Femoroacetabular impingement

Can intra-articular hip injections predict arthroscopy outcomes for femoroacetabular impingement syndrome? A systematic review

Background

Femoroacetabular Impingement (FAI) syndrome represents a prevalent aetiology of hip discomfort observed among both adolescent and adult populations. It is initially managed conservatively with oral anti-inflammatories and physiotherapy; some patients proceed to receiving an intra-articular (IA) hip injection, but ultimately, the gold-standard treatment is hip arthroscopy.

Study design

Systematic Review.

Purpose

To systematically investigate the relationship between response to IA anaesthetic or steroid hip injections and arthroscopy outcomes for FAI syndrome.

Methods

A systematic search of PubMed, Medline, CINAHL, SCOPUS, and Cochrane was conducted in line with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines.

Results

Seven studies (Level II-IV) were identified that met our inclusion and exclusion criteria. These studies collectively included 637 patients, demonstrating an average age of 37.5 years (and a range of 14-72 years). Two of the seven studies reported a statistically significant positive correlation between response to IA injections and arthroscopy outcomes. The remaining five studies found that although a positive IA injection response increased the odds of a good outcome post arthroscopy (defined across various studies as a post-operative modified Harris Hip score of >70 points, >79 points or an improvement by 8 or more points), this correlation was not statistically significant.

Conclusion

IA hip injections can be a useful prognostic tool, though they are not a consistently reliable predictor of which patients will have good arthroscopic outcomes.

Both Labral Debridement and Labral Repair Result in >90% Total Hip Arthroplasty-free Survival at 5-Year Follow-Up: An Analysis of the German Cartilage Registry (KnorpelRegister DGOU)

PURPOSE

To compare clinical outcome parameters between labral debridement and repair by analyzing the dataset of a multinational registry.

METHODS

The data are based on the hip module of the German Cartilage Registry (KnorpelRegister DGOU). The register included patients designated for cartilage or femoroacetabular impingement surgery (up to July 1, 2021; n = 2725). The assessment consisted of the patient's characteristics, the type of labral treatment, the length of labral therapy, the pathology, the grade of cartilage damage, and the type of performed approach. The clinical outcomes were documented by the international hip outcome tool via an online platform. Separated Kaplan-Meier analyses were used for total hip arthroplasty (THA)-free survival rates.

RESULTS

The debridement group (n = 673) showed a mean score increase of 21.9 ± 25.3 points. The repair group (n = 963) had a mean improvement of 21.3 ± 24.6 (P > .05). The 60-month THA-free survival rate was 90% to 93% for both groups (P > .05). A multivariance analysis showed that the grade of cartilage damage was the only independent statistically significant factor (P = .002-.001) influencing patients' outcomes and THA-free survival.

CONCLUSIONS

Labral debridement and repair led to good and reliable results. However, these results should not be interpreted with the conclusion that the cheaper and technically easier labral debridement is the recommended treatment due to comparable results in the present study. The clinical outcome and the THA-free survival seemed to be more influenced by the grade of cartilage damage.

LEVEL OF EVIDENCE

Level III, retrospective comparative therapeutic trial.

Unravelling the hip-spine dilemma from the CHECK-cohort: is sagittal pelvic morphology linked to radiographic signs of femoroacetabular impingement?

INTRODUCTION

To date the aetiology of femoroacetabular impingement (FAI) is still not completely understood. There are mechanical theories that suggest symptomatic FAI is linked to sagittal pelvic morphology and spinopelvic-femoral dynamics. The aim of this study is to evaluate the relation of sagittal pelvic morphology and orientation to radiographic signs of FAI. Additionally, we test whether the relation between FAI and spinopelvic parameters differs in osteoarthritic hips.

METHODS

From a prospective, observational cohort study, 1002 patients between 45 and 65 years old with a first episode of knee or hip pain were followed for 8 years. All patients who had lateral lumbar radiographs and clinical and radiographic follow-up of the hips were included in the present study. Range of internal rotation of the hip as well as radiographic signs of FAI (alpha and Wiberg angle) and presence of hip osteoarthritis (Kellgren and Lawrence) were systematically measured at baseline. Pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS)) were measured at 8-year follow-up. Associations between PI, PT, SS and FAI parameters were tested using generalised estimating equations.

RESULTS

421 subjects, 842 hips, were included. No significant relations between PI, PT or SS and alpha or Wiberg angle were found. Comparison of hips with and without radiological sign(s) of FAI showed no differences in PI, PT or SS. There was no relation between range of internal rotation of the hip and spinopelvic parameters.

CONCLUSION

Sagittal pelvic morphology and orientation are not related to the presence of radiological signs of FAI in this study population.

The Influence of Compensatory Pelvic Tilt on Patient-reported Outcome Measurements in FAI Patients Who Received Arthroscopic Treatment

OBJECTIVE

Pelvic compensation is common in femoroacetabular impingement (FAI) patients to reduce symptoms and increase range of motion. However, little attention was given to the postoperative clinical effect of pelvic compensation. Therefore, this study aims to compare the outcomes between pelvic compensation and normal pelvic position in femoroacetabular impingement (FAI) patients after hip arthroscopy.

METHODS

The retrospective study was conducted from January 2019 to June 2022, recruited consecutive patients who were diagnosed with FAI and received subsequent arthroscopic treatment. All patients completed an X-ray in the anterior-posterior standing position before and 4 weeks after surgery. Patients with pelvic compensation were compared with those who did not. Functional outcomes included hip disability and osteoarthritis outcome score (HOOS), modified Harris (mHHS) score, and lower-extremity activity scale (LEAS). Secondary outcomes included the EuroQol Five Dimensions Questionnaire (EQ-5D) and patient satisfaction. The intraclass correlation coefficient (ICC) was used to analyze interobserver and intraobserver reliability.

RESULTS

Ninety patients with a mean age of 39.40 years were included in the study. No significant compensation changes were noted within groups after the elimination of impingement. The functional scores showed no significant difference between groups (p(HOOS) = 0.352, p(mHHS) = 0.183, p(LEAS) = 0.865). The EQ-5D revealed statistically better performance in usual activities in the compensatory group (p = 0.044). There are no significant between-group differences in patients' satisfaction evaluations.

CONCLUSION

As assessed by Patient-Reported Outcome Measures (PROMs), patients with compensatory pelvic tilt demonstrated similar clinical outcomes without extra adverse events to patients with normal pelvic positioning in short-term follow-ups. Furthermore, compensatory pelvic tilt did not significantly enhance the range of motion or functional outcome at short-term follow-ups.

Patient positioning during the radiographic procedure affects the radiological signs of acetabular retroversion - A systematic review

Young adults presenting with non-traumatic hip pain may suffer from acetabular retroversion (AR). The previous studies have suggested that patient positioning during the radiographic procedure, that is, pelvic tilt and/or rotation may alter the appearance of the acetabulum. The purpose of this systematic review was to explore and collate existing literature on the correlation between pelvic positioning in weight-bearing anterior-posterior radiographs and the radiographic signs of AR, namely, the ischial spine sign (ISS) the cross-over sign (COS) and posterior wall sign (PWS). The preferred reporting items for systematic reviews and meta-analysis guidelines were followed. MEDLINE, EMBASE, PubMed, The Cochrane Library, and CINAHL were searched. The search string included the following keywords: Pelvic, tilt, rotation, positioning, inclination, incidence, AR, ISS, COS, PWS, and acetabular version. Two authors independently screened the studies identified in the search, extracted data, and critically assessed included studies for quality using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. In total, 2289 publications were screened. Fifteen articles were found eligible for full-text screening, and four articles met the inclusion criteria. Although the studies varied methodologically, all reported that pelvic positioning impacted radiographic signs of AR investigated. One study suggested that more than 9° of pelvic inclination would result in positive COS. No other benchmark values on the degree of pelvic tilt and rotation that would compromise the diagnosis of AR, that is, the detection of ISS, COS, and PWS were reported. At present, literature reporting on the correlation between patient positioning and AR is sparse. Four studies met the inclusion criteria, and they all reported a link between pelvic positioning and the radiographic appearance of AR.

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.

Open and arthroscopic management of femoroacetabular impingement: a review of current concepts

Femoroacetabular impingement (FAI) is a common femoral and/or acetabular abnormality that can cause progressive damage to the hip and osteoarthritis. FAI can be the result of femoral head/neck overgrowth, acetabular overgrowth or both femoral and acetabular abnormalities, resulting in a loss of native hip biomechanics and pain upon hip flexion and rotation. Radiographic evidence can include loss of sphericity of the femoral neck (cam impingement) and/or acetabular retroversion with focal or global overcoverage (pincer impingement). Operative intervention is indicated in symptomatic patients after failed conservative management with radiographic evidence of impingement and minimal arthritic changes of the hip, with the goal of restoring normal hip biomechanics and reducing pain. This is done by correcting the femoral head-neck relationship to the acetabulum through femoral and/or acetabular osteoplasty and treatment of concomitant hip pathology. In pincer impingement cases with small lunate surfaces, reverse periacetabular osteotomy is indicated as acetabular osteoplasty can decrease an already small articular surface. While surgical dislocation is regarded as the traditional gold standard, hip arthroscopy has become widely utilized in recent years. Studies comparing both open surgery and arthroscopy have shown comparable long-term pain reduction and improvements in clinical measures of hip function, as well as similar conversion rates to total hip arthroplasty. However, arthroscopy has trended toward earlier improvement, quicker recovery and faster return to sports. The purpose of this study was to review the recent literature on open and arthroscopic management of FAI.

A Deep Learning Algorithm for Radiographic Measurements of the Hip in Adults-A Reliability and Agreement Study

Hip dysplasia (HD) is a frequent cause of hip pain in skeletally mature patients and may lead to osteoarthritis (OA). An accurate and early diagnosis may postpone, reduce or even prevent the onset of OA and ultimately hip arthroplasty at a young age. The overall aim of this study was to assess the reliability of an algorithm, designed to read pelvic anterior-posterior (AP) radiographs and to estimate the agreement between the algorithm and human readers for measuring (i) lateral center edge angle of Wiberg (LCEA) and (ii) Acetabular index angle (AIA). The algorithm was based on deep-learning models developed using a modified U-net architecture and ResNet 34. The newly developed algorithm was found to be highly reliable when identifying the anatomical landmarks used for measuring LCEA and AIA in pelvic radiographs, thus offering highly consistent measurement outputs. The study showed that manual identification of the same landmarks made by five specialist readers were subject to variance and the level of agreement between the algorithm and human readers was consequently poor with mean measured differences from 0.37 to 9.56° for right LCEA measurements. The algorithm displayed the highest agreement with the senior orthopedic surgeon. With further development, the algorithm may be a good alternative to humans when screening for HD.

An Updated Review of Femoroacetabular Impingement Syndrome

Femoroacetabular impingement (FAI) is a chronic hip condition caused by femoral head and acetabular malformations resulting in abnormal contact across the joint. FAI often leads to labral, cartilaginous, and tissue damage that predispose this patient population to early osteoarthritis (OA). There are a variety of factors that increase the risk for FAI including younger age, Caucasian background, familial FAIS morphology, and competing in high-intensity sports during adolescence. Slow-onset, persistent groin pain is the most frequent initial presenting symptom. On physical examination, patients will typically have a positive FADIR test (flexion, adduction, internal rotation), also known as a positive impingement sign. FAI syndrome can be organized into three classifications; cam, pincer, or mixed. This classification refers to the characteristic morphological changes of the bony structures. The primary imaging modality for diagnosing FAI is a plain radiograph of the pelvis, which can be used to measure the alpha angle and the lateral center edge angle used to quantify severity. Conservative treatment is typically considered first-line treatment for mild to moderate FAI syndrome; however, the outcomes following postoperative surgical intervention have demonstrated excellent results. The most common surgical treatment option for FAI is done arthroscopically.

Training surgical skills on hip arthroscopy by simulation: a survey on surgeon's perspectives

Purpose

The purpose of this study is to investigate the importance of general and specific surgical skills for hip arthroscopy from the perspective of surgeons in China. Concurrently, we intend to identify the preferred type of simulation that would facilitate competency of surgical trainees in performing arthroscopy and reinforce their preparation for carrying out the actual surgical procedure.

Methods

An online survey comprising 42 questions was developed by experts in hip arthroscopy and sent to 3 online communities whose members are arthroscopic surgeons in China. The responses collected were based on a 5-point Likert scale, with an open-ended comment section. Data were analyzed using one-way AVOVA and post hoc Tukey’s test.

Results

A total of 159 valid responses from 66 junior specialist surgeons, 68 consultant surgeons, and 25 senior consultant surgeons (from 130 institutions in 27 out of 34 provincial administrative districts in China) were collected. Cognitive ability was identified as the overall most important attribute for hip arthroscopic trainees to possess, while skills relevant to the treatment of femoroacetabular impingement (FAI) were considered as the most important specific skills by the surgeons surveyed. In addition, simulation using cadaveric specimens was considered the most favorable method for surgeons to practice their surgical skills.

Conclusion

In designing a training program for hip arthroscopy, it is essential to incorporate features that evaluate cognitive skills. It would be helpful for trainees to specifically practice skills that are often used in the treatment of some very common diseases of the hip joint, such as FAI. Using high-fidelity physical models for simulation to train skills of hip arthroscopy could be an ideal alternative and effective way to overcome problems arising from the lack of accessibility to cadaveric specimens.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11548-022-02708-x.

Quantitative and Qualitative Ultrasound Evaluation for the Diagnosis of an Anterosuperior Acetabular Labral Tear

We investigated the diagnostic performance of qualitative and quantitative ultrasound criteria for anterosuperior acetabular labral tears (ALTs). In all, 118 people with ALTs (120 hips; case group) and 31 asymptomatic volunteers (42 hips; control group) at Peking University Third Hospital between August 2018 and November 2019 were consecutively included. The labral cleft, labral heterogeneous echogenicity, labral plump morphology, paralabral cyst and labral focal hyperechoic area were used as the qualitative criteria. The anterosuperior labral cross-section area (CSA) was measured as the quantitative criterion. The diagnostic utility of the quantitative and qualitative criteria were explored with magnetic resonance imaging as the diagnostic gold standard. Labral heterogeneous echogenicity was the most sensitive criterion for diagnosing ALTs (up to 80.00%), and the specificity of diagnosing ALTs with paralabral cysts, labral focal hyperechoic area and subcortical cysts of the femoral head and neck was as high as 90.48%-100%. The labral CSA in the case group was 0.27 cm² (0.21-0.39 cm²), which was significantly larger compared with the control group (0.18 cm² [0.14-0.23 cm²]; p < 0.001). The area under the receiver operating characteristic curve was 0.802 for diagnosing ALTs according to the labral CSA. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of the combined qualitative criteria for diagnosing ALTs were 90.00%, 71.43%, 90.00%, 71.43% and 85.19%, respectively. Labral heterogeneous echogenicity is a sensitive criterion for diagnosing ALTs, and paralabral cysts, labral focal hyperechoic, area and subcortical cysts of the femoral head and neck are specific criteria. The CSA of the anterosuperior acetabular labrum measured by ultrasound can be used as a quantitative criterion to diagnose ALTs. The combination of labral qualitative criteria provides higher sensitivity and accuracy in diagnosing ALTs.

Patient-Specific Risk Factors Exist for Hip Fractures After Arthroscopic Femoroacetabular Impingement Surgery, But Not for Dislocation—An Analysis of More Than 25,000 Hip Arthroscopies

Purpose

To identify postoperative complications and risk factors associated with hip fracture and dislocation following primary arthroscopic surgical management of femoroacetabular impingement (FAI) syndrome.

Methods

MarketScan was queried to identify patients who underwent FAI surgery from 2007 to 2016. Patients were stratified into 2 groups: acetabuloplasty only or femoroplasty only. A subanalysis of combined acetabuloplasty and femoroplasty also was undertaken. Surgical outcomes were followed postoperatively for 180 days. Multivariate logistic regression was used to control for with an alpha value of 0.05 set as significant.

Results

This study identified 13,809 patients (mean age, 36.3 years) who underwent primary acetabuloplasty or femoroplasty. We also identified 10,026 patients who underwent both procedures. Postoperative complication rates were similar between the cohorts (acetabuloplasty 17.1%, femoroplasty 19.9%, P = .0622). Rates of hip fracture (femoroplasty: 2.4% vs acetabuloplasty: 2.0%, P = .0302) and heterotopic ossification (femoroplasty: 11.3% vs acetabuloplasty: 8.8%, P < .0001) were greater in the femoroplasty-only cohort. Combined acetabuloplasty and femoroplasty was associated with the greatest complication burden of 21.6% (P < .0001). After multivariate regression, differences in age, sex, comorbid status, or procedure type did not influence odds in risk for postoperative hip dislocation. Adjusted data showed that neither femoroplasty nor acetabuloplasty influenced odds of hip fracture (P > .05). Patients who were aged younger than 20 years old were significantly less likely to fracture their hips postoperatively than patients aged 60+ years (odds ratio 0.3, 95% confidence interval 0.1-0.8). Hypertension was independently associated with increased odds of hip fracture (odds ratio 1.7, 95% confidence interval 1.2-3.5).

Conclusions

Older age, male sex, and hypertension all carry increased risk for a hip fracture following acetabuloplasty or femoroplasty. Patient- and procedure-specific factors that could be assessed with this database did not influence risk for hip dislocation.

Level of Evidence

Level III; retrospective comparative observation trial.

Association of Preoperative Opioid Use With Complication Rates and Resource Use in Patients Undergoing Hip Arthroscopy for Femoroacetabular Impingement

Background

Preoperative opioid use has been shown to be a negative predictor of patient outcomes, complication rates, and resource utilization in a variety of different orthopaedic procedures. To date, there are no studies investigating its effect on outcomes after hip arthroscopy in the setting of femoroacetabular impingement (FAI).

Purpose

To determine the association of preoperative opioid use with postoperative outcomes after hip arthroscopy in patients with FAI.

Study Design

Cohort study; Level of evidence, 3.

Methods

The Truven Health MarketScan Commercial Claims and Encounters Database was queried for all patients who underwent hip arthroscopy for FAI between 2011 and 2018. Opioid prescriptions filled in the 6 months preceding surgery were queried, and the average daily oral morphine equivalents (OMEs) in this period were computed for each patient. Patients were divided into 4 cohorts: opioid naïve, <1 OME per day, 1 to 5 OMEs per day, and >5 OMEs per day. Postoperative 90-day complications, health care utilization, perioperative costs, postoperative opioid use, and 1- and 3-year revision rates were then compared among cohorts.

Results

A total of 22,124 patients were ultimately included in this study; 31.2% of these patients were prescribed opioids preoperatively. Overall, the percentage of preoperative opioid-naïve patients increased from 64.5% in 2011 to 78.9% in 2018. Patients who received preoperative opioids had a higher rate of complications, increased resource utilization, and increased revision rates. Specifically, on multivariate analysis, patients taking >5 OMEs per day (compared with patients who were preoperatively opioid naïve) had increased odds of a postoperative emergency department visit (Odds Ratio, 2.23; 95% confidence interval [CI], 1.94-2.56; P < .001), 90-day readmission (OR, 2.25; 95% CI, 1.77-2.87; P < .001), increased acute postoperative opioid use (OR, 25.56; 95% CI, 22.98-28.43; P < .001), prolonged opioid use (OR, 10.45; 95% CI, 8.92-12.25; P < .001), and 3-year revision surgery (OR, 2.14; 95% CI, 1.36-3.36; P < .001). Perioperative adjusted costs were increased for all preoperative opioid users and were highest for the >5 OMEs per day cohort ($6255; 95% CI, $5143-$7368).

Conclusion

A large number of patients with FAI are prescribed opioids before undergoing hip arthroscopy, and use of these pain medications is associated with increased health care utilization, increased costs, prolonged opioid use, and early revision surgery.

Is a Femoro-Acetabular Impingement Type Cam Predictable after Slipped Capital Femoral Epiphysis?

(1) Background: Previous studies have proven a high incidence of a femoro-acetabular impingement (FAI) type cam in patients sustaining a slipped capital femoral epiphysis (SCFE). Thus, the current study analyzed, if a cam deformity is predictable after SCFE treatment; (2) Methods: 113 cases of SCFE were treated between 1 January 2005 and 31 December 2017. The radiological assessment included the slip angle after surgery (referenced to the femoral neck (epiphyseal tilt) and shaft axis as Southwick angle) and the last available lateral center edge angle (LCEA), the acetabular- and alpha angle. A correlation was performed between these parameters and the last alpha angle to predict a FAI type cam; (3) Results: After a mean follow-up of 4.3 years (±1.9; 2.0-11.2), 48.5% of the patients showed a FAI type cam and 43.2% a dysplasia on the affected side. The correlation between the epiphyseal tilt and alpha angle was statically significant (p = 0.017) with a medium effect size of 0.28; (4) Conclusions: The postoperative posterior epiphyseal tilt was predictive factor to determine the alpha angle. However, the cut-off value of the slip angle was 16.8° for a later occurrence of a FAI type cam indicating a small range of acceptable deviations from the anatomical position for SCFE reconstruction.

Relationship between cam morphology, hip symptoms, and hip osteoarthritis: the Musculoskeletal pain in Ullersaker STudy (MUST) cohort

BACKGROUND

The primary aim of this study was to determine the prevalence of cam morphology in a cohort of people aged 40-55 years. Secondary aims were to: (1) determine differences in participant characteristics, physical impairments, radiographic and ultrasound appearances of people with and without cam morphology; and (2) explore associations between cam morphology and radiographic measures of hip osteoarthritis (OA).

METHODS

107 people (68% women; 49 ± 4 years) from the Musculoskeletal pain in Ullensaker (MUST) Study underwent the clinical and imaging examinations. Examinations included questionnaires, hip range, functional task performance, pelvic radiographs and ultrasound. Alpha angle and radiographic hip OA (Kellgren Lawrence (KL) and minimal joint space (MJS)) were determined.

RESULTS

The prevalence of cam morphology was 42% and was bilateral in 47%. People with cam morphology were 6 times more likely to have a KL score ⩾2 (adjusted odds ratio [95% confidence intervals, p-value]) 6.386 [1.582-37.646, p = 0.012]) and 4 times more likely to have MJS <2.0 mm (adjusted odds ratio 4.032 [1.031-12.639, p = 0.045]). The prevalence of radiographic OA features ranged from 4-13% in people with cam morphology, and 0-3% in those without. Those with cam morphology also demonstrated reduced hip flexion and rotation range (p = 0.018-0.036) compared with those without. There was no association between ultrasonic features and patient reported outcomes, and cam morphology.

CONCLUSIONS

In a cohort aged 40-55 years, the prevalence of cam morphology was high (42%), with a significant relationship between cam morphology and radiographic measures of hip OA. Further longitudinal studies should explore the relationship between cam morphology and hip OA in younger people.

Intraoperative Computer Vision Integrated Interactive Fluoroscopy Correlates With Successful Femoroplasty on Clinic-Based Radiographs

PURPOSE

To quantitatively evaluate computer vision interface (CVI)-guided femoroplasty in the arthroscopic treatment of femoroacetabular impingement syndrome and compare those results with traditional unguided resections.

METHODS

Consecutive patients undergoing hip arthroscopy for femoroacetabular impingement syndrome between July 2019 and October 2019 were evaluated. Cases with CVI were identified along with controls, consisting of patients from the same study period who underwent surgery without the CVI and were balanced for age, sex, laterality, and preoperative alpha angles. Alpha angles were measured on pre- and postoperative clinic radiographs, as well as intraoperatively for the CVI group. Cam resections were quantified by measuring pre- and postresection alpha angles and compared between groups. The correlation between CVI views and office-based radiographs was assessed, and the 3 CVI views that best correlated with each of the 3 standard clinic radiographs were evaluated for accuracy and performance in detection of cam deformity with alpha angle ≥48° with the clinic-based films as the reference.

RESULTS

A total of 49 patients (51 hips) (average age, 28.7; 33 female patients) in the CVI group, and 51 patients (51 hips) (average age: 29.9; 35 female patients) in the control group. There were no significant differences between groups with respect to age, sex, laterality, or preoperative alpha angle (all P > .05). Significant alpha angle reduction occurred on all intraoperative and postoperative clinic views (all P < .01). The CVI views that best correlated with the clinic radiographs were 11:45 with the anteroposterior (ρ = 0.588, P = .0025), 12:30 with the Dunn lateral (ρ = 0.632, P = .0009), and 1:45 with the false-profile (ρ = 0.575, P = .0033). Greater reliability was observed with 12:30/Dunn (accuracy = 83.33%, P < .0001; sensitivity = 77.14%; specificity = 87.76%) and 1:45/false-profile (accuracy = 82.35%, P = .0051; sensitivity = 81.82%; specificity = 82.61%) than with 11:45/anteroposterior (accuracy = 69.15%, P = .0077; sensitivity = 56.10%; specificity = 79.25%).

CONCLUSIONS

CVI-guided cam resection results in successful resection of proximal femur cam lesions and represents a femoroplasty templating method that does not require preoperative computed tomography imaging or additional invasive intraoperative referencing modules. The accuracy and adequacy of this resection was validated by comparison with routine clinic radiographs.

LEVEL OF EVIDENCE

Therapeutic Level III: retrospective comparative analysis.

Correlation of the Imaging Features of Femoroacetabular Impingement Syndrome With Clinical Findings and Patient Functional Scores

The relationship among the severity of the imaging features of femoroacetabular impingement syndrome (FAIS), patient symptoms, and function has not been elucidated. Understanding this relationship helps to improve the prognostic value of imaging. The goal of this study was to examine the correlation of clinical findings, patient pain, and function with severity, as measured with radiographic and 3-dimensional magnetic resonance imaging (3D-MRI). Data collected prospectively through a longitudinally maintained hip database were reviewed, and 37 hips from 31 patients were included. All patients were examined by an experienced orthopedic surgeon, and preoperative radiographs and 3D-MRI were obtained. Preoperatively, the patients completed validated patient-reported outcome measures (PROMs). Mean±SD alpha angles were 69.4°±10.3°, 70.0°±10.3°, 70.6°±8.4°, and 74.8°±9.2° at 12 o'clock, 1 o'clock, 2 o'clock, and 3 o'clock, respectively. Mean lateral center edge angle was 30.1°±5.3°. The authors did not observe a statistically significant correlation between PROMs and the features measured by radiographs and 3D-MRI (P>.05). In this subset of prospectively imaged patients with FAIS, the authors did not find a correlation between the severity of symptoms measured by PROMs and features on radiographs and 3D-MRI. The severity of dysfunction is multifactorial, and anatomic severity, as measured radiographically and with 3D-MRI, may not correlate with symptoms. Further investigation is necessary to address the sources of patient pain. [Orthopedics. 2021;44(4):e577-e582.].

Leveraging unsupervised image registration for discovery of landmark shape descriptor

In current biological and medical research, statistical shape modeling (SSM) provides an essential framework for the characterization of anatomy/morphology. Such analysis is often driven by the identification of a relatively small number of geometrically consistent features found across the samples of a population. These features can subsequently provide information about the population shape variation. Dense correspondence models can provide ease of computation and yield an interpretable low-dimensional shape descriptor when followed by dimensionality reduction. However, automatic methods for obtaining such correspondences usually require image segmentation followed by significant preprocessing, which is taxing in terms of both computation as well as human resources. In many cases, the segmentation and subsequent processing require manual guidance and anatomy specific domain expertise. This paper proposes a self-supervised deep learning approach for discovering landmarks from images that can directly be used as a shape descriptor for subsequent analysis. We use landmark-driven image registration as the primary task to force the neural network to discover landmarks that register the images well. We also propose a regularization term that allows for robust optimization of the neural network and ensures that the landmarks uniformly span the image domain. The proposed method circumvents segmentation and preprocessing and directly produces a usable shape descriptor using just 2D or 3D images. In addition, we also propose two variants on the training loss function that allows for prior shape information to be integrated into the model. We apply this framework on several 2D and 3D datasets to obtain their shape descriptors. We analyze these shape descriptors in their efficacy of capturing shape information by performing different shape-driven applications depending on the data ranging from shape clustering to severity prediction to outcome diagnosis.

"Lessons from Rare Forms of Osteoarthritis"

Osteoarthritis (OA) is one of the most prevalent conditions in the world, particularly in the developed world with a significant increase in cases and their predicted impact as we move through the twenty-first century and this will be exacerbated by the covid pandemic. The degeneration of cartilage and bone as part of this condition is becoming better understood but there are still significant challenges in painting a complete picture to recognise all aspects of the condition and what treatment(s) are most appropriate in individual causes. OA encompasses many different types and this causes some of the challenges in fully understanding the condition. There have been examples through history where much has been learnt about common disease(s) from the study of rare or extreme phenotypes, particularly where Mendelian disorders are involved. The often early onset of symptoms combined with the rapid and aggressive pathogenesis of these diseases and their predictable outcomes give an often-under-explored resource. It is these "rarer forms of disease" that William Harvey referred to that offer novel insights into more common conditions through their more extreme presentations. In the case of OA, GWAS analyses demonstrate the multiple genes that are implicated in OA in the general population. In some of these rarer forms, single defective genes are responsible. The extreme phenotypes seen in conditions such as Camptodactyly Arthropathy-Coxa Vara-pericarditis Syndrome, Chondrodysplasias and Alkaptonuria all present potential opportunities for greater understanding of disease pathogenesis, novel therapeutic interventions and diagnostic imaging. This review examines some of the rarer presenting forms of OA and linked conditions, some of the novel discoveries made whilst studying them, and findings on imaging and treatment strategies.

The lateral joint space width is essential for the outcome after arthroscopically assisted mini-open arthrotomy for treatment of a femoroacetabular impingement: an analysis of prognostic factors for the success of this hip-preserving technique

PURPOSE

The purpose of this study was to analyze predicting factors for a conversion to a total hip replacement (THR) after mini-open arthrotomy for treatment of femoroacetabular impingement (FAI).

METHODS

Between 2011 and 2016, we identified 32 patients, who were treated for FAI with a mini-open arthrotomy and received after mean time of 2.1 ± 1.4 years a THR. These patients were compared to 47 cases who did not receive a THR (mean follow-up: 4.3 ± 0.7 years) to explore pre- and intra-operative factors associated with a conversion to THR. The results were presented in separated Kaplan-Meier curves with log rank test for significance and hazard ratios.

RESULTS

A lateral joint space width of > 4 mm showed a higher THR-free survival rate compared to < 4 mm (p = 0.001); analogously one-sided (acetabular/femoral) 3-4° cartilage damage had a comparable THR-free survival rate than 1-2° kissing lesions (p = 0.001). Furthermore, an intact labrum without treatment and good cartilage status, a refixed labrum after rim resection in case of a pincer type FAI, or a refixed teared labrum were associated with a longer THR-free time than an untreated labrum accompanied by a poor cartilage status or an ossified labrum (p = 0.002). The strongest independent factor for a conversion to THR was femoral cartilage damage grade 1 and higher (p = 0.046). However, the rate of available patients was 53.0%.

CONCLUSION

The success of a joint-preserving mini-open arthrotomy seems to be dependent on the status of the radiological joint space width and the intra-operative cartilage status of the lateral edge.

Arthroscopic Hip Surgery versus Conservative Therapy on Femoroacetabular Impingement Syndrome: A Meta-Analysis of RCTs

To determine the outcome and differences between arthroscopic hip surgery and conservative therapy in patients suffering from femoroacetabular impingement syndrome, we searched articles from PubMed, Embase, Cochrane, Web of Science and Clinicaltrials.gov using a Boolean search algorithm. Only randomized controlled trials comparing arthroscopic hip surgery and conservative therapy were included in this meta‐analysis of femoroacetabular impingement syndrome management. Two authors determined eligibility, extracted the needed data and assessed the risk of bias of eligible studies independently. Then we meta‐analyzed three articles to assess pooled estimate size (ES) and 95% confidence interval for Hip Outcome Score of activities of daily living (HOS ADL subscale), Hip Outcome Score sport (HOS sports subscale) and International Hip Outcome Tool (iHOT‐33) analyses were performed by using STATA version 14.0 MP (STATA, College Station, TX, USA) with the principal summary measures are mean between group difference, sample size, and standard deviation. We collected 52 articles in total after removing duplicates and screened by titles and abstracts. A total of three RCTs were included finally. There was definite evidence of additional benefit of arthroscopic hip surgery against conservative therapy in the field of improving quality of life (three trials, 575 participants, ES = 2.109, 95% CI: 1.373 to 2.845, I² = 42.8%, P = 0.000) and activity of daily living (two trials, 262 participants, ES = 9.220, 95% CI: 5.931 to 12.508, I² = 16.5%, P = 0.000). However, no significant difference could be seen in sports function improvement (two trials, ES = 7.562, 95% CI: −2.957 to 18.082, I² = 60.1%, P = 0.159). In conclusion, this meta‐analysis suggests that arthroscopic hip surgery provided essential benefit compared with conservative therapy in improving activity of daily living and quality of life.

Hip Arthroscopy for Femoracetabular Impingement in China: A Review and Meta-Analysis

OBJECTIVE

To explore the development of hip arthroscopy in China through reviewing the change of the application of hip arthroscopy operation on treating femoracetabular impingement (FAI).

METHOD

Papers were retrieved from January 1, 2005 to November 1, 2019, from databases CNKI, Wanfang Data, VIP, PubMed, and Embase. The keywords are Hip Impingement, Femoroacetabular impingement, Hip arthroscopy, Arthroscopic operation, Hip Arthroscopy operation, and Arthroscope, etc. The quality of papers was assessed through MINORS , and statistics and meta-analysis were performed by Word, Excel, and Revman 5.3 Zurich, Switzerland.

RESULTS

From a total of 8,953 papers, 46 review articles without data and 48 articles with data were involved, and 25 papers were included in the Meta-analysis. The twenty-five papers were selected from 48 papers with data, of which 41 were reported in Chinese, 11 were missing complete Harris scores, five did not mention the number of patients who had lost follow-up, three had minors quality scores below 7, one did not have enough FAI cases, and three did not have standard deviations in Harris scores. Overall, in China, the application of hip arthroscopy regarding FAI has flourished while maintaining a high level of treatment and has reached its peak in the past 2 years.

CONCLUSION

With the rapid development of hip arthroscopy in China, hip operation is widely recognized, many reports on its application on FAI have emerged successively, and the scope of application and technical level have been improved.

Outcomes in arthroscopic surgery and proposal rehabilitative treatment in femoral acetabular impingement syndrome

Background and aim of the work Femural Acetabular impingement syndrome (FAIS) is a patologic condition that can lead to hip pain, functional limitation and stiffness. In the last few decades orthopedics and physiotherapists have improved both surgery and riabilitative treatment leading to a better and better treatment. The target of this paper il to verify the efficiency of an early and multimodal physiotherapic treatment after and arthroscopic surgery of the FAIS   Materials and Methods We performed arthroscopic treatment and rehabilitation on 19 patients with mean age of 37±8,3 years, 12 males and 7 females. Each patient has been evaluated preoperatively (T0), postoperatively after 6 week (T1) and after 3 months of follow up (T2), the assessment was carried out by: administration of the VAS and WOMAC score for pain and function and joint examination of active hip movement through an inertial sensor system.   Results VAS score shows a decrease of pain after 6 week (mean decrease was 36%) and after 3 months (mean decrease was 33%). WOMAC score shows an increase of the funcional performance of the hip after 3 weeks and after 3 months (in both phases the mean score increase of the 44%) At last, the analysis of the active movement and of the hip joint showed a generalized increase in all movements both 6 weeks and 3 months after surgery, in particular for flexion (with the knee flexed) and internal rotation movements. of the hip.   Conclusion The results of this study are in line with the current scientific literature and the protocol used represents a valid tool to complete the surgical treatment. The proposal of an early, intensive treatment combined with hydrokinesitherapy seems to be safe and effective, however further studies are needed (increasing the sample size) to investigate the results.

Insurance Coverage Criteria for Femoroacetabular Impingement Surgery: Are They Responding to Improving Evidence?

BACKGROUND

With the rapidly growing body of FAI literature in the last decade, improved evidence exists to support FAI surgery. However, it remains unclear how well third-party insurance company's FAI policies have adapted over time to improved evidence. The purpose of this study was (1) to compare the 2020 FAI surgery criteria of four major insurance companies utilizing a multi-center cohort of FAI patients undergoing surgery to identify rates and causes of ineligibility, and (2) to compare the rates of approval based on changes in policy from 2012 to 2020.

METHODS

Four major insurance companies' coverage policies with specific criteria for the surgical treatment of FAI were applied to this population at two time points (2012 and 2020). The policies listed various combinations of age, symptom duration, radiographic signs of FAI, radiographic signs of osteoarthritis, and physical exam findings. A prospective, multi-center cohort of 712 patients (including 45.5% males and 54.5% females with a mean age of 28.7 years) undergoing surgical treatment of FAI was utilized for analysis of insurance policies.

RESULTS

Based on 2020 FAI policies across 4 insurers, 22.5% (range 18.4-28.4%) of FAI patients would be deemed ineligible. In 2012, the average percent exclusion of the four companies was 23.7%. The most likely reason to be excluded was either failure to meet imaging criteria (alpha angle >50° or positive cross-over sign) [13%, n=94]) or the absence of an impingement sign (9%, n=65). Other causes of exclusion were <6-month symptom duration (6%, n=44), age <15 years (4%, n=28), or skeletally immaturity (3%, n=23).

CONCLUSION

Our study shows that despite a six-year span of growing literature and updated policies, nearly 1 in 5 patients diagnosed with FAI would still potentially be denied coverage. This highlights a continued divide between surgeons and insurance companies. There is a major need for improved consensus regarding the diagnosis of FAI and appropriate indications for surgical intervention.Level of Evidence: IV.

Historical analysis of the diagnosis and management of femoroacetabular impingement prior to the year 2000: a systematic review

 

This systematic review aims to assess the diagnosis, indications and treatment of femoroacetabular impingement (FAI) prior to the year 2000 and to determine if historical concepts remain applicable today. PUBMED, MEDLINE and EMBASE were searched for literature evaluating the diagnosis/treatment of FAI prior to 2000. Cadaver/non-human, non-English and review studies were excluded. Quality assessment was performed using the Methodological Index for Non-Randomized Studies. Nine studies comprising 307 patients [315 hips; mean age of 32.6 ± 2.4 years (range, 12-58)] were included. Patients reported groin pain. Magnetic resonance arthrography (MRA; n = 76) and the anterior impingement test (AIT) (n = 88) were used to diagnose impingement. Surgical dislocation with a trochanteric flip osteotomy (n = 237) and Bernese periacetabular osteotomy (n = 40) were common treatments. Pain and range of motion improved for patients. Overall complication rate was 35% (n = 99), with heterotopic ossification (n = 79) most commonly reported. Prior to 2000, there was low quantity and quality of research on the diagnosis/management of FAI. Diagnostic evaluation was primarily through clinical examination (i.e. groin pain and AIT). MRA was occasionally used to detect labral degeneration; however, utilization of computed tomography (CT) and diagnostic injections were not reported. Surgical dislocation and osteotomies of the acetabulum yielded desirable short-term clinical outcomes with a moderate complication rate. No study reported using arthroscopy for FAI management prior to 2000. Clinicians today can learn from historical principles (i.e. clinical diagnosis of FAI, management with surgical correction of femoral head-neck offset) while applying novel techniques (i.e. CT, injections, arthroscopic surgical techniques and rehabilitation) to improve patient outcomes.

Level of Evidence

IV (systematic review of III and IV evidence).

Image quality of hip MR arthrography with intra-articular injection of hyaluronic acid versus gadolinium-based contrast agent in patients with femoroacetabular impingement

OBJECTIVE

To compare image quality of magnetic resonance arthrography (MRA) of the hip with intra-articular injection of high-viscosity hyaluronic acid (HA-MRA) versus Gd-based contrast agent (Gd-MRA) in patients with femoroacetabular impingement (FAI).

MATERIALS AND METHODS

Design: single-centre, observational, retrospective, inter-individual, and cross-sectional. FAI patients who underwent HA-MRA (3 mL of high-viscosity HA plus 17 mL of saline) were compared with 37 age- and sex-matched FAI patients who underwent Gd-MRA (20 mL of 2 mmol/L solution of gadopentetate dimeglumine). Two independent blinded radiologists assessed image quality for all sequences (two-dimensional proton density, non-fat-sat axial, fat-sat coronal and sagittal; three-dimensional dual-echo steady state), using a 5-point Likert scale considering separately labrum, cartilage, round ligament, transverse ligament, and capsule. Pearson χ² and Cohen κ were used.

RESULTS

The HA-MRA group was composed of 37 patients (23 males, 14 females; median age 38 years), the Gd-MRA group of 37 patients (21 males, 16 females; median age 38 years), without significant difference for age (p = 0.937) and sex (p = 0.636). Image quality did not differ between the two readers for any structure: labrum (p ≥ 0.340), cartilage (p ≥ 0.198), round ligament (p ≥ 0.255), transverse ligament (p ≥ 0.806), and capsule (p ≥ 0.314). Inter-reader agreement (κ) ranged from 0.785 to 1.000.

CONCLUSIONS

HA-MRA provided an image quality not significantly different from that of Gd-MRA. This may open the possibility of combining MRA and viscosupplementation in one single procedure.

Pathomechanics Underlying Femoroacetabular Impingement Syndrome: Theoretical Framework to Inform Clinical Practice

Over the last decade, there has been a marked increase in attention to, and interest in, femoroacetabular impingement syndrome (FAIS). Despite continued efforts by researchers and clinicians, the development, progression, and appropriate treatment of FAIS remains unclear. While research across various disciplines has provided informative work in various areas related to FAIS, the underlying pathomechanics, time history, and interaction between known risk factors and symptoms remain poorly understood. The purpose of this perspective is to propose a theoretical framework that describes a potential pathway for the development and progression of FAIS. This paper aims to integrate relevant knowledge and understanding from the growing literature related to FAIS to provide a perspective that can inform future research and intervention efforts.

Magnetic Resonance Arthrography, a valuable pre-operative imaging modality in femoro-acetabular impingement

Background

The diagnostic accuracy of MR arthrography in preoperative assessment of labral tears and chondral abnormalities in femoroacetabular impingement patients.

A non-randomized control study including 31 FAI patients (17 male and 14 females, mean age 31.9 years). All patients underwent MR arthrography after US-guided intra-articular contrast injection. Conventional and MR arthrography images were evaluated for bone abnormalities (including alpha angle and acetabular depth measurements), labral tears, and chondral abnormalities. The results were correlated to arthroscopy as the gold standard. Sensitivity, specificity, PPV, and NPV in the detection of labral tears and chondral abnormalities were statistically calculated.

Results

The included FAI patients presented cam (mean age 30.4 years ± 6.8 years), pincer (mean age 33.6 years ± 9.8 years), and mixed (mean age 36.6 years ± 12.9 years) types with the predominance of cam type. Cam type predominated in the male, while pincer and mixed types predominated in female patients. MR arthrography detected 41 labral tears in 23 patients with 87.5%, 71.4%, 91.3%, and 62.5% sensitivity, specificity, PPV, and NPV, respectively, and detected chondral abnormalities in 13 patients with 66.7%, 92.3%, 92.3%, and 66.7% sensitivity, specificity, PPV, and NPV, respectively.

Conclusion

MR arthrography is a valuable imaging modality in preoperative assessment of FAI patients. Besides identifying the type of impingement through alpha angle and acetabular depth measurements, it detects labral tears with high sensitivity and PPV. Although less sensitive in detection of chondral abnormalities, our results showed high specificity.

Efficacy of preemptive analgesia versus postoperative analgesia of celecoxib on postoperative pain, patients' global assessment and hip function recovery in femoroacetabular impingement patients underwent hip arthroscopy surgery

We aimed to investigate the efficacy of preemptive analgesia of celecoxib on postoperative pain, patients' global assessment (PGA) and hip function recovery compared to postoperative analgesia of celecoxib in femoroacetabular impingement (FAI) patients who underwent hip arthroscopy surgery (HAS). The 100 FAI patients underwent HAS were randomly allocated to preemptive analgesia group (N = 50) or postoperative analgesia group (N = 50) as a 1:1 ratio for 3 months. Pain visual analog scale (VAS) score, PGA score, rescue-use pethidine consumption and Harris hip score were assessed. Compared to postoperative analgesia group, pain VAS score decreased on day 1 (P = 0.036), day 2 (P = 0.046) and day 3 (P = 0.046), while was similar prior to operation (P = 0.587), on day 7 (P = 0.398), at month 1 (P = 0.461) and month 3 (P = 0.805) in preemptive analgesia group. Besides, rescue-use pethidine consumption was decreased in preemptive analgesia group than postoperative analgesia group within 3 days (P = 0.016) and within 7 days (P = 0.033) post-operation. For PGA score, it reduced on day 2 (P = 0.030) and day 3 (P = 0.048), while was similar prior to operation (P = 0.699), on day 1 (P = 0.699), day 7 (P = 0.224), at month 1 (P = 0.640) and month 3 (P = 0.400) in preemptive analgesia group than postoperative analgesia group. For Harris hip score, it was similar prior to operation (P = 0.372), on day 7 (P = 0.366), at month 1 (P = 0.466) and month 3 (P = 0.658) between the two groups. In conclusion, preemptive analgesia of celecoxib decreases short-term postoperative pain and PGA, but without effect on long-term hip function recovery than postoperative analgesia of celecoxib in FAI patients who underwent HAS.

Deep hip muscle activation during squatting in femoroacetabular impingement syndrome

BACKGROUND

Deep hip muscle retraining is a common objective of non-operative management for femoroacetabular impingement (FAI) syndrome. These muscles are considered to have an important role in hip joint stabilization, however, it is unclear whether their function is altered in the presence of hip pathology. This exploratory study aimed to investigate activation patterns of the hip muscles during two squatting tasks in individuals with and without FAI syndrome.

METHODS

Fifteen individuals with FAI syndrome (symptoms, clinical examination and imaging) and 14 age- and sex-comparable healthy controls underwent testing. Intramuscular fine-wire and surface electrodes recorded electromyographic activity of selected deep and superficial hip muscles during the squatting tasks. Activation patterns from individual muscles were compared between-groups using a wavelet-based linear mixed effects model (P < 0.05).

FINDINGS

There were no between-group differences for squat depth or speed during descent or ascent for either task. Participants with FAI syndrome exhibited patterns of activation that differed significantly to controls across all muscles (P < 0.05) when squatting using their preferred strategy. Unlike controls, participants with FAI syndrome exhibited a pattern of activation for obturator internus during descent that was similar in amplitude to ascent, despite the contrasting contraction type (i.e. eccentric vs concentric).

INTERPRETATION

Individuals with FAI syndrome appear to implement a protective strategy as the hip descends towards the impingement position. Future studies should examine patients prospectively to establish whether these strategies are counterproductive for pathology and warrant rehabilitation.

Do psychological factors or radiographic severity play a role in the age of onset in symptomatic developmental dysplasia of hip and femoroacetabular impingement syndrome?

Background

Age of onset in symptomatic developmental dysplasia of the hip (DDH) and femoroacetabular impingement syndrome (FAIS) varies. The purpose of this study was to investigate whether psychological factors, radiographic, and clinical variables were related to age of onset of hip pain in DDH and FAIS.

Methods

We collected demographic, clinical, and radiographic data on 56 DDH and 84 FAIS patients. Each was diagnosed based on radiographic findings and clinical history. Age of onset was operationalized by subtracting patient reported duration of symptoms from patient age at presentation. Pain catastrophizing (PCS) and depression were assessed with the pain catastrophizing scale and hospital anxiety and depression scale (HADS), respectively. Multiple linear regression modeling, with Lasso variable selection, was implemented.

Results

Pain catastrophizing, anxiety, and depression were not significantly related to age of DDH onset (p-values > 0.27) or age of FAIS onset (p-values > 0.29). LASSO-penalized linear regression revealed alpha Dunn angle, Tonnis grade, prior hip surgery, WOMAC pain score, and iHOT total score were associated with age of onset in FAIS (Adjusted R² = 0.3099). Lateral center edge angle (LCEA), alpha frog angle, Tonnis grade, SF12 physical functioning, and body mass index (BMI) were associated with age of DDH onset (Adjusted R² = 0.3578).

Conclusions

Psychological factors, as measured by PCS and HADS, were not associated with age of onset in DDH or FAIS. Functional impairment as measured by WOMAC pain and impaired active lifestyle as measured by iHOT were found to affect age of FAIS onset. For DDH, impaired physical functioning and increasing BMI were found to be associated with age of onset. Severity of the disease, as measured radiographically by LCEA and alpha Dunn angle, was also found to be associated with earlier age of onset in DDH and FAIS, respectively. A patient’s radiographic severity may have more of a relationship to the onset of pain than physiologic factors.

An Anatomical Study of the Anterosuperior Capsular Attachment Site on the Acetabulum

BACKGROUND

Despite the fact that many surgeons perform partial capsular detachment from the anterosuperior aspect of the acetabulum to correct acetabular deformities during hip arthroscopy, few studies have focused on whether these detachments influence hip joint stability. The aim of this study was to investigate the capsular attachment on the anterosuperior aspect of the acetabulum. We hypothesized that the attachment on the inferior aspect of the anterior inferior iliac spine (AIIS) is wide and fibrocartilaginous and might have a substantial role in hip joint stability.

METHODS

Fifteen hips from 9 cadavers of Japanese donors were analyzed. Eleven hips were analyzed macroscopically, and the other 4 were analyzed histologically. In all specimens, the 3-dimensional morphology of the acetabulum and AIIS was examined using micro-computed tomography (micro-CT).

RESULTS

Macroscopic analysis showed that the widths of the capsular attachments varied according to the location, and the attachment width on the inferior edge of the AIIS was significantly larger than that on the anterosuperior aspect of the acetabulum. Moreover, the capsular attachment on the inferior edge of the AIIS corresponded with the impression, which was identified by micro-CT. Histological analysis revealed that the hip joint capsule on the inferior edge of the AIIS attached to the acetabulum adjacent to the proximal margin of the labrum. In addition, the hip joint capsule attached to the inferior edge of the AIIS via the fibrocartilage.

CONCLUSIONS

The capsular attachment on the inferior edge of the AIIS was characterized by an osseous impression, large attachment width, and distributed fibrocartilage.

CLINICAL RELEVANCE

It appeared that the capsular attachment on the inferior edge of the AIIS was highly adaptive to mechanical stress, on the basis of its osseous impression, attachment width, and histological features. Anatomical knowledge of the capsular attachment on the inferior edge of the AIIS provides a better understanding of the pathological condition of hip joint instability.

What Are the Reference Values and Associated Factors for Center-edge Angle and Alpha Angle? A Population-based Study

BACKGROUND

The available evidence regarding normal ranges for the center-edge angle and the alpha angle derives from a few small studies, and associated factors such as sex and anthropometric factors have not been well evaluated. Knowing more about normal values for these parameters is critical, because this can inform decisions about when to perform elective hip preservation surgery. Population-level studies would provide considerable clarity on these issues, but to our knowledge, no such studies are available.

QUESTIONS/PURPOSES

The purposes of this study were (1) to use MRI in patients of a population-based study to establish normal values for the alpha and center-edge angles in the normal adult hip; and (2) to determine whether age, sex, or anthropometric variables were associated with differences in these values.

METHODS

We used MRI images (1.5 T) of 3226 participants of the Study of Health in Pomerania (SHIP). SHIP is a population-based study that started with 4308 participants in 1997. Participants were recruited randomly from official inhabitant data files as a stratified cluster sample of the population from a defined region in northeastern Germany. To ensure a representative epidemiologic cohort, stratification variables were sex, age, and city of residence. Between 2008 and 2012, 1094 of these participants underwent whole-body MRI with pelvic sequences in the second followup. In parallel, the next cohort, SHIP-Trend, started with the same protocol in which 2132 participants underwent MRI examination. Reference values were calculated by quantile regressions for the 2.5 and 97.5 percentiles. Associations with the demographic features sex, age, weight, height, body mass index (BMI), and waist circumference were analyzed by bivariate linear regression models.

RESULTS

The mean center-edge angle was 31° (± 7°) with a corresponding calculated normal range of 17° to 45°. The mean alpha angle was 55° (± 8°) with a corresponding calculated normal range between 39° and 71°. Men (30° ± 7°) had a lower center-edge angle than women (32° ± 8°) (p < 0.001, β = 1.4°; 95% confidence interval [CI], 0.9°-1.9°) and a higher alpha angle (57° ± 8° versus 52° ± 7°, p < 0.001, β = 5.7°; 95% CI, 5.2°-6.3°). Moreover, a higher center-edge angle for the left side was found (33° ± 8° versus 30° ± 8°, p < 0.001, β =3.2°; 95% CI, 3.0°-3.4°). In addition to sex, we found that age, height, waist circumference, and BMI affected both center-edge angle and alpha angle. Weight was associated with the alpha angle as well. Because of these associations, age- and sex-adjusted reference values with belonging formulas were calculated.

CONCLUSIONS

The range of normal center-edge and alpha angles is quite wide. Therefore, only markedly abnormal angles may be associated with pathology. Moreover, center-edge angle and alpha angle are associated with age, sex, and anthropometric factors, which have to be taken into account for better interpretation.

CLINICAL RELEVANCE

The association of abnormal radiographic values with true clinical hip pathology is tenuous at best. Assuming that a patient with an abnormal radiograph requires treatment is unwise. The clinical picture has to be substantial for therapeutic decisions.

The correlation between femoroacetabular impingement and superior retinacular artery interruption

The aim of this study was to investigate the relationship between femoroacetabular impingement (FAI) and superior retinacular artery interruption using plain radiographs and digital subtraction angiography (DSA).Sixty-one patients included in this study were divided into 2 groups based on the superior retinacular artery integrity as evaluated on DSA images. Group A included intact arteries: 33 patients (24 men, 9 women,); group B included interrupted arteries: 28 patients (21 men, 7 women). The parameters of abnormal radiographic findings thought to be associated with FAI, including positive crossover or figure-of-eight sign of acetabulum, lateral center edge angle (LCEA) >40°, Tönnis angle <0°, positive posterior wall sign, alpha angle >50°, and coxa profunda, were evaluated in all patients through plain radiographs.The cross-over sign (Group A: 0, Group B: 8, P = .0035), LCEA (Group A: 1, Group B: 7, P = .0190), Tönnis angle (Group A: 3, Group B: 13, P = .0026), and alpha angle (Group A: 7, Group B: 17, P = .0039) differed significantly between both groups. However, there were no statistically significant differences in posterior wall sign (Group A: 9, Group B: 12, P = .3143) or coxa profunda (Group A: 12, Group B: 8, P = .7096).Patients with interrupted blood supply of the superior retinacular arteries displayed more parameters of abnormal radiographic findings associated with FAI thereby indicating potential correlation between FAI and the interruption of superior retinacular arteries.

Does acetabular coverage influence the clinical outcome of arthroscopically treated cam-type femoroacetabular impingement (FAI)?

Aims

What represents clinically significant acetabular undercoverage in patients with symptomatic cam-type femoroacetabular impingement (FAI) remains controversial. The aim of this study was to examine the influence of the degree of acetabular coverage on the functional outcome of patients treated arthroscopically for cam-type FAI.

Patients and Methods

Between October 2005 and June 2016, 88 patients (97 hips) underwent arthroscopic cam resection and concomitant labral debridement and/or refixation. There were 57 male and 31 female patients with a mean age of 31.0 years (17.0 to 48.5) and a mean body mass index (BMI) of 25.4 kg/m² (18.9 to 34.9). We used the Hip2Norm, an object-oriented-platform program, to perform 3D analysis of hip joint morphology using 2D anteroposterior pelvic radiographs. The lateral centre-edge angle, anterior coverage, posterior coverage, total femoral coverage, and alpha angle were measured for each hip. The presence or absence of crossover sign, posterior wall sign, and the value of acetabular retroversion index were identified automatically by Hip2Norm. Patient-reported outcome scores were collected preoperatively and at final follow-up with the Hip Disability and Osteoarthritis Outcome Score (HOOS).

Results

At a mean follow-up of 2.7 years (1 to 8, sd 1.6), all functional outcome scores significantly improved overall. Radiographically, only preoperative anterior coverage had a negative correlation with the improvement of the HOOS symptom subscale (r = -0.28, p = 0.005). No significant difference in relative change in HOOS subscale scores was found according to the presence or absence of radiographic signs of retroversion.

Discussion

Our study demonstrated the anterior coverage as an important modifier influencing the functional outcome of arthroscopically treated cam-type FAI. Cite this article: Bone Joint J 2018;100-B:831-8.

Femoroacetabular impingement: a common cause of hip pain

Femoroacetabular impingement (FAI) is a common cause of hip pain that can affect a wide range of patients. It is due to altered bony morphology of the proximal femur and acetabulum, resulting in decreased function and progression to early osteoarthritis. Until the early 2000s, little was known or understood about the significance of FAI as a clinical entity. The field of hip preservation has grown exponentially since that time, and has led to many advances in caring for those with symptomatic impingement. This review details the early diagnosis and proper management of femoroacetabular impingement for the sports medicine practitioner.

Trunk, pelvis and hip biomechanics in individuals with femoroacetabular impingement syndrome: Strategies for step ascent

BACKGROUND

Femoroacetabular impingment (FAI) syndrome is common among young active adults and a proposed risk factor for the future development of hip osteoarthritis. Pain is dominant and drives clinical decision-making. Evidence for altered hip joint function in this patient population is inconsistent, making the identification of treatment targets challenging. A broader assessment, considering adjacent body segments (i.e. pelvis, trunk) and individual movement strategies, may better inform treatment programs. This exploratory study aimed to compare trunk, pelvis, and hip biomechanics during step ascent between individuals with and without FAI syndrome.

METHODS

Fifteen participants diagnosed with symptomatic cam-type or combined (cam plus pincer) FAI who were scheduled for arthroscopic surgery, and 11 age-, and sex-comparable pain- and disease-free individuals, underwent three-dimensional motion analysis during a step ascent task. Trunk, pelvis and hip biomechanics were compared between groups.

RESULTS

Participants with FAI syndrome exhibited altered ipsilateral trunk lean and pelvic rise towards the symptomatic side during single-leg support compared to controls. Alterations were not uniformly adopted across all individuals with FAI syndrome; those who exhibited more pronounced alterations to frontal plane pelvis control tended to report pain during the task. There were minimal between-group differences for hip biomechanics.

CONCLUSION

Exploratory data suggest biomechanics at the trunk and pelvis during step ascent differ between individuals with and without FAI syndrome. Those with FAI syndrome implement a range of proximal strategies for task completion, some of which may have relevance for rehabilitation. Longitudinal investigations of larger cohorts are required to evaluate hypothesized clinical and structural consequences.

Squatting Biomechanics in Individuals with Symptomatic Femoroacetabular Impingement

PURPOSE

Identification of the biomechanical alterations in individuals with symptomatic femoroacetabular impingement (FAI) is critical to understand the pathology and inform treatments. Yet hip function in this condition is poorly defined. Squatting requires large hip flexion range and involves motion toward the position of hip impingement; thus, it is likely to expose modified biomechanics in these individuals. This study aimed to determine whether hip and pelvis biomechanics differ between individuals with and without symptomatic FAI during an unconstrained deep squat and a constrained squat designed to limit compensation by the pelvis and trunk.

METHODS

Fifteen participants with symptomatic cam-type or combined (cam plus pincer) FAI who were scheduled for arthroscopic surgery and 14 age- and sex-matched controls without FAI underwent three-dimensional motion analysis during the two squatting tasks. Trunk, pelvis, and hip kinematics and hip kinetics were compared between groups.

RESULTS

There were no between-group differences in normalized squat depth for either task. Descent speed was slower for the FAI group during the unconstrained squat (P < 0.05). During the constrained squat, individuals with FAI demonstrated greater pelvic rise (P = 0.01) and hip adduction (P = 0.04) on the symptomatic side than controls. The hip external rotation moment was less in FAI patients during descent (P = 0.04), as was transverse plane hip angle variability (P = 0.04).

CONCLUSIONS

Individuals with symptomatic FAI can squat to a depth comparable with controls, regardless of task design. When the task is constrained, FAI patients demonstrate greater ipsilateral pelvic rise and maintain a more adducted hip position, which may coincide with a compensatory strategy to avoid end range flexion as the hip approaches impingement. These biomechanical alterations may put additional stress on adjacent regions and have relevance for rehabilitation.

The role of the ligamentum teres in the adult hip: redundant or relevant? A review

The ligamentum teres (LT) has traditionally been described as a redundant structure with no contribution to hip biomechanics or function. There has been renewed interest in the LT as a source of hip pathology due to the high prevalence of LT pathology observed at the time of hip arthroscopy. The LT acts a secondary stabilizer to supplement the work of the capsular ligaments and works in a sling-like manner to prevent subluxation of the hip at the extremes of motion. The presence of free nerve endings within the LT indicates a definite role in pain generation, with the LT undergoing various mechanical and histological adaptations to hip pathology.

Associations between body mass index across adult life and hip shapes at age 60 to 64: Evidence from the 1946 British birth cohort

OBJECTIVE

To examine the associations of body mass index (BMI) across adulthood with hip shapes at age 60-64years.

METHODS

Up to 1633 men and women from the MRC National Survey of Health and Development with repeat measures of BMI across adulthood and posterior-anterior dual-energy X-ray absorptiometry bone mineral density images of the proximal femur recorded at age 60-64 were included in analyses. Statistical shape modelling was applied to quantify independent variations in hip mode (HM), of which the first 6 were examined in relation to: i) BMI at each age of assessment; ii) BMI gain during different phases of adulthood; iii) age first overweight.

RESULTS

Higher BMI at all ages (i.e. 15 to 60-64) and greater gains in BMI were associated with higher HM2 scores in both sexes (with positive HM2 values representing a shorter femoral neck and a wider and flatter femoral head). Similarly, younger age first overweight was associated with higher HM2 scores but only in men once current BMI was accounted for. In men, higher BMI at all ages was also associated with lower HM4 scores (with negative HM4 values representing a flatter femoral head, a wider neck and smaller neck shaft angle) but no associations with BMI gain or prolonged exposure to high BMI were found. Less consistent evidence of associations was found between BMI and the other four HMs.

CONCLUSION

These results suggest that BMI across adulthood may be associated with specific variations in hip shapes in early old age.

Coordination of deep hip muscle activity is altered in symptomatic femoroacetabular impingement

Diagnosis of femoroacetabular impingement (FAI) is increasing, yet the associated physical impairments remain poorly defined. This morphological hip condition can cause joint pain, stiffness, impaired function, and eventually hip osteoarthritis. This exploratory study compared coordination of deep hip muscles between people with and without symptomatic FAI using analysis of muscle synergies (i.e., patterns of activity of groups of muscles activated in synchrony) during gait. Fifteen individuals (11 males) with symptomatic FAI (clinical examination and imaging) and 14 age- and sex-comparable controls without morphological FAI underwent testing. Intramuscular fine-wire and surface electrodes recorded electromyographic activity of selected deep and superficial hip muscles. A non-negative matrix factorization algorithm extracted three synergies which were compared between groups. Information regarding which muscles were activated together in the FAI group (FAI group synergy vector) was used to reconstruct individual electromyography patterns and compare groups. Variance accounted for (VAF) by three synergies was less for the control (94.8 [1.4]%) than FAI (96.0 [1.0]%) group (p = 0.03). VAF of obturator internus was significantly higher in the FAI group (p = 0.02). VAF of the reconstructed individual electromyography patterns with the FAI or control group vector were significantly higher for the FAI group (p < 0.01). Following reconstruction, VAF of quadratus femoris was significantly more reduced in controls (p = 0.04), indicating greater between-subject variability. Coordination of deep hip muscles in the synergy related to hip joint control during early swing differed between groups. This phase involves movement towards the impingement position, which has relevance for the interpretation of synergy differences and potential clinical importance. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1494-1504, 2017.

Management options for femoroacetabular impingement: a systematic review of symptom and structural outcomes

OBJECTIVE

The optimal therapy for femoroacetabular impingement (FAI) is unclear. The aim of this systematic review was to examine the evidence for surgical and non-surgical treatment of FAI on symptom and structural outcomes.

DESIGN

MEDLINE and EMBASE were searched electronically. Surgical and non-surgical management strategies were searched with "FAI". Studies which included comparison groups and reported symptom or structural outcomes were included (Levels I-III evidence). A risk of bias assessment was performed.

RESULTS

Eighteen studies comparing management strategies for FAI were identified. Most studies had high risk of bias. No study compared surgical and non-surgical treatment. When surgical approaches were compared there was evidence of superior symptom outcomes with arthroscopy compared to open surgery and with labral preservation. There was some evidence that surgical interventions are effective in reducing alpha angle (improved hip shape), but no data on whether this affects long-term outcomes. There was some weak evidence that surgery is associated with structural progression of hip osteoarthritis (OA).

CONCLUSIONS

Although evidence supports improvement in symptoms after surgery in FAI, no studies have compared surgical and non-surgical treatment. Therefore no conclusion regarding the relative efficacy of one approach over the other can be made. Surgery improves alpha angle but whether this alters the risk of development or progression of hip OA is unknown. This review highlights the lack of evidence for use of surgery in FAI. Given that hip geometry may be modified by non-surgical factors, clarifying the role of non-surgical approaches vs surgery for the management of FAI is warranted.

Etiology of Femoroacetabular Impingement in Athletes: A Review of Recent Findings

The relationship between hip deformities and osteoarthritis has recently received a lot of attention. In particular, it has been shown that both osteoarthritis and its precursors, such as the hip deformities that lead to femoroacetabular impingement (FAI), are more prevalent in elite athletes compared with the general population. However, the etiology of the above-mentioned types of hip deformity is not currently well understood. Many recent studies have attempted to shed light on the etiology of this disease. In this article, the main clinical, radiological, mechanobiological, and biomechanical findings of relevance to understanding the etiology of hip deformities leading to FAI are reviewed. Based on these findings, a consistent biomechanical theory explaining the development of hip deformities in athletes is then presented. According to the presented theory, the repetitive, impact-like musculoskeletal loads that athletes experience, particularly when they undertake extreme ranges of hip motion, cause the development of hip deformities. According to this theory, these musculoskeletal loads trigger abnormal growth patterns during the years of skeletal development and cause the formation of hip deformities. A number of hypotheses based on the proposed theory are then formulated that could be tested in future studies to ascertain whether the proposed theory could sufficiently describe the development of hip deformities in athletes.

Association between hip morphology and prevalence, clinical severity and progression of hip osteoarthritis over 3 years: The knee and hip osteoarthritis long-term assessment cohort results

OBJECTIVE

To assess the effects of variations in hip morphology on prevalence, clinical severity and progression of hip osteoarthritis.

METHODS

From 2007 to 2009, we conducted a study of 242 patients aged between 40 and 75 years with symptomatic lower limb osteoarthritis, as part of a population-based osteoarthritis cohort study in France. Standard radiographs of both hips were obtained at baseline and at three years. The progression of hip osteoarthritis was evaluated according to the radiological Kellgren-Lawrence score (KL) and clinical severity from the scores on a Visual Analogic Scale (VAS) for pain recorded yearly. Five measures were used to describe hip morphology: centre edge angle, acetabular index (AI), vertical centre anterior angle, acetabular depth and neck-shaft angle.

RESULTS

Of the 484 hips studied, 205 (42%) showed osteoarthritis at baseline and 16 (11 right and 5 left) underwent joint replacement during the follow-up. AI was the morphological measure most consistently and strongly associated with radiographic osteoarthritis at baseline (odds-ratio=1.05, 95% CI: 1.01-1.08 per degree of angle change), clinical severity (correlation coefficient with VAS during 3 years=0.15, P=0.004), radiological progression (odds-ratio=1.05, 95% CI: 1.00-1.10 per degree) and joint replacement (hazard ratio=1.18, 95% CI: 1.07-1.29 per degree).

CONCLUSIONS

Acetabular obliquity and especially AI is strongly, and likely causally, associated with the existence, severity and progression of hip osteoarthritis.

Hip joint biomechanics during gait in people with and without symptomatic femoroacetabular impingement

Femoroacetabular impingement (FAI) is a morphological hip condition that can cause hip/groin pain and impaired function in younger active adults, and may lead to stiffness, muscle weakness, structural damage, and hip osteoarthritis. Understanding the impairments associated with FAI is crucial to guide treatment and rehabilitation strategies. Evidence is limited and conflicting about whether hip biomechanics are impaired during walking in people with symptomatic FAI. The objective of this study was to determine whether kinematics and kinetics during gait differ between people with symptomatic FAI and control participants. Fifteen participants diagnosed with symptomatic cam-type or combined (cam plus pincer) FAI who were scheduled for arthroscopic surgery and 14 age-, and sex-matched disease-free controls underwent three-dimensional gait analysis. Tri-planar hip kinematics and kinetics were compared between the two groups. There were limited significant between-group differences with respect to spatiotemporal variables. Participants with FAI walked with less range of motion in the sagittal plane during a gait cycle, but did not exhibit any significant kinematic differences in the frontal or transverse planes. There were no systematic differences in kinetics between the groups in any plane. Findings suggest that individuals with symptomatic FAI have minimal impairments in gait biomechanics. Although these individuals demonstrate reduced hip joint motion in the sagittal plane, the size of the difference is small and its significance for symptoms and function is unclear. More pronounced deficits in hip kinetics and kinematics may be evident during functional tasks that challenge the hip towards the position of impingement.