Capsular attachment on the anterosuperior femoral head-neck junction: A hypothesis about femoroacetabular impingement.

Femoroacetabular impingement (FAI), characterized by a pathological contact between the proximal femur and acetabulum, is a common precursor of hip osteoarthritis. Cam morphology is a bony prominence that causes FAI and frequently forms on the anterosuperior femoral head-neck junction. Despite anatomical consensus regarding the femoral head-neck junction as a boundary area covered by the articular cartilage and joint capsule, it remains unclear whether the joint capsule is continuous with the anterosuperior articular cartilage. For the anatomical consideration of cam morphology formation, this study aimed to investigate the histological characteristics of the capsular attachment on the anterosuperior femoral head-neck junction, particularly focusing on the presence or absence of continuity of the joint capsule to the articular cartilage. A total of 21 anterosuperior regions (seven hips each for the 12:00, 1:30, and 3:00 positions) from seven hips (three males and four females; mean age at death, 68.7 years) were histologically analyzed in this study for quantitative evaluation of the capsular thickness using histological sections stained with Masson's trichrome, as well as qualitative evaluation of the capsular attachment. The present study showed that the joint capsule, which folded proximally to the femoral head-neck junction from the recess, exhibited a blend of the fibrous and synovial regions. Notably, it not only continued with the superficial layer of the articular cartilage, but also attached to the articular cartilage via the fibrocartilage. This continuous region was relatively fibrous with dense connective tissue running in the longitudinal direction. The capsular thickness at the recess point (mean, 1.7 ± 0.9 mm) and those at the distal end of the articular cartilage (0.35 ± 0.16 mm) were significantly greater than the control value for the most superficial layer thickness of the articular cartilage (0.019 ± 0.003 mm) (Dunnett's T3, both p-value <0.001). Based on the fibrous continuity between the joint capsule and articular cartilage and its thickness, this study suggests the anatomical possibility that some mechanical stress can be transmitted from the joint capsule to the articular cartilage at the frequent sites of cam morphology.

Increased Duration and Intensity of Physical Activity Are Associated With Increased Pain in Individuals With Femoroacetabular Impingement Syndrome: An Ecological Momentary Assessment Study.

OBJECTIVE: To investigate the relation between accelerometer-measured physical activity and real-time pain in individuals with femoroacetabular impingement syndrome (FAIS). We tested the hypothesis that increased duration of high intensity activity would contribute to momentary increases in pain. DESIGN: Observational study. SETTING: Participants' natural, day-to-day environment. PARTICIPANTS: Population-based sample of 33 individuals with unilateral FAIS. Important eligibility criteria included no concomitant hip disorders or previous hip surgery. Key sociodemographic features include that all participants were required to have a smartphone. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Duration and intensity of physical activity as measured by a waist-worn accelerometer, and instantaneous pain reported in real-time smartphone-based ecological momentary assessment surveys. Physical activity variables included each person's average sedentary time, light physical activity (LPA), and moderate to vigorous physical activity (MVPA) in the 90 minutes proceeding all pain surveys as well as fluctuation in sedentary, LPA, and MVPA above or below average prior to each individual survey. RESULTS: Linear mixed models revealed that the significant predictors of pain included fluctuation in sedentary time (B=-0.031, P<.001), average LPA (B=0.26, P=.035), and the interaction between fluctuation in LPA and fluctuation in MVPA (B=0.001, P<.001). Fluctuation in sedentary time above a person's average was associated with lower pain, while average LPA and fluctuations above average in both LPA and MVPA were associated with higher pain. CONCLUSIONS: These results suggest that individuals with FAIS can engage in health-enhancing MVPA but should focus on avoiding concurrent increase above average in both high intensity and LPA in the same 90-minute period. Future work is warranted testing the efficacy of such an approach on pain. Additionally, given that high levels of LPA may arise from a host of socioeconomic factors, additional research is needed to disentangle the effect of LPA on pain in FAIS.

UTE T2* cartilage mapping in the hip: a pilot study assessing cartilage in patients with femoroacetabular impingement.

BACKGROUND: UTE T2* cartilage mapping use in patients undergoing femoroacetabular impingement (FAI) has been lacking but may allow the detection of early cartilage damage. PURPOSE: To assess the reproducibility of UTE T2* cartilage mapping and determine the difference in UTE T2* values between FAI and asymptomatic patients and to evaluate the correlation between UTE T2* values and patient-reported symptoms. MATERIAL AND METHODS: Prospective evaluation of both hips (7 FAI and 7 asymptomatic patients). Bilateral hip 3-T MRI scans with UTE T2* cartilage maps were acquired. A second MRI scan was acquired 1-9 months later. Cartilage was segmented into anterosuperior, superior, and posterosuperior regions. Assessment was made of UTE T2* reproducibility (ICC). Mean UTE T2* values in patients were compared (t-tests) and correlation was made with patient-reported outcomes (Spearman's). RESULTS: ICCs of mean UTE T2* were as follows: acetabular, 0.82 (95% CI=0.50-0.95); femoral, 0.76 (95% CI=0.35-0.92). Significant strong correlation was found between mean acetabular UTE T2* values and iHOT12 (ρ = -0.63) and moderate correlation with mHHS (ρ = -0.57). There was no difference in mean UTE T2* values between affected vs. non-affected FAI hips. FAI-affected hips had significantly higher values in acetabulum vs. asymptomatic patients (13.47 vs. 12.55 ms). There was no difference in mean femoral cartilage values between the FAI-affected hips vs. asymptomatic patients. The posterosuperior femoral region had a higher mean value in non-affected FAI hips vs. asymptomatic patients (12.60 vs. 11.53 ms). CONCLUSION: UTE T2* cartilage mapping had excellent reproducibility. Affected FAI hips had higher mean acetabular UTE T2* values than asymptomatic patients. Severity of patient-reported symptoms correlates with UTE T2* acetabular cartilage values.

Which Acetabular Measurements Most Accurately Differentiate Between Patients and Controls? A Comparative Study.

BACKGROUND: Acetabular morphology is an important determinant of hip biomechanics. To identify features of acetabular morphology that may be associated with the development of hip symptoms while accounting for spinopelvic characteristics, one needs to determine acetabular characteristics in a group of individuals older than 45 years without symptoms or signs of osteoarthritis. Previous studies have used patients with unknown physical status to define morphological thresholds to guide management. QUESTIONS/PURPOSES: (1) To determine acetabular morphological characteristics in males and females between 45 and 60 years old with a high Oxford hip score (OHS) and no signs of osteoarthritis; (2) to compare these characteristics with those of symptomatic hip patients treated with hip arthroscopy or periacetabular osteotomy (PAO) for various kinds of hip pathology (dysplasia, retroversion, and cam femoroacetabular impingement); and (3) to assess which radiographic or CT parameters most accurately differentiate between patients who had symptomatic hips and those who did not, and thus, define thresholds that can guide management. METHODS: Between January 2018 and December 2018, 1358 patients underwent an abdominopelvic CT scan in our institution for nonorthopaedic conditions. Of those, we considered 5% (73) of patients as potentially eligible as controls based on the absence of major hip osteoarthritis, trauma, or deformity. Patients were excluded if their OHS was 43 or less (2% [ 28 ]), if they had a PROMIS less than 50 (1% [ 18 ]), or their Tönnis score was higher than 1 (0.4% [ 6 ]). Another eight patients were excluded because of insufficient datasets. After randomly selecting one side for each control, 40 hips were left for analysis (age 55 ± 5 years; 48% [19 of 40] were in females). In this comparative study, this asymptomatic group was compared with a group of patients treated with hip arthroscopy or PAO. Between January 2013 and December 2020, 221 hips underwent hip preservation surgery. Of those, eight were excluded because of previous pelvic surgery, and 102 because of insufficient CT scans. One side was randomly selected in patients who underwent bilateral procedure, leaving 48% (107 of 221) of hips for analysis (age 31 ± 8 years; 54% [58 of 107] were in females). Detailed radiographic and CT assessments (including segmentation) were performed to determine acetabular (depth, cartilage coverage, subtended angles, anteversion, and inclination) and spinopelvic (pelvic tilt and incidence) parameters. Receiver operating characteristics (ROC) analysis was used to assess diagnostic accuracy and determine which morphological parameters (and their threshold) differentiate most accurately between symptomatic patients and asymptomatic controls. RESULTS: Acetabular morphology in asymptomatic hips was characterized by a mean depth of 22 ± 2 mm, with an articular cartilage surface of 2619 ± 415 mm 2 , covering 70% ± 6% of the articular surface, a mean acetabular inclination of 48° ± 6°, and a minimal difference between anatomical (24° ± 7°) and functional (22° ± 6°) anteversion. Patients with symptomatic hips generally had less acetabular depth (20 ± 4 mm versus 22 ± 2 mm, mean difference 3 mm [95% CI 1 to 4]; p < 0.001). Hips with dysplasia (67% ± 5% versus 70% ± 6%, mean difference 6% [95% CI 0% to 12%]; p = 0.03) or retroversion (67% ± 5% versus 70% ± 6%, mean difference 6% [95% CI 1% to 12%]; p = 0.04) had a slightly lower relative cartilage area compared with asymptomatic hips. There was no difference in acetabular inclination (48° ± 6° versus 47° ± 7°, mean difference 0.5° [95% CI -2° to 3°]; p = 0.35), but asymptomatic hips had higher anatomic anteversion (24° ± 7° versus 19° ± 8°, mean difference 6° [95% CI 3° to 9°]; p < 0.001) and functional anteversion (22° ± 6° versus 13°± 9°, mean difference 9° [95% CI 6° to 12°]; p < 0.001). Subtended angles were higher in asymptomatic at 105° (124° ± 7° versus 114° ± 12°, mean difference 11° [95% CI 3° to 17°]; p < 0.001), 135° (122° ± 9° versus 111° ± 12°, mean difference 10° [95% CI 2° to 15°]; p < 0.001), and 165° (112° ± 9° versus 102° ± 11°, mean difference 10° [95% CI 2° to 14°]; p < 0.001) around the acetabular clockface. Symptomatic hips had a lower pelvic tilt (8° ± 8° versus 11° ± 5°, mean difference 3° [95% CI 1° to 5°]; p = 0.007). The posterior wall index had the highest discriminatory ability of all measured parameters, with a cutoff value of less than 0.9 (area under the curve [AUC] 0.84 [95% CI 0.76 to 0.91]) for a symptomatic acetabulum (sensitivity 72%, specificity 78%). Diagnostically useful parameters on CT scan to differentiate between symptomatic and asymptomatic hips were acetabular depth less than 22 mm (AUC 0.74 [95% CI 0.66 to 0.83]) and functional anteversion less than 19° (AUC 0.79 [95% CI 0.72 to 0.87]). Subtended angles with the highest accuracy to differentiate between symptomatic and asymptomatic hips were those at 105° (AUC 0.76 [95% CI 0.65 to 0.88]), 135° (AUC 0.78 [95% CI 0.70 to 0.86]), and 165° (AUC 0.77 [95% CI 0.69 to 0.85]) of the acetabular clockface. CONCLUSION: An anatomical and functional acetabular anteversion of 24° and 22°, with a pelvic tilt of 10°, increases the acetabular opening and allows for more impingement-free flexion while providing sufficient posterosuperior coverage for loading. Hips with lower anteversion or a larger difference between anatomic and functional anteversion were more likely to be symptomatic. The importance of sufficient posterior coverage was also illustrated by the posterior wall indices and subtended angles at 105°, 135°, and 165° of the acetabular clockface having a high discriminatory ability to differentiate between symptomatic and asymptomatic hips. Future research should confirm whether integrating these parameters when selecting patients for hip preservation procedures can improve postoperative outcomes.Level of Evidence Level III, prognostic study.

Prevalence of hip femoroacetabular impingement deformities in high-level (La Liga) male professional football players.

BACKGROUND: Femoroacetabular impingement (FAI) is considered one of the main causes of hip osteoarthritis in young adults, especially in athletes. In recent years, morphological changes in FAI in the hip have been linked to early and intense sports participation, but studying top-level athlete samples is not easy. This paper presents the prevalence of FAI radiological markers in 120 active white male professional football players in the Spanish First Division League (La Liga) and compares the morphological changes with those of a control group of healthy individuals without significant sport activity. METHODS: The precontract medical evaluation hip X-rays of 120 white male professional football players from four different First Division Spanish football teams were prospectively filed and retrospectively reviewed by a dedicated skeletal radiologist. The footballers' hip X-rays were compared with those of a control group of 80 healthy individuals (age-sex matched) without significant sport activity (obtained from routine work medical checks). RESULTS: The femoral head-neck deformity associated with the Cam type of femoroacetabular impingement was observed in 61.6% of professional football players and only in 11.6% of the control group (p <0.01). The presence of "herniation pit" (11.6%) and os acetabuli (13.3%) also reached statistical significance in the professional football players group. In the other analyzed parameters, no statistically significant differences between the groups were observed. CONCLUSIONS: White professional top-level football players have an increased incidence of abnormal lateral epiphyseal extension ("pistol grip deformity"), os acetabuli and herniation pits.

Comparison of MRI and arthroscopy findings for transitional zone cartilage damage in the acetabulum of the hip joint.

OBJECTIVE: To assess the performance of morphologic and hypointense signal changes on MRI to predict grades and types of acetabular cartilage damage in the chondrolabral transitional zone (TZ) of the hip identified at arthroscopy. MATERIALS AND METHODS: This retrospective single-center study reviewed conventional 3T MRI hip studies from individuals with symptomatic femoroacetabular impingement (FAI) and subsequent hip arthroscopy surgery within 6 months. Independent review was made by three radiologists for the presence of morphologic damage or a hypointense signal lesion in the TZ on MRI. Fleiss' kappa statistic was used to assess inter-reader agreement. The degree of TZ surfacing damage (modified Outerbridge grades 1-4) and presence of non-surfacing wave sign at arthroscopic surgery were collected. Relationship between sensitivity and lesion grade was examined. RESULTS: One hundred thirty-six MRI hip studies from 40 males and 74 females were included (mean age 28.5 years, age range 13-54 years). MRI morphologic lesions had a sensitivity of 64.9-71.6% and specificity of 48.4-67.7% for arthroscopic surfacing lesions, with greater sensitivity seen for higher grade lesions. Low sensitivity was seen for wave sign lesions (34.5-51.7%). MRI hypointense signal lesions had a sensitivity of 26.3-62% and specificity of 43.8-78.0% for any lesion. Inter-reader agreement was moderate for morphologic lesions (k = 0.601) and poor for hypointense signal lesions (k = 0.097). CONCLUSION: Morphologic cartilage damage in the TZ on MRI had moderate sensitivity for any cartilage lesion, better sensitivity for higher grade lesions, and poor sensitivity for wave sign lesions. The diagnostic value of hypointense signal lesions was uncertain.

Clinical Equipoise in the Management of Patients With Femoroacetabular Impingement Syndrome and Concomitant Tönnis Grade 2 Hip Osteoarthritis or Greater: An International Expert-Panel Delphi Study.

PURPOSE: To gather global-expert opinion on the management of patients with femoroacetabular impingement syndrome (FAIS) and Tönnis grade 2 hip osteoarthritis (OA) or greater. METHODS: An internet-based modified Delphi methodology was used via an online platform (Online Surveys) using the CREDES (Conducting and Reporting Delphi Studies) guidelines. The expert panel comprised 27 members from 18 countries: 21 orthopaedic surgeons (78%), 5 physiotherapists (18%), and 1 dual orthopaedic surgeon-sport and exercise medicine physician (4%). Comments and suggestions were collected during each round, and amendments were performed for the subsequent round. Between each pair of rounds, the steering panel provided the experts with a summary of results and amendments. Consensus was set a priori as minimum agreement of 80%. RESULTS: Complete participation (100%) was achieved in all 4 rounds. A final list of 10 consensus statements was formulated. The experts agreed that there is no single superior management strategy for FAIS with Tönnis grade 2 OA and that Tönnis grade 3 OA and the presence of bilateral cartilage defects (acetabular and femoral) is a contraindication for hip preservation surgery. Nonoperative management should include activity modification and physiotherapy with hip-specific strengthening, lumbo-pelvic mobility training, and core strengthening. There was no consensus on the need for 3-dimensional imaging for initial quantification of joint degeneration. CONCLUSIONS: There is clinical equipoise in terms of the best management strategy for patients with FAIS and Tönnis grade 2 OA, and therefore, there is an urgent need to perform a randomized controlled trial for this cohort of patients to ascertian the best management strategy. LEVEL OF EVIDENCE: Level V, expert opinion.

Increased Alpha Angles and Younger Age Increase the Risk of Contralateral Femoral Acetabular Impingement Syndrome Symptom Development and Surgical Intervention: A Systematic Review.

PURPOSE: To identify the preoperative risk factors associated with contralateral symptom development and surgical intervention for patients presenting with unilateral femoral acetabular impingement (FAI) syndrome. METHODS: A literature search was performed using PubMed and Scopus computerized databases according to the 2020 Preferred Reporting Items for Systematic Meta-Analyses guidelines. Studies evaluating preoperative risk factors associated with the contralateral progression of FAI were included. Quality assessment was completed using the Methodological Index for Non-Randomized Studies criteria. RESULTS: A total of 5 studies (n = 1,011 patients; mean age, 29.9 years) published from 2013 to 2022 met the inclusion/exclusion criteria. Mean follow-up ranged from 12 to 132 months. The overall rate of contralateral progression of symptomatic FAI ranged from 32.4% to 81%. Increased alpha angle was frequently reported factor associated with contralateral symptom progression, followed by decreased total arc of rotation, decreased internal rotation, reduced neck-shaft angle, and head-neck offset. The incidence rate of progression to contralateral surgery ranged from 15.7% to 24% of patients. Younger age was frequently reported factor associated with contralateral surgical intervention, followed by male sex, increased level of activity, and increased alpha angle. CONCLUSIONS: Increased alpha angle and younger age were commonly reported risk factors associated with an increased risk of symptom development and surgical progression of contralateral FAI, respectively. The overall rate of contralateral progression of symptomatic FAI and the rate of progression to surgical intervention ranged up to 81% and 24%, respectively. This information may help both patients and surgeons to establish expectations regarding development of contralateral hip symptoms and possible need for surgery. LEVEL OF EVIDENCE: Level III; systematic review of Level II-III studies.

Editorial Commentary: Hip Arthroscopy Benefits Patients With Tönnis Grade 0 or 1 Hip Arthritis and Is Not Recommended for Grade 3: Optimal Treatment of Femoroacetabular Impingement Syndrome for Grade 2 Arthritis May Be Determined by Age and Body Mass Index.

Femoroacetabular impingement syndrome (FAIS) is a possible cause of early osteoarthritis, and restoration of normal anatomy can potentially prevent future major cartilage damage. Symptomatic cam lesions can lead to debonding of articular cartilage, resulting in superolateral cartilage lesions in 93% of patients. Patients with pincer lesions often exhibit cartilage lesions in the anterior and superolateral glenoid rim. Whereas the efficacy of prophylactic surgery remains uncertain, surgical intervention appears to yield superior short-term clinical outcomes compared with conservative treatment. Yet, there is a relatively high prevalence of asymptomatic individuals in the general population with either cam (25%) or pincer (67%) deformities, so prophylactic treatment of asymptomatic patients cannot be recommended. Symptomatic FAIS patients with Tönnis grades 0 and 1 (minimal hip arthritis) benefit from hip arthroscopy. Patients with higher grades of osteoarthritis may be unsuitable hip arthroscopy candidates and face a higher risk of conversion to hip replacement. The existing evidence regarding the treatment of patients with FAIS and Tönnis grade 2 or higher remains inconclusive. Generally, surgery tends to have favorable outcomes for younger patients with a normal body mass index, whereas nonsurgical alternatives should be explored in cases with severe joint space narrowing, Tönnis grade 3, and bilateral cartilage lesions.

Editorial Commentary: Clinical Equipoise Regarding Arthroscopic Management of Femoroacetabular Impingement With Tönnis Grade 2 Osteoarthritis May Mean We Don't Know or Don't Agree: It Does Not Mean We Don't Care.

Management of patients with femoroacetabular impingement and moderate (Tönnis grade 2) osteoarthritis remains a debated topic. Outcomes show that such patients can benefit from hip arthroscopy, yet the improvement may not be as favorable as desired. Although certain factors, such as Tönnis grade 3 hip OA, older age, higher body mass index, bipolar cartilage defects, and joint space less than 2 mm, may influence surgeons to avoid arthroscopic treatment, the threshold for grade 2 OA is not as clear. Moreover, although radiographs may appear similar in patients with Tönnis grade 2, there may be a wide range of chondral damage seen arthroscopically. Thus, until higher-level studies are performed, it is the responsibility of the surgeon to delineate appropriate treatment strategies for individual patients in this category, and most of all, it is crucial for surgeons to set reasonable expectations for patients when considering hip arthroscopy. This highlights the importance of careful preoperative evaluation and patient education.

Medicaid Insurance Is Associated With More Complications and Emergency Department Visits but Equivalent 5-Year Secondary Surgery Rate After Primary Hip Arthroscopy.

PURPOSE: To compare 90-day complications, 30-day emergency department (ED) visits, and 5-year rate of secondary surgeries for patients with Medicaid vs commercial insurance undergoing primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and/or labral tears using a large national database. METHODS: The PearlDiver Mariner151 database was used to identify patients with International Classification of Diseases, Tenth Revision diagnosis codes for FAIS and/or labral tear who underwent primary hip arthroscopy with femoroplasty, acetabuloplasty, and/or labral repair between 2015 and 2021. Patients with Medicaid were matched 1:4 to a control group of commercially insured patients based on age, sex, body mass index, and Elixhauser Comorbidity Index. Rates of 90-day complications and 30-day ED visits were compared using multivariate regression models. Five-year rates of secondary surgeries-revision arthroscopy or total hip arthroplasty-were compared between cohorts by Kaplan-Meier analysis. RESULTS: A total of 2,033 Medicaid patients were matched with 8,056 commercially insured patients. Rates of adverse events were low; however, Medicaid patients were significantly more likely than commercially insured patients to experience any 90-day complication (2.12% vs 1.43%; odds ratio [OR], 1.2; P = .02). Medicaid patients also experienced more 30-day ED visits than commercially insured patients (8.61% vs 4.28%), and on multivariate logistic regression, insurance status was the strongest determinant of 30-day ED visits (relative to commercial, Medicaid OR, 2.02; P < .001). Despite these differences, 5-year rates of secondary surgeries were comparable between groups (6.1% vs 6.0%; P = .6). CONCLUSIONS: In this large national database study, Medicaid patients undergoing primary hip arthroscopy showed significantly greater odds of experiencing 90-day postoperative complications and 30-day ED visits compared to commercially insured patients. Nevertheless, both groups had similar survivorship rates at 5-year follow-up, similar to prior estimates irrespective of insurance. These results document encouraging secondary surgery rates in Medicaid patients.

Satisfactory Clinical Outcomes and Continuance of Sports After Hip Arthroscopic Labral Repair in Young Competitive Athletes at Minimum 8.5-Year Follow-Up.

PURPOSE: To evaluate long-term patient-reported outcomes and achievement rates of patient acceptable symptomatic state (PASS) in young athletes undergoing hip arthroscopy, and to report long-term sports continuance and reoperation. METHODS: Inclusion criteria consisted of age <24 years at surgery, femoroacetabular impingement undergoing primary hip arthroscopy with labral repair, and participation in sport with intent to return to sport after surgery. The enrollment period was from April 2009 to June 2014. Modified Harris Hip Scores (mHHS), Hip Outcome Score (HOS), HOS Activities of Daily Living (HOS-ADL), and HOS Sport (HOS-Sport) were collected preoperatively, 2 years' postoperatively, and final follow-up. Patients were evaluated for PASS achievement, reoperation, and sports participation. RESULTS: Forty-two hips in 37 patients (11 male, 26 female, age: 17.7 ± 2.1 years, range 13.6-23.0, body mass index 22.8 ± 2.9, range 17.6-33.7) met inclusion criteria and were followed for 10.0 ± 1.3 years (range 8.5-13.0) postoperatively. Mean mHHS, HOS-ADL and HOS-Sports outcome scores at minimum 8.5 years were 82.2 ± 12.9, 89.6 ± 10.9, and 81.8 ± 16.4, respectively, with significant (P < .001) postoperative improvements. Thirty survey respondents (83%) met PASS for mHHS, 27 (75%) for HOS-ADL, and 24 (67%) for HOS-Sports. At minimum 8.5-year follow-up, only 9 of 37 (24%) cited their hip as the reason for stopping sport. Of the remaining patients, 17 of 28 (61%), continued playing their initial sport. There was no difference in patient-reported outcomes between patients who endorsed sports continuance and patients who did not report sports continuance and did not cite their hip as a reason (P ≥ .229). At final follow-up, 4 hips (10%) had undergone subsequent surgical intervention at a mean of 4.8 ± 3.3 years (range 1.0-8.4) postoperatively. CONCLUSIONS: Durable mid-term outcomes and satisfactory PASS achievement rates are observed in young amateur athletes undergoing primary hip arthroscopy. At minimum 8.5-year follow up, approximately 1 in 4 patients discontinue their sports due to hip related reasons. LEVEL OF EVIDENCE: Level IV, case-series.

Development of Machine-Learning Algorithms to Predict Attainment of Minimal Clinically Important Difference After Hip Arthroscopy for Femoroacetabular Impingement Yield Fair Performance and Limited Clinical Utility.

PURPOSE: To determine whether machine learning (ML) techniques developed using registry data could predict which patients will achieve minimum clinically important difference (MCID) on the International Hip Outcome Tool 12 (iHOT-12) patient-reported outcome measures (PROMs) after arthroscopic management of femoroacetabular impingement syndrome (FAIS). And secondly to determine which preoperative factors contribute to the predictive power of these models. METHODS: A retrospective cohort of patients was selected from the UK's Non-Arthroplasty Hip Registry. Inclusion criteria were a diagnosis of FAIS, management via an arthroscopic procedure, and a minimum follow-up of 6 months after index surgery from August 2012 to June 2021. Exclusion criteria were for non-arthroscopic procedures and patients without FAIS. ML models were developed to predict MCID attainment. Model performance was assessed using the area under the receiver operating characteristic curve (AUROC). RESULTS: In total, 1,917 patients were included. The random forest, logistic regression, neural network, support vector machine, and gradient boosting models had AUROC 0.75 (0.68-0.81), 0.69 (0.63-0.76), 0.69 (0.63-0.76), 0.70 (0.64-0.77), and 0.70 (0.64-0.77), respectively. Demographic factors and disease features did not confer a high predictive performance. Baseline PROM scores alone provided comparable predictive performance to the whole dataset models. Both EuroQoL 5-Dimension 5-Level and iHOT-12 baseline scores and iHOT-12 baseline scores alone provided AUROC of 0.74 (0.68-0.80) and 0.72 (0.65-0.78), respectively, with random forest models. CONCLUSIONS: ML models were able to predict with fair accuracy attainment of MCID on the iHOT-12 at 6-month postoperative assessment. The most successful models used all patient variables, all baseline PROMs, and baseline iHOT-12 responses. These models are not sufficiently accurate to warrant routine use in the clinic currently. LEVEL OF EVIDENCE: Level III, retrospective cohort design; prognostic study.

Editorial Commentary: Extreme Hip Labral Size (Both Small and Large) Shows Inferior Outcomes After Arthroscopic Labral Repair With Femoroacetabular Impingement Treatment.

Arthroscopic management of hip femoroacetabular impingement shows reliable improvement in pain and patient-reported outcomes, high survivorship, and low conversion to total hip arthroplasty, particularly in the absence of dysplasia. Concomitant labral repair-or augmentation versus reconstruction when indicated- consistently shows better results than labral debridement. The effect of labral size on outcomes has been studies in several series. Some studies show that smaller labra show inferior outcomes after repair, others show labral size makes no difference in outcomes, and one showed that patients large labra actually had worse outcomes. Perhaps labral size at either extreme does worse. Labral size is likely to remain one of many factors worth evaluating when prognosticating repair outcomes or indicating when advanced reconstructive options are warranted.

Editorial Commentary: A Majority of Athletes Return to Sport After Hip Arthroscopy and Show Mid-Term Durability Regardless of High Impact Activity.

At least 3 of 4 athletes will not only return to sport after hip arthroscopy but also maintain durability in their sport regardless of high-impact activity. Hoping our injured athletes can return to sport after their injury would prove an insufficient answer to our injured patients' expectations of a mathematically precise answer. As it turns out, Mathematical Hope exists as a term to describe the way we calculate probability. Because scientific research has shed light on the great outcomes that can be obtained from the arthroscopic treatment of a joint, we are now able to witness amazing comeback stories in the news and incredible outcomes from short- to long-term in scientific journals. Hip arthroscopy has now been supported by numerous research publications, turning our doubts into certainties, as high return to sport rates at high levels of performance are increasingly published.

Editorial Commentary: Female Patients With Lower Body Mass Index Show the Best Outcomes After Hip Arthroscopy, and Arthroscopic Treatment of Femoroacetabular Impingement in Higher-Body Mass Index Female Patients Results in Improved Outcomes.

Which patients will benefit most from hip arthroscopy? Careful patient selection and conservative indications, such as patients with an alpha angle of 60° or greater or a lateral center-edge angle of 40° or greater who fail a trial of conservative treatment, may benefit from hip arthroscopy for femoroacetabular impingement (FAI). In female patients in particular, a lower body mass index (BMI) will predict the most benefit from arthroscopic treatment. That said, patients with a higher BMI can also substantially improve after treatment of FAI. The true art of medicine is determining indications for an individual patient in addition to providing evidence-based counseling and education. We must not forget that sometimes "any improvement" can be a good outcome for a patient who is in pain.

Editorial Commentary: Patients With Lumbar Pathology or Ipsilateral Knee Pathology Improve After Hip Arthroscopy, but Outcomes Are Not as Good as in Patients With Femoroacetabular Impingement Syndrome Without Concomitant Pathology.

From the lumbar spine to foot, the joints of the lower extremity are all intimately connected. Their movements are synchronized in a complex biomechanical dance. Pain in one joint tends to affect the joint above and joint below. Understanding the influence of adjacent-joint disease on the hip can help us better counsel patients undergoing hip surgery. Low-back pathology has been shown to negatively influence outcomes after hip arthroscopy. Ipsilateral knee pain appears to do the same. Patients with femoroacetabular impingement syndrome with ipsilateral knee pain should be counseled that their outcomes may not be quite as good as those without knee pain, but they should be able to expect meaningful improvement of their symptoms, both at the hip and at the knee after hip arthroscopy.

Editorial Commentary: Femoral Version and Capsular Thickness Analysis in Hip Preservation Surgery-Surgical Indications Are as Important as Surgical Technique.

Optimal treatment of patients with femoroacetabular impingement syndrome requires both thoughtful decision-making and skillful operative technique. Traditional evidence-based literature and routine clinical practice overemphasize the role of the alpha angle on the femoral side and lateral center edge angle on the acetabular side. Femoral and acetabular version are critical values that influence outcomes and warrant measurement and consideration. Without version analysis, an uniformed, possibly poor, decision may be made. The literature and clinical practice also place dichotomous emphasis on labral (torn/intact) and capsular (torn/intact) integrity, with minimal appreciation of the morphological details of both. Not all capsules are created equal. "Normal" capsule thickness is a nebulous concept, with thinner anterior capsules more prone to anterior instability. Intuitively, it biomechanically stands to reason that excessive femoral anteversion (and excessive anterior cranial and central acetabular version) would place additional stress on the anterior capsule. Excessive femoral anteversion is associated with a thinner anterior capsule. Whether the latter is a reactive process (implies causation) or simply 2 concordant metrics (only correlation) has yet to be determined. In patients with nonarthritic hip pain, comprehensive quantitative consideration of both femoral and acetabular version and capsular thickness determines the optimal hip preservation procedure. Surgical indications are as important as surgical technique.

Editorial Commentary: Small Labral Size on Magnetic Resonance Imaging Is an Indication for Labral Reconstruction in the Setting of Revision Hip Arthroscopy.

Revision hip arthroscopy is an increasingly common procedure as rates of primary hip arthroscopy rise. Etiologies for symptom recurrence may include residual femoroacetabular impingement, cam over-resection, labral pathology, chondral wear, adhesions, and instability. This has spawned sophisticated surgical techniques in hip arthroscopy including labral reconstruction. Indications for labral reconstruction in the revision setting obviously include labral deficiency. In addition, in the absence of other obvious reasons for failure of the primary procedure, a labral reconstruction should be considered for diminutive labra. The ability to predict labral size before surgery based on magnetic resonance imaging can be invaluable.

Physical Therapy May Not Be Successful for Patients With Cam-Type Femoroacetabular Impingement Syndrome and May Result in Insufficient Hip Range of Motion When Femoral Anteversion Is Less Than 16° and α-Angle Is Greater Than 65°.

PURPOSE: To identify factors associated with insufficient range of motion (ROM) improvement after the posterior pelvic tilt change in cam-type femoroacetabular impingement syndrome. METHODS: Preoperative computed tomography images from 71 consecutive patients with femoroacetabular impingement syndrome treated with arthroscopic cam resection were evaluated. Using a dynamic computer simulation program, 3-dimensional models with a 10° posterior pelvic tilt from the supine functional pelvic plane (baseline) were created by computed tomography models. Patients were divided into 2 groups: those who experienced >10° (effective group) and ≤10° (ineffective group) improvements in internal rotation at 90° flexion after a 10° posterior pelvic tilt. Demographic characteristics; preoperative range of internal rotation at 90° flexion; and radiographic parameters, including Tönnis grade, lateral center-edge angle, acetabular roof obliquity angle, central acetabular anteversion, cranial acetabular anteversion, femoral anteversion, and α angle, were compared in the 2 groups. Univariate and multivariable logistic regression analyses were performed to evaluate factors associated with insufficient ROM improvement following a 10° posterior pelvic tilt. RESULTS: The 71 patients included 58 men and 13 women, of mean age 41.4 ± 14.6 years. Posterior pelvic tilt was effective in 13 hips and ineffective in 58. Univariate analysis showed that preoperative range of internal rotation at 90°flexion, femoral anteversion, and α angle differed significantly in the 2 groups. Multivariable analysis showed that femoral anteversion <16° (odds ratio 7.4; 95% confidence interval 1.6-35; P = .012) and α angle >65° (odds ratio 6.7; 95% confidence interval 1.2-37; P = .027) were significant factors associated with insufficient ROM improvement after posterior pelvic tilt. CONCLUSIONS: Physical therapy may not be successful for patients with cam-type femoroacetabular impingement syndrome and may result in insufficient hip ROM when femoral anteversion is less than 16° and α-angle is greater than 65°. CLINICAL RELEVANCE: Patients with a prominent cam-type deformity and lower anterior femoral anteversion are at high risk of clinical failure following improvement in pelvic mobility by conservative treatment alone and are likely to benefit from surgery for cam deformity.