Is hip muscle strength normalised in patients with femoroacetabular impingement syndrome one year after surgery?: Results from the HAFAI cohort

Follow-up Treatment after Cartilage Therapy of the Knee Joint - a Recommendation of the DGOU Clinical Tissue Regeneration Working Group

The first follow-up treatment recommendation from the DGOU's Clinical Tissue Regeneration working group dates back to 2012. New scientific evidence and changed framework conditions made it necessary to update the follow-up treatment recommendations after cartilage therapy.As part of a multi-stage member survey, a consensus was reached which, together with the scientific evidence, provides the basis for the present follow-up treatment recommendation.The decisive criterion for follow-up treatment is still the defect localisation. A distinction is made between femorotibial and patellofemoral defects. In addition, further criteria regarding cartilage defects are now also taken into account (stable cartilage edge, location outside the main stress zone) and the different methods of cartilage therapy (e. g. osteochondral transplantation, minced cartilage) are discussed.The present updated recommendation includes different aspects of follow-up treatment, starting with early perioperative management through to sports clearance and resumption of contact sports after cartilage therapy has taken place.

Stratified care in hip arthroscopy: can we predict successful and unsuccessful outcomes? Development and external temporal validation of multivariable prediction models

OBJECTIVE

Although hip arthroscopy is a widely adopted treatment option for hip-related pain, it is unknown whether preoperative clinical information can be used to assist surgical decision-making to avoid offering surgery to patients with limited potential for a successful outcome. We aimed to develop and validate clinical prediction models to identify patients more likely to have an unsuccessful or successful outcome 1 year post hip arthroscopy based on the patient acceptable symptom state.

METHODS

Patient records were extracted from the Danish Hip Arthroscopy Registry (DHAR). A priori, 26 common clinical variables from DHAR were selected as prognostic factors, including demographics, radiographic parameters of hip morphology and self-reported measures. We used 1082 hip arthroscopy patients (surgery performed 25 April 2012 to 4 October 2017) to develop the clinical prediction models based on logistic regression analyses. The development models were internally validated using bootstrapping and shrinkage before temporal external validation was performed using 464 hip arthroscopy patients (surgery performed 5 October 2017 to 13 May 2019).

RESULTS

The prediction model for unsuccessful outcomes showed best and acceptable predictive performance on the external validation dataset for all multiple imputations (Nagelkerke R2 range: 0.25-0.26) and calibration (intercept range: -0.10 to -0.11; slope range: 1.06-1.09), and acceptable discrimination (area under the curve range: 0.76-0.77). The prediction model for successful outcomes did not calibrate well, while also showing poor discrimination.

CONCLUSION

Common clinical variables including demographics, radiographic parameters of hip morphology and self-reported measures were able to predict the probability of having an unsuccessful outcome 1 year after hip arthroscopy, while the model for successful outcome showed unacceptable accuracy. The externally validated prediction model can be used to support clinical evaluation and shared decision making by informing the orthopaedic surgeon and patient about the risk of an unsuccessful outcome, and thus when surgery may not be appropriate.

Patient-Perceived Outcomes Improve Faster Than Hip Strength in Recovery After Surgical Correction for Symptomatic Femoroacetabular Impingement

Background: Patients with symptomatic femoroacetabular impingement (FAI) have hip strength deficits, instability, and increased risk for concomitant injury. While surgical intervention is an effective method of treatment for FAI, more information is needed about the recovery process. Purposes: We sought to understand how patients with FAI recover from surgical correction in the short term. Do patients' perceptions of improvement correspond with measured improvements in hip strength? Methods: We conducted a prospective cohort study of 17 patients (11 male, age range: 16-38 years) who were diagnosed with symptomatic FAI at a single surgeon's practice. Hip strength (flexion, extension, and abduction) was measured preoperatively and at 14, 26, and 52 weeks postoperatively. Patient-reported outcomes using the modified Harris Hip Score (mHHS) and Hip Outcome Osteoarthritis Score (HOOS) subscales were measured at the same time points and at 2 weeks postoperatively. Results: Compared with preoperative values, there was a significant increase in postoperative values at 26 and 52 weeks in normalized isokinetic hip extension (29% and 38%, respectively) and normalized hip abduction (48% and 55%, respectively). No differences in strength were observed at 14 weeks. Modified Harris Hip Score and all HOOS subscales were decreased by 2 weeks postoperatively, and by 14 weeks mHHS improved by 21%, and HOOS subscales improved as well (activities of daily living by 18%, pain by 34%, quality of life by 69%, sport and recreation by 36%, and symptoms by 28%). Conclusion: We observed that patient-reported outcomes including symptoms, function, and satisfaction improved at 14 weeks, while objective measures of hip strength improved at 26 weeks following surgical correction of FAI. More rigorous study is indicated.

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.

Hip kinematics and kinetics in patients with femoroacetabular impingement syndrome before and 1 year after hip arthroscopic surgery. Results from the HAFAI cohort

INTRODUCTION

Patients with femoroacetabular impingement syndrome (FAIS) experience decreased function. Consequently, earlier studies have evaluated gait biomechanics in these patients, but a larger study evaluating gait biomechanics before and after an intervention standardising gait speed is lacking. We aimed at investigating gait kinematics and kinetics in patients with FAIS compared with pain-free controls before and 1 year after hip arthroscopic surgery. Secondary, we aimed at analysing gait pattern separately for the sexes and to investigate associations between peak kinematics and kinetics and the Copenhagen Hip and Groin Outcome Score (HAGOS).

MATERIALS AND METHODS

Sixty patients with FAIS and 30 pain-free controls were tested at a standardised gait speed (1.40 m/s ± 10%). Patients were tested twice: before and 1 year after surgery. Kinematics and kinetics were recorded using infrared high-speed cameras and a force plate. Participants answered HAGOS.

RESULTS

The largest difference among groups was that gait differed between males and females. Neither before nor after surgery could we demonstrate large alterations in gait pattern between patients and pain-free controls. Male patients demonstrated associations between peak kinematics and kinetics and HAGOS Sports function.

CONCLUSIONS

Gait pattern was only vaguely altered in patients with FAIS compared with pain-free controls before and after surgery when using at standardised gait speed. Hence, analysing gait in patients with FAIS does not seem of major importance. Nevertheless, there was an association between HAGOS Sports function and peak kinematics and kinetics in male patients, implying that there could be a clinical importance.

Five-Year Follow-up After Hip Arthroscopic Surgery in the Horsens-Aarhus Femoroacetabular Impingement (HAFAI) Cohort

Background:

Patients with femoroacetabular impingement syndrome (FAIS) are offered hip arthroscopic surgery to decrease hip pain, improve their function, and decrease development of hip osteoarthritis (OA). Nonetheless, long-term follow-up data are few.

Purpose:

To investigate patient-reported outcomes, clinical tests, reoperations, and radiographic status 5 years after primary hip arthroscopy in patients with FAIS.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 60 patients (age, 36 ± 9 years; 63% female) diagnosed with FAIS were included in the study and followed for 5 years after hip arthroscopy. Follow-up included Copenhagen Hip and Groin Outcome Score (HAGOS); Hip Sports Activity Scale; and clinical tests (flexion, adduction, internal rotation [FADIR]; flexion, abduction, external rotation [FABER]; and psoas muscle/tendon major pain provocation). Radiographic evaluation included lateral joint-space width (LJSW) and Tönnis classification for hip OA. Reoperations and conversion to total hip replacement (THR) were recorded. We calculated the proportion of patients who exceeded the minimal important change (MIC), achieved the Patient Acceptable Symptom State (PASS), and were within the 95% reference interval of age- and sex-matched persons with no hip problems. Changes were investigated using paired t tests.

Results:

Compared with preoperatively, all HAGOS subscales were improved substantially 5 years after surgery (mean, ≥21 points; P < .001), and 67% to 89% of patients reported improvements exceeding MIC. Between 56% and 80% achieved PASS, but only 7% to 24% reached the 95% reference interval for the HAGOS subscales. A total of 36% had a positive FADIR test and 25% had a positive FABER test, which were improvements compared with preoperatively (P < .001 for both). Patients with a positive FADIR test had significantly worse HAGOS subscales. Six patients (10%) had a THR since their primary hip arthroscopy. In the remaining patients, the mean LJSW was decreased (-0.4 mm; P = .043), and hip OA had worsened in 9 patients (23%; P = .003).

Conclusion:

Five years after surgery, the majority of patients experienced HAGOS improvements exceeding MIC while also showing an acceptable PASS. However, clinical tests, participation in physical activities, and quality of life indicated that many patients still experience hip problems.

Registration:

NCT04590924 (ClinicalTrials.gov identifier).

Outcomes following surgical management of femoroacetabular impingement: a systematic review and meta-analysis of different surgical techniques

Outcomes following different types of surgical intervention for femoroacetabular impingement (FAI) are well reported individually but comparative data are deficient. The purpose of this study was to conduct a systematic review (SR) and meta-analysis to analyze the outcomes following surgical management of FAI by hip arthroscopy (HA), anterior mini open approach (AMO), and surgical hip dislocation (SHD). This SR was registered with PROSPERO. An electronic database search of PubMed, Medline, and EMBASE for English and German language articles over the last 20 years was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We specifically analyzed and compared changes in patient-reported outcome measures (PROMs), α-angle, rate of complications, rate of revision, and conversion to total hip arthroplasty (THA). A total of 48 articles were included for final analysis with a total of 4,384 hips in 4,094 patients. All subgroups showed a significant correction in mean α angle postoperatively with a mean change of 28.8° (95% confidence interval (CI) 21 to 36.5; p < 0.01) after AMO, 21.1° (95% CI 15.1 to 27; p < 0.01) after SHD, and 20.5° (95% CI 16.1 to 24.8; p < 0.01) after HA. The AMO group showed a significantly higher increase in PROMs (3.7; 95% CI 3.2 to 4.2; p < 0.01) versus arthroscopy (2.5; 95% CI 2.3 to 2.8; p < 0.01) and SHD (2.4; 95% CI 1.5 to 3.3; p < 0.01). However, the rate of complications following AMO was significantly higher than HA and SHD. All three surgical approaches offered significant improvements in PROMs and radiological correction of cam deformities. All three groups showed similar rates of revision procedures but SHD had the highest rate of conversion to a THA. Revision rates were similar for all three revision procedures.

Hip Strength Before and After Arthroscopic Femoroacetabular Impingement Surgery

Femoroacetabular impingement (FAI) and labral pathology are associated with pain, decreased function, and hip strength deficits. Existing data are in conflict regarding when hip strength normalizes following arthroscopic treatment of FAI. The objective of this study was to identify preoperative hip strength relative to the contralateral hip not undergoing surgery as well as when postoperative strength in 4 functional muscle groups normalizes following arthroscopic treatment of FAI. Ninety-eight individuals with radiographic evidence of FAI and labral pathology underwent arthroscopic labral repair. Pre-surgical hip strength testing was performed in the symptomatic "surgical hip" and the contralateral "non-surgical hip." Hip strength measurements were repeated at 8 and 16 weeks postoperatively. Significant preoperative hip strength deficits were noted in the surgical hip compared with the non-surgical hip in flexion, extension, and adduction. At 8 weeks postoperatively, hip strength in the surgical hip improved to being equivalent to that in the non-surgical hip in adduction and extension, remained equivalent to that of the non-surgical hip in abduction, and decreased in flexion relative to the non-surgical hip. At 16 weeks, hip strength remained equivalent in the surgical hip and the non-surgical hip in abduction and adduction, but the surgical hip exceeded the non-surgical hip in extension. While flexion strength improved between 8 and 16 weeks postoperatively for the surgical hip, it had not fully recovered to that of the non-surgical hip. Using a structured postoperative rehabilitation protocol, abduction strength was maintained at 8 weeks postoperatively, while adduction and extension strength had improved to those of the non-surgical hip. At 16 weeks postoperatively, hip abduction and adduction had strength equivalent to those of the non-surgical hip. Despite preoperative improvement, flexion of the surgical hip lagged behind that of the non-surgical hip 16 weeks postoperatively. [Orthopedics. 2021;44(3):148-153.].

Reliability of hip muscle strength measured in principal and intermediate planes of movement

BACKGROUND

Muscle strength testing is widely used in clinical and athletic populations. Commercially available dynamometers are designed to assess strength in three principal planes (sagittal, transverse, frontal). However, the anatomy of the hip suggests muscles may only be recruited submaximally during tasks performed in these principal planes.

OBJECTIVE

To evaluate the inter-session reliability of maximal isometric hip strength in the principal planes and three intermediate planes.

METHODS

Twenty participants (26.1 ± 2.7 years, 50% female) attended two testing sessions 6.2 ± 1.8 days apart. Participants completed 3-5 maximal voluntary isometric contractions for hip abduction, adduction, flexion, extension, and internal and external rotation measured using a fixed uniaxial load cell (custom rig) and commercial dynamometer (Biodex). Three intermediate hip actions were also tested using the custom rig: extension with abduction, extension with external rotation, and extension with both abduction and external rotation.

RESULTS

Moderate-to-excellent intraclass correlation coefficients were observed for all principal and intermediate muscle actions using the custom rig (0.72-0.95) and the Biodex (0.85-0.95). The minimum detectable change was also similar between devices (custom rig = 11-31%; Biodex = 9-20%). Bland-Altman analysis revealed poor agreement between devices (range between upper and lower limits of agreement = 77-131%).

CONCLUSIONS

Although the custom rig and Biodex showed similar reliability, both devices may lack the sensitivity to detect small changes in hip strength commonly observed following intervention.

Maximal hip muscle strength and rate of torque development 6-30 months after hip arthroscopy for femoroacetabular impingement syndrome: A cross-sectional study

OBJECTIVES

Reduced sports function is often observed after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Impaired muscle strength could be reasons for this. We aimed to investigate hip muscle strength after hip arthroscopy for FAIS and its association with sports function and participation.

DESIGN

Cross-sectional study.

METHODS

We included 45 patients (34 males; mean age: 30.6 ± 5.9 years) after unilateral hip arthroscopy for FAIS (mean follow-up [range]: 19.3 [9.8-28.4] months). Maximal isometric hip muscle strength (Nm/kg) including early- (0-100 ms) and late-phase (0-200 ms) rate of torque development (Nm∗kg^-1∗s^-1) for adduction, abduction, flexion, and extension was measured with an externally fixated handheld dynamometer and compared between operated and non-operated hip. Associations between muscle strength and self-reported sports function and return to sport were investigated.

RESULTS

For maximal hip muscle strength, no between-hip differences were observed for adduction, abduction, flexion, and extension (p ≥ 0.102). For rate of torque development, significantly lower values were observed for the operated hip in flexion at both 0-100 ms (mean difference: 1.58 Nm∗kg^-1∗s^-1, 95% CI [0.39; 2.77], p = 0.01) and 0-200 ms (mean difference: 0.72 Nm∗kg^-1∗s^-1, 95% CI [0.09; 1.35], p = 0.027). Higher maximal hip extension strength was significantly associated with greater ability to participate fully in preinjury sport at preinjury level (odds ratio: 17.71 95% CI [1.77; 177.60]).

CONCLUSIONS

After hip arthroscopy for FAIS subjects show limited impairments in maximal and explosive hip muscle strength between operated and non-operated hip. Higher muscle strength was positively associated with higher sports function and ability to participate in sport.

Evaluation of outcome reporting trends for femoroacetabular impingement syndrome- a systematic review

PURPOSE

The aim of this systematic review was to evaluate the trends in the literature regarding surgical treatment for femoroacetabular impingement syndrome (FAIS) and to present which patient-reported outcome-measures (PROMs) and surgical approaches are included.

METHODS

This systematic review was conducted with the PRISMA guidelines. The literature search was performed on PubMed and Embase, covering studies from 1999 to 2020. Inclusion criteria were clinical studies with surgical treatment for FAIS, the use of PROMs as evaluation tool and studies in English. Exclusion criteria were studies with patients < 18 years, cohorts with < 8 patients, studies with primarily purpose to evaluate other diagnoses than FAIS and studies with radiographs as only outcomes without using PROMs. Data extracted were author, year, surgical intervention, type of study, level of evidence, demographics of included patients, and PROMs.

RESULTS

The initial search yielded 2,559 studies, of which 196 were included. There was an increase of 2,043% in the number of studies from the first to the last five years (2004-2008)-(2016-2020). There were 135 (69%) retrospective, 55 (28%) prospective and 6 (3%) Randomized Controlled Trials. Level of evidence ranged from I-IV where Level III was most common (44%). More than half of the studies (58%) originated from USA. Arthroscopic surgery was the most common surgical treatment (85%). Mean follow-up was 27.0 months (± 17 SD), (range 1.5-120 months). Between 1-10 PROMs were included, and the modified Harris Hip Score (mHHS) was most commonly used (61%).

CONCLUSION

There has been a continuous increase in the number of published studies regarding FAIS with the majority evaluating arthroscopic surgery. The mHHS remains being the most commonly used PROM.

How Many Patients Achieve an Acceptable Symptom State After Hip Arthroscopy for Femoroacetabular Impingement Syndrome? A Cross-sectional Study Including PASS Cutoff Values for the HAGOS and iHOT-33

Background

Hip arthroscopy is a viable treatment for femoroacetabular impingement syndrome (FAIS). Clinically relevant improvements in hip function and pain after surgery are often reported, but it is less clear how many patients achieve an acceptable symptom state (Patient Acceptable Symptom State [PASS]).

Purpose

To investigate the proportion of patients who achieved a PASS 12 to 24 months after hip arthroscopy and to determine the cutoff scores of the 2 recommended and valid patient-reported outcome measures (the subscales of the Copenhagen Hip and Groin Outcome Score [HAGOS] and the International Hip Outcome Tool-33 [iHOT-33]) for which patients are most likely to achieve PASS.

Study Design

Cohort study; Level of evidence, 3.

Methods

Eligible study patients were identified in the Danish Hip Arthroscopy Registry. An electronic questionnaire was used to collect data on PASS, HAGOS, and iHOT-33 12 to 24 months after surgery. PASS was measured using an anchor question. Receiver operating characteristic curve analyses were applied to identify the PASS cutoff values of HAGOS and iHOT-33 scores.

Results

A total of 137 individuals (mean age at surgery, 35.4 ± 9.4 years) were included in the study at a mean follow-up of 18.5 ± 3.2 months after surgery. At follow-up, 64 individuals (46.7%; 95% CI, 38.6-55.1) reported PASS. Higher HAGOS and iHOT-33 values were observed for participants who reported PASS compared with those who did not report PASS (Cohen d ≥ 1.06; P < .001). Cutoff scores for HAGOS subscales (42.5-82.5) and iHOT-33 (67.00) showed excellent to outstanding discriminative ability in predicting PASS (area under the curve, 0.82-0.92).

Conclusion

In total, 46% of individuals having hip arthroscopy for FAIS achieved PASS at 12 to 24 months of follow-up. Patients who achieved PASS had statistically significant and substantially better self-reported hip function compared with those who did not achieve PASS. Cutoff values at HAGOS subscales and iHOT-33 showed excellent to outstanding discriminative ability in predicting patients with PASS.

Arthroscopic correction of femoroacetabular impingement improves athletic performance in male athletes

PURPOSE

To measure the changes in athletic performance in athletes treated arthroscopically for femoroacetabular impingement and compare results to a matched controlled athletic cohort, over a 1-year period.

METHODS

Male athletes scheduled for arthroscopic correction of symptomatic FAI were recruited and tested (pre-operatively and 1-year postsurgery) for measures of athletic performance which included acceleration (10-m sprint), change of direction speed (CODS), squatting depth, and reactive strength index (RSI). The FAI group was compared to a matched, healthy, control group who were tested at baseline and 1 year later with no disruption to their regular training or competition status; the prevalence of anterior groin pain during testing in either group was recorded. Hip range of motion (ROM) was also measured for both groups at baseline and at 1 year in the FAI group to look for change following intervention.

RESULTS

Prior to surgery, the FAI group were slower than the control group (p < 0.001) for acceleration (3% slower) and CODS (10% slower). At 1 year, 91% of the FAI group returned to full competition at an average time of 17 weeks, while substantial reductions in pain were also noted during acceleration (51-6%, p = 0.004), CODS (62-8%, p = 0.001), and squat test (38-8%, p = 0.003). Significant improvements were seen in the FAI group for CODS (7%, p < 0.001) and squat depth measures (6%, p = 0.004) from baseline to 1 year (significant time × group interaction effects were noted for these also). The changes in performance in the control group over time were non-significant across all of the measures (n.s.). At 1-year postsurgery, there were no statistically significant differences between the groups for any of the athletic measures. There was a significant and clinically important improvement in range of hip motion in the FAI group at 1-year postsurgery (p < 0.05).

CONCLUSION

Symptomatic FAI causes substantial reductions in athletic performance compared to healthy competitors placing these athletes at a distinct performance disadvantage. The results from the current study demonstrate that arthroscopic correction (including labral repair) in athletes with symptomatic FAI, reduces pain and restores athletic performance to a level which is comparable to healthy athletes, at 1 year.

LEVEL OF EVIDENCE

II.

Preoperative Hip Extension Strength Is an Independent Predictor of Achieving Clinically Significant Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome

BACKGROUND

The effect of preoperative hip strength on outcomes after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) is unclear. The purpose of this study was to determine whether preoperative isometric hip strength is associated with outcome scores at 6 months as well as achieving the minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS) in patients undergoing hip arthroscopy for FAIS.

HYPOTHESIS

Increased preoperative isometric strength will be correlated with short-term postoperative outcomes and will be predictive of achieving higher functional status.

STUDY DESIGN

Case series.

LEVEL OF EVIDENCE

Level 4.

METHODS

Data from 92 consecutive patients undergoing primary hip arthroscopy for treatment of FAIS from March through August 2018 were analyzed. All patients included in the analysis had preoperative measures of isometric hip strength on both affected and unaffected limbs, as well as preoperative and 6-month patient-reported outcome (PRO) scores. Analysis was performed to determine correlations between normalized isometric hip strength measurements and PROs and whether strength measurements were predictive of achieving MCID or PASS.

RESULTS

A total of 74 (80.4%) patients had 6-month PROs and were included in the final analysis. Hip extension strength on both sides was correlated with all postoperative PROs (all P > 0.05). Abduction strength on both sides was correlated with postoperative Hip Outcome Score-Activities of Daily Living subscale score, achieving MCID on at least 1 score threshold, and reaching the international Hip Outcome Tool-12 threshold score for achieving PASS (all P < 0.05). Regression analysis showed that extension strength on the affected side was the only strength measurement predictor of achieving PASS (1.043; P = 0.049).

CONCLUSION

Preoperative isometric hip extension and abduction strength are correlated with 6-month postoperative PRO scores. Furthermore, hip extension strength is a predictor of achieving clinically meaningful outcomes.

CLINICAL RELEVANCE

This study highlights the possible importance of preoperative optimization of hip function to maximize outcomes in patients undergoing hip arthroscopy for FAIS.

Despite patient-reported outcomes improve, patients with femoroacetabular impingement syndrome do not increase their objectively measured sport and physical activity level 1 year after hip arthroscopic surgery. Results from the HAFAI cohort

PURPOSE

Patients with femoroacetabular impingement syndrome (FAIS) are young and middle-aged persons living physically active lives including sports activities. However, measurements of the physical activity level before and after hip arthroscopic surgery in patients with FAIS using both self-reported and objective accelerometer-based measures are lacking. Furthermore, comparing patients with a reference group of persons reporting no hip problems and conducting subgroup analyses investigating changes in physical activity level and self-reported outcomes according to pre-surgery activity level may further highlight the activity pattern for patients.

METHODS

Sixty patients with FAIS eligible for hip arthroscopic surgery were consecutively included in a prospective cohort study (HAFAI cohort) together with 30 reference persons reporting no hip problems. Participants completed the Copenhagen Hip and Groin Outcome Score (HAGOS) together with questions regarding their sports activities. Furthermore, participants wore a three-axial accelerometer for five consecutive days during waking hours. The accelerometer-based data were analysed and presented as total activity and type, frequency and duration of activities.

RESULTS

Patients experienced significant and clinically relevant changes in all HAGOS scores. 88% of patients participated in some kind of sports activity 1 year after surgery. Overall, objectively measured physical activity did not change from before to 1 year after surgery. However, subgroup analyses of the most sedentary patients preoperatively revealed significant changes towards a more active pattern. Compared to reference persons, patients performed less bicycling and running.

CONCLUSION

Despite clinically relevant changes in self-reported outcomes, patients did not increase their overall physical activity level 1 year after surgery. Physical activity levels were lower in patients than in the reference group and patients continued bicycling and running less compared with the reference group.

LEVEL OF EVIDENCE

II.

No association between femoral or acetabular angles and patient-reported outcomes in patients with femoroacetabular impingement syndrome-results from the HAFAI cohort

Patients with femoroacetabular impingement syndrome (FAIS) are diagnosed using imaging, but detailed description especially the acetabular shape is lacking and may help give more insight to the pathogenesis of FAIS. Furthermore, associations between patient-reported outcomes (PROs) and the radiological angles might highlight which radiological angles affect outcomes experienced by the patients. Hence, the aims of this study were (i) to describe computer tomography (CT) acquired angles in patients with FAIS and (ii) to investigate the association between radiological angles and the Copenhagen Hip and Groin Outcome Score (HAGOS) in patients with FAIS. Patients scheduled for primary hip arthroscopic surgery for FAIS were included. Based on CT, following angles were measured before and 1 year after surgery; femoral anteversion, alpha, lateral centre edge, acetabular index, anterior sector, posterior sector and acetabular anteversion. All patients completed the HAGOS. Sixty patients (63% females) aged 36 ± 9 were included. One year after surgery, significant alterations in the alpha angle and the acetabular index angle were found. Neither baseline PROs nor changes in PROs were associated with the radiological angles or changes in angles. Since neither changes in CT angles nor baseline scores were associated with HAGOS, the improvements felt by patients must origin from somewhere else. These findings further underlines that morphological changes seen at imaging should not be treated arthroscopically without a patient history of symptoms and clinical findings.

Short term outcomes of hip arthroscopy on hip joint mechanics and cartilage health in patients with femoroacetabular impingement syndrome

BACKGROUND

Femoroacetabular acetabular impingement syndrome consists of abnormal hip joint morphology resulting in painful hip joint impingement. Hip arthroscopy corrects the abnormal morphology and reduces clinical symptoms associated with femoroacetabular impingement syndrome yet the effects of hip arthroscopy on gait mechanics and cartilage health are not well understood.

METHODS

Ten femoroacetabular impingement syndrome patients and 10 matched asymptomatic controls underwent gait analysis consisting of three-dimensional hip joint kinematics and kinetics. Femoroacetabular impingement syndrome patients underwent gait analysis and quantitative magnetic resonance imaging of the surgical hip joint before and seven months post-surgery. Patient reported outcomes were obtained from all study participants and were used to quantify hip joint pain, function and quality of life.

FINDINGS

Prior to surgery, femoroacetabular impingement syndrome patients demonstrated hip joint kinematics or kinetics as the control group. After surgery, femoroacetabular impingement syndrome patients exhibited improved patient reported outcomes, similar hip joint kinematic patterns, increased hip flexion and decreased hip extension moment impulses within the surgical limb. The femoroacetabular impingement syndrome patients that ambulated with increased HFMI post-surgery demonstrated a decrease in femoral cartilage T1ρ and T2 values.

INTERPRETATION

Femoroacetabular impingement syndrome patients exhibited improved clinical symptoms yet ambulated with altered sagittal plane hip joint loading after hip arthroscopy. Increased hip flexion moment impulse post-surgery was associated with improved cartilage health within the surgical limb. These study findings suggest that sagittal plane hip joint loading at short-term follow-up after hip arthroscopy is associated with cartilage health and may be an important biomechanical parameter in post-operative rehabilitation programs.

Editorial Commentary: The Gain in Pain After Hip Arthroscopic Surgery: What Is Clinically Relevant, and Is Pain Related to Function in Patients With Femoroacetabular Impingement Syndrome?

Hip arthroscopic surgery improves patient-reported outcomes in patients with femoroacetabular impingement syndrome and/or hip chondropathy. The minimal clinically important change on a pain visual analog scale has now been calculated in this patient group, and the pain level 1 year after surgery has been related to function. Next step: identifying what causes pain and decreased function 1 year after surgery.