendelian randomization (MR) to evaluate its causal relationship with hip osteoarthritis (OA).

METHODS

Observational analyses examined associations between AA measurements derived from hip dual x-ray absorptiometry (DXA) scans from the UK Biobank study and radiographic hip OA outcomes and subsequent total hip replacement. Following these analyses, an AA GWAS meta-analysis was performed (N = 44,214) using AA measurements previously derived in the Rotterdam Study. Linkage disequilibrium score regression assessed the genetic correlation between AA and hip OA. Genetic associations considered significant (P < 5 × 10-8 ) were used as AA genetic instrument for 2-sample MR analysis.

RESULTS

DXA-derived AA showed expected associations between AA and radiographic hip OA (adjusted odds ratio [OR] 1.63 [95% confidence interval (95% CI) 1.58, 1.67]) and between AA and total hip replacement (adjusted hazard ratio 1.45 [95% CI 1.33, 1.59]) in the UK Biobank study cohort. The heritability of AA was 10%, and AA had a moderate genetic correlation with hip OA (rg  = 0.26 [95% CI 0.10, 0.43]). Eight independent genetic signals were associated with AA. Two-sample MR provided weak evidence of causal effects of AA on hip OA risk (inverse variance weighted OR 1.84 [95% CI 1.14, 2.96], P = 0.01). In contrast, genetic predisposition for hip OA had stronger evidence of a causal effect on increased AA (inverse variance weighted β = 0.09 [95% CI 0.04, 0.13], P = 4.58 × 10-5 ).

CONCLUSION

Expected observational associations between AA and related clinical outcomes provided face validity for the DXA-derived AA measurements. Evidence of bidirectional associations between AA and hip OA, particularly for risk of hip OA on AA, suggests that hip shape modeling secondary to a genetic predisposition to hip OA contributes to the well-established relationship between hip OA and cam morphology in older adults.

Biomechanical Analysis of Hip Braces after Hip Arthroscopic Surgery for Femoroacetabular Impingement Syndrome: An Observational Study

Currently, hip braces are recommended and typically worn by femoroacetabular impingement (FAI) patients after hip arthroscopic surgery. However, there is currently a lack of literature regarding the biomechanical effectiveness of hip braces. The purpose of this study was to investigate the biomechanical effect of hip braces after hip arthroscopic surgery for FAI. Overall, 11 patients who underwent arthroscopic FAI correction and labral preservation surgery were included in the study. Standing-up and walking tasks in unbraced and braced conditions were performed at 3 weeks postoperatively. For the standing-up task, videotaped images of the hip's sagittal plane were recorded while patients stood from a seated position. After each motion, the hip flexion-extension angle was calculated. For the walking task, acceleration of the greater trochanter was measured using a triaxial accelerometer. For the standing-up motion, the mean peak hip flexion angle was found to be significantly lower in the braced condition than in the unbraced condition. Furthermore, the mean peak acceleration of the greater trochanter was significantly lower in the braced condition than in the unbraced condition. Patients undergoing arthroscopic FAI correction surgery would benefit from usage of a hip brace in terms of protecting repaired tissues during early postoperative recovery.

Single-Leg Squat Test in the Clinical Setting Does Not Discriminate Patients With Femoroacetabular Impingement Syndrome From Asymptomatic Individuals

CONTEXT

Laboratorial 3-dimensional kinematic analyses have shown changes in the single-leg squat's (SLS) pattern of patients with femoroacetabular impingement syndrome (FAIS). However, it is unknown whether clinicians are able to detect these changes using 2-dimensional kinematics.

OBJECTIVE

To compare the frontal plane 2-dimensional kinematics of patients with FAIS and asymptomatic individuals in the SLS test performed in a clinical setting.

DESIGN

Case-control study.

SETTING

Physical therapy clinic.

PARTICIPANTS

Twenty men with bilateral FAIS and 20 asymptomatic men.

MAIN OUTCOME MEASURES

Two-dimensional kinematic analysis was collected in the frontal plane during the execution of the SLS test. The outcomes were squat depth, pelvic drop (pelvis angle relative to the horizontal plane), hip adduction (femur angle relative to the pelvis), and knee valgus (femur angle relative to the tibia).

RESULTS

Most and least painful limbs of patients with FAIS had squat depth (9.8% [2.9%] and 9.5% [3.1%] of height), pelvic drop (4.2° [3.9°] and 3.7° [4.2°]), hip adduction (74.9° [5.8°] and 75.9° [5.7°]), and knee valgus (4.0° [11.0°] and 5.0° [9.9°]) similar to asymptomatic individuals (9.0% [2.3%], 4.8° [2.6°], 73.7° [4.9°], and -1.7° [8.5°]; P > .05 for all).

CONCLUSION

The frontal plane 2-dimensional kinematic analysis of the SLS test in the clinical setting is not able to distinguish patients with FAIS from asymptomatic individuals.

What is the Rate of Response to Nonoperative Treatment for Hip-Related Pain? A Systematic Review With Meta-analysis

OBJECTIVE: We aimed to (1) determine the rate of satisfactory response to nonoperative treatment for nonarthritic hip-related pain, and (2) evaluate the specific effect of various elements of physical therapy and nonoperative treatment options aside from physical therapy. DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: We searched 7 databases and reference lists of eligible studies from their inception to February 2022. STUDY SELECTION CRITERIA: We included randomized controlled trials and prospective cohort studies that compared a nonoperative management protocol to any other treatment for patients with femoroacetabular impingement syndrome, acetabular dysplasia, acetabular labral tear, and/or nonarthritic hip pain not otherwise specified. DATA SYNTHESIS: We used random-effects meta-analyses, as appropriate. Study quality was assessed using an adapted Downs and Black checklist. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. RESULTS: Twenty-six studies (1153 patients) were eligible for qualitative synthesis, and 16 were included in the meta-analysis. Moderate certainty evidence suggests that the overall response rate to nonoperative treatment was 54% (95% confidence interval: 32%, 76%). The overall mean improvement after physical therapy treatment was 11.3 points (7.6-14.9) on 100-point patient-reported hip symptom measures (low to moderate certainty) and 22.2 points (4.6-39.9) on 100-point pain severity measures (low certainty). No definitive specific effect was observed regarding therapy duration or approach (ie, flexibility exercise, movement pattern training, and/or mobilization) (very low to low certainty). Very low to low certainty evidence supported viscosupplementation, corticosteroid injection, and a supportive brace. CONCLUSION: Over half of patients with nonarthritic hip-related pain reported satisfactory response to nonoperative treatment. However, the essential elements of comprehensive nonoperative treatment remain unclear. J Orthop Sports Phys Ther 2023;53(5):1-21. Epub 9 March 2023. doi:10.2519/jospt.2023.11666.

Comprehensive assessment and classification of upper and lower limb pain in athletes: a scoping review

BACKGROUND

Upper and lower limb (peripheral) pain is prevalent in athletes. Contemporary research prioritises multidimensional pain assessment and classification. This study aims to review comprehensive athlete pain assessment practices against the reference standard (International Olympic Committee, IOC Athlete Pain framework), identifying trends and highlighting gaps.

METHODS AND ANALYSIS

Six databases were searched using a comprehensive search strategy. This review followed the Joanna Briggs Institute standardised methodology for scoping reviews and is reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. Title and abstract, full-text screening and data charting were completed by two independent reviewers.

INCLUSION CRITERIA

Original research, systematic reviews and clinical practice guidelines reporting assessment or classification of pain in athletes of any age with chronic or acute peripheral pain in English on human participants from database inception.

RESULTS

470 studies with 175 different pain assessment tools were mapped against the IOC Athlete Pain Framework. Papers included tools from neurophysiological (470/100%), biomechanical (425/90%), affective (103/22%), cognitive (59/13%) and socioenvironmental (182/39%) domains. Pain classification was included in 108 studies (23%). 4 studies (0.85%) defined pain. Athletes with physical disability were included in 13 (3%) studies and no studies included athletes with intellectual disabilities. Socioeconomic factors were addressed in 29 (6%) studies.

DISCUSSION

Neurophysiological and biomechanical domains are frequently addressed. Affective, socioenvironmental and cognitive tools are under-represented. Potential tools for use by researchers and clinicians are highlighted. Defining and classifying pain and determining predominant pain mechanisms is needed in both research and clinical practice. More work on underrepresented populations is needed.

CONCLUSION

This review informs researchers and clinicians working with athletes in pain how pain assessment and classification is currently conducted and highlights future priorities.

Does femoroacetabular impingement syndrome affect range of motion? A systematic review with meta-analysis

BACKGROUND

It is unclear whether femoroacetabular impingement syndrome (FAIS) affect hip range of motion (ROM).

SOURCES OF DATA

We performed a systematic review with meta-analysis searching six electronic databases from inception to March 21, 2022. We included studies assessing hip ROM in FAIS, FAI morphology without symptoms (FAIm), and healthy controls. Mean differences between groups were measured in ROM degrees with 95% confidence interval (CI).

AREAS OF AGREEMENT

A total of 17 studies (1702 hips) were included. Comparison of FAIS patients versus healthy controls showed that hip ROM was clinically and statistically reduced in FAIS for internal rotation (90° hip flexion, -8.01°, 95% CI: -11.21, -4.90; 0° hip flexion -6.38°, 95% CI: -9.79, -2.97); adduction (90° hip flexion, -4.74°, 95% CI: -8.13, -1.34); flexion (-5.41°, 95% CI: -7.05, -3.49), abduction (0° hip flexion, -5.76°, 95% CI: -8.38, -3.23), and external rotation (90° hip flexion, -3.5°, 95% CI: -5.32, -1.67) ranging from low to high certainty of evidence. Comparison of FAIm versus healthy controls showed no statistically significant differences in any direction of movement, albeit with uncertainty of evidence.

AREAS OF CONTROVERSY

The certainty of evidence was unclear, particularly for asymptomatic FAIm.

GROWING POINTS

Hip ROM may be reduced in all directions except extension in FAIS compared to controls. Hip ROM may not be restricted in asymptomatic FAIm.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further studies are needed to resolve the uncertainty of evidence about ROM restrictions in asymptomatic FAIm compared to healthy controls.

Hip muscle strength in male and female patients with femoroacetabular impingement syndrome: Comparison to healthy controls and athletes

OBJECTIVES

To examine hip muscle strength deficits in patients with femoroacetabular impingent syndrome (FAIS), with special emphasis on potential sex- and comparison-related (between-subject vs within-subject) differences.

DESIGN

Cross-sectional comparative study.

PARTICIPANTS

Forty FAIS patients (20 women), 40 healthy controls (20 women) and 40 athletes (20 women).

MAIN OUTCOME MEASURES

Hip abduction, adduction and flexion isometric strength was tested using a commercially-available dynamometer. Two between-subject comparisons (FAIS patients vs controls and FAIS patients vs athletes) and one within-subject comparison (inter-limb asymmetry) of strength deficits were conducted, based on the calculation of respective percent differences.

RESULTS

For all hip muscle groups, women were 14-18% weaker than men (p < 0.001), but no sex-related interactions were observed. For all hip muscle groups, FAIS patients were 16-19% weaker than controls (p = 0.001) and 24-30% weaker than athletes (p < 0.001). For FAIS patients, the involved hip abductors were 8.5% weaker than the uninvolved ones (p = 0.015), while no inter-limb asymmetry was observed for the other hip muscles.

CONCLUSION

Sex had no influence on hip muscle strength deficits in FAIS patients while a major impact of comparison method/group was observed. Hip abductors showed consistent deficits for all comparison methods, suggestive of a possible greater impairment compared to hip flexors and adductors.

Arthroscopic Decompression of the Anterior Inferior Iliac Spine

Background

Pathologic contact between the femoral neck and anterior inferior iliac spine (AIIS or subspine) often occurs concomitantly with femoroacetabular impingement, contributing to hip pain and dysfunction1-4. We perform arthroscopic AIIS decompression to alleviate this source of extra-articular impingement and eliminate a potential cause of persistent pain following primary hip arthroscopy5-7.

Description

After identifying abnormal AIIS morphology on preoperative false-profile radiographs and/or 3D computed tomography, we utilize a beaver blade to make a small incision in the proximal capsule and rectus femoris tendon. This peri-capsulotomy window grants access to the subspine region. We then shuttle an arthroscopic burr into place within this window and begin debriding the subspine deformity under direct visualization. Fluoroscopy is utilized intraoperatively to ensure adequate resection, using intraoperative false-profile views achieved by canting the C-arm approximately 40°. Resection is considered adequate when the AIIS deformity is no longer readily apparent on false-profile views and when intraoperative range-of-motion testing confirms no further impingement with hip hyperflexion.

Alternatives

Femoroacetabular impingement can be treated nonoperatively with use of physical therapy and activity modification8; however, outcomes following nonoperative treatment are inferior to those following hip arthroscopy, according to various studies9-12. There are no known alternative treatments specific to subspine impingement.

Rationale

As patients with subspine deformities progress through hip flexion, the femoral neck collides with the AIIS, limiting range of motion. As such, subspine deformities have been shown to be more common in dancers and other high-flexion athletes13,14. Additionally, studies have demonstrated that low femoral version of <5° is associated with increased contact between the distal femoral neck and the AIIS. This pathologic contact can occur even in the absence of an obvious subspine deformity15. In both of these patient populations, surgeons should have a high suspicion for subspine impingement, and a subspine decompression should be performed during hip arthroscopy in order to maximize patient outcomes.

Expected Outcomes

This is a safe procedure that, if performed when indicated, can improve outcomes following primary hip arthroscopy. A recent systematic review found a pooled complication risk of 1.1%, a pooled revision risk of 1.0%, and significant postoperative improvements in patient-reported outcome measures16.

Important Tips

Suspect subspine impingement in high-flexion athletes and patients with low femoral version, even in the absence of an obvious deformity.Ensure adequate visualization of the entire subspine deformity by creating a pericapsular window.Confirm thorough resection with use of fluoroscopic imaging intraoperatively, including false-profile views demonstrating absent subspine deformity.

Acronyms and Abbreviations

FAI = femoroacetabular impingementAP = anteroposterior, refers to the technique used to obtain one of the pelvic radiographs3D CT = three-dimensional computed tomographyLCEA = lateral center-edge angle, a measurement used to quantify severity of hip dysplasiaOR = operating roomAlpha = alpha angle, a measurement used to measure femoral head-neck offset and assess the severity of a cam deformityIc = iliocapsularisRFd = direct head of rectus femorisRFr = reflected head of rectus femorisCap = hip capsuleGMi = gluteus minimusmHHS = modified Harris Hip ScoreHOS-ADL = Hip Outcome Score - Activities of Daily LivingHOS-SSS = Hip Outcome Score - Sports Specific Subscale.

High-level soccer players have a low rate of return to performance after hip arthroscopy for femoroacetabular impingement syndrome

PURPOSE

Femoroacetabular impingement syndrome (FAIS) is a known cause of impaired sports performance in athletes and the relationship between FAIS and soccer players has previously been described. Hip arthroscopy is a viable treatment option that can facilitate athletes' return to sport (RTS). The aim of this study was to evaluate the RTS and return to performance (RTP) with objective measurements in high-level soccer players after hip arthroscopy for FAIS.

METHOD

Soccer players, with a hip sports activity scale (HSAS) level of 7 or 8 before symptom onset and undergoing hip arthroscopy for FAIS between 2011 and 2019 were identified in the Gothenburg hip arthroscopic registry. A total of 83 high-level soccer players, with a mean age of 23.9 (SD 4.4) years at surgery, were included. To verify the activity level and further stratify players as elite or sub-elite, player statistics were collected from soccer-specific scout webpages and the Swedish national soccer association. The return to sport was defined as return to one game of soccer. Return to performance was defined as playing at the same level, or higher, and participating in at least 80% of the number of games played the season before symptom onset or the season before surgery either the first or second season after hip arthroscopy.

RESULTS

In total, 71 (85.5%, 95% confidence interval (CI) 76.1-92.3%) of the players returned to sport the first or second season after surgery. Compared to the season before symptom onset, 31 (37.3%, 95% CI 27.0-48.7%) players returned to performance the first or second season after surgery, and 32 (38.6%, 95% CI 28.1-49.9%) players returned to performance the first or second season after surgery compared to the season before surgery.

CONCLUSION

A high rate of elite and sub-elite soccer players return to soccer after hip arthroscopy for FAIS. However, less than half of the players RTP when evaluating performance through level of play and number of games played.

LEVEL OF EVIDENCE

Level IV.

Improved Mental Health Status and Patient-Reported Outcomes After Hip Arthroscopy for Femoroacetabular Impingement

BACKGROUND

Femoroacetabular impingement (FAI) is often a chronic problem, which can lead to a decrease in mental well-being.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine patient mental health improvement after hip arthroscopy and if this improvement correlated with improved outcomes. It was hypothesized that patients with low mental health (LMH) status would improve after hip arthroscopy for FAI and that their patient-reported outcomes (PROs) would significantly improve after surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent hip arthroscopy with labral repair between 2008 and 2015 were included. The minimum follow-up was 2 years. PROs included the modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sports (HOS-Sports), and 12-Item Short Form Health Survey (SF-12). The minimal clinically important difference and Patient Acceptable Symptom State (PASS) were determined for HOS-ADL, HOS-Sports, and the mHHS based on previously published studies. Patients who scored <46.5 on the SF-12 Mental Component Summary (MCS) were in the LMH group, and those who scored ≥46.5 were in the high mental health (HMH) group.

RESULTS

In total, 120 (21%) of the 566 patients were in the LMH group and 446 (79%) patients were in the HMH group preoperatively. There was no difference in age or sex between groups. Patients in the LMH group had lower mHHS, HOS-ADL, and HOS-Sports at the mean 4-year follow-up and were less likely to reach PASS for the scores. Postoperatively, 84% (478/566) of the entire group was in the HMH group. A total of 88 (73%) of the LMH group improved to HMH. A multiple linear regression model for change in MCS identified independent predictors of changes in preoperative MCS to be LMH group preoperatively, change in HOS-Sports, and change in mHHS (r² = 0.4; P < .001).

CONCLUSION

HMH was achieved in 84% of the patients after hip arthroscopy for FAI. Improvement in MCS was correlated with function and activity, as indicated by a significant correlation with HOS-ADL and HOS-Sports. A small percentage of patients did see a decline in their MCS score. This study showed that patients with LMH scores before hip arthroscopy for FAI can improve to normal/high mental health, and this correlated with higher PROs.

A radiomics approach to the diagnosis of femoroacetabular impingement

Introduction

Femoroacetabular Impingement (FAI) is a hip pathology characterized by impingement of the femoral head-neck junction against the acetabular rim, due to abnormalities in bone morphology. FAI is normally diagnosed by manual evaluation of morphologic features on magnetic resonance imaging (MRI). In this study, we assess, for the first time, the feasibility of using radiomics to detect FAI by automatically extracting quantitative features from images.

Material and methods

17 patients diagnosed with monolateral FAI underwent pre-surgical MR imaging, including a 3D Dixon sequence of the pelvis. An expert radiologist drew regions of interest on the water-only Dixon images outlining femur and acetabulum in both impingement (IJ) and healthy joints (HJ). 182 radiomic features were extracted for each hip. The dataset numerosity was increased by 60 times with an ad-hoc data augmentation tool. Features were subdivided by type and region in 24 subsets. For each, a univariate ANOVA F-value analysis was applied to find the 5 features most correlated with IJ based on p-value, for a total of 48 subsets. For each subset, a K-nearest neighbor model was trained to differentiate between IJ and HJ using the values of the radiomic features in the subset as input. The training was repeated 100 times, randomly subdividing the data with 75%/25% training/testing.

Results

The texture-based gray level features yielded the highest prediction max accuracy (0.972) with the smallest subset of features. This suggests that the gray image values are more homogeneously distributed in the HJ in comparison to IJ, which could be due to stress-related inflammation resulting from impingement.

Conclusions

We showed that radiomics can automatically distinguish IJ from HJ using water-only Dixon MRI. To our knowledge, this is the first application of radiomics for FAI diagnosis. We reported an accuracy greater than 97%, which is higher than the 90% accuracy for detecting FAI reported for standard diagnostic tests (90%). Our proposed radiomic analysis could be combined with methods for automated joint segmentation to rapidly identify patients with FAI, avoiding time-consuming radiological measurements of bone morphology.

High survivorship and excellent 5-year outcomes in patients older than 40 years undergoing arthroscopy for femoroacetabular impingement

PURPOSE

To assess 5-year clinical outcome, in adults > 40 years of age, following hip arthroscopy for femoroacetabular impingement compared to a younger, matched, control group.

METHODS

All primary arthroscopies for FAI between 2009 and 2016 were considered (n = 1762). Hips presenting with Tönnis > 1, lateral centre edge angle < 25°, or prior hip surgery were excluded. Younger (< 40 years) and older hips (> 40 years) were matched for gender, Tönnis grade, capsular repair and radiological parameters. Survival (avoidance of total hip replacement {THR}) was compared between the groups. Patient reported outcome measures (PROMs) were also completed at baseline and 5 years to assess changes in functional capacity. Additionally, hip range of motion (ROM) was assessed at baseline and review. The minimal clinically important difference (MCID) was determined and compared between groups.

RESULTS

Ninety-seven older hips were matched to 97 younger controls (78% male in both groups). The average age of the older group at the time of surgery was 48.0 ± 5.7 years, compared to 26.7 ± 6.0. Six (6.2%) of the older hips and 1 (1%) of younger hips converted to THR (p = 0.043, effect size = 0.74, large). There were statistically significant improvements in all PROMs. At follow-up, there were no differences in PROMs between groups; significant improvements in hip ROM were also observed with no difference in ROM between groups at either time point. Similar achievement of MCIDs was observed in both groups.

CONCLUSIONS

Older patients experience a high survivorship rate at 5 years, although this may be lower than younger patients. Where THR is avoided, large clinically significant improvements in pain and function are observed.

LEVEL OF EVIDENCE

Level IV.

London International Consensus and Delphi study on hamstring injuries part 1: classification

Muscle injury classification systems for hamstring injuries have evolved to use anatomy and imaging information to aid management and prognosis. However, classification systems lack reliability and validity data and are not specific to individual hamstring muscles, potentially missing parameters vital for sport-specific and activity-specific decision making. A narrative evidence review was conducted followed by a modified Delphi study to build an international consensus on best-practice decision-making for the classification of hamstring injuries. This comprised a digital information gathering survey to a cohort of 46 international hamstring experts (sports medicine physicians, physiotherapists, surgeons, trainers and sports scientists) who were also invited to a face-to-face consensus group meeting in London . Fifteen of these expert clinicians attended to synthesise and refine statements around the management of hamstring injury. A second digital survey was sent to a wider group of 112 international experts. Acceptance was set at 70% agreement. Rounds 1 and 2 survey response rates were 35/46 (76%) and 99/112 (88.4%) of experts responding. Most commonly, experts used the British Athletics Muscle Injury Classification (BAMIC) (58%), Munich (12%) and Barcelona (6%) classification systems for hamstring injury. Issues identified to advance imaging classifications systems include: detailing individual hamstring muscles, establishing optimal use of imaging in diagnosis and classification, and testing the validity and reliability of classification systems. The most used hamstring injury classification system is the BAMIC. This consensus panel recommends hamstring injury classification systems evolve to integrate imaging and clinical parameters around: individual muscles, injury mechanism, sporting demand, functional criteria and patient-reported outcome measures. More research is needed on surgical referral and effectiveness criteria, and validity and reliability of classification systems to guide management.

Outcomes of Arthroscopic Decompression of the Anterior Inferior Iliac Spine: A Systematic Review and Meta-analysis

BACKGROUND

Anterior inferior iliac spine (AIIS) impingement has been increasingly recognized as a source of extra-articular impingement and hip pain. However, no aggregate data analysis of patient outcomes after AIIS decompression has been performed.

PURPOSE

To evaluate outcomes after arthroscopic AIIS decompression.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were queried for all English-language studies reporting outcomes of arthroscopic AIIS decompression performed in isolation or in conjunction with hip impingement correction surgery. After screening, 10 articles were included. The indications for AIIS decompression were recorded, and weighted mean improvements in patient-reported outcome (PRO) scores, complication rates, and revision rates were calculated.

RESULTS

A total of 547 patients (311 women; 57%) were identified, with a total of 620 operative hips. The mean age was 28.42 ± 5.6 years, and the mean follow-up was 25.22 ± 11.1 months. A total of 529 hips (85%) underwent AIIS decompression, 530 hips (85%) underwent femoral osteochondroplasty, and 458 hips (74%) underwent labral repair. Of the patients, 13% underwent bilateral AIIS decompression. The mean modified Harris Hip Score improved from 61.3 ± 6.9 to 88.7 ± 4.7 postoperatively (change, 27.4 ± 5.7 points; P < .001), the Hip Outcome Score-Activities of Daily Living improved from 67.2 ± 10.6 to 91.1 ± 3.2 postoperatively (change, 24.0 ± 8.0 points; P = .001), and the Hip Outcome Score-Sports Specific Subscale improved from 36.8 ± 19.2 to 82.8 ± 3.8 postoperatively (change, 46.0 ± 18.2 points; P = .002). The pooled risk of postoperative complications was 1.1% (95% CI, 0.1%-2.1%), and the pooled risk of needing revision surgery was 1.0% (95% CI, 0.1%-2.0%). No complication was directly attributed to the AIIS decompression portion of the procedure.

CONCLUSION

PROs improved significantly after hip arthroscopy with AIIS decompression, with a low risk of postoperative complications and subsequent revision surgeries. Failure to identify extra-articular sources of hip pain in outcomes of femoroacetabular impingement syndrome, including from the AIIS, could lead to poorer outcomes and future revision surgery.

Limited External Rotation and Hip Extension Due to Posterior Extra-articular Ischiofemoral Hip Impingement in Female Patients With Increased Femoral Anteversion: Implications for Sports, Sexual, and Daily Activities

BACKGROUND

Posterior femoroacetabular impingement (FAI) is poorly understood. Patients with increased femoral anteversion (FV) exhibit posterior hip pain.

PURPOSE

To correlate hip impingement area with FV and with combined version and to investigate frequency of limited external rotation (ER) and hip extension (<40°, <20°, and <0°) due to posterior extra-articular ischiofemoral impingement.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Osseous patient-specific three-dimensional (3D) models based on 3D computed tomography scans were generated of 37 female patients (50 hips) with positive posterior impingement test (100%) and increased FV >35° (Murphy method). Surgery was performed in 50% of patients (mean age, 30 years; 100% female). FV and acetabular version (AV) were added to calculate combined version. Subgroups of patients (24 hips) with increased combined version >70° and patients (9 valgus hips) with increased combined version >50° were analyzed. The control group (20 hips) had normal FV, normal AV, and no valgus. Bone segmentation was performed to generate 3D models of every patient. Validated 3D collision detection software was used for simulation of impingement-free hip motion (equidistant method). Impingement area was evaluated in combined 20° of ER and 20° of extension.

RESULTS

Posterior extra-articular ischiofemoral impingement occurred between the ischium and the lesser trochanter in 92% of patients with FV >35° in combined 20° of ER and 20° of extension. Impingement area in combined 20° of ER and 20° of extension was larger with increasing FV and with higher combined version; correlation was significant (P < .001, r = 0.57, and r = 0.65). Impingement area was significantly (P = .001) larger (681 vs 296 mm2) for patients with combined version >70° (vs <70°, respectively) in combined 20° of ER and 20° of extension. All symptomatic patients with increased FV >35° (100%) had limited ER <40°, and most (88%) had limited extension <40°. The frequency of posterior intra- and extra-articular hip impingement of symptomatic patients (100% and 88%, respectively) was significantly (P < .001) higher compared with the control group (10% and 10%, respectively). The frequency of patients with increased FV >35° with limited extension <20° (70%) and patients with limited ER <20° (54%) was significantly (P < .001) higher compared with the control group (0% and 0%, respectively). The frequency of completely limited extension <0° (no extension) and ER <0° (no ER in extension) was significantly (P < .001) higher for valgus hips (44%) with combined version >50° compared with patients with FV >35° (0%).

CONCLUSION

All patients with increased FV >35° had limited ER <40°, and most of them had limited extension <20° due to posterior intra- or extra-articular hip impingement. This is important for patient counselling, for physical therapy, and for planning of hip-preservation surgery (eg, hip arthroscopy). This finding has implications and could limit daily activities (long-stride walking), sexual activity, ballet dancing, and sports (eg, yoga or skiing), although not studied directly. Good correlation between impingement area and combined version supports evaluation of combined version in female patients with positive posterior impingement test or posterior hip pain.

High Survivorship and Comparable Patient-Reported Outcomes at a Minimum 5 Years After Hip Arthroscopic Surgery in Patients With Femoroacetabular Impingement, With and Without Lateral Rim Dysplasia

BACKGROUND

Femoroacetabular impingement (FAI) in patients with dysplasia presents a unique challenge to surgeons. Short-term outcomes are conflicting, while longer term follow-up data are only emerging.

PURPOSE

To quantify midterm (minimum 5-year follow-up) outcomes after the arthroscopic correction of FAI in the presence of lateral rim dysplasia compared with a matched control group with FAI with normal acetabular coverage.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Prospective outcome data, collected in a consecutive series of patients undergoing arthroscopic FAI correction with lateral rim dysplasia (lateral center-edge angle [LCEA] of 13°-25°), were reviewed (N = 75 cases). An age- and sex-matched control group of 120 cases was also formed (LCEA >25°). Survivorship was defined as the avoidance of total hip replacement and assessed using a Kaplan-Meier curve with the log-rank test. Survival rates and patient-reported outcome measure (PROM) scores (modified Harris Hip Score [mHHS], University of California, Los Angeles [UCLA], 36-Item Short Form Health Survey [SF-36], and Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] preoperatively and at 5 years postoperatively) were compared between the groups. The proportion of patients across groups achieving the minimal clinically important difference (MCID) was compared for each PROM. The dysplasia group was also analyzed independently to identify any factors that may indicate a less favorable outcome using regression analysis. The group was divided into 2 subgroups: borderline dysplasia (LCEA of 20°-25°) and severe dysplasia (LCEA <20°).

RESULTS

The survival rate in the dysplasia group was 97%. There was no statistical difference with respect to survival rates or any PROM scores (P > .05 for all) between the groups. There were similar rates of achieving the MCID between the groups for the mHHS, UCLA, and WOMAC. The FAI control group had a higher rate of achieving the MCID for the SF-36 (P = .012; effect size = 0.274 [small]). Subgroup analysis indicated a lower survival rate (78% vs 100%, respectively; P < .001) in female cases in the dysplasia group (n = 9) compared with male cases in the dysplasia group (n = 66). The UCLA score in female cases in the dysplasia group at 5 years was statistically lower compared with that in male cases in the dysplasia group (6 vs 10, respectively; P = .003; effect size = 0.378 [medium]), but no other outcome revealed any differences between the sexes. There were also no variables identified on regression analysis that accurately predicted a poorer outcome in the dysplasia group. When stratified by severity, there was no difference in survivorship or outcomes between those with severe dysplasia (LCEA <20°; n = 11) and those with borderline dysplasia (LCEA of 20°-25°; n = 64).

CONCLUSION

An arthroscopic intervention was a successful treatment option for FAI in the presence of lateral rim dysplasia at midterm follow-up. Irrespective of the severity of dysplasia, patients can expect similar improvements to those in patients with normal femoral head coverage.

London International Consensus and Delphi study on hamstring injuries part 2: operative management

The key indications for surgical repair of hamstring injuries (HSIs) remain unclear in the literature due to a lack of high-level evidence and expert knowledge. The 2020 London International Hamstring Consensus meeting aimed to highlight clear surgical indications and to create a foundation for future research. A literature review was conducted followed by a modified Delphi process, with an international expert panel. Purposive sampling was used with two rounds of online questionnaires and an intermediate round involving a consensus meeting. The initial information gathering (round 1) questionnaire was sent to 46 international experts, which comprised open-ended questions covering decision-making domains in HSI. Thematic analysis of responses outlined key domains, which were evaluated by a smaller international subgroup (n=15) comprising clinical academic sports medicine physicians, physiotherapists and orthopaedic surgeons in a consensus meeting. After group discussion of each domain, a series of consensus statements were prepared, debated and refined. A round 2 questionnaire was sent to 112 international hamstring experts to vote on these statements and determine level of agreement. The consensus threshold was set a priori at 70% agreement. Rounds 1 and 2 survey respondents were 35/46 (76%) and 99/112 (88.4%), respectively. The consensus group agreed that the indications for operative intervention included: gapping at the zone of tendinous injury (87.2% agreement) and loss of tension (70.7%); symptomatic displaced bony avulsions (72.8%); and proximal free tendon injuries with functional compromise refractory to non-operative treatment (72.2%). Other important considerations for operative intervention included: the demands of the athlete/patient and the expected functional outcome (87.1%) based on the anatomy of the injury; the risk of functional loss/performance deficit with non-operative management (72.2%); and the capacity to restore anatomy and function (87.1%). Further research is needed to determine whether surgery can reduce the risk of reinjury as consensus was not reached within the whole group (48.2%) but was agreed by surgeons (70%) in the cohort. The consensus group did not support the use of corticosteroids or endoscopic surgery without further evidence. These guidelines will help standardise treatment of HSIs, specifically the indications and decision-making for surgical intervention.

The Effect of a Formal Nonoperative Management Program Combining a Hip Injection With Structured Adjunctive Exercise Rehabilitation in Patients With Symptomatic Femoroacetabular Impingement Syndrome

BACKGROUND

Although the initial treatment recommendations for femoroacetabular impingement syndrome (FAIS) may include nonsurgical therapies such as injections and rehabilitation, many patients undergo isolated injections or a rudimentary exercise regimen.

PURPOSE

To investigate the benefit of an intra-articular hip injection and concomitant structured exercise rehabilitation program in patients with symptomatic FAIS ≥6 months.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

For this study we recruited 49 patients with a mean age of 32.8 years (range, 16-56 years) and symptoms ≥6 months (range, 6-250 months) associated with FAIS, as confirmed via magnetic resonance imaging and radiography. After a guided intra-articular injection of corticosteroid and local anesthetic, patients underwent a structured 12-week rehabilitation program. Patients were assessed before and after injection (8 weeks and 4, 6, 12, and 24 months) with a range of patient-reported outcome measures (PROMs), including the 33-item International Hip Outcome Tool, Hip Outcome Score, modified Harris Hip Score, the Tegner Activity Score, a visual analog scale assessing the frequency and severity of hip pain, and a Global Rating of Change scale. Range of motion, peak isometric hip strength, and hop tests were assessed. Absolute scores and limb symmetry indices were calculated. The percentage of patients transitioning toward surgery over the period was evaluated.

RESULTS

Of the 44 patients who underwent the injection and completed the initial 8-week rehabilitation component, 14 (31.8%) progressed toward surgical intervention over the 24-month postinjection period owing to dissatisfaction and/or symptom recurrence. Patients who progressed toward surgery, as compared with those who did not, reported significantly worse (P < .05) PROMs presurgery and more pain within the first 4 weeks after injection. In the nonoperative cohort, a significant improvement (P < .05) in all PROMs was observed, with 93% of these patients satisfied overall. The Global Rating of Change did not improve, although this was measured only after the injection, reflecting no further significant perceived global change from 8 weeks to 24 months. A significant increase (P < .05) in all hip range of motion and most isometric strength measures was observed at 8 weeks after injection, with these improvements largely sustained until 24 months. Bilateral improvements in hop capacity were observed, with hop test LSIs significantly improving for the single (p = 0.009), triple (p = 0.029) and triple crossover (p = 0.005) hop tests for distance.

CONCLUSION

Although 32% of patients progressed toward surgery, significant improvement in hip pain, symptoms, and physical function was observed in the majority of patients with symptomatic FAIS as a result of a targeted nonoperative management pathway consisting of an intra-articular injection and a structured exercise program.

Do patients with femoroacetabular impingement syndrome who undergo hip arthroscopy display improved alpha angle (magnetic resonance imaging) and radiographic hip morphology?

AIMS

To compare (a) the change in radiological bony morphology between participants with femoroacetabular impingement (FAI) syndrome who underwent arthroscopic hip surgery compared to physiotherapist-led non-surgical care and (b) the change in radiological bony morphology between participants with FAI syndrome who underwent arthroscopic hip surgery involving cam resection or acetabular rim trimming or combined cam resection and acetabular rim trimming.

METHODS

Maximum alpha angle measurements on magnetic resonance imaging and Hip2 Norm standardized hip measurements on radiographs were recorded at baseline and at 12 months postoperatively. One-way analysis of covariance and independent T tests were conducted between participants who underwent arthroscopic hip surgery and physiotherapist-led non-surgical care. Independent T tests and analysis of variance were conducted between participants who underwent the 3 different arthroscopic hip procedures.

RESULTS

Arthroscopic hip surgery resulted in significant improvements to mean alpha angle measurements (decreased from 70.8° to 62.1°) (P value < .001, 95% CI -11.776, -4.772), lateral center edge angle (LCEA) (P value = .030, 95% CI -3.403, -0.180) and extrusion index (P value = 0.002, 95% CI 0.882, 3.968) compared to physiotherapist-led management. Mean maximum 1-year postoperative alpha angle was 59.0° (P value = .003, 95% CI 4.845, 18.768) for participants who underwent isolated cam resection. Measurements comparing the 3 different arthroscopic hip procedures only differed in total femoral head coverage (F[2,37] = 3.470, P = .042).

CONCLUSION

Arthroscopic hip surgery resulted in statistically significant improvements to LCEA, extrusion index and alpha angle as compared to physiotherapist-led management. Measured outcomes between participants who underwent cam resection and/or acetabular rim trimming only differed in total femoral head coverage.

Hip Arthroscopy for Femoroacetabular Impingement Syndrome Shows Good Outcomes and Low Revision Rates, With Young Age and Low Postoperative Pain Score Predicting Excellent 5-Year Outcomes

PURPOSE

To evaluate the clinical outcomes of hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and their predictors at a minimum 5 years' follow-up.

METHODS

We retrospectively analyzed patients with FAIS after first-time unilateral hip arthroscopy between January 2010 and July 2016. Patient-reported outcomes (PROs) included the validated modified Harries Hip Score (mHHS) and Visual Analog Scale for Pain (Pain VAS). We included patients with Tönnis grade 0 or 1 and reported PROs, and excluded patients with previous hip diseases or bilateral symptoms. Bivariate and multivariate analyses were used for data analysis.

RESULTS

We included 159 patients with a mean follow-up of 6.4 years, aged 36.18 ± 8.61 years, 41.5% female, and a mean body mass index of 23.61 ± 3.45. The mean postoperative mHHS was 88.82 ± 11.60, and the mean Pain VAS was 1.93 ± 1.89, significantly better than before surgery (P < .001). Postoperative alpha angle (P = .003) and lateral center edge angle (P < .001) were significantly decreased. Most patients (83.7%) achieved clinically important improvement based on patient-acceptable symptom state and minimal clinically important difference (MCID). The overall revision surgery rate was 2.5%. There were no conversions to total hip arthroplasty. Bivariate analysis indicated that age (P < .001), preoperative mHHS (P = .002), and postoperative Pain VAS (P <.001) correlated with postoperative mHHS at a minimum 5 years' follow-up. Multivariate regression analysis of MCID showed that age (P <.001), preoperative PROs (P < .01 for both), and postoperative Pain VAS (P < .001) were significant outcome predictors.

CONCLUSION

Patients with FAIS after first-time unilateral hip arthroscopy showed significant improvement in PROs at mid-term follow-up, with a low revision surgery rate. Young patients and those with low postoperative Pain VAS showed excellent outcomes at a minimum 5 years' follow-up.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Change in functional biomechanics following a targeted exercise intervention in patients with acetabular retroversion and femoroacetabular impingement syndrome

BACKGROUND

Acetabular retroversion is a form of hip dysplasia that may cause femoroacetabular impingement syndrome (FAIS), leading to pain and restricted hip range of motion. An exercise intervention aiming at altering pelvis tilt and related functional biomechanics may be a useful first-line intervention for patients who are not eligible for surgical repositioning.

RESEARCH QUESTION

Does squat and gait biomechanics change following an 8-week targeted exercise program in individuals with symptomatic acetabular retroversion and FAIS?

METHODS

This prospective intervention study used participants as their own controls. Examinations were conducted at three time-points: T1 baseline; T2 following an 8-week control period; T3 after 8 weeks' intervention. At each time-point, three-dimensional motion analysis of a deep squat and level gait was performed, and pain intensity was recorded using a numerical rating scale (NRS 0-10). The intervention consisted of a home-exercise program to improve core stability and pelvic movement. Differences in waveforms between time-points across pelvis and lower-limb biomechanics were evaluated using statistical parametric mapping. Delta (Δ, differences between T1-T2 and T2-T3) was used to evaluate changes in spatiotemporal gait parameters and pain.

RESULTS

Nineteen patients (18 females), mean age 22.6 (SD 4.5) years, BMI (kg/m2) 23.0 (SD 4.1), were included. Changes (Δ T1-T2 vs. Δ T2-T3) in squat biomechanics were observed as: (i) decreased anterior pelvic tilt, (ii) deeper vertical pelvis position, and (iii) increased knee flexion angle. Contrary, no significant changes in gait biomechanics, Δ walking speed, Δ step length, or NRS for pain were found.

SIGNIFICANCE

Following a targeted exercise intervention, participants were able to squat deeper, potentially allowing better hip function. The deepened squat position was accompanied by increased knee flexion and reduced anterior pelvic tilt. Gait biomechanics and patient-reported pain remained unchanged post-intervention. These findings are important for future design of exercise interventions targeting pelvic tilt in symptomatic individuals.

Are Exercise Therapy Protocols For The Treatment of Hip-Related Pain Adequately Described? A Systematic Review of Intervention Descriptions

Background

Hip-related pain is an umbrella term encompassing pain from non-arthritic hip joint pathologies, such as femoroacetabular impingement syndrome, hip dysplasia, and labral tears. Exercise therapy is commonly recommended for these conditions, but the reporting completeness of these interventions is currently unclear.

Purpose

The aim of this systematic review was to assess the reporting completeness of exercise therapy protocols for people with hip-related pain.

Study design

Systematic review according to PRISMA guidelines.

Materials and Methods

A systematic search was conducted, searching the MEDLINE, CINAHL, and Cochrane databases. The search results were independently screened by two researchers. Inclusion criteria were studies using exercise therapy in people with non-arthritic hip-related pain. Two independent researchers used the Cochrane risk of bias tool version 2 to analyze risk of bias, and the Consensus on Exercise Reporting Template (CERT) checklist and score (1-19) to synthesize reporting completeness.

Results

Fifty-two studies used exercise therapy for hip-related pain, but only 23 were included in the synthesis as 29 studies had no description of the intervention. CERT scores ranged from 1 to 17 (median 12, IQR 5-15). The most well-described items were tailoring (87%), and the least well-described items were motivation strategies (9%) and starting level (13%). Studies used exercise therapy alone (n=13), or in combination with hip arthroscopy (n=10).

Conclusion

Only 23 of 52 eligible studies reported sufficient details to be included in the CERT synthesis. The median CERT score was 12 (IQR 5-15), with no study reaching the maximum score of 19. Lack of reporting makes it difficult to replicate interventions in future research, and to draw conclusions on efficacy and dose-response to exercise therapy for hip-related pain.

Level of evidence

Level 1, systematic review.

Puncture Capsulotomy Technique for Hip Arthroscopy: Midterm Functional Outcomes

Background

The most common surgical approaches in hip arthroscopy are interportal and T-capsulotomy. However, these methods may introduce capsular instability. Puncture capsulotomy preserves capsuloligamentous integrity by avoiding iatrogenic transection of the iliofemoral capsular ligament.

Purpose

To present minimum 2-year functional outcomes for patients who underwent arthroscopic treatment for acetabular labral tears and concomitant femoroacetabular impingement using the puncture capsulotomy technique.

Study Design

Case series; Level of evidence, 4.

Methods

The authors conducted a retrospective review of prospectively collected data on patients who underwent arthroscopic acetabular labral tear treatment between December 2013 and May 2019. Included were patients aged ≥18 years who underwent hip arthroscopy by a single surgeon and completed a minimum of 2 years of patient-reported outcome measure (PROM) surveys. Intraoperatively, patients underwent hip arthroscopy via puncture capsulotomy to treat labral tears and any concomitant femoroacetabular impingement. Clinical outcome data consisted of PROMs.

Results

A total of 163 hips were included; the mean patient follow-up was 30.4 months (range, 24-60 months; 95% CI, 28.5-32.3 months). Patients had a mean age of 37.9 years (range, 36.1-39.6 years), with a mean body mass index of 25.9 (range, 25.2-26.5). There were significant improvements in mean [95% CI] baseline to final follow-up scores for the 33-Item International Hip Outcome Tool (iHOT-33) (39.6 [36.8-42.4] vs 76.1 [72.7-79.6]), Hip Outcome Score-Activities of Daily Living (70.0 [67.0-73.0] vs 89.3 [87.3-91.3]), modified Harris Hip Score (60.1 [57.9-62.4] vs 84.9 [82.5-87.2]), and Hip Outcome Score-Sports Specific Subscale (41.8 [37.9-45.6] vs 75.7 [71.7-79.7]) (P < .001 for all). Additionally, the mean [95% CI] visual analog scale pain scores were noted to significantly improve throughout the duration of the postoperative period (from 6.3 [5.9-6.7] to 2.2 [1.8-2.6]; P < .001). There were no incidences of infection, avascular necrosis of the femoral head, dislocation/instability, or femoral neck fracture. At the 2-year follow-up, 81.0%, 62.0%, and 58.9% of hips achieved previously published clinically meaningful iHOT-33 thresholds for minimally clinically important difference, Patient Acceptable Symptom Score, and substantial clinical benefit, respectively.

Conclusion

Puncture capsulotomy demonstrated significantly improved functional and clinically meaningful outcomes at a minimum 2-year follow-up, along with a minimal complication rate.

Evaluating the Need for Preoperative MRI Before Primary Hip Arthroscopy in Patients 40 Years and Younger With Femoroacetabular Impingement Syndrome: A Multicenter Comparative Analysis

Background

Routine hip magnetic resonance imaging (MRI) before arthroscopy for patients with femoroacetabular impingement syndrome (FAIS) offers questionable clinical benefit, delays surgery, and wastes resources.

Purpose

To assess the clinical utility of preoperative hip MRI for patients aged ≤40 years who were undergoing primary hip arthroscopy and who had a history, physical examination findings, and radiographs concordant with FAIS.

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 1391 patients (mean age, 25.8 years; 63% female; mean body mass index, 25.6) who underwent hip arthroscopy between August 2015 and December 2021 by 1 of 4 fellowship-trained hip surgeons from 4 referral centers. Inclusion criteria were FAIS, primary surgery, and age ≤40 years. Exclusion criteria were MRI contraindication, reattempt of nonoperative management, and concomitant periacetabular osteotomy. Patients were stratified into those who were evaluated with preoperative MRI versus those without MRI. Those without MRI received an MRI before surgery without deviation from the established surgical plan. All preoperative MRI scans were compared with the office evaluation and intraoperative findings to assess agreement. Time from office to arthroscopy and/or MRI was recorded. MRI costs were calculated.

Results

Of the study patients, 322 were not evaluated with MRI and 1069 were. MRI did not alter surgical or interoperative plans. Both groups had MRI findings demonstrating anterosuperior labral tears treated intraoperatively (99.8% repair, 0.2% debridement, and 0% reconstruction). Compared with patients who were evaluated with MRI and waited 63.0 ± 34.6 days, patients who were not evaluated with MRI underwent surgery 6.5 ± 18.7 days after preoperative MRI. MRI delayed surgery by 24.0 ± 5.3 days and cost a mean $2262 per patient.

Conclusion

Preoperative MRI did not alter indications for primary hip arthroscopy in patients aged ≤40 years with a history, physical examination findings, and radiographs concordant with FAIS. Rather, MRI delayed surgery and wasted resources. Routine hip MRI acquisition for the younger population with primary FAIS with a typical presentation should be challenged.

Combined 3-Dimensional CT and Multidirectional CT Arthrography for Femoroacetabular Impingement and Hip Lesions: A Cross-sectional Study Comparing Imaging and Hip Arthroscopic Surgery Findings

Background

There is limited research investigating the diagnostic strength of 3-dimensional computed tomography (3D-CT) and multidirectional CT arthrography (CTA) for femoroacetabular impingement (FAI) and related hip lesions.

Purpose

To evaluate the diagnostic strength of combined 3D-CT and CTA in patients with FAI and related hip lesions by comparing it with hip arthroscopic surgery findings.

Study Design

Cohort study (diagnosis); Level of evidence, 2.

Methods

This study included patients who were suspected of having FAI and related hip lesions and who underwent a combination of 3D-CT and CTA and subsequent hip arthroscopic surgery between December 2013 and December 2017. The CT and intraoperative arthroscopic findings were recorded and compared. The sensitivity, specificity, and accuracy of 3D-CT for FAI and those of CTA for related hip lesions were calculated.

Results

A total of 114 patients with 114 hips were included in our study. There were 101 patients with positive findings and 13 patients with negative findings for FAI (including cam, pincer, and combined morphology) according to 3D-CT. The sensitivity, specificity, and accuracy of 3D-CT for FAI were 91.58%, 57.14%, and 89.47%, respectively. The sensitivity, specificity, and accuracy of CTA for labral tears were 94.64%, 100.00%, and 94.73%, respectively. For acetabular cartilage defects, the sensitivity, specificity, and accuracy of CTA were 60.71%, 91.37%, and 76.31%, respectively. For femoral cartilage defects, the sensitivity, specificity, and accuracy of CTA were 82.22%, 76.81%, and 78.94%, respectively.

Conclusion

The study results indicated that 3D-CT was able to provide excellent accuracy for FAI compared with hip arthroscopic surgery findings. In addition, multidirectional CTA demonstrated promising diagnostic strength for hip lesions such as labral tears and chondral defects.

Femoral impingement in maximal hip flexion is anterior-inferior distal to the cam deformity in femoroacetabular impingement patients with femoral retroversion : implications for hip arthroscopy

AIMS

Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients.

METHODS

A retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method).

RESULTS

Mean impingement-free flexion of patients with mixed-type FAI (110° (SD 8°)) and patients with pincer-type FAI (112° (SD 8°)) was significantly (p < 0.001) lower compared to the control group (125° (SD 13°)). The frequency of extra-articular subspine impingement was significantly (p < 0.001) increased in patients with pincer-type FAI (57%) compared to cam-type FAI (22%) in 125° flexion. Bony impingement in maximal flexion was located anterior-inferior at femoral four and five o'clock position in patients with cam-type FAI (63% (10 of 16 hips) and 37% (6 of 10 hips)), and did not involve the cam deformity. The cam deformity did not cause impingement in maximal flexion.

CONCLUSION

Femoral impingement in maximal flexion was located anterior-inferior distal to the cam deformity. This differs to previous studies, a finding which could be important for FAI patients in order to avoid exacerbation of hip pain in deep flexion (e.g. during squats) and for hip arthroscopy (hip-preservation surgery) for planning of bone resection. Hip impingement in flexion has implications for daily activities (e.g. putting on shoes), sports, and sex.Cite this article: Bone Joint Res 2023;12(1):22-32.

Olympic fencer with femoroacetabular impingement syndrome uses active rehabilitation to avoid surgery: A case report

INTRODUCTION

Femoroacetabular impingement (FAI) syndrome is a musculoskeletal condition characterized by hip symptoms. Conservative therapy is indicated prior to surgical intervention. However, no literature has described conservative management of FAI in detail. This report provides a detailed active rehabilitation plan for an elite athlete with FAI to guide future research and clinicians.

CASE PRESENTATION

A 30-year-old male Olympic fencing athlete presented with unilateral hip pain less than 1 year prior to the Olympic Games. Radiographic imaging demonstrated bilateral cam morphology. Hip mobilizations and stretching did not provide a meaningful pain reduction. Cortisone injection was then suggested prior to the Games where surgery was suggested following the Games.

MANAGEMENT AND OUTCOME

Active rehabilitative exercises targeted motor control of the lumbo-pelvic-hip complex, which led to significant pain reduction and full return to sport. Surgical intervention and cortisone injections were deemed unnecessary due to resolution of symptoms.

CONCLUSION

Athletes with FAI syndrome may benefit from specific active rehabilitation exercises. Future clinical trials should explore rehabilitative exercises that address improved motor control to manage individuals with FAI syndrome.

Which hip morphology measures and patient factors are associated with age of onset and symptom severity in femoroacetabular impingement syndrome?

BACKGROUND

Bony morphology is central to the pathomechanism of femoroacetabular impingement syndrome (FAIS), however isolated radiographic measures poorly predict symptom onset and severity. More comprehensive morphology measurement considered together with patient factors may better predict symptom presentation. This study aimed to determine the morphological parameter(s) and patient factor(s) associated with symptom age of onset and severity in FAIS.

METHODS

99 participants (age 32.9 ± 10.5 years; body mass index (BMI 24.3 ± 3.1 kg/m²; 42% females) diagnosed with FAIS received standardised plain radiographs and magnetic resonance scans. Alpha angle in four radial planes (superior to anterior), acetabular version (AV), femoral torsion, lateral centre-edge, anterior centre-edge (ACEA) and femoral neck-shaft angles were measured. Age of symptom onset (age at presentation minus duration of symptoms), international Hip Outcome Tool-33 (iHOT-33) and modified UCLA activity scores were recorded. Backward stepwise regression assessed morphological parameters and patient factors (age, sex, BMI, symptom duration, annual income, private/public healthcare system accessed) to determine variables independently associated with onset age and iHOT-33 score.

RESULTS

Earlier symptom onset was associated with larger superoanterior alpha angle (p = 0.007), smaller AV (p = 0.023), lower BMI (p = 0.010) and public healthcare system access (p = 0.041) (r² = 0.320). Worse iHOT-33 score was associated with smaller ACEA (p = 0.034), female sex (p = 0.040), worse modified UCLA activity score (p = 0.010) and public healthcare system access (p < 0.001) (r² = 0.340).

CONCLUSIONS

Age of symptom onset was chiefly predicted by femoral and acetabular bony morphology measures, whereas symptom severity predominantly by patient factors. Factors measured explained a small amount of variance in the data; additional unmeasured factors may be more influential.

Patients with cam-type femoroacetabular impingement demonstrate increased change in bone-to-bone distance during walking: A dual fluoroscopy study

Cam-type femoroacetabular impingement (FAI) syndrome is a painful, structural hip disorder. Herein, we investigated hip joint mechanics through in vivo, dynamic measurement of the bone-to-bone distance between the femoral head and acetabulum in patients with cam FAI syndrome and morphologically screened controls. We hypothesized that individuals with cam FAI syndrome would have larger changes in bone-to-bone distance compared to the control group, which we would interpret as altered joint mechanics as signified by greater movement of the femoral head as it articulates within the acetabulum. Seven patients with cam FAI syndrome and 11 asymptomatic individuals with typical morphology underwent dual fluoroscopy imaging during level and inclined walking (upward slope). The change in bone-to-bone distance between femoral and acetabular bone surfaces was evaluated for five anatomical regions of the acetabulum at each timepoint of gait. Linear regression analysis of the bone-to-bone distance considered two within-subject factors (activity and region) and one between-subjects factor (group). Across activities, the change in minimum bone-to-bone distance was 1.38-2.54 mm for the cam FAI group and 1.16-1.84 mm for controls. In all regions except the anterior-superior region, the change in bone-to-bone distance was larger in the cam group than the control group (p ≤ 0.024). An effect of activity was detected only in the posterior-superior region where larger changes were noted during level walking than incline walking. Statement of clinical significance: Patients with cam FAI syndrome exhibit altered hip joint mechanics during the low-demand activity of walking; these alterations could affect load transmission, and contribute to pain, tissue damage, and osteoarthritis.

Acetabular labrum and cartilage contact mechanics during pivoting and walking tasks in individuals with cam femoroacetabular impingement syndrome

Femoroacetabular impingement syndrome (FAIS) is a motion-related pathology of the hip characterized by pain, morphological abnormalities of the proximal femur, and an elevated risk of joint deterioration and hip osteoarthritis. Activities that require deep flexion are understood to induce impingement in cam FAIS patients, however, less demanding activities such as walking and pivoting may induce pain as well as alterations in kinematics and joint stability. Still, the paucity of quantitative descriptions of cam FAIS has hindered understanding underlying hip joint mechanics during such activities. Previous in silico studies have employed generalized model geometry or kinematics to simulate impingement between the femur and acetabulum, which may not accurately capture the interplay between morphology and motion. In this study, we utilized models with participant-specific bone and articular soft tissue anatomy and kinematics measured by dual-fluoroscopy to compare hip contact mechanics of cam FAIS patients to controls during four activities of daily living (internal/external pivoting and level/incline walking). Averaged across the gait cycle during incline walking, patients displayed increased strain in the anterior joint (labrum strain: p-value = 0.038, patients: 11.7 ± 6.7 %, controls: 5.0 ± 3.6 %; cartilage strain: p-value = 0.029, patients: 9.1 ± 3.3 %, controls: 4.2 ± 2.3). Patients also exhibited increased average anterior cartilage strains during external pivoting (p-value = 0.039; patients: 13.0 ± 9.2 %, controls: 3.9 ± 3.2 %]). No significant differences between patient and control contact area and strain were found for level walking and internal pivoting. Our study provides new insights into the biomechanics of cam FAIS, including spatiotemporal hip joint contact mechanics during activities of daily living.

Moderators, Mediators, and Prognostic Indicators of Treatment With Hip Arthroscopy or Physical Therapy for Femoroacetabular Impingement Syndrome: Secondary Analyses From the Australian FASHIoN Trial

BACKGROUND

Although randomized controlled trials comparing hip arthroscopy with physical therapy for the treatment of femoroacetabular impingement (FAI) syndrome have emerged, no studies have investigated potential moderators or mediators of change in hip-related quality of life.

PURPOSE

To explore potential moderators, mediators, and prognostic indicators of the effect of hip arthroscopy and physical therapy on change in 33-item international Hip Outcome Tool (iHOT-33) score for FAI syndrome.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Overall, 99 participants were recruited from the clinics of orthopaedic surgeons and randomly allocated to treatment with hip arthroscopy or physical therapy. Change in iHOT-33 score from baseline to 12 months was the dependent outcome for analyses of moderators, mediators, and prognostic indicators. Variables investigated as potential moderators/prognostic indicators were demographic variables, symptom duration, alpha angle, lateral center-edge angle (LCEA), Hip Osteoarthritis MRI Scoring System (HOAMS) for selected magnetic resonance imaging (MRI) features, and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) score. Potential mediators investigated were change in chosen bony morphology measures, HOAMS, and dGEMRIC score from baseline to 12 months. For hip arthroscopy, intraoperative procedures performed (femoral ostectomy ± acetabular ostectomy ± labral repair ± ligamentum teres debridement) and quality of surgery graded by a blinded surgical review panel were investigated for potential association with iHOT-33 change. For physical therapy, fidelity to the physical therapy program was investigated for potential association with iHOT-33 change.

RESULTS

A total of 81 participants were included in the final moderator/prognostic indicator analysis and 85 participants in the final mediator analysis after exclusion of those with missing data. No significant moderators or mediators of change in iHOT-33 score from baseline to 12 months were identified. Patients with smaller baseline LCEA (β = -0.82; P = .034), access to private health care (β = 12.91; P = .013), and worse baseline iHOT-33 score (β = -0.48; P < .001) had greater iHOT-33 improvement from baseline to 12 months, irrespective of treatment allocation, and thus were prognostic indicators of treatment response. Unsatisfactory treatment fidelity was associated with worse treatment response (β = -24.27; P = .013) for physical therapy. The quality of surgery and procedures performed were not associated with iHOT-33 change for hip arthroscopy (P = .460-.665 and P = .096-.824, respectively).

CONCLUSION

No moderators or mediators of change in hip-related quality of life were identified for treatment of FAI syndrome with hip arthroscopy or physical therapy in these exploratory analyses. Patients who accessed the Australian private health care system, had smaller LCEAs, and had worse baseline iHOT-33 scores, experienced greater iHOT-33 improvement, irrespective of treatment allocation.

Sex-Specific Differences in Hip Muscle Cross-sectional Area and Fatty Infiltration in Patients With Femoroacetabular Impingement Syndrome

Background

Patients with femoroacetabular impingement syndrome (FAIS) show sex-specific differences in hip muscle function, hip morphology, and symptoms. Possible differences in hip muscle characteristics between men and women with FAIS are unknown.

Purpose

To compare hip muscle cross-sectional area (CSA) and fatty infiltration between men and women with FAIS and investigate possible associations with patient-reported outcomes.

Study Design

Cohort study; Level of evidence, 3.

Methods

We retrospectively analyzed preoperative axial pelvic magnetic resonance imaging scans of 104 patients (54 women) who underwent hip surgery for FAIS. The main outcome measures were side-to-side percentage asymmetry in hip muscle CSA and involved-side fatty infiltration as measured with the Goutallier scale for a total of 10 hip muscles. Patient-reported outcomes included duration of hip symptoms, iHOT-12 (12-item International Hip Outcome Tool), and Hip Sports Activity Scale.

Results

Women showed larger hip abductor muscle CSA asymmetry than men (P = .018), particularly for the gluteus medius (P = .049), while men exhibited more fatty streaks (grade 1) in the gluteus medius (P = .015) than women. Duration of symptoms was associated only with fatty infiltration of obturator externus in men (r _S = -0.55, P = .018). iHOT-12 was associated with CSA asymmetry of the gluteus minimus (r = -0.41, P = .011) and iliopsoas (r = -0.36, P = .028) in men and with piriformis fatty infiltration (r _S = -0.56, P = .030) in women. The Hip Sports Activity Scale was associated with iliopsoas CSA asymmetry (r _S = 0.32, P = .026) and with fatty infiltration of the tensor fasciae latae (r _S = -0.45, P = .046) and obturator externus (r _S = -0.50, P = .023) in women.

Conclusion

Patients with FAIS demonstrated few sex-specific quantitative and qualitative alterations of hip muscles. Women showed greater hip abductor muscle atrophy than men, particularly for the gluteus medius, while men showed a higher degree of fatty infiltration in this same muscle. The duration of hip symptoms was not associated with muscle atrophy. Patient-reported hip pain/function and sport activity level were only moderately associated with isolated muscular variables.

Gluteal activation during squatting reduces acetabular contact pressure in persons with femoroacetabular impingement syndrome: A patient-specific finite element analysis

BACKGROUND

Femoroacetabular impingement syndrome is a motion-related clinical disorder resulting from abnormal hip joint morphology. Mechanical impingement, in which the aspherical femoral head (cam morphology) abuts with the acetabular rim, is created with simultaneous hip flexion, internal rotation, and adduction. Impaired function of the gluteal muscles may be contributory to femoroacetabular impingement syndrome progression. The purpose of this study was to assess the influence of gluteal muscle recruitment on acetabular contact pressure during squatting in persons with cam femoroacetabular impingement syndrome.

METHODS

Eight individuals (4 males, 4 females) with a diagnosis of cam femoroacetabular impingement syndrome underwent CT imaging of the pelvis and proximal femora, and a biomechanical assessment of squatting (kinematics, kinetics, and electromyography). Two maximal depth bodyweight squat conditions were evaluated: 1) non-cued squatting; and 2) cued gluteal activation squatting. Utilizing subject-specific electromyography-driven hip and finite element modeling approaches, hip muscle activation, kinematics, bone-on-bone contact forces, and peak acetabular contact pressure were compared between squat conditions.

FINDINGS

Modest increases in gluteus maximus (7% MVIC, P < 0.0001) and medius (6% MVIC, P = 0.009) activation were able to reduce hip internal rotation on average 5° (P = 0.024), and in doing so reduced acetabular contact pressure by 32% (P = 0.023). Reductions in acetabular contact pressure occurred despite no change in hip abduction and increased bone-on-bone contact forces occurring in the cued gluteal activation condition.

INTERPRETATION

Our findings highlight the importance of gluteal activation in minimizing mechanical impingement and provide a foundation for interventions aimed at preventing the development and progression of femoroacetabular impingement syndrome.

Results of Arthroscopic Treatment for Femoroacetabular Impingement

Background. Femoroacetabular impingement (FAI) is one of the most frequent causes of hip pain and limited hip mobility in young and middle-aged patients. It is a result of repeated injury of hip structures, that leads to degenerative changes in hip labrum, cartilage and subchondral bone and provokes progressive development of hip osteoarthritis. Aim of study to analyze own experience of treating patients with femoroacetabular impingement and identify factors affecting its outcomes. Methods. Retrospective, uncontrolled, single-center clinical study included 128 patients with FAI which had 150 surgeries on 149 joints in in the period from 2013 to 2021. All patients underwent physical examination and X-ray diagnostics, their FAI type was identified. The alpha angle of external part of femoral head in anterior-posterior position and in the modified Dunn 45 position, as well as Tonnis angle, lateral central-marginal angle in Ogata modification and the height of articular gap along the lateral (LS) and medial edges (MS) of sclerosed acetabulum part were calculated. The i-HOT-33 and HOS scales were used to assess preoperative status and postoperative results. Results. The average follow-up period was 3.9 years (SD 1.71; min 1.05 and max 8.16). The study included 55 (43.0%) women and 73 (57.0%) men which underwent 64 (42.7%) and 86 (57.3%) surgeries respectively. The most common types of FAI, according to our data, were mixed type (53% of joints) and сam type (27.5% of joints). Insufficient coverage of the femoral head by the acetabulum (borderline dysplasia) in combination with the сam deformity of the femoral head was observed in 18.1%. Pincer-type FAI was observed in 1.4% of joints. We obtained the worst results with a combination of сam deformity and borderline dysplasia in comparison with cam- and mix-type FAI according to the i-HOT-33 and HOS scales. Patients age, deep cartilage damage, irreparable labrum damage and height decrease of the lateral part of the articular gap determined negative effect on treatment results according to the i-HOT-33 and HOS scales. Conclusion. Hip arthroscopy showed good short- and midterm outcomes in patients with FAI. Pain syndrome is most often manifested in patients with pathology of hip soft tissue structures concomitant to FAI. The combination of сam deformity and insufficient femoral head coverage, deep cartilage damage and a height decrease of the articular gap are important predictors of poor treatment results.

Spinopelvic Parameters Do Not Influence Outcomes Following Primary Hip Arthroscopy for the Treatment of Femoroacetabular Impingement Syndrome

Purpose

To evaluate the influence of spinopelvic parameters on short-term postoperative patient-reported outcomes (PROs) following primary hip arthroscopy for the treatment of femoroacetabular impingement syndrome (FAIS).

Methods

Patients undergoing primary hip arthroscopy between January 2012 and December 2015 were retrospectively reviewed. Hip Outcome Score - Activities of Daily Living, Hip Outcome Score - Sports-Specific Subscale, modified Harris Hip Score, International Hip Outcome Tool-12, and visual analog scale pain were recorded preoperatively and at final follow-up. Lumbar lordosis (LL), pelvic tilt (PT), sacral slope, and pelvic incidence (PI) were measured on lateral radiographs in standing position. Patients were split into subgroups for individual analyses based on previous literature cutoffs: |PI-LL|> or <10°, PT> or <20°, and PI <40°, 40° < PI < 65°, and PI >65°. PROs and rate of achievement of patient acceptable symptom state (PASS) were compared between subgroups at final follow-up.

Results

Sixty-one patients who underwent unilateral hip arthroscopy were included in the analysis, and 66% of patients were female. Mean patient age was 37.6 ± 11.3 years, whereas mean body mass index was 25.0 ± 5.7. Mean follow-up time was 27.6 ± 9.0 months. No significant difference in preoperative nor postoperative PROs were appreciated in patients with spinopelvic mismatch (|PI-LL| >10°) versus those without, whereas patients with mismatch achieved PASS according to the modified Harris Hip Score (P = .037) and International Hip Outcome Tool-12 (P = .030) at greater rates. When we compared patients with a PT ≥20° versus PT <20°, no significant differences in postoperative PROs were present. When we compared patients in the following pelvic incidence groups: PI <40°, 40° < PI <65°, and PI >65°, no significant differences in 2-year PROs or rates of PASS achievement for any PRO were appreciated (P > .05 for all).

Conclusions

In this study, spinopelvic parameters and traditional measures of sagittal imbalance did not influence PROs in patients undergoing primary hip arthroscopy for FAIS. Patients with sagittal imbalance (|PI-LL|> 10° or PT >20°) achieved a greater rate of PASS.

Level of Evidence

IV; Prognostic case series.

Patients With Femoroacetabular Impingement Obtain Information From Low-Quality Sources Online and Are Most Interested in Conservative Treatment and Expected Recovery

Purpose

To investigate the type of questions patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) are searching online and determine the type and quality of the online sources from the top results to each query by the "people also ask" Google algorithm.

Methods

Three search strings pertaining to FAI were carried out through Google. The webpage information was manually collected from the "People also ask" Google algorithm. Questions were categorized using Rothwell's classification method. Each website was assessed using Journal of the American Medical Association Benchmark Criteria for source quality.

Results

A total of 286 unique questions were collected with their associated webpages. The most common questions included: "How do you treat femoroacetabular impingement and labral tears without surgery?" "What is the recovery process after hip arthroscopy and are there limitations after surgery?" and "How do you diagnose hip impingement and differentiate from other causes of hip pain?" The Rothwell Classification of questions were fact (43.4%), policy (34.3%), and value (20.6%). The most common webpage categories were Medical Practice (30.4%), Academic (25.8%), and Commercial (20.6%). The most common subcategories were Indications/Management (29.7%) and Pain (13.6%). Government websites had the highest average Journal of the American Medical Association score (3.42), whereas Single Surgeon Practice websites had the lowest (1.35). Conclusions: Commonly asked questions on Google regarding FAI and labral tears pertain to the indications and management of pathology as well as pain control and restrictions in activity. The majority of information is provided by medical practice, academic, and commercial sources, which have highly variable academic transparency.

Clinical Relevance

By better understanding which questions patients ask online, surgeons can personalize patient education and enhance patient satisfaction and treatment outcomes after hip arthroscopy.

Defining Parameters for Surgical Correction and Hip Complications for Femoroacetabular Impingement Syndrome: Results of an International Modified Delphi Study

OBJECTIVES

To develop recommendations for clinical and radiographic criteria to help define the "acceptable" surgical correction of femoroacetabular impingement syndrome (FAIS) and identify/define complications postoperatively.

METHODS

A 3-phase modified Delphi study was conducted involving a case-based survey; a Likert/multiple choice-based survey concerning radiographic and physical examination characteristics to help define FAIS correction, as well as the prevalence and definition of potential postoperative complications; and 2 consensus meetings.

RESULTS

Of the 75 experts invited, 54 completed the Phase I survey, 50 completed the Phase II survey (72% and 67% response rate), and 50 participated in the Phase III consensus meetings. For both typical and atypical (complex) cases, there was consensus that fluoroscopy with multiple views and dynamic hip assessment should be used intraoperatively (96% and 100%, respectively). For typical FAIS cases, the Expert Panel agreed that Dunn lateral and anteroposterior radiographs were the most important radiographs to evaluate the hip postoperatively (88%, consensus). When asked about evaluating the correction of cam impingement postoperatively, 87% voted that they use subjective evaluation of the "sphericity" of the femoral head. In the case of focal and global pincer-type FAIS, there was consensus that the reduction or elimination of the crossover sign (84%) and lateral center-edge angle (91%) were important to inform the extent of the FAIS correction. There was consensus for recommending further investigation at 6 months postoperatively if hip pain had increased/plateaued (92% agreed); that additional investigation and treatment should occur between 6 and 12 months (90% agreed); and that a reoperation may be recommended at 12 months or later following this investigation period (89% agreed).

CONCLUSIONS

This consensus project identified the importance of using fluoroscopy and dynamic hip assessment intraoperatively; Dunn lateral and anteroposterior view radiographs postoperatively; evaluating the "sphericity" of the femoral head for cam-type correction and the use of dynamic hip assessment; reducing/eliminating the crossover sign for focal pincer-type FAIS; evaluating the lateral center-edge angle for global pincer-type FAIS; and avoiding overcorrection of pincer-type FAIS. In cases in which postoperative hip pain increased/plateaued, further investigation and treatment is warranted between 6 and 12 months, and a reoperation may be recommended at a minimum of 12 months depending on the cause of the hip pain.

CLINICAL RELEVANCE

Hip arthroscopy surgeons have yet to reach a firm agreement on what constitutes an "acceptable" or "good" surgery radiographically and how they can achieve desired clinical outcomes. Although this was a comprehensive effort, more study is needed to determine therapeutic thresholds that can be universally applied.

Oxford consensus on primary cam morphology and femoroacetabular impingement syndrome: part 1-definitions, terminology, taxonomy and imaging outcomes

INTRODUCTION

Primary cam morphology is a mostly benign bony prominence that develops at the femoral head-neck junction of the hip, but it is highly prevalent in many athlete populations. In the small proportion of athletes for whom it is not benign, the resulting hip osteoarthritis can be debilitating. Clinicians, athletes, patients and researchers do not yet agree on important primary cam morphology elements. We aimed to ascertain and improve the level of agreement on primary cam morphology definitions, terminology, taxonomy and imaging outcome measures.

METHODS

To collect and aggregate informed opinions, an expert panel-the Young Athlete's Hip Research Collaborative-rated primary cam morphology definition, terminology, taxonomy and imaging outcome statements through an online Delphi exercise followed by an online meeting to explore areas of tension and dissent. Reporting followed Conducting and REporting DElphi Studies.

RESULTS

A diverse and inclusive Delphi panel (n=65 for rounds 1 and 2, representing 18 countries; 6 stakeholder groups; 40% women) agreed on 35 of 47 statements in 4 domains, while surfacing areas of tension and dissent. This Delphi panel agreed on four key issues essential to moving research and clinical care forward around primary cam morphology. They agreed on: (1) definition, confirming its conceptual attributes (tissue type, size, location, shape and ownership); (2) terminology-use 'morphology' and not terms with a negative connotation like 'lesion', 'abnormality' or 'deformity'; (3) taxonomy, distinguishing between primary and secondary cam morphology, and (4) imaging outcomes, a continuous bone/cartilage alpha angle on radial femoral head-neck MRI for primary cam morphology aetiology research.

CONCLUSION

This consensus provides athletes, patients, clinicians and researchers with a strong foundation to guide more precise communication, better clinical decision-making and higher value research about primary cam morphology and its natural history.

Evolution of Hip Muscles Strength in Femoroacetabular Impingement Patients Treated by Arthroscopy or Surgical Hip Dislocation: A Retrospective Exploratory Study

Hip arthroscopy and surgical hip dislocation (SHD) can be adequate surgical options for patients suffering from femoroacetabular impingement (FAI) syndrome, but there is to date no published data on their impact on hip muscles strength. The purpose of this retrospective study was, therefore, to evaluate it on a consecutive series of 50 FAI patients treated either by arthroscopy (n = 29, aged 27.4 ± 7.5 years, 76% of women) or SHD (n = 21, aged 25.9 ± 6.5 years, 38% of women) at La Tour Hospital between 2020 and 2021. The bilateral isometric strengths of eight hip-related muscles were evaluated before and three months after surgery (halfway through the rehabilitation program). For arthroscopy, a statistically significant (p < 0.05) reduction in hip muscles strength could be noted on the operated hamstrings (1.49 ± 0.43 vs. 1.39 ± 0.38 Nm/kg), flexors (1.88 ± 0.46 vs. 1.73 ± 0.41 Nm/kg), abductors (1.97 ± 0.42 vs. 1.72 ± 0.40 Nm/kg) and external rotators (1.17 ± 0.40 vs. 1.04 ± 0.37 Nm/kg). The abductors were the most affected muscles, with 45% of the patients suffering from a strength reduction ≥15%. The non-operated external rotators were also affected but to a lesser extent (1.21 ± 0.38 vs. 1.10 ± 0.36 Nm/kg). For SHD, a statistically significant strength reduction could be noted on the operated extensors (2.28 ± 0.84 vs. 2.05 ± 0.70 Nm/kg), abductors (1.87 ± 0.49 vs. 1.65 ± 0.41 Nm/kg), quadriceps (2.96 ± 0.92 vs. 2.44 ± 0.89 Nm/kg), external rotators (1.16 ± 0.42 vs. 0.93 ± 0.36 Nm/kg) and internal rotators (1.26 ± 0.38 vs. 0.96 ± 0.30 Nm/kg). The internal rotators were the most affected muscles, with 75% of the patients suffering from a strength reduction ≥15%. To conclude, particular attention should be paid to operated abductors for patients treated by arthroscopy as well as operated internal/external rotators, abductors and quadriceps for those treated by surgical hip dislocation. It reinforces that a rehabilitation method based on isolated muscle reinforcement and functional exercises that goes beyond three postoperative months is needed.

Oxford consensus on primary cam morphology and femoroacetabular impingement syndrome: part 2-research priorities on conditions affecting the young person's hip

INTRODUCTION

Primary cam morphology is highly prevalent in many athlete populations, causing debilitating hip osteoarthritis in some. Existing research is mired in confusion partly because stakeholders have not agreed on key primary cam morphology elements or a prioritised research agenda. We aimed to inform a more rigorous, inclusive and evidence-based approach to research on primary cam morphology and its natural history by working towards agreement on a set of research priorities for conditions affecting the young person's hip.

METHODS

An international expert panel-the Young Athlete's Hip Research (YAHiR) Collaborative-rated research priority statements through an online two-round Delphi exercise and met online to explore areas of tension and dissent. Panellists ranked the prioritised research statements according to the Essential National Health Research (ENHR) ranking strategy. Reporting of results followed REPRISE (REporting guideline for PRIority SEtting of health).

RESULTS

A diverse Delphi panel (n=65, Delphi rounds 1 and 2; three ENHR strategy surveys: n=49; n=44; n=42) from 18 countries representing six stakeholder groups, prioritised and ranked 18 of 38 research priority statements. The prioritised statements outlined seven research domains: (1) best practice physiotherapy, (2) rehabilitation progression and return to sport, (3) exercise intervention and load management, (4) primary cam morphology prognosis and aetiology, (5) femoroacetabular impingement syndrome prognosis and aetiology, (6) diagnostic criteria, and (7) screening. The panel recommended areas of tension and dissent for the research community to focus on immediately.

CONCLUSION

While informing more rigorous, inclusive and evidence-based research, this consensus is a roadmap for researchers, policy-makers and funders to implement research dedicated to reducing the cost and burden of hip disease related to primary cam morphology.

Females with hip-related pain display altered lower limb mechanics compared to their healthy counterparts in a drop jump task

BACKGROUND

Hip-related pain describes femoroacetabular impingement syndrome, acetabular dysplasia, and other hip pain conditions without clear morphological features. Movement strategies in this population, notably sex-related patterns, are poorly understood and may provide insights into why females report more pain and worse function. This study examined the sex-related differences during a drop vertical jump task between those with hip-related pain and healthy controls.

METHODS

Patients with hip-related pain and healthy controls completed five repetitions of a drop jump while their kinematics and kinetics were recorded using a motion capture system and force plates. Hip, knee, and ankle joint angles and external joint moments during landing were used in general estimating equations for comparison of group by sex by limb interactions. Time series data were further investigated using statistical parametric mapping.

FINDINGS

Females with hip-related pain had 9.1° less hip flexion (P = .041) and 9.2° less knee flexion (P = .024) than healthy females, and 8.3° less knee flexion than male counterparts with hip-related pain (P = .039). Males demonstrated 1.4° less hip flexion on the affected side compared to their uninvolved side (P = .004). Statistical parametric mapping results showed significant differences in knee flexion angle for females with hip-related pain compared to healthy females (P = .042). There were no significant differences in hip, knee, or ankle moments.

INTERPRETATION

Females with hip-related pain showed kinematic patterns distinct from healthy controls. Sex may be an important variable of interest in characterizing movement impairments in this population and movement impairments may be an appropriate target for intervention for these patients.

Efficacy and safety of preoperative versus postoperative NSAIDs on pain relief in patients undergoing hip arthroscopy surgery: A multicentre, randomized, controlled trial

WHAT IS KNOWN AND OBJECTIVE

Postoperative pain relief is a critical issue for hip arthroscopy surgery (HAS). This study aimed to investigate the effect of preemptive non-steroidal anti-inflammatory drugs (NSAIDs) for postoperative analgesia in femoroacetabular impingement (FAI) patients receiving HAS.

METHODS

This multicenter, randomized, controlled study enrolled 204 FAI patients receiving HAS, then assigned them to preoperative (PRE, N = 103) or postoperative (POS, N = 101) group as a 1:1 ratio; the PRE group administrated NSAIDs from 24 h pre-surgery to day 7 (D7) post-surgery, while the POS group administrated NSAIDs from 12 h post-surgery to D7 post-surgery.

RESULTS AND DISCUSSION

Pain at rest was reduced at D1 (p = 0.016) and D2 (p = 0.023); pain at movement was decreased at D1 (p = 0.002), D2 (p = 0.020), and D3 (p = 0.030) in the PRE group compared with POS group, but not at other time points (all p > 0.05). Patient's satisfaction was increased at D1 (p = 0.013) and D3 (p = 0.029) in the PRE group compared to the POS group, but not at D7 (p = 0.145). Pethidine was less consumed at D3 (p = 0.038) and D7 (p = 0.017) in the PRE group in contrast with the POS group. Harris hip scores were similar at D7 (p = 0.124), month 1 (M1) (p = 0.273), and M3 (p = 0.360) between groups. Adverse events incidence was similar between groups (all p > 0.05). Besides, subgroup analysis discovered that pain was not influenced by the types of NSAID in both groups (all p > 0.05).

WHAT IS NEW AND CONCLUSION

Starting NSAIDs before HAS provides better short-term pain relief and improves patient's satisfaction compared with its postoperative utilization, while does not induce additional adverse events in FAI patients.

Normative values of the alpha angle and triangular index measured from the hip radiographs of an African population

INTRODUCTION

Undetected femoroacetabular impingement (FAI), caused by asphericity of the femoral head, has been implicated as a leading cause of hip osteoarthritis in later stages. Two known types of impingement of the femur head with the acetabulum include the cam-type and pincer type, and the alpha angle and triangular index are indices applied in determining the presence of FAI in a hip radiograph.

OBJECTIVE

To determine the normal range and upper limit of normal of the alpha angle and triangular index of an African population using non-pathological hip radiographs.

MATERIALS AND METHODS

Hip radiographs of 104 subjects reported to be normal were retrospectively studied. The images were reassessed jointly by three radiographers and afterwards by three consultant radiologists. The alpha angle and triangular index of selected radiographs were measured with appropriate electronic callipers. Values obtained were correlated with the age and gender of the patients.

RESULTS

The mean ± SD of the alpha angle for the population studied was 46.70 ± 12.34⁰ with a range of 33.30⁰-96.82⁰ (males: 45.09 ± 12.03⁰, females: 47.32 ± 12.37⁰), and the upper limit of normal obtained was 79.16⁰. The mean triangular index was 1.71±1.38 with a range of 0.03-5.98 (males: 1.77 ± 1.39, females: 1.65 ± 1.36), 4.12 being the upper limit of normal. There was no statistically significant difference between measurements of both indices with age and gender. However, there was excellent agreement between and within raters for both measurements (alpha angle: 0.992; triangular index: 0.924).

CONCLUSION

The upper limits of normal for the alpha angle and triangular index of the studied population are 79.16⁰ and 4.12. Age and gender were independent of the values measured, and the measurements demonstrated excellent inter-rater and intra-rater agreement. A normal range is thus provided, with upper limits beyond which a possible femoroacetabular impingement may be diagnosed.

Differences in hip torque ratios between individuals with femoroacetabular impingement syndrome and asymptomatic individuals: A cross-sectional study

BACKGROUND

Hip torque ratios are considered a useful measure for patients with hip pain. However, evidence regarding this measure for patients with femoroacetabular impingement syndrome is scarce. The primary aim of this study was to compare hip external-internal rotation and abduction-adduction torque ratios between patients with femoroacetabular impingement syndrome and asymptomatic individuals. The secondary aim was to compare hip torque ratios between the asymptomatic group and femoroacetabular impingement syndrome patients grouped according to the severity of symptoms and functional limitations.

METHODS

Hip abduction-adduction and external-internal rotation torque ratios of 134 individuals with femoroacetabular impingement syndrome and 134 asymptomatic matched controls was assessed through isokinetic testing. Severity of symptoms and functional limitations was assessed through the iHOT-33. Mann Whitney U and Kruskall-Wallis tests were used to compare hip torque ratios between asymptomatic individuals and patients with femoroacetabular impingement syndrome and to patients with femoroacetabular impingement syndrome with different severities of symptoms and functional limitations.

FINDINGS

No differences were identified in hip abduction-adduction (U = 7659.5, p = 0.192) and external-internal rotation (U = 8787.5, p = 0.764) torque ratios between patients with femoroacetabular impingement syndrome and asymptomatic individuals. Hip abduction-adduction torque ratio was higher (p = 0.0127) in patients with a severe state (median = 1.80, IQR = 0.61) when compared to asymptomatic individuals (median = 1.52, IQR = 0.45) (moderate effect size, r = 0.45).

INTERPRETATION

Patients with severe symptoms and functional limitations related to FAI syndrome presented greater hip abduction-adduction torque ratio than asymptomatic individuals, suggesting a decreased adduction torque capacity relative to abduction torque in this subgroup of femoroacetabular impingement.

Improvement in pain and patient-related outcome measures following hip arthroscopy in patients with femoroacetabular impingement syndrome and concomitant generalized ligamentous laxity: a systematic review

PURPOSE

Within orthopaedic sports medicine, concomitant ligamentous laxity is often found to be a negative prognostic factor for post-operative outcomes following various procedures. The effect of ligamentous laxity on outcomes following hip arthroscopy remains infrequently reported. Therefore, the purpose of this study is to report on the outcomes of hip arthroscopy for the treatment of femoroacetabular impingement syndrome (FAIS) with concomitant generalized ligamentous laxity (GLL).

METHODS

A systematic search was performed in Medline, EMBASE, CENTRAL, and SPORTDiscus (from inception to April 2021) for studies reporting outcomes following hip arthroscopy for symptomatic FAIS in patients with concomitant GLL.

RESULTS

Six studies representing 213 patients and 231 hips were included. Outcomes of pain and functional scores as measured by VAS, Harris Hip Score, and Hip Disability and Osteoarthritis Outcomes Score were tabulated. A mean improvement of 4.8 on VAS was observed. Improvements of 30.0 on HHS, 33.1 for ssHOS, and 23.9 for ADL-HOS were observed.

CONCLUSION

Hip arthroscopy is an effective method of alleviating pain and improving function with statistically significant improvements in all PROM in patients with concomitant FAIS with GLL.

LEVEL OF EVIDENCE

IV.

PROSPERO REGISTRATION

CRD42021248864.

Diagnostic Accuracy of Clinical Tests and Imaging Exams for Femoroacetabular Impingement: An Umbrella Review of Systematic Reviews

OBJECTIVE

To synthesize available evidence about diagnostic accuracy of clinical tests and imaging examinations for femoroacetabular impingement (FAI) syndrome.

DESIGN

Umbrella review.

SETTING

N/A.

PARTICIPANTS

N/A.

INTERVENTIONS

N/A.

MAIN OUTCOME MEASURES

Systematic reviews (SR) indexed in Embase, LIVIVO, PubMed, SCOPUS, the Cochrane Library, and Web of Science were searched in a 2-phase process. SR assessing diagnostic accuracy were considered eligible.

RESULTS

From 1520 studies, 6 SR were included, which evaluated 24 primary studies related to FAI syndrome. Of these, 5 SR assessed clinical tests, and a substantial heterogeneity was found concerning reference standards adopted across primary studies, which included arthroscopy, clinical examination (associated or not with imaging exams), intra-articular injections, and open surgery. Most clinical tests presented higher values of sensitivity compared with specificity, although evidence was considered limited because the same primary studies were often included across SR. Nonetheless, evidence around the flexion adduction internal rotation (FADIR) test was considered stronger and its use as a screening tool was consistently supported. Only one SR assessed the accuracy of imaging examinations, which adopted open surgery as the sole reference standard. Most imaging exams presented considerably high values of sensitivity, although specificity values were notably lower.

CONCLUSIONS

No robust recommendations can be provided for most clinical tests, although the FADIR test, in particular, was consistently supported as a screening tool. Moreover, although imaging examinations showed considerably high sensitivity values, evidence was considered sparse and further research is strongly recommended to validate its use as reference standards for diagnostic accuracy data.

Does Femoroacetabular Impingement Syndrome Affect Self-Reported Burden in Football Players With Hip and Groin Pain?

BACKGROUND

It is unknown if football players with femoroacetabular impingement (FAI) syndrome report worse burden than those with other causes of hip/groin pain, and to what extent this is mediated by cartilage defects and labral tears.

HYPOTHESIS

Football players with FAI syndrome would report worse burden than other symptomatic players, with the effect partially mediated by cartilage defects and/or labral tears.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Football (soccer and Australian football) players (n = 165; 35 women) with hip/groin pain (≥6 months and positive flexion-adduction-internal rotation test) were recruited. Participants completed 2 patient-reported outcome measures (PROMs; the International Hip Outcome Tool-33 [iHOT-33] and Copenhagen Hip and Groin Outcome Score [HAGOS]) and underwent hip radiographs and magnetic resonance imaging (MRI). FAI syndrome was determined to be present when cam and/or pincer morphology were present. Cartilage defects and labral tears were graded as present or absent using MRI. Linear regression models investigated relationships between FAI syndrome (dichotomous independent variable) and PROM scores (dependent variables). Mediation analyses investigated the effect of cartilage defects and labral tears on these relationships.

RESULTS

FAI syndrome was not related to PROM scores (unadjusted b values ranged from -4.693 (P = 0.23) to 0.337 (P = 0.93)) and cartilage defects and/or labral tears did not mediate its effect (P = 0.22-0.97).

CONCLUSION

Football players with FAI syndrome did not report worse burden than those with other causes of hip/groin pain. Cartilage defects and/or labral tears did not explain the effect of FAI syndrome on reported burden.

CLINICAL RELEVANCE

FAI syndrome, cartilage defects, and labral tears were prevalent but unrelated to reported burden in symptomatic football players.

Preoperative Magnetic Resonance Imaging Offers Questionable Clinical Utility, Delays Time to Hip Arthroscopy, and Lacks Cost-Effectiveness in Patients Aged ≤40 Years With Femoroacetabular Impingement Syndrome: A Retrospective 5-Year Analysis

PURPOSE

To assess the clinical utility of preoperative magnetic resonance imaging (MRI) and quantify the delay in surgical care for patients aged ≤40 years undergoing primary hip arthroscopy with history, physical examination, and radiographs concordant with femoroacetabular impingement syndrome (FAIS).

METHODS

From August 2015 to December 2020, 1,786 consecutive patients were reviewed from the practice of 1 fellowship-trained hip arthroscopist. Inclusion criteria were FAIS, primary surgery, and age ≤40 years. Exclusion criteria were MRI contraindication, reattempt of conservative management, or concomitant periacetabular osteotomy. After nonoperative treatment options were exhausted and a surgical plan was established, patients were stratified by those who presented with versus without MRI. Those without existing MRI received one, and any deviations from the surgical plan were noted. All preoperative MRIs were compared with office evaluation and intraoperative findings to assess agreement. Demographic data, Hip Disability and Osteoarthritis Outcome Score (HOOS)-Pain, and time from office to MRI or arthroscopy were recorded.

RESULTS

Of the patients indicated by history, physical examination, and radiographs alone (70% female, body mass index 24.8 kg/m², age 25.9 years), 198 patients presented without MRI and 934 with MRI. None of the 198 had surgical plans altered after MRI. Patients in both groups had MRI findings demonstrating anterosuperior labral tears that were visualized and repaired intraoperatively. Mean time from office to arthroscopy for patients without MRI versus those with was 107.0 ± 67 and 85.0 ± 53 days, respectively (P < .001). Time to MRI was 22.8 days. No difference between groups was observed among the 85% of patients who surpassed the HOOS-Pain minimal clinically important difference (MCID).

CONCLUSION

Once indicated for surgery based on history, physical examination, and radiographs, preoperative MRI did not alter the surgical plan for patients aged ≤40 years with FAIS undergoing primary hip arthroscopy. Moreover, preoperative MRI delayed time to arthroscopy. The necessity of routine preoperative MRI in the young primary FAIS population should be challenged.