The etiology of femoroacetabular impingement: what we know and what we don't

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.

Patients With Lateral and Anterolateral Cam Morphology Have Greater Deformities Versus Typical Anterolateral Deformity Alone but No Differences in Postoperative Outcomes: A Propensity-Matched Analysis at Minimum 5-Year Follow-Up

PURPOSE

To compare pre- and postoperative findings between patients undergoing hip arthroscopy for femoroacetabular impingement syndrome with lateral impingement versus those without lateral impingement METHODS: Patients who underwent primary hip arthroscopy for femoroacetabular impingement syndrome between 2012 and 2017 with minimum 5-year follow-up were included. Alpha angle (AA) was measured on preoperative anteroposterior (AP) and 90° Dunn radiographs. Patients with AA >60° on Dunn view but not AP view (no lateral impingement) were propensity matched by sex, age, and body mass index in a 1:3 ratio to patients with AA >60° on both views (lateral impingement). Demographic characteristics, radiographic and intraoperative findings, reoperation rates, and patient-reported outcomes (PROs) were compared between groups. Categorical variables were compared using the Fisher exact testing and continuous variable using 2-tailed Student t tests.

RESULTS

Sixty patients with lateral impingement (65.0% female, age: 35.3 ± 13.0 years) were matched to 180 patients without lateral impingement (65.0% female, age: 34.7 ± 12.5 years, P ≥ .279). Patients with lateral impingement had larger preoperative AAs on both Dunn (71.0° ± 8.8° vs 67.6° ± 6.1°, P = .001) and AP radiographs (79.0° ± 12.1° vs 48.2° ± 6.5°, P < .001). However, there were no differences in postoperative AAs on either view (Dunn: 39.0° ± 6.1° vs 40.5° ± 5.3°, AP: 45.8° ± 9.0° vs 44.9° ± 7.0°, P ≥ .074). Labral tears began more superiorly in patients with lateral impingement (12:00 ± 0:49 vs 12:17 ± 0:41, P = .030), and they demonstrated greater rates of acetabular and femoral cartilage damage (P = .030 for both); however, there were no differences in PROs or reoperation rates between the groups at 5-year follow-up.

CONCLUSIONS

Although cam deformities located laterally and anterolaterally are larger than those located anterolaterally alone, both can be resected adequately, resulting in similar postoperative radiographic measurements, PROs, and survivorship.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Femoroacetabular Impingement in Ice Hockey Athletes

ABSTRACT

Femoroacetabular impingement (FAI) in ice hockey is a concern for many athletes. The biomechanics of skating and the injury mechanism, prevalence, identification, and treatment protocols currently available for FAI in ice hockey athletes are important for all coaches and practitioners to understand. This article discusses the underlying anatomical issues and biomechanical considerations surrounding FAI. Furthermore, this article describes the interventions that can be used when encountering FAI and well-established protocols to aid in the return to play. Finally, prevention strategies that can aid in injury prevention are discussed.

The Majority of Sports Medicine and Arthroscopy-Related Randomized Controlled Trials Reporting Nonsignificant Results Are Statistically Fragile

PURPOSE

To evaluate the robustness of sports medicine and arthroscopy related randomized controlled trials (RCTs) reporting nonsignificant results by calculating the reverse fragility index (RFI) and reverse fragility quotient (RFQ).

METHODS

All sports medicine and arthroscopic-related RCTs from January 1, 2010, through August 3, 2021, were identified. Randomized-controlled trials comparing dichotomous variables with a reported P value ≥ .05 were included. Study characteristics, such as publication year and sample size, as well as loss to follow-up and number of outcome events were recorded. The RFI at a threshold of P < .05 and respective RFQ were calculated for each study. Coefficients of determination were calculated to determine the relationships between RFI and the number of outcome events, sample size, and number of patients lost to follow-up. The number of RCTs in which the loss to follow-up was greater than the RFI was determined.

RESULTS

Fifty-four studies and 4,638 patients were included in this analysis. The mean sample size and loss to follow-up were 85.9 patients and 12.5 patients, respectively. The mean RFI was 3.7, signifying that a change of 3.7 events in one arm was needed to flip the results of the study from non-significant to significant (P < .05). Of the 54 studies investigated, 33 (61%) had a loss to follow-up greater than their calculated RFI. The mean RFQ was 0.05. A significant correlation between RFI with sample size (R2 = 0.10, P = .02) and the total number of observed events (R2 = 0.13, P < .01) was found. No significant correlation existed between RFI and loss to follow-up in the lesser arm (R2 = 0.01, P = .41).

CONCLUSIONS

The RFI and RFQ are statistical tools that allow the fragility of studies reporting nonsignificant results to be appraised. Using this methodology, we found that the majority of sports medicine and arthroscopy-related RCTs reporting nonsignificant results are fragile.

CLINICAL RELEVANCE

RFI and RFQ serve as tools that can be used to assess the validity of RCT results and provide additional context for appropriate conclusions.

Why Is There a Range in Time Returning to Preoperative Activity Habits After Femoroacetabular Impingement Treatment in Recreational Athletes?

CONTEXT

Professional athletes showed excellent results after hip preserving procedures. However, there is still a lack of knowledge regarding the rate of return to activity and the rehabilitation time of recreational athletes. Thus, the aim of this study was to investigate factors that were associated with an extended return-to-activity time in nonprofessional athletes.

DESIGN

Retrospective, quantitative case-control study.

METHODS

This study included 47 cases (45 nonprofessional athletes), which were divided according to return-to-activity time (short term: 0.0-7.0 mo vs long term: >7.0 mo). The clinical outcome were evaluated with the modified Harris hip score, the nonarthritic hip score, the Western Ontario and McMaster Universities Osteoarthritis Index, and the University of California, Los Angeles activity score. For statistical analysis between both groups, an unpaired student t test and a paired Wilcoxon test were used. In addition, the sports behavior, intraoperative findings, and surgical procedures were also assessed.

RESULTS

After a mean follow-up of 4.3 years (±0.6; 3.4-5.6), the overall postoperative modified Harris hip score was 81.8 points, the nonarthritic hip score was 75.8 points, the Western Ontario and McMaster Universities Osteoarthritis Index was 36.7 points, and the University of California, Los Angeles activity score was 7.9. Compared with the preoperative results, all scores improved significantly (P < .001). Patients of the short-term return-to-activity group showed a higher preoperative activity diversity and, postoperatively, a higher rate in high-impact sports (P = .024).

CONCLUSIONS

After mini-open arthrotomy for femoroacetabular impingement syndrome treatment, 92.5% of the recreational athletes returned to sports activity. The findings did not detect factors influencing the return-to-activity time. However, a higher preoperative diversity of activities and a shift to high-level impact sport activities might support a shorter rehabilitation.

Conservative Physiotherapy Treatment of Femoroacetabular Impingement

The femoro-acetabular impingement (FAI) syndrome is a motion-related disorder of the hip joint with premature contact between the acetabulum and the proximal femur. It is a relatively new clinical entity and no strict treatment protocols and guidelines have been established yet. Furthermore, patients are often misdiagnosed and not properly treated. We report a clinical case of a young adult female patient presenting with a bilateral FAI-CAM type deformity during the last 2 years. An individual progressive global elastic resistant training program was established which involved stimulation to all affected muscle groups using Pilates concept. Hip-specific and functional lower limb strengthening targeted the deep hip external rotators, abductors and flexors in the transverse, frontal, and sagittal planes. Improving the dynamic stability and Core stability was the main aim of the challenging physiotherapy treatment in this case. A good functional result was registered at 6 months follow up. All therapeutic activities were performed in a pain free range of motion which was of paramount importance for achieving excellent patient compliance and successful outcome respectively. The applied treatment strategy demonstrated to be reliable and could be a helpful tool in the armamentarium of contemporary physiotherapy when dealing with the FAI group of patients.

Slipped Capital Femoral Epiphysis Managed by Ganz Safe Surgical Dislocation of Hip: A Case Report with 2 Years Follow-up

Introduction

Slipped capital femoral epiphysis (SCFE) is commonly managed by in situ screw fixation. However, higher grades of slips require restoration of normal anatomy of the femoral head without compromising the blood supply.

Case Report

A 16-year-old adolescent male presented with the left hip pain and progressive limping for 4 days with no history of previous trauma. On examination, the patient had severe tenderness and gross restriction of movements. Radiological examination revealed Grade 2 acute on chronic SCFE with unstable slip. Modified Dunn procedure through Ganz surgical hip dislocation facilitated the complete restoration of normal anatomy without avascular necrosis of femoral head changes at 2 years of follow-up.

Conclusion

Ganz safe surgical dislocation of the hip is safe for the femoral head, preserving its blood supply in toto and the modified Dunn procedure facilitated the complete restoration of normal anatomy even in acute on chronic type of SCFE cases.

Prevalence of femoroacetabular impingement in elite baseball players

CAM-type femoroacetabular impingement continues to be an underrecognized cause of hip pain in elite athletes. Properties inherent to baseball such as throwing mechanics and hitting may enhance the risk of developing a cam deformity. Our goal is to gain an appreciation of the radiographic prevalence of cam deformities in elite baseball players. Prospective evaluation and radiographs of 80 elite baseball players were obtained during the 2016 preseason entrance examination. A sports medicine fellowship-trained orthopedic surgeon with experience treating hip disorders used standard radiographic measurements to assess for the radiographic presence of cam impingement. Radiographs with an alpha angle &gt;55° on modified Dunn views were defined as cam positive. Of the 122 elite baseball players included in our analysis, 80 completed radiographic evaluation. Only 7.3% (9/122) of players reported hip pain and 1.6% (4/244) had a positive anterior impingement test. The prevalence of cam deformities in right and left hips were 54/80 (67.5%) and 40/80 (50.0%), respectively. The mean alpha angle for cam-positive right and left hips were 64.7 ± 6.9° and 64.9 ± 5.8°, respectively. Outfielders had the highest risk of right-sided cam morphology (Relative Risk (RR) = 1.6). Right hip cam deformities were significantly higher in right-handed pitchers compared with left-handed pitchers (P = 0.02); however, there was no significant difference in left hip cam deformities between left- and right-handed pitchers (P = 0.307). Our data suggest that elite baseball players have a significantly higher prevalence of radiographic cam impingement than the general population.

Controversial Issues in Arthroscopic Surgery for Femoroacetabular Impingement

Femoroacetabular impingement (FAI) is a common cause of painful hip in the young and middle-aged population. This condition frequently leads to a labral tear, damage of acetabular cartilage, and secondary arthritis of the hip. When nonsurgical managements are not effective, surgical procedures (open surgery and hip arthroscopy) are indicated. Due to its less invasiveness, hip arthroscopy has replaced open surgery during the last two decades. The effectiveness of arthroscopic surgery in pain relief for FAI syndrome has been well established. The procedure is also expected to slow or prevent further progression to hip arthritis. In this review, we provide the updated knowledge of arthroscopic procedures for the management of FAI syndrome.

Preoperative Intra-articular Steroid Injections as Predictors of Hip Arthroscopy: 2-Year Outcomes

BACKGROUND

In patients with femoroacetabular impingement, preoperative diagnostic injections are commonly used to establish a diagnosis of intra-articular pathology. In some cases, intra-articular steroid injections are also used for therapeutic purposes.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine if a positive response to intra-articular steroid injection was predictive of superior outcomes after hip arthroscopy to determine if the response to intra-articular steroid injection was predictive of outcomes after hip arthroscopy. It was hypothesized that a positive response to a preoperative hip injection would be predictive of improved short- to midterm outcomes after hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This was a retrospective study of 208 patients who elected to have ultrasound-guided intra-articular steroid injection before they underwent hip arthroscopy between January 2016 and December 2016. Patients were divided into 2 groups: those who showed improvement in pain after the injection (steroid responder group) and those who showed no response (nonresponder group). The authors compared the preoperative and 2-year postoperative patient-reported outcomes (modified Harris Hip Score [mHHS] and Hip Outcome Score-Activities of Daily Living [HOS-ADL]) and radiographic findings between groups. Clinical endpoints, including rates of revision and conversion to total hip arthroplasty, were also reviewed.

RESULTS

There were 88 patients in the nonresponder group and 120 patients in the responder group, with no significant between-group differences in preoperative descriptive variables. The responder group had significantly higher 2-year mHHS and HOS-ADL, pre- to postoperative change in mHHS and HOS-ADL, percentage of patients achieving the patient acceptable symptomatic state (PASS) on the mHHS, and percentage of patients reaching the minimum clinically important difference and the PASS on the HOS-ADL. There was no difference in Tönnis grade, acetabular labrum articular disruption grade, revision rate, or conversion to total hip arthroplasty between the 2 groups.

CONCLUSION

The response to preoperative intra-articular injection did aid in predicting 2-year patient-reported outcomes of hip arthroscopy for femoroacetabular impingement. Overall, the result of a preoperative intra-articular injection can be a helpful clinical tool for surgical decision-making and counseling patients on expected outcomes after hip arthroscopy.

3D MRI of the Hip Joint: Technical Considerations, Advantages, Applications, and Current Perspectives

Magnetic resonance imaging (MRI) is a common choice among various imaging modalities for the evaluation of hip conditions. Conventional MRI with two-dimensional acquisitions requires a significant amount of time and is limited by partial-volume artifacts and suboptimal fluid-to-cartilage contrast. Recent hardware and software advances have resulted in development of novel isotropic three-dimensional (3D) single-acquisition protocols that cover the volume of the entire hip and can be reconstructed in arbitrary planes for submillimeter assessment of bony and labro-cartilaginous structures in their planes of orientation. This technique facilitates superior identification of small labral tears and other hip lesions with better correlations with arthroscopy. In this review, we discuss technical details related to 3D MRI of the hip, its advantages, and its role in commonly encountered painful conditions that can be evaluated with great precision using this technology. The entities described are femoroacetabular impingement with acetabular labral tears, acetabular dysplasia, avascular necrosis, regional tendinopathies and tendon tears, bursitis, and other conditions.

Pediatric and Adolescent Figure Skating Injuries: A 15-Year Retrospective Review

OBJECTIVE

To analyze the characteristics of injuries sustained by young figure skaters who were evaluated at regional pediatric sports medicine clinics.

DESIGN

Retrospective chart review (2003-2017).

SETTING

Sports medicine clinics at a tertiary-level pediatric medical center.

PATIENTS

Two hundred ninety-four figure skaters (271 female and 23 male). Age rage: 9 to 19 years. Mean age: 14.2 ± 2.3 years.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Mechanism of injury (acute vs overuse), injured body areas, diagnoses for most commonly injured body areas, and distribution of bone stress injuries.

RESULTS

Eight hundred sixty-four figure skating-related injuries were identified. Approximately 68.9% were overuse and 31.1% were acute. In female figure skaters, the most frequently injured body areas were foot/ankle (29.6%), knee (19.3%), and back (15.8%). In male figure skaters, they were foot/ankle (25.4%), hip (16.4%), and knee (14.9%). Most common diagnoses at these body areas were tendinopathy (foot/ankle), extensor mechanism (knee), and posterior column bone stress injuries (back). All injuries to anterior knee structures, excluding bone contusions, were categorized as extensor mechanism injuries. About 11.8% of all injuries were bone stress reactions/fractures with the majority occurring at the back (42.2%), foot/ankle (32.4%), and lower leg (15.7%).

CONCLUSION

Most injuries sustained by figure skaters were overuse and occurred most commonly at the foot/ankle (29.6%), knee (19.3%), and back (15.8%). Approximately 1 in 10 injuries were bone stress reactions/fractures, and nearly 1 in every 3 skaters who presented with back pain was diagnosed with a posterior column bone stress injury. Health care providers who take care of young figure skaters need to maintain a high index of suspicion for overuse injuries, especially bone stress reactions/fractures.

Characteristics of hip impingement syndrome in patients with multiple hereditary exostoses

BACKGROUNDS

This study aimed to investigate the characteristic deformities of the hip in multiple hereditary exostoses patients (MHE) and its association with the hip impingement syndrome.

MATERIALS AND METHODS

Between 2001 and 2019, total 51 patients (102 hips) were evaluated in this study. Patients with MHE were classified to femoro-acetabular impingement (FAI) symptom group, ischio-femoral impingement (IFI) symptom group and non-impingement symptom group by comparing the symptoms, clinical signs and imaging studies. To assess the morphometry of the hip in patients with MHE, the femoral neck-shaft angle, Sharp's acetabular angle and center-edge (CE) angle were evaluated. Alpha angle was further evaluated to investigate the FAI using radiographs, and the minimum ischio-femoral distance was further measured to investigate the IFI using computed-tomographic (CT) study.

RESULTS

On hip impingement symptom analysis, FAI symptom and IFI symptom were confirmed in 14 hip joints and 18 hip joints, respectively. Unlike general population, the number of the hip with IFI-symptom was higher than those with FAI symptom in this study. In morphometric evaluation of MHE hips, coxa valga was most prominent deformity with occasional tendency of mild acetabular dysplasia. In a comparison of morphometric study between the impingement symptom group and non-symptom group, the FAI symptom showed significant differences of morphometric measure values than those of the non-symptom group (FAI symptom group vs. Non-FAI symptom group; Femoral neck-shaft angle (153.9 vs 142.6), Sharp's angle (45.0 vs 41.5), CE angle (21.1 vs 28.8) and alpha angle (76.7 vs 57.9)). Similarly, the IFI symptom group also showed significant differences of morphometric measure values than those of the non-symptom group (IFI-symptom vs. Non-IFI symptom; Femoral neck-shaft angle (150.9 vs 142.7), Sharp's angle (44.7 vs 41.4), CE angle (21.1 vs 29.3) and alpha angle (73.3 vs 56.8)). In addition, the minimum ischio-femoral distance measured using CT was significantly decreased in the IFI symptom group (IFI symptom group: 6.6, Non-IFI symptom group: 16.4).

CONCLUSION

The results suggest that the characteristic deformities represented by coxa valga in the MHE hip act as an offset for FAI symptoms, on the contrary, act as a trigger for IFI symptoms.

LEVEL OF EVIDENCE

Level III.

Morphological Changes of the Hip Commonly Associated With Femoroacetabular Impingement Are Not Correlated With Rotational Range of Hip Motion in Elite Soccer Athletes

BACKGROUND

Morphological changes characteristic of femoroacetabular impingement (FAI) are common in soccer players. However, the clinical relevance of such anatomical variations is still not well-defined.

HYPOTHESIS

We hypothesized that high alpha angle values and/or acetabular retroversion index (ARI) are correlated with rotational range of motion (ROM) of the hip and that there are clinical-radiological diferences between the dominant lower limb (DLL) and nondominant lower limb (NDLL) in professional soccer players.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 59 male professional soccer players (average age 25.5 years, range 18-38 years) were evaluated in the preseason. As main outcome measures, we evaluated the alpha angle and the ARI and hip IR and ER ROM with radiographic analysis.

RESULTS

The measurements taken on DLL and NDLL were compared and a significant difference was found between the sides in the ER (P = 0.027), where the DLL measures were 1.54° (95% CI, 0.18-2.89) greater than the NDLL. There were no significant differences between the sides in the measures of IR (P > 0.99), total ROM (P = 0.07), alpha angle (P = 0.250), and ARI (P = 0.079). The correlations between the rotation measurements and the alpha angle in each limb were evaluated and the coefficient values showed no correlation; so also between the ARI and rotation measures.

CONCLUSION

Morphological changes of the femur or acetabulum are not correlated with hip IR and ER ROM in male professional soccer players. ER on the dominant side was greater than on the nondominant side. There was no significant difference in the other measurements between sides.

CLINICAL RELEVANCE

In clinical practice, it is common to attribute loss of hip rotational movement to the presence of FAI. This study shows that anatomical FAI may not have a very strong influence on available hip rotational movement in professional soccer athletes.

The Prevalence of Cam Morphology: A Cross-Sectional Evaluation of 3,558 Cadaveric Femora

Purpose: We sought to determine (1) the prevalence of cam deformity in the population and that of bilateral cam deformity, (2) the typical location of a cam lesion, and (3) the typical size of a cam lesion by direct visualization in cadaveric femora. Methods: Two observers inspected 3,558 human cadaveric femora from the Hamann-Todd Osteological Collection from the Cleveland Museum of Natural History. Any asphericity >2 mm from the anterior femoral neck line was classified as a cam lesion. Once lesions had been inspected, the prevalence in the population, prevalence by gender, and prevalence of bilateral deformity were determined. Additionally, each lesion was measured and localized to a specific quadrant on the femoral neck based upon location of maximal deformity. Results: Cam lesions were noted in 33% of males and 20% of females. Eighty percent of patients with a cam lesion had bilateral lesions. When stratified by location of maximal deformity, 90.9% of lesions were in the anterosuperior quadrant and 9.1% were in the anteroinferior quadrants. The average lesion measured 17 mm long × 24 mm wide × 6 mm thick in men and 14 mm × 22 mm × 4 mm in women (p < 0.05). Conclusions: The population prevalence of cam deformity determined by direct visualization in cadavers may be higher than has been suggested in studies utilizing imaging modalities. Level of Evidence : Level II, diagnostic study.

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.

The dimensions of the hip capsule can be measured using magnetic resonance imaging and may have a role in arthroscopic planning

PURPOSE

The purpose of this study was to systematically evaluate the dimensions and thickness of the hip joint capsule. Secondarily, the study assessed whether there were any described correlations between capsule thickness and stability of the hip joint.

METHODS

Four databases (PubMed, Ovid [MEDLINE], Cochrane Database, and EMBASE) were searched from database inception to May 2018, and two reviewers independently and in duplicate screened the resulting literature. Methodological quality of all included papers was assessed using the Methodological index for non-randomized studies (MINORS) criteria. Mean differences were combined in a meta-analysis using a random effects model when possible.

RESULTS

A total of 14 studies (1 level I, 1 level II, 4 level III, 5 level IV) were identified including 796 patients (1013 hips) with a mean age of 39.5 years (range 2-95). Of the included patients, 55.2% were female and they were followed up for a mean of 7.6 months (range 1-12.5 months). The thickness of the capsule was measured in cadaveric specimens, ultrasound, and magnetic resonance imaging (MRI), with MRI measurements reported most consistently and with the least variation. Mean thickness of the anterior capsule in patients without hip disease on MRI ranged from 4.4 and 4.7 mm. Mean thickness of the anterior capsule in patients with FAI ranged between 4.9 and 5.0 mm. Males had significantly thicker capsules than females (mean difference = 1.92 mm, 0.35-3.49, P = 0.02). Clinical laxity of the hip joint, as well as female gender was correlated with thinner anterior joint capsules.

CONCLUSION

The thickness of the anterior hip capsule can be measured consistently using MRI. A thinner anterior capsule may be associated with clinical laxity of the hip joint. The relevance of capsular thickness on postoperative instability following hip arthroscopy is poorly understood and warrants further investigation. The thickness of the anterior hip capsule, as measured on MRI, has the potential to be used as part of the clinical decision-making in capsular management strategies.

LEVEL OF EVIDENCE

IV.

Hip-related groin pain, patient characteristics and patient-reported outcomes in patients referred to tertiary care due to longstanding hip and groin pain: a cross-sectional study

BACKGROUND

Due to advances in hip arthroscopy, the number of surgical procedures has increased dramatically. The diagnostic challenge in patients with longstanding hip and groin pain, as well as the increasing number of hip arthroscopies, may lead to a higher number of patients referred to tertiary care for consideration for surgery. Therefore, the aims were: 1) to describe the prevalence of hip-related groin pain in patients referred to tertiary care due to longstanding hip and groin pain; and 2) to compare patient characteristics and patient-reported outcomes for patients categorized as having hip-related groin pain and those with non-hip-related groin pain.

METHODS

Eighty-one patients referred to the Department of Orthopedics at Skåne University Hospital for longstanding hip and groin pain were consecutively included and categorized into hip-related groin pain or non-hip-related groin pain using diagnostic criteria based on current best evidence (clinical examination, radiological examination and intra-articular block injection). Patient characteristics (gender (%), age (years), BMI (kg/m²)), results from the Hip Sports Activity Scale (HSAS), the SF-36, the Copenhagen Hip and Groin Outcome Score (HAGOS), and pain distribution (pain manikin) were collected. Parametric and non-parametric statistics were used as appropriate for between-group analysis.

RESULTS

Thirty-three (47%) patients, (30% women, 70% men, p < 0.01), were categorized as having hip-related groin pain. The hip-related groin pain group had a higher activity level during adolescence (p = 0.013), and a higher pre-injury activity level (p = 0.034), compared to the non-hip-related groin pain group. No differences (mean difference (95% CI)) between hip-related groin pain and non-hip-related groin pain were observed for age (0 (- 4; 4)), BMI (- 1.75 (- 3.61; 0.12)), any HAGOS subscales (p ≥ 0.318), any SF-36 subscales (p ≥ 0.142) or pain distribution (p ≥ 0.201).

CONCLUSIONS

Only half of the patients referred to tertiary care for long-standing hip and groin pain, who were predominantly men with a high activity level, had hip-related groin pain. Self-reported pain localization and distribution did not differ between patients with hip-related groin pain and those with non-hip-related groin pain, and both patient groups had poor perceived general health, and hip-related symptoms and function.

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.

Prevalence of femoroacetabular impingement and effect of training frequency on aetiology in paediatric football players

PURPOSE:

The aim of this study was to determine the prevalence of asymptomatic radiographic findings of femoroacetabular impingement (FAI) in paediatric football players in different age groups and to investigate aetiological factors.

METHODS:

Paediatric male athletes between 10 and 17 years of age from 8 soccer teams were recruited. In addition to an annual control check-up, anteroposterior pelvis and frog-leg radiographs as well as the curriculum vitae of the athletes, their injuries, and real-time complaints were recorded. The alpha angle, lateral centre-edge angle, Tönnis angle, and collodiaphyseal angle were measured and morphological abnormalities were noted.

RESULTS:

There were 214 male football players with a mean age of 13.4 ± 3.2 years included in the study. In the morphological analysis of hips, there was FAI in 30% of the athletes. In the analysis of FAI prevalence in 3 subgroups based on age (Group 1: 10-12 years [ n = 25], Group 2: 13-15 years [ n = 104], Group 3: 16-17 years [ n = 85]), there was 0% FAI in Group 1, 19.1% in Group 2 and 60% in Group 3. In the analysis of aetiological factors, there was no significant difference between the right and left hips of players regarding alpha angles and FAI prevalence. However, the prevalence of FAI was higher in players who had been playing football for 3 years or more and who had been training for 12.5 hours/week or more.

CONCLUSION:

Training for 12.5 hours or more per week in paediatric football players doubled the risk development of FAI morphology.

Femoroacetabular Impingement in Pediatric Patients

Subacute, nontraumatic hip pain is often a diagnostic challenge. Femoroacetabular impingement (FAI) is a common cause of atraumatic hip pain that is poorly understood. FAI is a result of abnormal morphologic changes in either the femoral head or the acetabulum. FAI is more prevalent in people who perform activities requiring repetitive hip flexion, but it remains common in the general population. Evaluation begins with physical examination maneuvers to rule out additional hip pathology and provocation tests to reproduce hip pain. Diagnosis is often made by radiography or magnetic resonance imaging. Initial treatment is generally more conservative, featuring activity modification and physical therapy, whereas more aggressive treatment requires operative management.

Arthroscopic excision of heterotopic ossification in the rectus femoris muscle causing extra-articular anterior hip impingement

Subspine impingement is an extra-articular hip impingement syndrome that usually occurs when there is abnormal contact between an enlarged or malorientated anterior inferior iliac spine (AIIS) and the distal anterior femoral neck in straight flexion of the hip. We present the case of a 13-year-old boy with a history of left groin pain and loss of range of movement of the hip for over six months following an avulsion fracture of the AIIS during a game of rugby. He was diagnosed with subspine impingement secondary to a large lesion of heterotopic ossification in the rectus femoris; this was dissected and extracted from the muscle in toto arthroscopically. This case highlights the importance of heterotopic ossification after injury as an important cause for subspine impingement in the young adult hip. This is the first report and describes subspine impingement secondary to a large lesion of heterotopic ossification.

High Rate of Return to High-Intensity Interval Training After Arthroscopic Management of Femoroacetabular Impingement Syndrome

BACKGROUND

Since the inception of CrossFit in 2000, the popularity of high-intensity interval training (HIIT) in the United States has risen dramatically. While HIIT is a highly efficient exercise for weight loss and improved conditioning, some literature reports injuries in up to 34% of HIIT participants. We sought to evaluate the functional and sports-specific results of hip arthroscopic surgery in recreational HIIT participants.

PURPOSE

To evaluate patients' ability to return to HIIT after hip arthroscopic surgery for femoroacetabular impingement syndrome (FAIS).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Consecutive patients with FAIS who had identified themselves as participating in HIIT and had undergone hip arthroscopic surgery for the treatment of FAIS by a single fellowship-trained surgeon between 2012 and 2015 were reviewed. Demographic data; preoperative physical examination findings; preoperative imaging results; preoperative patient-reported outcome (PRO) scores including the modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports-Specific Subscale (HOS-SSS), and visual analog scale (VAS) for pain; and postoperative examination and PRO scores at a minimum 2 years after surgery, including a HIIT-specific questionnaire, were assessed for all patients.

RESULTS

Thirty-two patients (13 male, 19 female) with a mean age of 34.7 ± 6.9 years (range, 21-49 years) were identified with a minimum 24-month follow-up. Among these, 22 participated in CrossFit, 4 in Shred415, 3 in Orangetheory, and 3 in self-directed cross-training including plyometrics. Preoperatively, 14 patients had discontinued HIIT because of activity-related hip complaints, 17 patients had scaled back involvement in HIIT, and 1 patient maintained her baseline routine. Postoperatively, 28 of 32 patients (88%) returned to HIIT at a mean of 9.8 ± 5.7 months after surgery (range, 3-24 months); 96% returned to HIIT at the same level as or better than before the injury. Fear of reinjury was the most common reason for cessation (3/4). Preinjury and postoperative involvement in HIIT were comparable (5.3 vs 5.1 h/wk, respectively; P = .8). All patients had significant improvements in the HOS-ADL score (69.7 ± 17.3 to 94.2 ± 8.4; P < .001), HOS-SSS score (49.2 ± 21.2 to 83.3 ± 21.4; P < .001), mHHS score (59.9 ± 14.2 to 85.4 ± 11.6; P < .001), and VAS for pain score (7.5 ± 1.8 to 1.1 ± 1.3; P < .001) from preoperatively to postoperatively.

CONCLUSION

Arthroscopic treatment of FAIS in recreational HIIT participants resulted in significant improvements in hip function and predictably high rates of patient satisfaction. Postoperatively, 88% of patients returned to HIIT, 44% noted improvement from preinjury HIIT performance, and the mean weekly participation was comparable with before the injury.

Characterization and Correction of Symptomatic Hip Impingement in American Football Linemen

BACKGROUND

Femoroacetabular impingement (FAI) morphology can lead to range-of-motion deficits in football players. It is therefore important for physicians treating these players to be aware of the location and implications of FAI morphology.

PURPOSE/QUESTIONS

We sought to characterize the radiographic deformity and dynamic impingement observed in a consecutive series of American football linemen with symptomatic, mechanical hip pain who underwent surgical treatment for FAI and to use software analysis to identify the location of impingement and terminal range of motion and the effects of simulated correction.

METHODS

A retrospective analysis was conducted of 17 hips in 13 football linemen who underwent arthroscopic correction for symptomatic FAI. Computed tomography (CT) scans were used to generate preoperative three-dimensional models of the hips. Femoral and acetabular measurements, maximum hip flexion, abduction, internal rotation at 90° flexion (IR90), and flexion/adduction/internal rotation (FADIR) were determined, and areas of bony collision were defined. Simulated femoral correction was performed and motion analysis was repeated.

RESULTS

Mean femoral version was 13.1° (range, 0 to 26°), while mean femoral neck-shaft angle was 132.1° (range, 123 to 145°). Mean maximum alpha angle on the radial reformatted CT was 69.2° (range, 48 to 95°) and was located at the 12:45 clock-face position (range, 11:30 to 2:15). Mean acetabular version values at 1:30 and 3:00 were 1.1° (range, - 11 to 11°) and 12.7° (range, 2 to 20°), respectively. Fifty-three percent of hips showed a "crossover" sign. Mean lateral center-edge angle was 31.7° (range, 25 to 44°). CT-derived motion analysis demonstrated a mean preoperative flexion of 108.2° (range, 73 to 127°), IR90 of 20.5° (range, 0 to 52°), and FADIR of 12.3° (range, 0 to 39°). Simulated correction resulted in significant improvements in flexion (6.6°), IR90 (11.3°), and FADIR (10.6°).

CONCLUSIONS

While cephalad retroversion was observed in approximately half of the hips, a significant cam deformity was seen maximally at 12:45, a more posterior cam location than that of the general population. Managing this pathology required obtaining preoperative and intraoperative images to characterize lesions and allow for their complete correction. With complete correction of the deformity, simulated range of motion demonstrated significant improvement in flexion, IR90, and FADIR maneuvers.

Hip arthroscopy for femoroacetabular impingement

The purpose of this article is to give a general overview of femoroacetabular impingement (FAI) and how it could be treated arthroscopically, with some details about indications, the procedure itself and some of the complications associated with the surgery.

FAI is a dynamic condition of the hip that can be a source of pain and disability and could potentially lead to arthritis.

When symptomatic, and if conservative treatment fails, FAI can be addressed surgically.

The goal of surgical treatment for FAI is to recreate the spherical contour of the femoral head, improve femoral offset, normalize coverage of the acetabulum, repair/reconstruct chondral damage and repair/reconstruct the labrum to restore normal mechanics and joint sealing.

Advances in equipment and technique have contributed to an increase in the number of hip arthroscopy procedures performed worldwide and have made it one of the more common treatment options for symptomatic FAI.

Hip arthroscopy is a procedure with an extremely steep and long learning curve.

Cite this article: EFORT Open Rev 2018;3:121-129. DOI: 10.1302/2058-5241.3.170041

Cam Deformities and Limited Hip Range of Motion Are Associated With Early Osteoarthritic Changes in Adolescent Athletes: A Prospective Matched Cohort Study

BACKGROUND

The natural history of femoroacetabular impingement (FAI) remains incompletely understood. In particular, there is limited documentation of joint damage in adolescent patients with limited range of motion (LROM) of the hip, which is commonly associated with FAI.

PURPOSE

To evaluate changes in magnetic resonance imaging (MRI), radiographs, and clinical examinations over 5 years in a group of athletes from a wide variety of sports with asymptomatic LROM of the hip compared with matched controls.

STUDY DESIGN

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

METHODS

The authors screened 226 male and female athletes aged 12 to 18 years presenting for preparticipation sports physical examinations. Using a goniometer, we identified 13 participants with at least one hip having internal rotation <10° with the hip flexed to 90°. Overall, 21 of 26 hips (81%) had internal rotation <10°. These participants were age- and sex-matched to 13 controls with internal rotation >10°. At the time of enrollment, all participants were asymptomatic and underwent a complete hip examination and radiographic imaging with radiographs (anteroposterior [AP] and von Rosen views) and non-arthrogram MRI. Participants returned at 5-year follow-up and underwent repeat hip examinations, imaging (AP and lateral radiographs and non-arthrogram MRI), and hip function questionnaires. MRI scans were classified as "normal" versus "abnormal" based on the presence of any of 13 scored chondral, labral, or osseous abnormalities. Comparisons between the LROM group and control group were performed using generalized linear models (either linear, logistic, or log-binomial regression as appropriate for the outcome) with generalized estimating equations to account for the within-participant correlation due to patients having both hips included. Relative risk (RR) estimates are reported with 95% CIs.

RESULTS

At the time of study enrollment, 16 of 26 hips (62%) in the LROM group had abnormal MRI findings within the acetabular labrum or cartilage compared with 8 of 26 hips (31%) in the control group (RR, 2.0; 95% CI, 0.95-4.2; P = .067). The mean alpha angle measured from radial MRI sequences was 58° in the LROM group versus 44° in the control group ( P < .0001). In the LROM group, 13 of 26 hips (50%) had a positive anterior impingement sign, whereas 0 of 26 hips (0%) had a positive anterior impingement sign in the control group. At 5-year follow-up, 18 of 19 hips (95%) in the LROM group had abnormal MRI findings compared with 14 of 26 hips (54%) in the control group (RR, 1.7; 95% CI, 1.1-2.7; P = .014). New or progressive findings were documented on MRI in 15 of 20 hips in the LROM group compared with 8 of 26 hips in the control group (RR, 2.4; 95% CI, 1.2-4.8; P = .011). Six of 22 hips (27%) in the LROM group progressed from Tönnis grade 0 to Tönnis grade 1 in degenerative changes, whereas all 26 hips in the control group remained at Tönnis grade 0 on hip radiographs. In the LROM group, 11 of 22 hips (50%) had a positive anterior impingement sign, whereas 1 of 26 hips (4%) had a positive anterior impingement sign in the control group. A cam deformity (alpha angle >55° on lateral radiographs) was present in 20 of 22 hips (91%) in the LROM group and 12 of 26 hips (46%) in the control group ( P = .0165). The following variables at baseline were associated with an increased risk of degenerative changes at 5-year follow-up for the entire cohort: decreased hip internal rotation, positive anterior impingement sign, decreased hip flexion, increased alpha angle, and presence of a cam lesion.

CONCLUSION

At 5 years, young athletes with LROM of the hip showed increased progressive degenerative changes on MRI and radiographs compared with matched controls. Although the majority of these participants remained asymptomatic, those with features of FAI had radiographic findings consistent with early osteoarthritis. These outcomes suggest that more aggressive screening and counseling of young active patients may be helpful to prevent hip osteoarthritis in those with FAI.

The Fragility of Statistically Significant Findings From Randomized Trials in Sports Surgery: A Systematic Survey

BACKGROUND

High-quality, evidence-based orthopaedic care relies on the generation and translation of robust research evidence. The Fragility Index is a novel method for evaluating the robustness of statistically significant findings from randomized controlled trials (RCTs). It is defined as the minimum number of patients in 1 arm of a trial that would have to change status from a nonevent to an event to alter the results of the trial from statistically significant to nonsignificant.

PURPOSE

To calculate the Fragility Index of statistically significant results from clinical trials in sports medicine and arthroscopic surgery to characterize the robustness of the RCTs in these fields.

METHODS

A search was conducted in Medline, EMBASE, and PubMed for RCTs related to sports medicine and arthroscopic surgery from January 1, 2005, to October 30, 2015. Two reviewers independently assessed titles and abstracts for study eligibility, performed data extraction, and assessed risk of bias. The Fragility Index was calculated using the Fisher exact test for all statistically significant dichotomous outcomes from parallel-group RCTs. Bivariate correlation was performed to evaluate associations between the Fragility Index and trial characteristics.

RESULTS

A total of 48 RCTs were included. The median sample size was 64 (interquartile range [IQR], 48.5-89.5), and the median total number of outcome events was 19 (IQR, 10-27). The median Fragility Index was 2 (IQR, 1-2.8), meaning that changing 2 patients from a nonevent to an event in the treatment arm changed the result to a statistically nonsignificant result, or P ≥ .05.

CONCLUSION

Most statistically significant RCTs in sports medicine and arthroscopic surgery are not robust because their statistical significance can be reversed by changing the outcome status on only a few patients in 1 treatment group. Future work is required to determine whether routine reporting of the Fragility Index enhances clinicians' ability to detect trial results that should be viewed cautiously.

Femoroacetabular Impingement Syndrome: A Cause of Hip Pain in Adolescents and Young Adults

The primary objective of this review is further education of the general practitioner, or family medicine physician, on an important, but often missed, cause of hip pain in the adolescent and young adult population, femoroacetabular impingement (FAI) syndrome. We hope that further understanding of the etiology, examination, diagnosis, and treatment of FAI, will lead to more accurate diagnosis and timely referral to the Orthopedic hip specialist for definitive treatment and management. Thus, preventing the complications, or late sequelae, associated with the condition.

Hip Imaging in Athletes: Sports Imaging Series

Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016.

Medial synovial fold cyst in the hip leading to pectineofoveal impingement

Pectineofoveal impingement is a relatively rare condition, which can cause hip or groin pain along with mechanical symptoms of clicking in the young adult. We present the case of a 13-year-old girl who was referred to us with left hip pain, which had been affecting her for over six months along with mechanical symptoms of clicking. Following appropriate clinical examination and investigations the patient underwent arthroscopic surgery of her hip. At arthroscopy, a cyst was identified on the medial synovial fold, which was abutting against the zona orbicularis leading to pectineofoveal impingement. The cyst was decompressed and the synovial fold excised arthroscopically. Following arthroscopic intervention, the patient did extremely well and remains asymptomatic at the last follow-up (7 months following the procedure). The case highlights the importance of the medial synovial fold pathology as an important cause for pain and mechanical symptoms in the young adult hip.

Sources and quality of literature addressing femoroacetabular impingement: a scoping review 2011-2015

A systematic review was performed to explore the current trends over the last 5 years in femoroacetabular impingement (FAI) literature and compare the quality and sources of publications in the literature to that published previously. We identified 1066 relevant studies including 186,572 patients. The number of publications increased during the reviewed time period with the most dramatic increase from 2011 to 2013. Seventy-three percent (N = 786) of all studies were of levels 4 and 5 quality evidence. The percent of publications which were levels 1, 2 and 3 increased by almost twofold from 16.1 % (N = 26) to 28.7 % (N = 51) between 2011 and 2015. In comparison to previous work, there has been 3.5-fold increase in the number of publications over the past 5 years with a shift towards improving the level of evidence available guiding the arthroscopic management of FAI.

LEVEL OF EVIDENCE

IV-Systematic Review.

Three-dimensional Imaging and Computer Navigation in Planning for Hip Preservation Surgery

Hip preservation surgery is performed to address femoroacetabular impingement, alleviate any associated pain, and reduce the risk of early onset of osteoarthritis. In the last decade, arthroscopy has become more popular in addressing femoroacetabular impingement, due to its minimally invasive approach. However, poor visualization and limited spatial awareness of the joint make arthroscopy of the hip difficult, resulting in a steep learning curve. This paper reviews the utility and benefits of 3-dimensional imaging and computer navigation and what these tools may add to the preoperative planning stages of hip preservation surgery.

Inter- and intra-observer agreement of femoroacetabular impingement (FAI) parameters comparing plain radiographs and advanced, 3D computed tomographic (CT)-generated hip models in a surgical patient cohort

PURPOSE

The purpose of our study was to investigate whether advanced, 3D computed tomographic (CT)-generated hip models improves inter-and intra-observer agreement when compared to plain radiographs in identifying femoroacetabular impingement (FAI) morphology.

METHODS

Eight consecutive patients who underwent surgery for FAI pathology were selected for this study. Preoperative CT scan image data were used to create high resolution, 3D hip reconstruction models. Four observers (two attending hip surgeons and radiologists) performed a blinded review of preselected radiographs and 3D CT hip models. Alpha and lateral center-edge angle measurements, location of cam lesion and the presence of a "crossover sign" were assessed. Inter- and intra-observer agreement was determined by calculating the intra-class correlation coefficients (ICC) or kappa coefficients to evaluate agreement for categorical variables.

RESULTS

The parameter that demonstrated the highest and poorest inter-observer agreement was the presence of a "crossover sign" using 3D CT-generated high resolution hip models (ICC = 0.76, p = 0.00) and anteroposterior pelvis radiography, respectively (ICC = 0.20, p = 0.02). Alpha angle values were significantly higher using plain radiographs when compared to 3D hip reconstruction models (61.1° ± 10.4° versus 55.4° ± 14.4°, p = 0.003). Furthermore, when compared to radiographs, 3D hip reconstruction models demonstrated significantly higher intra-observer agreement (ICC = 0.856 versus 0.405, p = 0.005) when determining the presence of a "crossover sign".

CONCLUSIONS

Our findings were suggestive that for most commonly used FAI morphology parameters, CT-generated hip models demonstrated little benefit over plain radiographs in improving inter-observer agreement among providers.

LEVEL OF EVIDENCE

III.

Does high level youth sports participation increase the risk of femoroacetabular impingement? A review of the current literature

Sports participation can be an integral part of adolescent development with numerous positive short and long-term effects. Despite these potential benefits very high levels of physical activity, during skeletal maturation, have been proposed as a possible cause of cam-type femoroacetabular impingement (FAI). The influence of physical activity on the developing physis has been previously described both in animal studies and epidemiological studies of adolescent athletes. It is therefore important to determine whether the development of FAI is secondary to excessive physical activity or a combination of a vulnerable physis and a set level of physical activity. A review of the current literature suggests that adolescent males participating in ice-hockey, basketball and soccer, training at least three times a week, are at greater risk than their non-athletic counterparts of developing the femoral head-neck deformity associated with femoroacetabular impingement.

New perspectives on femoroacetabular impingement syndrome

Femoroacetabular impingement (FAI) is characterized by an abnormality in the shape of the femoral head-neck or acetabulum that results in impingement between these two structures. Arthroscopic treatment has become the preferred method of management of FAI owing to its minimally invasive approach. Surgical correction involves resection of impinging osseous structures as well as concurrent management of the associated chondral and labral pathology. Research from the past 5 years has shown that repair of the labrum results in a better anatomic correction and improved outcomes compared with labral debridement. Research is underway to improve cartilage assessment by using innovative imaging techniques and biochemical tests to inform predictions of prognosis. Several ongoing randomized controlled trials, including the Femoroacetabular Impingement Trial (FAIT) and the Femoroacetabular Impingement Randomized Controlled Trial (FIRST), will provide critical information regarding the diagnosis, management and prognosis of patients undergoing arthroscopic management of FAI.

Femoroacetabular impingement and osteoarthritis of the hip

OBJECTIVE

To outline the clinical presentation, physical examination findings, diagnostic criteria, and management options of femoroacetabular impingement (FAI).

SOURCES OF INFORMATION

PubMed was searched for relevant articles regarding the pathogenesis, diagnosis, treatment, and prognosis of FAI.

MAIN MESSAGE

In recent years, FAI has been increasingly recognized as a potential precursor and an important contributor to hip pain in the adult population and idiopathic hip osteoarthritis later in life. Femoroacetabular impingement is a collection of bony morphologic abnormalities of the hip joint that result in abnormal contact during motion. Cam-type FAI relates to a non-spherical osseous prominence of the proximal femoral neck or head-neck junction. Pincer-type FAI relates to excessive acetabular coverage over the femoral head, which can occur owing to several morphologic variants. Patients with FAI present with chronic, deep, or aching anterior groin pain most commonly in the sitting position, or during or after activity. Patients might also experience occasional sharp pains during activity. A thorough history should be taken that includes incidence of trauma and exercise frequency. A physical examination should be performed that includes a full hip, low back, and abdominal examination to assess for alternate causes of anterior groin pain. Diagnosis of FAI should be confirmed with radiography. Femoroacetabular impingement can be managed conservatively with rest, modification of activities, medications, and physiotherapy, or it can be treated surgically.

CONCLUSION

Femoroacetabular impingement is an important cause of anterior groin pain. Early recognition and intervention by the primary care provider might be critical to alleviating morbidity and preventing FAI progression.

The Natural History of Femoroacetabular Impingement

Femoroacetabular impingement (FAI) is a clinical syndrome resulting from abnormal hip joint morphology and is a common cause of hip pain in young adults. FAI has been posited as a precursor to hip osteoarthritis (OA); however, conflicting evidence exists and the true natural history of the disease is unclear. The purpose of this article is to review the current understanding of how FAI damages the hip joint by highlighting its pathomechanics and etiology. We then review the current evidence relating FAI to OA. Lastly, we will discuss the potential of hip preservation surgery to alter the natural history of FAI, reduce the risk of developing OA and the need for future arthroplasty.

Hip impingement: beyond femoroacetabular

In the last 20 years, femoroacetabular impingement has been at the forefront of clinical practice as a cause of hip pain in young adults. As arthroscopic techniques for the hip continue to evolve, the possible presence of a new group of conditions creating mechanical conflict in and around the hip joint (ischiofemoral, subspine and iliopsoas impingement) has recently been elucidated whilst interest in already known 'impingement' syndromes (pelvic-trochanteric and pectineofoveal impingement) is now revived. This article attempts to increase awareness of these relatively uncommon clinical entities by describing their pathomorphology, contact mechanics, treatment and published results available to present. It is hoped that such knowledge will diversify therapeutic options for the clinician, thereby improving outcomes in a small but not negligible portion of patients with previously unexplained persistent symptoms.

Methodological quality of systematic reviews addressing femoroacetabular impingement

PURPOSE

As the body of literature on femoroacetabular impingement (FAI) continues to grow, clinicians turn to systematic reviews to remain current with the best available evidence. The quality of systematic reviews in the FAI literature is currently unknown. The goal of this study was to assess the quality of the reporting of systematic reviews addressing FAI over the last 11 years (2003-2014) and to identify the specific methodological shortcomings and strengths.

METHODS

A search of the electronic databases, MEDLINE, EMBASE and PubMed, was performed to identify relevant systematic reviews. Methodological quality was assessed by two reviewers using the revised assessment of multiple systematic reviews (R-AMSTAR) scoring tool. An intraclass correlation coefficient (ICC) with 95 % confidence intervals (CI) was used to determine agreement between reviewers on R-AMSTAR quality scores.

RESULTS

A total of 22 systematic reviews were assessed for methodological quality. The mean consensus R-AMSTAR score across all studies was 26.7 out of 40.0, indicating fair methodological quality. An ICC of 0.931, 95 % CI 0.843-0.971 indicated excellent agreement between reviewers during the scoring process.

CONCLUSIONS

The systematic reviews addressing FAI are generally of fair methodological quality. Use of tools such as the R-AMSTAR score or PRISMA guidelines while designing future systematic reviews can assist in eliminating methodological shortcomings identified in this review. These shortcomings need to be kept in mind by clinicians when applying the current literature to their patient populations and making treatment decisions. Systematic reviews of highest methodological quality should be used by clinicians when possible to answer clinical questions.

The Patient Acceptable Symptomatic State for the Modified Harris Hip Score and Hip Outcome Score Among Patients Undergoing Surgical Treatment for Femoroacetabular Impingement

BACKGROUND

There is minimal information available on the threshold at which patients consider themselves to be well for patient-reported outcome measures used in patients treated with hip arthroscopy for femoroacetabular impingement (FAI).

PURPOSE

To determine the patient acceptable symptomatic state (PASS) for the modified Harris Hip Score (mHHS) and the Hip Outcome Score (HOS) in patients with FAI treated with arthroscopic hip surgery.

STUDY DESIGN

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

METHODS

A consecutive series of patients at a single institution with FAI who were treated with arthroscopic labral surgery, acetabular rim trimming, and femoral osteochondroplasty were eligible. The mHHS (score range, 0-100) and the HOS (score range, 0-100) were administered at baseline and at 12 months postoperatively. An external anchor question at 1 year postoperatively was utilized to determine PASS values: "Taking into account all the activities you have during your daily life, your level of pain, and also your functional impairment, do you consider that your current state is satisfactory?"

RESULTS

There were 130 patients (mean ± SD age, 35.6 ± 11.7 years), and 42.3% were male. Based on a receiver operator curve analysis, the PASS values-at which patients considered their status to be satisfactory-at 1 year after surgery were 74 (mHHS), 87 (HOS-activities of daily living subscale), and 75 (HOS-sports subscale). The PASS threshold was not affected by baseline scores across different instruments. However, patients with higher baseline scores were more likely to achieve the PASS (odds ratios: 3.36 [mHHS], 3.83 [HOS-activities of daily living], 3.38 [HOS-sports]). Age and sex were not significantly related to the odds of achieving the PASS for the mHHS or the HOS.

CONCLUSION

This is the first study to determine the PASS for 2 commonly used hip joint patient-reported outcome measures in patients undergoing surgery for FAI. The study findings can allow researchers to determine if interventions related to FAI are meaningful to patients at the individual level across various domains and will also be useful for responder analyses in future randomized trials related to hip arthroscopy and the treatment of FAI.

Operative treatment of femoroacetabular impingement

Femoroacetabular impingement is a common pathologic disorder of the hip that causes pain and has been implicated in the development of early osteoarthritis in young adults. This disorder includes 2 different subtypes: cam impingement and pincer impingement. When nonsurgical treatment methods fail, surgical options are indicated. These options have been increasingly investigated over recent years and show promising results. Several surgical techniques have been described, including surgical dislocation of the hip, mini-open procedures, hip arthroscopy, and periacetabular osteotomies. Nevertheless, the preferred mode of surgical management of femoroacetabular impingement remains a source of controversy. Only short-term and midterm outcome data are available regarding the efficacy of these surgical techniques. This review details 5 approaches for surgical management of femoroacetabular impingement: open surgical dislocation, a combined arthroscopic and open approach, hip arthroscopy, a mini-open anterior approach, and periacetabular osteotomy. It focuses specifically on surgical technique, outcomes, and their efficacy in treatment of femoroacetabular impingement.