Hip Outcome Score-Sports Subscale Research Articles

The Association of Preoperative Hip Pain Duration With Delayed Achievement of Clinically Significant Outcomes After Hip Arthroscopic Surgery for Femoroacetabular Impingement Syndrome.

Patients with hip pain ≥2 years before hip arthroscopic surgery for femoroacetabular impingement syndrome (FAIS) have been shown to achieve inferior short-term and midterm outcomes compared with patients with a shorter pain duration, although there is limited literature that has evaluated the time to achieve clinically significant outcomes (CSOs) in this population. To compare the time to achieve CSOs after hip arthroscopic surgery for FAIS in patients with and without prolonged hip pain and to identify independent predictors of the delayed achievement of CSOs. Cohort study; Level of evidence, 3. Patients who underwent primary hip arthroscopic surgery for FAIS between January 2012 and July 2019 with 6-month, 1-year, and 2-year Hip Outcome Score-Activities of Daily Living (HOS-ADL) and Hip Outcome Score-Sports Subscale (HOS-SS) scores were identified. Patients with prolonged hip pain (preoperative duration ≥2 years) were propensity score matched to a control group (preoperative duration <2 years), controlling for age, sex, and body mass index (BMI). The times to achieve the minimal clinically important difference and Patient Acceptable Symptom State were compared between groups using Kaplan-Meier survival analysis. Multivariate Cox regression considering age, sex, BMI, pain duration, activity level, and chondral status was used to identify independent predictors of the delayed achievement of CSOs. A total of 179 patients with prolonged hip pain were matched to 179 control patients (mean pain duration, 60.5 ± 51.2 vs 9.7 ± 5.1 months, respectively; P < .001) of a similar age, sex, and BMI (P≥ .488) with similar baseline HOS-ADL and HOS-SS scores (P≥ .971). The prolonged hip pain group showed delayed achievement of the minimal clinically important difference and Patient Acceptable Symptom State for both the HOS-ADL and HOS-SS on Kaplan-Meier analysis (P≤ .020). On multivariate Cox regression, hip pain duration ≥2 years was shown to be an independent predictor of the delayed achievement of CSOs, with hazard ratios ranging from 1.32 to 1.65 (P≤ .029). Additional independent predictors of the delayed achievement of CSOs included increasing age, increasing BMI, female sex, self-endorsed weekly participation in physical activity, and high-grade chondral defects (hazard ratio range, 1.01-4.89; P≤ .045). Findings from this study demonstrate that preoperative hip pain duration ≥2 years was an independent predictor of the delayed achievement of CSOs after primary hip arthroscopic surgery for FAIS.

The Promising 2-Year Performance of the Patient-Reported Outcomes Measurement Information System in Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Background: Minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) thresholds have been previously defined for the Patient-Reported Outcomes Measurement Information System (PROMIS) at 1-year follow-up in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome; however, the MCID and PASS thresholds are yet to be defined for the PROMIS at 2-year follow-up. Purpose: (1) To establish MCID and PASS thresholds for the PROMIS Pain Interference (PROMIS-PI) and PROMIS Physical Function (PROMIS-PF) at 2-year follow-up and (2) to correlate PROMIS scores with hip-specific patient-reported outcome measure (PROM) scores. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Patients undergoing primary hip arthroscopy for femoroacetabular impingement syndrome between August and November 2020 with preoperative and minimum 2-year postoperative data were identified. Collected scores included those for the PROMIS-PI, PROMIS-PF, Hip Outcome Score–Activities of Daily Living (HOS-ADL), Hip Outcome Score–Sports Subscale (HOS-SS), International Hip Outcome Tool–12 (iHOT-12), and visual analog scale (VAS) for pain. MCID thresholds were calculated using the distribution-based method and PASS thresholds using the anchor-based method. Pearson correlation coefficients were used to compare scores between PROMs. Results: A total of 65 patients met the criteria for inclusion (72.3% female; mean age, 36.9 ± 13.5 years; mean body mass index, 26.2 ± 6.0). The mean follow-up was 25.3 ± 3.3 months. Significant preoperative to postoperative improvements were observed for all PROMs (P < .001). MCID thresholds and achievement rates were as follows: HOS-ADL, 10.1 and 75%, respectively; HOS-SS, 13.8 and 79%, respectively; iHOT-12, 14.0 and 67%, respectively; VAS pain, –13.8 and 78%, respectively; PROMIS-PI, –4.7 and 65%, respectively; and PROMIS-PF, 5.8 and 60%, respectively. PASS thresholds and achievement rates were as follows: HOS-ADL, 78.7 and 67%, respectively; HOS-SS, 76.4 and 62%, respectively; iHOT-12, 67.4 and 60%, respectively; VAS pain, 25.5 and 61%, respectively; PROMIS-PI, 57.0 and 65%, respectively; and PROMIS-PF, 45.6 and 58%, respectively. PROMIS-PI scores correlated most strongly with HOS-ADL (r = −0.836), HOS-SS (r = −0.767), and iHOT-12 (r = −0.719) scores and exhibited at least moderate correlations (r≥−0.595) with the other PROM scores. PROMIS-PF demonstrated moderate correlations with all the other PROM scores (r≥−0.586). Strong correlations were seen between the hip-specific PROM scores (r≥−0.745). Conclusion: This study defined 2-year MCID and PASS thresholds for the PROMIS-PI and PROMIS-PF and demonstrated moderate to strong correlations between PROMIS scores and hip-specific PROM scores.

Clinical Outcomes After Arthroscopic Treatment of Extraspinal Diffuse Idiopathic Skeletal Hyperostosis (DISH) Involving the Hip Joint.

The hip joint can be affected by extraspinal diffuse idiopathic skeletal hyperostosis (DISH). This study aimed to compare the clinical characteristics of hips with DISH to those with mixed-type femoroacetabular impingement symptoms (FAIS). In addition, patient-reported outcome (PRO) scores were reported among patients with DISH involving the hip joint who underwent arthroscopic treatment. A retrospective analysis was performed using data from patients who underwent hip arthroscopy between 2017 and 2021. Patients who had a preoperative diagnosis of extraspinal DISH of the hip joint and postoperative Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports Subscale (HOS-SSS), International Hip Outcome Tool 12-component form (iHOT-12), modified Harris Hip Score (mHHS) and visual analog scale (VAS) for pain scores were enrolled in the study. The patients' characteristics were compared with those of a control group (1:2) consisting of mixed-type patients with FAIS. The control group was matched in terms of age, sex, body mass index (BMI), and symptom duration. Eleven hips (0.87%) with extraspinal DISH (study group) were matched to 22 FAIS hips (control group). All the patients were male. The mean age of patients was 42.0 ± 8.0 in the study group. The study group was characterized by a larger preoperative alpha angle (79.1 ± 6.8 vs 64.8 ± 9.7, P < .001), lateral center-edge angle (LCEA) (49.7 ± 6.0 vs 40.7 ± 3.2, P < .001), and postoperative LCEA (36.6 ± 3.0 vs 34.2 ± 2.0, P = .013). In addition, a higher proportion of acetabular (81.8% vs 31.8%, P = .007) and femoral head chondral lesions (45.5% vs 9.1%, P = .016). Cartilage damage has the potential to affect the prognosis of arthroscopic treatment. Nevertheless, at the final follow-up, patients with DISH experienced a significant increase in range of motion (ROM), notable enhancements in all PROs, and favorable rates of minimal clinically important difference (MCID) for the PROs. The occurrence of DISH in the hip joint is considerably infrequent, characterized by hip pain and limited ROM. Despite increased alpha angle and LCEA, and more acetabular and femoral head chondral damage noted at the time hip arthroscopy, patients with DISH observed a significant improvement in ROM, notable enhancements in all PROs, and favorable rates of MCID for the PROs.

Hip Arthroscopic Surgery With Chondrolabral Refixation, Osteochondroplasty, and Routine Capsular Closure for Femoroacetabular Impingement Syndrome: Clinical Outcomes at a Minimum 10-Year Follow-up

Background: Hip arthroscopic surgery for femoroacetabular impingement syndrome (FAIS) has proven to be an effective surgical intervention, with high rates of return to sport and work as well as favorable outcomes at short- and midterm follow-up. However, limited data exist on outcomes at long-term follow-up. Purpose: To evaluate patient-reported outcomes (PROs) at a minimum 10-year follow-up after primary hip arthroscopic surgery including labral repair, femoral osteochondroplasty, acetabular osteochondroplasty, and capsular closure for FAIS. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent primary hip arthroscopic surgery for FAIS between June 2012 and January 2013 were identified. PROs were collected preoperatively and at a minimum of 10 years postoperatively, including the Hip Outcome Score–Activities of Daily Living (HOS-ADL), Hip Outcome Score–Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), International Hip Outcome Tool–12 (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Unique minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) thresholds were calculated, and their rates of achievement were analyzed. An alpha level of <.05 was used to determine statistical significance. Results: A total of 94 patients (55 female; mean age, 34.3 ± 12.4 years) were analyzed with a mean follow-up of 10.1 ± 0.3 years (range, 10.0-10.7 years). Patients demonstrated significant 10-year improvement across all PRO measures (P < .001). MCID and PASS thresholds were calculated as follows: HOS-ADL (10.4 and 85.3, respectively), HOS-SS (14.6 and 60.2, respectively), mHHS (8.8 and 76.0, respectively), VAS pain (14.6 and 27.5, respectively), and iHOT-12 (PASS: 71.4). The majority of patients achieved the MCID and PASS for each PRO measure: HOS-ADL (73.4% and 70.9%, respectively), HOS-SS (78.5% and 77.2%, respectively), mHHS (81.0% and 70.9%, respectively), VAS pain (88.6% and 70.9%, respectively), and iHOT-12 (PASS: 73.4%). Overall, 9 patients (9.6%) underwent subsequent revision hip arthroscopic surgery at a mean 4.9 ± 3.7 years (range, 1.1-10.1 years) postoperatively, and 6 patients (6.4%) underwent conversion to total hip arthroplasty at a mean 4.1 ± 3.1 years (range, 0.9-9.3 years) postoperatively. Conclusion: Patients who underwent primary hip arthroscopic surgery for FAIS utilizing contemporary methods of labral repair, acetabular and/or femoral osteochondroplasty, and capsular closure commonly experienced sustained clinical improvement and reported high levels of satisfaction at a minimum 10-year follow-up with low rates of reoperation.

Defining the Percent Thresholds for Achieving the Maximum Outcome Improvement of the Modified Harris Hip Score, the Non-Arthritic Hip Score, the Hip Outcome Score-Sports Subscale, the Visual Analog Scale for Pain, and the International Hip Outcome Tool-12 in Revision Hip Arthroscopy at Minimum 2-Year Follow-Up

To determine the respective percent thresholds for achieving the maximal outcome improvement (MOI) for the modified Harris Hip Score (mHHS), the Non-Arthritic Hip Score (NAHS), the Hip Outcome Score-Sports Subscale (HOS-SSS), the visual analog scale (VAS) for pain, and the International Hip Outcome Tool-12 (iHOT-12) that were associated with satisfaction following revision hip arthroscopy, and to identify predictors for achieving the MOI. An anchor question was provided to patients who underwent revision hip arthroscopy between April 2017 and July 2020. Patients were included for the final analysis if they answered the anchor question and had minimum 2-year follow-up. Receiver operating characteristic analysis was used to determine the thresholds for the percentage of the MOI predictive of satisfaction. A P-value of < .05 was considered significant. In total, 318 patients underwent revision hip arthroscopy. Of those patients, 292 (91.8%) had minimum 2-year follow-up. Of this cohort, 68 answered the anchor question, with 49 (72.1%) female and 19 (27.9%) male patients. The mean age, and body mass index time were 32.9 ± 13 years and 25.4 ± 5.1, respectively. It was determined that 42.1%, 50%, 48.1%, 50%, and 50% of MOI were the thresholds for maximal predictability of satisfaction for mHHS, NAHS, HOS-SS, VAS for pain, and the iHOT-12, respectively. The presence of unaddressed subspine impingement was a significant predictor for achieving the MOI threshold for the VAS (odds ratio 1.40; 95% confidence interval 1.00-1.95; P= 0.0273). Following revision hip arthroscopy, the percent thresholds for achieving the MOI at a minimum 2-year follow-up for the mHHS, NAHS, HOS-SS, VAS for pain, and iHOT-12 were 42.1%, 50%, 48.1%, 50%, and 50.9%, respectively. Addressing residual subspine impingement was identified as significant positive predictor for achieving the MOI. Level IV, case-series.

Effect of Differing Orientation and Magnitude of Femoral Torsion on Outcomes and Achievement of the MCID and PASS at 5 Years After Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Background: Femoral torsion measurements and outcomes are variable throughout the literature and have focused on short-term follow-up. However, there is a paucity of literature investigating clinically meaningful outcomes at midterm follow-up after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Purpose: To quantify femoral version using computed tomography imaging in patients with FAIS and to explore the relationship between version abnormalities and 5-year outcomes after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent primary hip arthroscopy for FAIS between January 2012 and November 2017 were identified. Patients were included if they had 5-year follow-up with completion of ≥1 patient-reported outcome (PRO) scores and excluded if they had Tönnis grade >1, revision hip surgery, a concomitant hip procedure, a developmental disorder, or a lateral center-edge angle <20°. Torsion groups were defined as severe retrotorsion (<0°), moderate retrotorsion (0.1°-5°), normal torsion (5.1°-20°), moderate antetorsion (20.1°-25°), and severe antetorsion (>25.1°) based on computed tomography measurements. Patient characteristics were analyzed among the torsion cohorts, as were preoperative and 5-year PROs: Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, modified Harris Hip Score, international Hip Outcome Tool, visual analog scale for pain, and visual analog scale for satisfaction. Achievement rates of cohort-specific thresholds for the minimal clinically important difference and Patient Acceptable Symptom State were calculated and compared among cohorts. Results: A total of 362 patients (244 female, 118 male; mean ± SD age, 33.1 ± 11.5 years; body mass index, 26.9 ± 17.8) met inclusion/exclusion criteria and were analyzed at a final mean follow-up of 64.3 ± 9.4 months (range, 53.5-115.5 months). Mean femoral torsion was 12.8°± 9.2°. The number of patients within each group was 20 for severe retrotorsion (torsion, −6.3°± 4.9°), 45 for moderate retrotorsion (2.7°± 1.3°), 219 for normal torsion (12.2°± 4.1°), 39 for moderate antetorsion (21.9°± 1.3°), and 39 for severe antetorsion (29.0°± 4.2°). No significant differences in age, body mass index, sex, smoking status, workers’ compensation, psychiatric history, back pain, or physical activity were found among the torsional groups. All groups demonstrated significant improvements at 5 years postoperatively (P < .01 for all). All torsion subgroups demonstrated similar pre- to postoperative changes in PROs (P≥ .515) and PRO values at 5-year follow-up (P≥ .098). There were no significant differences in the achievement of the minimal clinically important difference (P≥ .422) or Patient Acceptable Symptom State (P≥ .161) for any of the PROs among the torsion groups. Conclusion: The orientation and severity of femoral torsion at the time of hip arthroscopy for FAIS in this study’s cohort did not affect the propensity for clinically meaningful outcome improvement at midterm follow-up.

Borderline Dysplastic Hips Undergoing Hip Arthroscopy Achieve Equivalent Patient Reported Outcomes When Compared With Hips With Normal Acetabular Coverage: A Systematic Review and Meta-Analysis.

To systematically review and meta-analyze studies reporting lateral center edge angle as it relates to patient-reported outcome (PRO) measures and clinically notable outcome assessments for patients undergoing hip arthroscopy for femoroacetabular impingement syndrome or labral pathology with borderline dysplastic hips (BDH). PubMed, EMBASE, and the Web of Science Core Collection databases were queried for articles evaluating lateral center edge angle as a predictor of PRO after hip arthroscopy. Articles were eligible for meta-analysis if they compared PROs measures between patients with normal acetabular coverage and borderline dysplasia and were at least level III evidence. Continuous random-effects models with standardized mean differences were used to compare postoperative Hip Outcome Score-Activities of Daily Living and sports subscales, modified Harris Hip Score, international Hip Outcome Tool scores, Satisfaction, and Visual Analog Scale Pain scores between normal coverage and borderline dysplastic groups. Overall, 989 hips undergoing arthroscopy from six investigations were included in this meta-analysis, including 315 borderline dysplastic subjects (mean age 27.5 years) and 674 subjects with normal coverage (mean age 26.9 years). Borderline dysplastic and normal coverage cohorts were followed for an average of 37.0 and 36.8 months, respectively. Postoperative PRO measures (Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sports Subscale, modified Harris Hip Score, international Hip Outcome Tool-12, Satisfaction, and Visual Analog Scale Pain) collected approximately three years after hip arthroscopy were not markedly different between subjects with BDH when compared with patients with normal coverage. In a meta-analysis of the available literature, patients with BDH are able to equally reach statistically similar clinical outcomes after isolated hip arthroscopy as compared with control subjects without dysplasia at short-term follow-up. A BDH should not be considered a contraindication to hip arthroscopy when optimal PRO achievement is the goal. Level III, Systematic Review and Meta-Analysis.

External Validation of a Machine Learning Algorithm for Predicting Clinically Meaningful Functional Improvement After Arthroscopic Hip Preservation Surgery

Background: Individualized risk prediction has become possible with machine learning (ML), which may have important implications in enhancing clinical decision making. We previously developed an ML algorithm to predict propensity for clinically meaningful outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome. External validity of prognostic models is critical to determine generalizability, although it is rarely performed. Purpose: To assess the external validity of an ML algorithm for predicting clinically meaningful improvement after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: An independent hip preservation registry at a tertiary academic medical center was queried for consecutive patients/athletes who underwent hip arthroscopy for femoroacetabular impingement syndrome between 2015 and 2017. By assuming a minimal clinically important difference (MCID) outcome/event proportion of 75% based on the original study, a minimum sample of 132 patients was required. In total, 154 patients were included. Age, body mass index, alpha angle on anteroposterior pelvic radiographs, Tönnis grade and angle, and preoperative Hip Outcome Score–Sports Subscale were used as model inputs to predict the MCID for the Hip Outcome Score–Sports Subscale 2 years postoperatively. Performance was assessed using identical metrics to the internal validation study and included discrimination, calibration, Brier score, and decision curve analysis. Results: The concordance statistic in the validation cohort was 0.80 (95% CI, 0.71 to 0.87), suggesting good to excellent discrimination. The calibration slope was 1.16 (95% CI, 0.74 to 1.61) and the calibration intercept 0.13 (95% CI, –0.26 to 0.53). The Brier score was 0.15 (95% CI, 0.12 to 0.18). The null model Brier score was 0.20. Decision curve analysis revealed favorable net treatment benefit for patients with use of the algorithm as compared with interventional changes made for all and no patients. Conclusion: The performance of this algorithm in an independent patient population in the northeast region of the United States demonstrated superior discrimination and comparable calibration to that of the derivation cohort. The external validation of this algorithm suggests that it is a reliable method to predict propensity for clinically meaningful improvement after hip arthroscopy and is an essential step forward toward introducing initial use in clinical practice. Potential uses include integration into electronic medical records for automated prediction, enhanced shared decision making, and more informed allocation of resources to optimize patient outcomes.

Paper 47: Clinical Outcomes in Patients with Femoral Acetabular Impingement Syndrome and Acetabular Retroversion: A 3D Analysis

Objectives:To use computed tomography (CT)-based three-dimensional (3D) bone models to (1) quantify acetabular version in patients with femoroacetabular impingement syndrome (FAIS) and (2) explore the relationship between the magnitude of acetabular version and clinical outcomes following hip arthroscopy.Methods:Preoperative CT scans were acquired in 105 consecutive patients prior to hip arthroscopy for FAIS, of which 84 (80.0%) completed minimum two-year patient reported outcomes. 3D models of the pelvis and femur were generated by semi-automated segmentation, and aligned to a standard coordinate system. Acetabular version was quantified at the 12, 2, and 3 o’clock position. (Figure I) Acetabular version classifications were based on the version at the 3 o’clock position, and were defined as follows: acetabular retroversion (AR [<15°]), normal acetabular version (NV [15°-25°]), and acetabular anteversion (AA [>25°]). Patient demographic characteristics and clinical outcomes including the Hip Outcome Score – Activities of Daily Living (HOS-ADL), Hip Outcome Score – Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), international Hip Outcome Tool (iHOT-12), and Visual Analog Scale (VAS) for pain and satisfaction were analyzed.Results:Mean age and body mass index (BMI) of patients was 33.9±12.6 years and 26.0±5.4 kg/m2, respectively, while 70.2% were female. The average acetabular version at 12, 2, and 3 o’clock for the study cohort was 9.3° ± 9.3°, 12.3° ± 7.4°, and 20.9° ± 5.7°, respectively (Figure II). After stratification based on the magnitude of acetabular anteversion at the 3 o’clock position, the number of patients and the average torsion within each group were as follows: AR (n=12; 11.3°±2.7°), NT (n=56; 20.7°±2.9°), AA (n=16; 28.5°±2.7°) (Figure III). At minimum two-year follow-up, significant between group differences in mHHS, iHOT-12, VAS for pain and satisfaction (P < 0.05) were appreciated (Table I). Post hoc analysis with Bonferroni correction (P < 0.0167) found lower scores on mHHS, iHOT-12, VAS for pain and satisfaction in patients with AR compared to NV (Table I). Lower VAS for satisfaction scores were reported in patients with AR when compared to AA (P = 0.006), but not mHHS (0.023), iHOT-12 (0.032), or VAS for pain (0.072) (Table I).Conclusions:Patients with AR reported inferior outcomes when compared to patients with NV and AA following hip arthroscopy for FAIS.

Outcomes for the Arthroscopic Treatment of Femoroacetabular Impingement Syndrome With Acetabular Retroversion: A 3D Computed Tomography Analysis

Background: Increased attention has been directed toward the acetabular morphology in the management of patients with femoroacetabular impingement syndrome (FAIS). Whether acetabular version influences patient-reported outcomes remains poorly understood. Purpose: To use computed tomography (CT)–based 3-dimensional (3D) bone models to (1) quantify acetabular version in patients with FAIS, (2) compare acetabular version on 3D bone models with current plain radiographic parameters, and (3) explore the relationship between the magnitude of acetabular version and minimum 2-year clinical outcomes after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: Three-dimensional models of the pelvis and femur were generated by semiautomated segmentation and aligned to a standard coordinate system. Acetabular version was quantified at the 3-o’clock position, and 3 groups were identified: acetabular retroversion (AR; <15°), normal acetabular version (NV; 15°-25°), and acetabular anteversion (AA; >25°). Patient demographic characteristics, plain radiographic parameters, and clinical outcomes were analyzed, including the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, modified Harris Hip Score (mHHS), International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Results: Preoperative CT scans were acquired in 105 consecutive patients before hip arthroscopy for FAIS, of which 84 (80.0%) completed minimum 2-year patient-reported outcomes. The mean ± SD age and body mass index of patients were 33.9 ± 12.6 years and 26.0 ± 5.4, respectively; 70.2% were female. The number of patients and the mean central acetabular version within each group were as follows: AR (n = 12; 11.3°± 2.7°), NV (n = 56; 20.7°± 2.9°), and AA (n = 16; 28.5°± 2.7°). Posterior wall sign was the only plain radiographic parameter that was significantly more observed in the AR group than in the other 2 groups. At minimum 2-year follow-up, significant between-group differences in the mHHS, iHOT-12, and VAS for pain and satisfaction (P < .05) were appreciated, while post hoc analysis with Bonferroni correction (P < .0167) found lower scores on the mHHS, iHOT-12, and VAS for pain and satisfaction in patients with AR as compared with NV. Lower scores on the VAS for satisfaction were reported in patients with AR when compared with AA (P = .006) but not on the mHHS (P = .023), iHOT-12 (P = .032), or VAS for pain (P = .072). Conclusion: Traditional plain radiographic indices to describe AR, including crossover sign and ischial spine sign, were not reliable in defining AR according to 3D models derived from CT scans. Only the posterior wall sign was observed in a higher proportion in the AR group. Patients with AR demonstrated inferior outcomes when compared with patients with NV and AA after hip arthroscopy for FAIS.

Association Between Preoperative Patient Factors and Clinically Meaningful Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Machine Learning Analysis

Background: The International Hip Outcome Tool 12-Item Questionnaire (IHOT-12) has been proposed as a more appropriate outcome assessment for hip arthroscopy populations. The extent to which preoperative patient factors predict achieving clinically meaningful outcomes among patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) remains poorly understood. Purpose: To determine the predictive relationship of preoperative imaging, patient-reported outcome measures, and patient demographics with achievement of the minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB) for the IHOT-12 at a minimum of 2 years postoperatively. Study Design: Case-control study; Level of evidence, 3. Methods: Data were analyzed for consecutive patients who underwent hip arthroscopy for FAIS between 2012 and 2018 and completed the IHOT-12 preoperatively and at a minimum of 2 years postoperatively. Fifteen novel machine learning algorithms were developed using 47 potential demographic, clinical, and radiographic predictors. Model performance was evaluated with discrimination, calibration, decision-curve analysis and the brier score. Results: A total of 859 patients were identified, with 685 (79.7%) achieving the MCID, 535 (62.3%) achieving the PASS, and 498 (58.0%) achieving the SCB. For predicting the MCID, discrimination for the best-performing models ranged from fair to excellent (area under the curve [AUC], 0.69-0.89), although calibration was excellent (calibration intercept and slopes: –0.06 to 0.02 and 0.24 to 0.85, respectively). For predicting the PASS, discrimination for the best-performing models ranged from fair to excellent (AUC, 0.63-0.81), with excellent calibration (calibration intercept and slopes: 0.03-0.18 and 0.52-0.90, respectively). For predicting the SCB, discrimination for the best-performing models ranged from fair to good (AUC, 0.61-0.77), with excellent calibration (calibration intercept and slopes: –0.08 to 0.00 and 0.56 to 1.02, respectively). Thematic predictors for failing to achieve the MCID, PASS, and SCB were presence of back pain, anxiety/depression, chronic symptom duration, preoperative hip injections, and increasing body mass index (BMI). Specifically, thresholds associated with lower likelihood to achieve a clinically meaningful outcome were preoperative Hip Outcome Score–Activities of Daily Living <55, preoperative Hip Outcome Score–Sports Subscale >55.6, preoperative IHOT-12 score ≥48.5, preoperative modified Harris Hip Score ≤51.7, age >41 years, BMI ≥27, and preoperative α angle >76.6°. Conclusion: We developed novel machine learning algorithms that leveraged preoperative demographic, clinical, and imaging-based features to reliably predict clinically meaningful improvement after hip arthroscopy for FAIS. Despite consistent improvements after hip arthroscopy, meaningful improvements are negatively influenced by greater BMI, back pain, chronic symptom duration, preoperative mental health, and use of hip corticosteroid injections.

Treatment of Full-Thickness Acetabular Chondral Flaps During Hip Arthroscopy: Bone Marrow Aspirate Concentrate Versus Microfracture.

Background:The optimal treatment strategy for patients with full-thickness chondral flaps undergoing hip arthroscopy is controversial.Purpose:To compare functional outcomes of patients who underwent bone marrow aspirate concentrate (BMAC) application with those of patients who underwent microfracture.Study Design:Cohort study; Level of evidence, 3.Methods:This was a retrospective case series of prospectively collected data on patients who underwent arthroscopic acetabular labral repair by 1 surgeon between June 2014 and April 2020. The inclusion criteria for this study were age ≥18 years, preoperative radiographs of the pelvis, arthroscopic acetabular labral repair, exposed subchondral bone with overlying chondral flap seen at the time of hip arthroscopy, microfracture or BMAC to address this lesion, and completed patient-reported outcome measures (PROMs) (International Hip Outcome Tool–33 [iHOT-33], Hip Outcome Score–Activities of Daily Living [HOS-ADL], Hip Outcome Score–Sports Subscale [HOS-Sport], modified Harris Hip Score [mHHS], and visual analog scale [VAS] for pain) at enrollment and 12-month follow-up. Clinical outcomes were assessed using PROM scores.Results:A total of 81 hips with full-thickness chondral flaps were included in this study: 50 treated with BMAC and 31 treated with microfracture. There were no significant differences between groups in age, sex, body mass index, tear size, radiographic osteoarthritis, or radiographic femoroacetabular impingement. In the BMAC cohort, all PROM scores improved significantly from preoperatively to follow-up: 41.7 to 75.6 for iHOT-33, 67.6 to 91.0 for HOS-ADL, 41.5 to 72.3 for HOS-Sport, 59.4 to 87.2 for mHHS, and 6.2 to 2.2 for VAS pain (P < .001 for all). In the microfracture cohort, the score improvements were 48.0 to 65.1 for iHOT-33 (P = .001), 80.5 to 83.3 for HOS-ADL (P = .275), 59.2 to 62.4 for HOS-Sport (P = .568), 70.4 to 78.3 for mHHS (P = .028), and 4.9 to 3.6 for VAS pain (P = .036). Regarding clinically meaningful outcomes, 77.6% of the BMAC group and 50.0% of the microfracture group met the minimal clinically important difference for iHOT-33 at the 12-month follow-up (P = .013).Conclusion:Patients with full-thickness chondral flaps at the time of hip arthroscopy experienced greater improvements in functional outcome scores at the 12-month follow-up when treated with BMAC as opposed to microfracture.

Return to Sport in Athletes With Borderline Hip Dysplasia After Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Background: Data on outcomes in patients with borderline hip dysplasia (BHD) who undergo hip arthroscopy remain limited, particularly in regard to return to sport (RTS). Purpose: To evaluate outcomes in patients with BHD and their ability to RTS after hip arthroscopy for treatment of femoroacetabular impingement syndrome (FAIS). Study Design: Case series; Level of evidence, 4. Methods: Consecutive patients with self-reported athletic activity and radiographic evidence of BHD, characterized by a lateral femoral center-edge angle (LCEA) between 18° and 25° and a Tönnis angle >10°, who underwent hip arthroscopy for FAIS between November 2014 and March 2017 were identified. Patient characteristics and clinical outcomes including the Hip Outcome Score–Activities of Daily Living (HOS-ADL), Hip Outcome Score–Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), international Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction were analyzed at minimum 2-year follow-up. In addition, all patients completed an RTS survey. Results: A total of 41 patients with a mean age and body mass index (BMI) of 29.6 ± 13.4 years and 25.3 ± 5.6, respectively, were included. Mean LCEA and Tönnis angle for the study population were 22.7°± 1.8° and 13.3°± 2.9°, respectively. A total of 31 (75.6%) patients were able to RTS after hip arthroscopy at a mean of 8.3 ± 3.2 months. A total of 14 patients (45.2%) were able to RTS at the same level of activity, 16 patients (51.6%) returned to a lower level of activity, and only 1 (3.2%) patient returned to a higher level of activity. Of the 11 high school and collegiate athletes, 10 (90.9%) were able to RTS. All patients demonstrated significant improvements in all patient-reported outcome measures (PROMs) as well as in pain scores at a mean of 26.1 ± 5.4 months after surgery. Patients who were able to RTS had a lower preoperative BMI than patients who did not RTS. Analysis of minimum 2-year PROMs demonstrated better HOS-ADL, HOS-SS, mHHS, iHOT-12, and VAS outcomes for pain in patients able to RTS versus those who did not RTS (P < .05). Conclusion: Of the patients with BHD studied here, 75.6% of patients successfully returned to sport at a mean of 8.3 ± 3.2 months after hip arthroscopy for FAIS. Of the patients who successfully returned to sport, 45.2% returned at the same level, and 3.2% returned at a higher activity level.

Clinically Significant Outcome Improvement After Hip Arthroscopy in Patients With Femoroacetabular Impingement Syndrome and Severe Femoral Torsion.

Background:The influence of femoral torsion on clinically significant outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) has not been well-studied.Purpose:To quantify femoral torsion in FAIS patients using magnetic resonance imaging (MRI) and explore the relationship between femoral torsion and clinically significant outcome improvement after hip arthroscopy.Study Design:Cohort study; Level of evidence, 3.Methods:Included were patients who underwent hip arthroscopy for FAIS between January 2012 and August 2018 and had 2-year follow-up and preoperative MRI scans containing transcondylar slices of the knee. Participants were categorized as having severe retrotorsion (SR; <0°), normal torsion (NT; 0°-25°), and severe antetorsion (SA; >25°) as measured on MRI. Patient-reported outcomes (PROs) included the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, modified Harris Hip Score, 12-item International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Achievement of Patient Acceptable Symptom State (PASS) and substantial clinical benefit (SCB) were analyzed among cohorts.Results:Included were 183 patients (SR, n = 13; NT, n = 154; SA, n = 16) with a mean age, body mass index, and femoral torsion of 30.6 ± 12.1 years, 24.0 ± 4.4 kg/m2, and 12.55° ± 9.58°, respectively. The mean torsion was –4.5° ± 2.6° for the SR, 12.1° ± 6.8° for the NT, and 31.0° ± 3.6° for the SA group. There were between-group differences in the proportion of patients who achieved PASS and SCB on the iHOT-12, pain VAS, and any PRO (P < .05). Post hoc analysis indicated that the SA group achieved lower rates of PASS and SCB on the iHOT-12 and pain VAS, and lower rates of PASS on any PRO versus the SR group (P < .05); the SR group achieved higher rates of PASS and SCB on pain VAS scores versus the NT group (P = .003).Conclusion:The orientation and severity of femoral torsion during hip arthroscopy influenced the propensity for clinically significant outcome improvement. Specifically, patients with femoral retrotorsion and femoral antetorsion had higher and lower rates of clinically significant outcome improvement, respectively.

The Natural Course of Recovery After Hip Arthroscopy for Femoroacetabular Impingement According to the International Hip Outcome Tool–12 and Hip Outcome Score Sports Subscale

Background: A paucity of literature exists regarding trajectories of functional and sports-specific recovery after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Purpose: To determine if subgroups of patients exist based on the recovery trajectory of patient-reported outcomes (PROs) after hip arthroscopy for FAIS in the short-term period and to determine clinical predictors for these subgroups of patients. Study Design: Case-control study; Level of evidence, 3. Methods: A prospectively maintained repository was queried for patients who had undergone primary hip arthroscopy for the treatment of FAIS between January 2012 and May 2018. Patients who completed the preoperative, 1-year, and 2-year International Hip Outcome Tool–12 (iHOT-12) or the Hip Outcome Score Sports Subscale (HOS-SS) were included. The latent class growth analysis (LCGA) and growth mixture models (GMMs) were used to identify subgroups of patients based on trajectories of recovery for the iHOT-12 and the HOS-SS utilizing preoperative, 1-year, and 2-year follow-ups. LCGA and GMM models using 1 to 6 classes for each PRO were performed, and the best-fit model for each PRO was selected. After final model selection, a multivariable multinomial logistic regression was performed, with the largest class being the reference group to determine clinical predictors of subgroup membership. Results: A total of 443 and 556 patients were included in the iHOT-12 and HOS-SS analyses, respectively. For the iHOT-12, we identified the following 3 subgroups: early progressors (70%), late regressors (22.3%), and late progressors (7.7%). Predictors of late regression were workers’ compensation status, psychiatric history, preoperative chronic pain, and lower preoperative iHOT-12 scores; and late progressors were less likely to participate in sports. For the HOS-SS, we identified the following 4 subgroups: early progressors (47.7%), late regressors (17.4%), late progressors (6.8%), and steady progressors (28.1%). Predictors of less favorable recovery trajectories (late regressors and late progessors) were older age, male sex, back pain, psychiatric history, preoperative chronic pain, greater alpha angle, and lower preoperative HOS-SS scores. Conclusion: Using the growth mixture modeling, 3 natural courses of health-related quality of life (early progression, late regression, and late progression) and 4 natural courses of recovery of athletic function (steady progression, late regression, late progression, and early progression) were identified. Preoperative psychiatric conditions, chronic pain, workers’ compensation status, and lower iHOT-12 scores were predictive of less than favorable trajectories of recovery according to the iHOT-12, and male sex, older age, back pain, preoperative narcotic use, and lower preoperative HOS-SS were predictors of less favorable recovery trajectories according to the HOS-SS.

Patient-Reported Outcomes Measurement Information System Test Is Less Responsive Than Legacy Hip-Specific Patient-Reported Outcome Measures in Patients Undergoing Arthroscopy for Femoroacetabular Impingement Syndrome

PurposeTo evaluate and compare the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) computerized adaptive test and PROMIS Pain Interference (PI) instruments versus legacy patient-reported outcome measures (PROMs) in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome at 1-year follow-up.MethodsPatients undergoing primary hip arthroscopy for the treatment of femoroacetabular impingement syndrome without concomitant procedures performed by a single surgeon between August 2018 and January 2019 were identified. The PROMIS PF score, PROMIS PI score, Hip Outcome Score–Activities of Daily Living Subscale (HOS-ADL), Hip Outcome Score–Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), International Hip Outcome Tool 12 (iHOT-12), and visual analog scale (VAS) pain score were obtained preoperatively and at 6 months and 1 year postoperatively. Bivariate correlation analyses between PROMIS and legacy PROMs were performed. The floor and ceiling effects, responsiveness, and relative efficiency (RE) of each PROM were calculated.ResultsThis study included 124 patients with an average age of 32.7 ± 12.3 years. The PROMIS PF score showed very good correlations with the HOS-ADL (r = 0.73, P < .001) and mHHS (r = 0.70, P < .001) and good correlations with the HOS-SS (r = 0.62, P < .001), iHOT-12 score (r = 0.62, P < .001), and VAS pain score (r = –0.64, P < .001). The PROMIS PI score showed very good inverse correlations with the HOS-ADL (r = –0.72, P < .001) and mHHS (r = –0.79, P < .001) and good correlations with the HOS-SS (r = –0.64, P < .001), iHOT-12 score (r = –0.65, P < .001), and VAS pain score (r = 0.65, P < .001). No floor effect was observed for any measure. Ceiling effects were not observed in the PROMIS PROMs but were detected for the HOS-ADL (16.1%) and mHHS (19.3%). The effect size was large for all outcomes: iHOT-12 score, d = 1.77; HOS-ADL, d = 1.37; HOS-SS, d = 1.45; PROMIS PI score, d = 1.05; and PROMIS PF score, d = 1.01. The iHOT-12 score was more responsive than the PROMIS PI score (RE = 1.69), PROMIS PF score (RE = 1.75), HOS-ADL (RE = 1.29), and HOS-SS (RE = 1.22).ConclusionsAt 1-year follow-up, PROMIS PROMs displayed very good correlations with legacy PROMs. However, PROMIS PROMs had lower effect sizes and were not as responsive as legacy PROMs.Level of EvidenceLevel II, development of diagnostic criteria on the basis of consecutive patients.

Association Between Orientation and Magnitude of Femoral Torsion and Propensity for Clinically Meaningful Improvement After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Computed Tomography Analysis

Background: Femoral torsion imaging measurements and classifications are heterogeneous throughout the literature, and the influence of femoral torsion on clinically meaningful outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) has not been well studied. Purpose: To (1) perform a computed tomography (CT)–based analysis to quantify femoral torsion in patients with FAIS and (2) explore the relationship between the orientation and magnitude of femoral torsion and the propensity for clinically meaningful outcome improvement after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: Consecutive patients who underwent hip arthroscopy for FAIS between January 2012 and April 2018 were identified. Inclusion criteria were the presence of preoperative CT imaging with transcondylar slices of the knee and minimum 2-year outcome measures. Exclusion criteria were revision hip arthroscopy, Tönnis grade >1, congenital hip condition, hip dysplasia (lateral center-edge angle <20°), and concomitant gluteus medius or minimus repair. Torsion groups were defined as severe retrotorsion (SR; <0°), moderate retrotorsion (MR; 0°-5°), normal torsion (N; 5°-20°), moderate antetorsion (MA; 20°-25°), and severe antetorsion of antetorsion (SA; >25°). Treatment did not differ based on femoral torsion. Patient characteristics and clinical outcomes were analyzed, including the Hip Outcome Score–Activities of Daily Living (HOS-ADL), Hip Outcome Score–Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), international Hip Outcome Tool (iHOT-12), visual analog scale (VAS) for pain, and VAS for satisfaction. Achievement of the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) by torsion stratification was analyzed using the chi-square test. Inter- and intrarater reliabilities for CT measurements were 0.980 (P < .001) and 0.974 (P < .001), respectively. Results: The study included 573 patients with a mean ± SD age and body mass index of 32.6 ± 11.8 years and 25.6 ± 10.6, respectively. The mean ± SD femoral torsion for the study population was 12.3°± 9.3°. After stratification, the number of patients within each group and the mean ± SD torsion for each group were as follows: SR (n = 36; –6.5°± 7.1°), MR (n = 80; 2.8°± 1.4°), N (n = 346; 12.3°± 4.1°), MA (n = 64; 22.2°± 1.4°), and SA (n = 47; 30.3°± 3.7°). No significant differences in age, body mass index, sex, tobacco use, workers’ compensation status, or participation in physical activity were observed at baseline. No significant differences were seen in pre- and postoperative VAS pain, mHHS, HOS-ADL, HOS-SS, iHOT-12, or postoperative VAS satisfaction among the cohorts. Furthermore, no statistically significant differences were found in the proportion of patients who achieved the MCID or the PASS for any outcome among the groups. Conclusion: The orientation and severity of femoral torsion at the time of hip arthroscopy for FAIS did not influence the propensity for clinically significant outcome improvement.

Defining Clinically Significant Improvement on the Patient-Reported Outcomes Measurement Information System Test at 1-Year Follow-up for Patients Undergoing Hip Arthroscopy for the Treatment of Femoroacetabular Impingement Syndrome

Background: Although minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB) have been defined for hip-specific legacy patient-reported outcome measures, these metrics have not been defined for the Patient-Reported Outcomes Measurement Information System (PROMIS) instruments for patients undergoing hip arthroscopy. Purpose: To define the MCID, PASS, and SCB thresholds for the PROMIS Physical Function (PF) computerized adaptive test (CAT) and PROMIS Pain Interference (PI) instruments in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Study Design: Cohort study (Diagnosis); Level of evidence, 2. Methods: Patients undergoing primary hip arthroscopy between August 2018 and January 2019 for the treatment of FAIS were retrospectively analyzed. Patients were administered the PROMIS-PF, PROMIS-PI, Hip Outcome Score (HOS)–Activities of Daily Living, HOS–Sports Subscale, modified Harris Hip Score, and International Hip Outcome Tool–12 preoperatively and at 1 year postoperatively. MCID was calculated using the distribution method, whereas PASS and SCB were calculated using an anchor-based method. Patients achieving clinically significant outcomes (CSOs) were compared with those who did not achieve CSOs via chi-square and independent-samples t tests, and a multivariate logistic regression was conducted to determine predictors of CSO achievement. Results: 124 patients with a mean age of 32.7 ± 12.3 years were included in the analysis. The threshold scores required to achieve MCID, PASS, and SCB, respectively, were as follows: PROMIS-PI (–3.1, 53.7, 51.9) and PROMIS-PF (3.3, 47.0, 49.9). Patients achieved any MCID, PASS, and SCB for PROMIS scores at a rate of 89.0%, 71.8%, and 62.1%, respectively, compared with 87.1%, 76.6%, and 71.8% for legacy patient-reported outcome measurements. For PROMIS-PF, higher preoperative PROMIS-PF score was a positive predictor of CSO achievement, and patients achieving SCB were significantly younger (30.3 ± 12 vs 35.6 ± 12 years; P = .017) with significantly lower body mass index (BMI) (24.7 ± 6.4 vs 27.9 ± 7; P = .009). Preoperative chronic pain and history of orthopaedic surgery were negative predictors of PROMIS-PI CSO achievement, whereas higher (worse) preoperative PROMIS-PI scores were a positive predictor. Conclusion: Our study defined the MCID, PASS, and SCB for the PROMIS-PF CAT and PROMIS-PI CAT at 1 year postoperatively. Patients with higher preoperative PROMIS scores, younger age, and lower BMI were more likely to achieve CSO, whereas preoperative chronic pain and history of orthopaedic surgery were negative predictors of CSO achievement.

Repeat Revision Hip Arthroscopy Outcomes Match That of Initial Revision But Not That of Primary Surgery for Femoroacetabular Impingement Syndrome

To (1) report on pre- and postoperative patient-reported outcome (PRO) scores for patients undergoing repeat revision surgery in short-term follow-up and (2) compare minimal clinically important difference (MCID) and patient acceptable symptomatic state achievement between primary, revision, and repeat revision hip arthroscopy cohorts. Data from consecutive patients undergoing revision hip arthroscopy from January 2012 to February 2019 were retrospectively reviewed. Hips that underwent 2 revision hip arthroscopic surgeries were identified and matched 1:3 to patients undergoing revision surgery and 1:3 to patients undergoing primary surgery by age, sex, and body mass index. Baseline demographic data, surgical indications, and hip-specific PROs were collected were obtained preoperatively and at minimum 1-year follow-up. MCID was calculated individually for each cohort. Twenty patients who underwent repeat revision were matched to 60 patients who underwent revision and 60 primary patients. Patients who underwent repeat revision achieved MCID on all investigated PROs at a similar rate to patients undergoing primary surgery (90.0% vs 91.7%, P= .588) and at a greater rate than patients undergoing first-time revision surgery (90.0% vs 71.7%, P= .045). Patients who underwent repeat revision achieved patient acceptable symptomatic state on all investigated PROs at a similar rate to patients who underwent first-time revision (30.0% vs 55.0%, P= .053) but at a significantly lower rate than primary patients (30.0% vs 76.7%, P < .001). However, patients undergoing repeat revision surgery had significantly lower preoperative PROs (P < .001 for all) and no significant difference in PROs at minimum 1-year follow-up compared with patients undergoing revision (P > .05). Compared with the primary cohort, patients who underwent repeat revision had significantly lower Hip Outcome Score-Activities of Daily Living (77.3 ± 16.7 vs 86.1 ± 14.4; P= .034), Hip Outcome Score-Sports Subscale (60.6 ± 27.2 vs 76.1 ± 23.8; P < .001), and modified Harris Hip Score (69.2 ± 19.3 vs 81.7 ± 16.1; P= .048) at a minimum of 1-year follow-up. Second-time revision hip arthroscopy, which often requires advanced procedures, results in clinically significant improvement in PROs; however, outcomes for repeat revision cases are similar to first-time revision cases but inferior to those obtained following primary surgeries. Level III, retrospective case-control study.

Machine Learning Algorithms Predict Functional Improvement After Hip Arthroscopy for Femoroacetabular Impingement Syndrome in Athletes.

Despite previous reports of improvements for athletes following hip arthroscopy for femoroacetabular impingement syndrome (FAIS), many do not achieve clinically relevant outcomes. The purpose of this study was to develop machine learning algorithms capable of providing patient-specific predictions of which athletes will derive clinically relevant improvement in sports-specific function after undergoing hip arthroscopy for FAIS. A registry was queried for patients who had participated in a formal sports program or athletic activities before undergoing primary hip arthroscopy between January 2012 and February 2018. The primary outcome was achieving the minimal clinically important difference (MCID) in the Hip Outcome Score-Sports Subscale (HOS-SS) at a minimum of 2 years postoperatively. Recursive feature selection was used to identify the combination of variables, from an initial pool of 26 features, that optimized model performance. Six machine learning algorithms (stochastic gradient boosting, random forest, adaptive gradient boosting, neural network, support vector machine, and elastic-net penalized logistic regression [ENPLR]) were trained using 10-fold cross-validation 3 times and applied to an independent testing set of patients. Models were evaluated using discrimination, decision-curve analysis, calibration, and the Brier score. A total of 1,118 athletes were included, and 76.9% of them achieved the MCID for the HOS-SS. A combination of 6 variables optimized algorithm performance, and specific cutoffs were found to decrease the likelihood of achieving the MCID: preoperative HOS-SS score of ≥58.3, Tönnis grade of 1, alpha angle of ≥67.1°, body mass index (BMI) of >26.6 kg/m2, Tönnis angle of >9.7°, and age of >40 years. The ENPLR model demonstrated the best performance (c-statistic: 0.77, calibration intercept: 0.07, calibration slope: 1.22, and Brier score: 0.14). This model was transformed into an online application as an educational tool to demonstrate machine learning capabilities. The ENPLR machine learning algorithm demonstrated the best performance for predicting clinically relevant sports-specific improvement in athletes who underwent hip arthroscopy for FAIS. In our population, older athletes with more degenerative changes, high preoperative HOS-SS scores, abnormal acetabular inclination, and an alpha angle of ≥67.1° achieved the MCID less frequently. Following external validation, the online application of this model may allow enhanced shared decision-making.