Causes and risk factors for revision hip preservation surgery

Multivariate linear-mixed analysis of changes in anterior inferior iliac spine impingement incidence with posterior pelvic tilt: a computer simulation study

It is well known that increased posterior tilt of the pelvis is an effective strategy for avoiding impingement of the femur with the pelvis during movement. Daily repetitive collisions become mechanical loads, and the more frequently they occur, the more tissue damage and pain they cause. Therefore, reducing the rate of occurrence of impingement is important to avoid aggravation of symptoms. This study aimed to evaluate the effects of changes in posterior pelvic tilt on the risk of impingement between the femur and the anterior inferior iliac spine (AIIS)/subspine in various functional postures. Patients with femoroacetabular impingement syndrome (FAIS) who were candidates for hip arthroscopic osteochondroplasty between October 2013 and June 2020 were included. A three-dimensional reconstructed model was used to simulate the incidence of impingement at 12 hip positions required for activities of daily living. We predicted value of the spatial incidence of impingement assumed that hip motion should exceed 130/30 degrees without impingement. Impingement was measured at three pelvic positions: an anterior tilt of 10°, in the functional pelvic plane and a posterior tilt of 10°. Multivariate linear-mixed models were used to assess the effect of covariate-adjusted posterior pelvic tilt on the impingement incidence in the AIIS region. AIIS type, center-edge angle, acetabular version and femoral version were used as covariates. The impingement rates and locations of the three pelvic tilt postures were assessed. Seventy-eight patients (60 males and 18 females; average age, 46 ± 15.1 years) with FAIS were analyzed. A multivariate linear-mixed model revealed a coefficient of -0.8% (95% confidence interval -0.9 to -0.7%; P < 0.001) for posterior pelvic tilt. Thus, posterior pelvic tilt affects AIIS impingement incidence. After adjusting for anatomical effects, the posterior pelvic tilt should be addressed to avoid impingement.

Patients Undergoing Revision Hip Arthroscopy Demonstrate Comparable Survivability and Improvement but Worse Postoperative Outcomes Compared to Patients Undergoing Primary Hip Arthroscopy: A Propensity Matched Study at Five-Year Follow-Up

PURPOSE

To compare mid-term clinical outcomes between patients undergoing primary hip arthroscopy (HA) versus revision hip arthroscopy (RHA) for femoroacetabular impingement syndrome (FAIS).

METHODS

A retrospective cohort study was conducted on 1,862 patients who underwent hip arthroscopy for FAIS from January 2012 to April 2017. Patients who underwent RHA were propensity matched in a 1:4 ratio by age, sex, body mass index (BMI), and exercise status to patients who underwent primary HA. Preoperative and postoperative radiographs were assessed. Patient-reported outcomes before and at 5 years after surgery, including the Hip Outcome Score Activities of Daily Living subscale (HOS-ADL) and 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 compared between groups. Minimally clinically important difference and patient-acceptable symptomatic state (PASS) achievement rates were compared using previously published thresholds.

RESULTS

Fifty-one patients who underwent RHA (35 female, 16 male; age 36.2 ± 10.2 years; BMI 26.5 ± 5.9) were followed up for 63.9 ± 9.2 months and then propensity matched in a 1:4 ratio by sex, age, and BMI to 204 control patients who underwent primary HA. At midterm follow-up, patients in the RHA cohort had significantly lower scores for HOS-SS (RHA 64.9 ± 32.5 vs HA 75.3 ± 26.2, P = .044), mHHS (RHA 72.2 ± 22.4 vs HA 80.1 ± 18.1, P = .039), and iHOT-12 (RHA 61.4 ± 29.3 vs HA 71 ± 27.6, P = .043) compared to primary HA patients. Rates of achieving PASS were significantly decreased for HOS-SS (RHA 38.3% vs HA 55.4%, P = .039) and iHOT-12 (RHA 41.9% vs HA 59.9%, P = .035) in the RHA cohort. There were no significant differences in rates of conversion to THA or subsequent reoperation on the index hip between groups.

CONCLUSIONS

Patients undergoing revision hip arthroscopy demonstrate comparable survivability and magnitude of improvement but may experience worse overall outcome scores and meet thresholds for clinically significant outcomes less often when compared to primary hip arthroscopy patients.

LEVEL OF EVIDENCE

Level III; retrospective comparative study.

Evaluating the Use of PROMs in Paediatric Orthopaedic Registries

Patient-reported outcome measures (PROMs) provide structured information on the patient's health experience and facilitate shared clinical decision-making. Registries that collect PROMs generate essential information about the clinical course and efficacy of interventions. Whilst PROMs are increasingly being used in adult orthopaedic registries, their use in paediatric orthopaedic registries is not well known. The purpose of this systematic review was to identify the frequency and scope of registries that collect PROMs in paediatric orthopaedic patient groups. In July 2023, six databases were systematically searched to identify studies that collected PROMs using a registry amongst patients aged under 18 years with orthopaedic diagnoses. Of 3190 identified articles, 128 unique registries were identified. Three were exclusively paediatric, 27 were majority paediatric, and the remainder included a minority of paediatric patients. One hundred and twenty-eight registries collected 72 different PROMs, and 58% of these PROMs were not validated for a paediatric population. The largest group of orthopaedic registries collected PROMs on knee ligament injuries (21%). There are few reported dedicated orthopaedic registries collecting PROMs in paediatric populations. The majority of PROMs collected amongst paediatric populations by orthopaedic registries are not validated for patients under the age of 18 years. The use of non-validated PROMs by registries greatly impedes their utility and impact. Dedicated orthopaedic registries collecting paediatric-validated PROMs are needed to increase health knowledge, improve decision-making between patients and healthcare providers, and optimise orthopaedic management.

Arthroscopic Decompression of the Anterior Inferior Iliac Spine

Background

Pathologic contact between the femoral neck and anterior inferior iliac spine (AIIS or subspine) often occurs concomitantly with femoroacetabular impingement, contributing to hip pain and dysfunction1-4. We perform arthroscopic AIIS decompression to alleviate this source of extra-articular impingement and eliminate a potential cause of persistent pain following primary hip arthroscopy5-7.

Description

After identifying abnormal AIIS morphology on preoperative false-profile radiographs and/or 3D computed tomography, we utilize a beaver blade to make a small incision in the proximal capsule and rectus femoris tendon. This peri-capsulotomy window grants access to the subspine region. We then shuttle an arthroscopic burr into place within this window and begin debriding the subspine deformity under direct visualization. Fluoroscopy is utilized intraoperatively to ensure adequate resection, using intraoperative false-profile views achieved by canting the C-arm approximately 40°. Resection is considered adequate when the AIIS deformity is no longer readily apparent on false-profile views and when intraoperative range-of-motion testing confirms no further impingement with hip hyperflexion.

Alternatives

Femoroacetabular impingement can be treated nonoperatively with use of physical therapy and activity modification8; however, outcomes following nonoperative treatment are inferior to those following hip arthroscopy, according to various studies9-12. There are no known alternative treatments specific to subspine impingement.

Rationale

As patients with subspine deformities progress through hip flexion, the femoral neck collides with the AIIS, limiting range of motion. As such, subspine deformities have been shown to be more common in dancers and other high-flexion athletes13,14. Additionally, studies have demonstrated that low femoral version of <5° is associated with increased contact between the distal femoral neck and the AIIS. This pathologic contact can occur even in the absence of an obvious subspine deformity15. In both of these patient populations, surgeons should have a high suspicion for subspine impingement, and a subspine decompression should be performed during hip arthroscopy in order to maximize patient outcomes.

Expected Outcomes

This is a safe procedure that, if performed when indicated, can improve outcomes following primary hip arthroscopy. A recent systematic review found a pooled complication risk of 1.1%, a pooled revision risk of 1.0%, and significant postoperative improvements in patient-reported outcome measures16.

Important Tips

Suspect subspine impingement in high-flexion athletes and patients with low femoral version, even in the absence of an obvious deformity.Ensure adequate visualization of the entire subspine deformity by creating a pericapsular window.Confirm thorough resection with use of fluoroscopic imaging intraoperatively, including false-profile views demonstrating absent subspine deformity.

Acronyms and Abbreviations

FAI = femoroacetabular impingementAP = anteroposterior, refers to the technique used to obtain one of the pelvic radiographs3D CT = three-dimensional computed tomographyLCEA = lateral center-edge angle, a measurement used to quantify severity of hip dysplasiaOR = operating roomAlpha = alpha angle, a measurement used to measure femoral head-neck offset and assess the severity of a cam deformityIc = iliocapsularisRFd = direct head of rectus femorisRFr = reflected head of rectus femorisCap = hip capsuleGMi = gluteus minimusmHHS = modified Harris Hip ScoreHOS-ADL = Hip Outcome Score - Activities of Daily LivingHOS-SSS = Hip Outcome Score - Sports Specific Subscale.

Outcomes of Arthroscopic Decompression of the Anterior Inferior Iliac Spine: A Systematic Review and Meta-analysis

BACKGROUND

Anterior inferior iliac spine (AIIS) impingement has been increasingly recognized as a source of extra-articular impingement and hip pain. However, no aggregate data analysis of patient outcomes after AIIS decompression has been performed.

PURPOSE

To evaluate outcomes after arthroscopic AIIS decompression.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were queried for all English-language studies reporting outcomes of arthroscopic AIIS decompression performed in isolation or in conjunction with hip impingement correction surgery. After screening, 10 articles were included. The indications for AIIS decompression were recorded, and weighted mean improvements in patient-reported outcome (PRO) scores, complication rates, and revision rates were calculated.

RESULTS

A total of 547 patients (311 women; 57%) were identified, with a total of 620 operative hips. The mean age was 28.42 ± 5.6 years, and the mean follow-up was 25.22 ± 11.1 months. A total of 529 hips (85%) underwent AIIS decompression, 530 hips (85%) underwent femoral osteochondroplasty, and 458 hips (74%) underwent labral repair. Of the patients, 13% underwent bilateral AIIS decompression. The mean modified Harris Hip Score improved from 61.3 ± 6.9 to 88.7 ± 4.7 postoperatively (change, 27.4 ± 5.7 points; P < .001), the Hip Outcome Score-Activities of Daily Living improved from 67.2 ± 10.6 to 91.1 ± 3.2 postoperatively (change, 24.0 ± 8.0 points; P = .001), and the Hip Outcome Score-Sports Specific Subscale improved from 36.8 ± 19.2 to 82.8 ± 3.8 postoperatively (change, 46.0 ± 18.2 points; P = .002). The pooled risk of postoperative complications was 1.1% (95% CI, 0.1%-2.1%), and the pooled risk of needing revision surgery was 1.0% (95% CI, 0.1%-2.0%). No complication was directly attributed to the AIIS decompression portion of the procedure.

CONCLUSION

PROs improved significantly after hip arthroscopy with AIIS decompression, with a low risk of postoperative complications and subsequent revision surgeries. Failure to identify extra-articular sources of hip pain in outcomes of femoroacetabular impingement syndrome, including from the AIIS, could lead to poorer outcomes and future revision surgery.

Femoral Version May Impact Hip Arthroscopy Outcomes in Select Patient Populations: A Systematic Review

PURPOSE

To provide further clarity regarding the management of patients with abnormal femoral version in the setting of hip arthroscopy and will discuss the definition of femoral version, the diagnostic and clinical evaluation of abnormal femoral version, and several described measurement techniques.

METHODS

A systematic review was conducted in literature published before August 2021 that measured femoral version and reported patient-reported outcomes measures or rates of subsequent procedures following hip arthroscopy. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed and the electronic databases, PubMed, OvidMedLine, Scopus, and Web of Science were searched. Two blinded reviews screened and evaluated data quality using the Newcastle-Ottawa Scale.

RESULTS

Eighteen studies were included with 11 studies reporting patient outcomes and 7 studies reporting rates of subsequent procedures. The most commonly used definition of femoral version was 5° to 20° of femoral anteversion. Computed tomography scan was the most commonly used imaging modality. The majority of studies (7 of 11) demonstrated that femoral version does not have an impact on patient-reported outcomes measures and is not predictive of clinically meaningful improvement scores. However, in select studies, patients with femoral retroversion were found to experience slightly inferior outcomes following hip arthroscopy for femoroacetabular impingement. While femoral retroversion may be a risk factor for subsequent procedures, 3 of 7 studies refute this claim. Although in patients with borderline hip dysplasia, excessive femoral anteversion led to greater rates of subsequent hip procedures.

CONCLUSIONS

While the majority of studies show that femoral version does not have an impact on patient-reported outcomes following hip arthroscopy, those with femoral retroversion and with excessive anteversion with coexisting borderline hip dysplasia need to be educated on their increased risk of subsequent operation. Ultimately, this review suggests that clinical improvement can likely be achieved regardless of femoral version.

LEVEL OF EVIDENCE

IV; systematic review of Level I-IV studies.

Arthroscopic Hip Capsular Reconstruction Using Iliotibial Band Allograft as a Salvage Option for Unrepairable Capsular Defects Demonstrates Good Survivorship and Improved Patient-Reported Outcomes

PURPOSE

To describe patient outcomes 3 to 5 years after arthroscopic hip capsule reconstruction.

METHODS

Between January 2007 and December 2016, patients aged 18 to 50 years who underwent arthroscopic hip capsular reconstruction using an Iliotibial band allograft by the senior author and had minimum of 3-year follow-up were identified. Patients were excluded if they had previous open hip surgery, advanced osteoarthritis (Tönnis grade >2), significant acetabular dysplasia (lateral center edge angle <20°), avascular necrosis, or Legg-Calve-Perthes disease. Outcome scores including the Hip Outcome Score (HOS)-Activities of Daily Living scale, modified Harris Hip Score, HOS-Sports scale, SF-12, and Western Ontario & McMaster Universities Osteoarthritis Index were compared in addition to failure rate, revision rate, and patient satisfaction rate with the outcome (range, 1-10). All patients were assessed by the senior author pre- and postoperatively.

RESULTS

Thirty-nine patients met the inclusion criteria. The mean age of the cohort was 32 ± 10 years, with 6 male and 33 female patients. The average number of previous hip arthroscopy surgeries was 2 ± 1. Six patients (15%) converted to total hip arthroplasty at an average of 2.1 years (range 7 months to 6 years) following capsular reconstruction. Four patients required revision hip arthroscopy after the arthroscopic capsular reconstruction. All arthroscopic revisions occurred in female patients with the primary intraoperative finding of capsulolabral adhesions at the time of revision. At mean follow-up of 4.3 years (range 3-6.8 years), the 29 patients who did not require subsequent surgery had significant improvements from preoperatively to postoperatively in HOS-Activities of Daily Living and HOS-Sport with 90% reaching minimal clinically important difference. All other scores showed significant improvement. Survival for patients not requiring total hip arthroplasty was 86% at 3 years, with a mean survival of 5.7 years (95% confidence interval 4.97-6.4).

CONCLUSIONS

Arthroscopic hip capsular reconstruction with iliotibial band allograft is a successful treatment option for patients with symptomatic capsular defects, demonstrating improved patient-reported outcomes maintained at mean follow-up time of 4 years. This technique offers restoration of the anatomic structure and function of the capsular ligaments to improve pain and instability.

LEVEL OF EVIDENCE

IV, case series.

Arthroscopic Treatment of Mild/Borderline Hip Dysplasia with Concomitant Femoroacetabular Impingement-Literature Review

Purpose of Review

This literature review aims to survey the current knowledge about the management FAI in the setting of borderline hip dysplasia.

Recent Findings

With better understanding, hip arthroscopy has recently been advocated for treating mild or borderline hip dysplasia (BDH) with concomitant femoroacetabular impingement (FAI) despite early studies that condemned its use. Recent outcome data have demonstrated that hip arthroscopy is a viable option in BDH, with and without FAI, and has been gaining wider acceptance. Hip arthroscopy can address the concomitant soft tissue and bony intra-articular pathologies and obviate the necessity for other surgeries. Moreover, hip arthroscopy may be used as an adjuvant treatment to other procedures such as a periacetabular osteotomy (PAO).

Summary

Hip arthroscopy for BDH is an evolving procedure with promising short- and mid-term outcomes. The combination of BDH and FAI is becoming recognized as a problem in its own right, requiring dedicated treatment.

Revision Hip Arthroscopy in High-Level Athletes: Minimum 2-Year Outcomes Comparison to a Propensity-Matched Primary Hip Arthroscopy Control Group

BACKGROUND

Outcomes of revision hip arthroscopy in the athletic population have not been well established.

PURPOSE

(1) To report clinical outcomes for high-level athletes undergoing revision hip arthroscopy in the setting of femoroacetabular impingement syndrome (FAIS) or labral tears and (2) to compare these outcomes against a propensity-matched group of high-level athletes undergoing primary hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data for professional, college, and high school athletes were prospectively collected and retrospectively reviewed between January 2012 and October 2018. Patients were included if they underwent revision or primary hip arthroscopy and had preoperative and minimum 2-year patient-reported outcome (PRO) scores for modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score Sports-Specific Subscale (HOS-SSS), and visual analog scale (VAS) for pain. The findings and outcomes of revision athletes were compared with a propensity-matched control group of high-level athletes undergoing primary hip arthroscopy.

RESULTS

A total of 32 hips (29 patients) undergoing revision hip arthroscopy and 92 hips (88 patients) undergoing primary hip arthroscopy were included in our final analysis with a median follow-up time of 29.5 months (95% CI, 27.2-32.1 months) and 36.5 months (95% CI, 33.5-37.7 months), respectively. Athletes undergoing revision surgery showed significant improvement in all recorded PRO measurements and achieved patient acceptable symptomatic state (PASS) and minimal clinically important difference (MCID) for mHHS at high rates (80.6% and 83.9%, respectively). When compared with a propensity-matched primary control group, patients undergoing revision surgery demonstrated lower preoperative and postoperative scores for mHHS, NAHS, and HOS-SSS, but the magnitude of improvement in functional scores was similar between groups. Athletes undergoing revision surgery achieved PASS for HOS-SSS at lower rates than the control group (P = .005), and they were less likely to attempt to return to sport compared with the control group (62.5% vs 87.0%; P < .01).

CONCLUSION

Revision hip arthroscopy is a viable treatment option to improve PROs in high-level athletes at minimum 2-year follow-up. The study group showed significant improvement in functional scores and a high rate of successful outcomes. They experienced similar magnitude of improvement as that of a propensity-matched control group; however, they achieved lower postoperative PRO scores and attempted to return to sport at lower rates.

Subspine Hypertrophy: Higher Incidence of Symptomatic versus Asymptomatic Hips in Patients with Unilateral Femoroacetabular Impingement

Objective

To compare the difference of anterior inferior iliac spine (AIIS) and subspine hypertrophic deformity between symptomatic and asymptomatic hips in patients traditionally diagnosed with femoroacetabular impingement (FAI), and investigate the correlation of subspine decompression with AIIS variation and subspine hypertrophic deformity.

Methods

We retrospectively reviewed 70 patients with unilateral symptomatic FAI who underwent hip arthroscopy. The operative hips and contralateral hips naturally formed the symptomatic groups and asymptomatic control groups, respectively. The morphometric comparison of the hip joint was performed between the operative and contralateral sides of each patient. Radiological assessment was performed by two observers (an experienced musculoskeletal radiologist and an experienced surgeon). Three‐dimensional (3D)‐CT images of each patient were blindly reviewed to determine the AIIS variation and subspine hypertrophic deformity. Reformatted two‐dimensional (2D)‐CT images and anterior–posterior (AP) pelvic plain radiographs were blindly reviewed to determine FAI‐related morphological measurements. Moreover, the surgical assessment was reviewed by one experienced surgeon to interpret whether subspine decompression was performed. The correlation of subspine decompression with AIIS variation and subspine hypertrophy was analyzed.

Results

Out of 70 patients with unilateral symptomatic FAI, 37 were males (52.9%) and 23 (32.9%) had symptoms involving the left hip. The mean age was 39.3 ± 10.4 years and the mean BMI was 24.3 ± 3.6. The distribution of AIIS variants in symptomatic hips did not differ significantly from that in asymptomatic hips (χ² = 3.092, P = 0.213). Twenty‐nine hips in the symptomatic group (41.4%) and 12 hips in the asymptomatic group (17.1%) were identified as positive for subspine hypertrophy. The incidence of positive subspine hypertrophy was significantly higher in the symptomatic hips compared to the asymptomatic hips (χ² = 9.968, P = 0.002). FAI‐related morphological parameters including α angle, lateral center‐edge angle, acetabular anteversion, crossover sign, and Tonnis grade were highly symmetrical and did not show significant differences between symptomatic and asymptomatic hips. Fifty‐four of 70 hips (77.1%) had labral tears extended to the acetabular rim corresponding to the AIIS. Forty‐seven hips of 70 hips (67.1%) underwent subspine decompression, which was significantly correlated with AIIS variation and subspine hypertrophic deformity (P = 0.019 and 0.001, respectively).

Conclusion

Subspine hypertrophic deformity was found to be more common in symptomatic side vs asymptomatic side in patients with unilateral symptomatic femoroacetabular impingement. Subspine hypertrophy may be considered as an underlying indication for subspine decompression besides low‐lying AIIS.

Predicting the Risk of Subsequent Hip Surgery Before Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Machine Learning Analysis of Preoperative Risk Factors in Hip Preservation

BACKGROUND

The number of patients requiring reoperation has increased as the volume of hip arthroscopy for femoroacetabular impingement syndrome (FAIS) has increased. The factors most important in determining patients who are likely to require reoperation remain elusive.

PURPOSE

To leverage machine learning to better characterize the complex relationship across various preoperative factors (patient characteristics, radiographic parameters, patient-reported outcome measures [PROMs]) for patients undergoing primary hip arthroscopy for FAIS to determine which features predict the need for future ipsilateral hip reoperation, namely, revision hip arthroscopy, total hip arthroplasty (THA), hip resurfacing arthroplasty (HRA), or periacetabular osteotomy (PAO).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A cohort of 3147 patients undergoing 3748 primary hip arthroscopy procedures were included from an institutional hip preservation registry. Preoperative computed tomography of the hip was obtained for each patient, from which the following parameters were calculated: the alpha angle; the coronal center-edge angle; the neck-shaft angle; the acetabular version angle at 1, 2, and 3 o'clock; and the femoral version angle. Preoperative PROMs included the modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS)-Activities of Daily Living subscale (HOS-ADL) and the Sport Specific subscale, and the international Hip Outcome Tool (iHOT-33). Random forest models were created for revision hip arthroscopy, the THA, the HRA, and the PAO. Area under the curve (AUC) for the receiver operating characteristic curve and accuracy were calculated to evaluate each model.

RESULTS

A total of 171 patients (4.6%) underwent subsequent hip surgery after primary hip arthroscopy for FAIS. The AUC and accuracy, respectively, were 0.77 (fair) and 76% for revision hip arthroscopy (mean, 26.4-month follow-up); 0.80 (good) and 81% for THA (mean, 32.5-month follow-up); 0.62 (poor) and 69% for HRA (mean, 45.4-month follow-up); and 0.76 (fair) and 74% for PAO (mean, 30.4-month follow-up). The most important factors in predicting reoperation after primary hip arthroscopy were higher body mass index (BMI) and lower preoperative HOS-ADL for revision hip arthroscopy, greater age and lower preoperative iHOT-33 for THA, increased BMI for HRA, and larger neck-shaft angle and lower preoperative mHHS for PAO.

CONCLUSION

Despite the low failure rate of hip arthroscopy for FAIS, our study demonstrated that machine learning has the capability to identify key preoperative risk factors that may predict subsequent ipsilateral hip surgery before the index hip arthroscopy. Knowledge of these demographic, radiographic, and patient-reported outcome data may aid in preoperative counseling and expectation management to better optimize hip preservation.

Revision Hip Arthroscopy in the Native Hip: A Review of Contemporary Evaluation and Treatment Options

Hip arthroscopy is a reproducible and efficacious procedure for the treatment of femoroacetabular impingement syndrome (FAIS). Despite this efficacy, clinical failures are observed, clinical entities are challenging to treat, and revision hip arthroscopy may be required. The most common cause of symptom recurrence after a hip arthroscopy that leads to a revision arthroscopy is residual cam morphology as a result of inadequate femoral osteochondroplasty and restoration of head–neck offset, though several other revision etiologies including progressive chondral and labral pathologies also exist. In these cases, it is imperative to perform a comprehensive examination to identify the cause of a failed primary arthroscopy as to assess whether or not a revision hip arthroscopy procedure is indicated. When a secondary procedure is indicated, approaches may consist of revision labral repair, complete labral reconstruction, or labral augmentation depending on labral integrity. Gross instability or imaging-based evidence of microinstability may necessitate capsular augmentation or plication. If residual cam or pincer morphology is present, additional resection of the osseous abnormalities may be warranted. This review article discusses indications, the evaluation of patients with residual symptoms after primary hip arthroscopy, and the evaluation of outcomes following revision hip arthroscopy through an evidence-based discussion. We also present a case example of a revision hip arthroscopy procedure to highlight necessary intraoperative techniques during a revision hip arthroscopy.

Complete Capsular Closure Provides Higher Rates of Clinically Significant Outcome Improvement and Higher Survivorship Versus Partial Closure After Hip Arthroscopy at Minimum 5-Year Follow-Up

PURPOSE

To (1) compare the rates of reaching threshold hip-specific outcome scores for achieving the minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS) in patients who underwent partial versus complete T-capsulotomy repair and (2) identify the failure rates in each group 5 years after undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS).

METHODS

Data from consecutive patients who underwent hip arthroscopy for FAIS performed by a single fellowship-trained surgeon from January 2011 to March 2013 were collected and analyzed. Baseline data, hip-specific outcomes, and clinical failure rates were recorded at a minimum of 5 years postoperatively. Patients with partial T-capsulotomy repair were matched 1:3 by age, body mass index, and sex to patients with complete T-capsulotomy repair. Threshold scores for achieving the MCID and PASS were calculated and compared between the 2 groups. Additionally, rates of revision and conversion to total hip arthroplasty (THA) were compared between the groups.

RESULTS

A total of 379 patients were available for analysis (39 partial and 340 complete repairs), with 100 patients included in the matching process (25 in the partial-repair group and 75 in the complete-repair group). Comparison of radiographic parameters, including the Tönnis grade, alpha angle, and lateral center-edge angle, between the 2 groups showed no statistically significant difference (P > .05 for all). Comparison of postoperative score averages between the partial- and complete-closure groups showed a significant difference in the Hip Outcome Score-Activities of Daily Living Subscale (85.4 ± 17.7 vs 94.6 ± 7.8, P < .001), Hip Outcome Score-Sports Subscale (76.6 ± 26.2 vs 89.3 ± 16.8, P = .034), modified Harris Hip Score (83.2 ± 19.7 vs 90.5 ± 11.2, P = .035), and visual analog scale pain score (24.5 ± 30.8 vs 13.4 ± 15.8, P = .035). A total of 65 complete-repair patients (95.6%) achieved the MCID for at least 1 outcome measure versus 18 patients with partial repair (78.3%) (P = .04). A total of 69 complete-repair patients (92%) achieved the PASS for at least 1 outcome measure versus 18 partial-repair patients (72%) (P = .017). Of the 39 partial-repair patients, 35.9% (n = 14) underwent revision or conversion to THA, as compared with 2.9% (n = 10) in the overall cohort.

CONCLUSIONS

At a minimum 5-year follow-up, patients with complete capsular closure after hip arthroscopy for FAIS show superior long-term outcomes and achieve higher rates of meaningful clinical success when compared with patients with partial capsular closure. Furthermore, patients with partial capsular repair undergo revision or conversion to THA at high rates.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Posterior Extra-articular Ischiofemoral Impingement Can Be Caused by the Lesser and Greater Trochanter in Patients With Increased Femoral Version: Dynamic 3D CT-Based Hip Impingement Simulation of a Modified FABER Test

Background:

Posterior extra-articular hip impingement has been described for valgus hips with increased femoral version (FV). These patients can present clinically with lack of external rotation (ER) and extension and with a positive posterior impingement test. But we do not know the effect of the combination of deformities, and the impingement location in early flexion is unknown.

Purpose:

To evaluate patient-specific 3-dimensional computed tomography (3D CT) scans of hips with increased FV and control hips for differences in range of motion, location and prevalence of osseous posterior intra- and extra-articular hip impingement.

Study Design:

Case series; Level of evidence, 4.

Methods:

Osseous 3D models based on segmentation of 3D CT scans were analyzed for 52 hips (38 symptomatic patients) with positive posterior impingement test and increased FV (>35°). There were 26 hips with an increased McKibbin instability index >70 (unstable hips). Patients were mainly female (96%), with an age range of 18 to 45 years. Of them, 21 hips had isolated increased FV (>35°); 22 hips had increased FV and increased acetabular version (AV; >25°); and 9 valgus hips (caput-collum-diaphyseal angle >139°) had increased FV and increased AV. The control group consisted of 20 hips with normal FV, normal AV, and no valgus (caput-collum-diaphyseal angle <139°). Validated 3D CT–based collision detection software for impingement simulation was used to calculate impingement-free range of motion and location of hip impingement. Surgical treatment was performed after the 3D CT–based impingement simulation in 27 hips (52%).

Results:

Hips with increased FV had significantly (P < .001) decreased extension and ER at 90° of flexion as compared with the control group. Posterior impingement was extra-articular (92%) in hips with increased FV. Valgus hips with increased FV and AV had combined intra- and extra-articular impingement. Posterior hip impingement occurred between the ischium and the lesser trochanter at 20° of extension and 20° of ER. Impingement was located between the ischium and the greater trochanter or intertrochanteric area at 20° of flexion and 40° of ER, with a modification of the flexion-abduction-ER (FABER) test.

Conclusion:

Posterior extra-articular ischiofemoral hip impingement can be caused by the lesser and greater trochanter or the intertrochanteric region. We recommend performing the modified FABER test during clinical examination in addition to the posterior impingement test for female patients with high FV. In addition, 3D CT can help for surgical planning, such as femoral derotation osteotomy and/or hip arthroscopy or resection of the lesser trochanter.

Clinical outcomes after revision hip arthroscopy in patients with femoroacetabular impingement syndrome (FAIS) are inferior compared to primary procedures. Results from the Danish Hip Arthroscopy Registry (DHAR)

PURPOSE

As many as 10% of primary hip arthroscopies end up with a revision arthroscopy procedure when treating patients suffering from femoroacetabular impingement syndrome (FAIS). In general, revision procedures are indicated because of residual impingement, but only a few studies present outcome data from revision hip arthroscopy after failed FAIS surgical treatment. The purpose of this study was to evaluate clinical outcomes after revision hip arthroscopy in a FAIS cohort and compare outcomes with a primary FAIS hip arthroscopy cohort and describe potential causes of failure after the primary hip arthroscopy. It was hypothesized that subjective outcomes improve after revision hip arthroscopy although outcomes were expected to be inferior to primary hip arthroscopic outcomes.

METHODS

Three-hundred and thirty-one arthroscopic revision hip FAIS patients were included from the Danish Hip Arthroscopy Registry (DHAR). Patient-related outcome measures (PROM's), Copenhagen Hip and Groin Outcome Scores (HAGOS), Hip Sports Activity Scale (HSAS), EQ-5D and Numeric Rating Scale (NRS) pain, were assessed in the study cohort prior to the primary procedure and at revision and at follow-up one year after the revision procedure. These data were compared with 4154 primary hip arthroscopic FAIS patients.

RESULTS

One-year after revision surgery, mean follow-up (in months ± SD): 12.3 ± 1.6, significant improvements (p < 0.05) in all PROMs was demonstrated, but FAIS patients in the primary hip arthroscopic cohort demonstrated significantly higher outcomes, in all PROMs, when compared at one-year follow-up. Scar tissue, residual osseous impingement and insufficient healing of the labral repair were reported as the main reasons for revision surgery. The conversion to total hip arthroplasty was low (6.4%).

CONCLUSION

Revision hip arthroscopy in FAIS patients improves subjective outcomes significantly, although they are poorer than after primary FAIS hip arthroscopy. Main reasons for revision arthroscopy was scar tissue, residual femoroacetabular impingement and insufficient healing of labral repair.

LEVEL OF EVIDENCE

Level III.

Biochemical MRI With dGEMRIC Corresponds to 3D-CT Based Impingement Location for Detection of Acetabular Cartilage Damage in FAI Patients

Background

Anterior femoroacetabular impingement (FAI) is associated with labral tears and acetabular cartilage damage in athletic and young patients. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is an imaging method for detecting early damage to cartilage.

Purpose

We evaluated the following questions: (1) What is the sensitivity and specificity of morphological magnetic resonance imaging (MRI) and dGEMRIC for detecting cartilage damage? Do the mean acetabular and femoral dGEMRIC indices differ between (2) superior acetabular clock positions with and without impingement and (3) between cam- and pincer-type FAI?

Study Design

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

Methods

This was a retrospective comparative study of 21 hips (20 patients with symptomatic anterior FAI) without osteoarthritis on anteroposterior radiographs. Morphological MRI and dGEMRIC (3.0-T, 3-dimensional [3D] T1 maps, dual-flip angle technique) of the same hip joint were compared. Intraoperative acetabular cartilage damage was assessed in patients who underwent surgical treatment. Computed tomography (CT)-based 3D bone models of the same hip joint were used as the gold standard for the detection of impingement, and dGEMRIC indices and zones of morphologic damage were compared with the CT-based impingement zones.

Results

Of the 21 hips, 10 had cam-type FAI and 8 had pincer-type FAI according to radiographs. The mean age was 30 ± 9 years (range, 17-48 years), 71% were female, and surgical treatment was performed in 52%. We found a significantly higher sensitivity (69%) for dGEMRIC compared with morphological MRI (42%) in the detection of cartilage damage (P < .001). The specificity of dGEMRIC was 83% and accuracy was 78%. The mean peripheral acetabular and femoral dGEMRIC indices for clock positions with impingement (485 ± 141 and 440 ± 121 ms) were significantly lower compared with clock positions without impingement (596 ± 183 and 534 ± 129 ms) (P < .001). Hips with cam-type FAI had significantly lower acetabular dGEMRIC indices compared with hips with pincer-type FAI on the anterosuperior clock positions (1 to 3 o'clock) (P = .018).

Conclusion

MRI with dGEMRIC was more sensitive than morphological MRI, and lower dGEMRIC values were found for clock positions with impingement as detected on 3D-CT. This could aid in patient-specific diagnosis of FAI, preoperative patient selection, and surgical decision making to identify patients with cartilage damage who are at risk for inferior outcomes after hip arthroscopy.

Achievement of Meaningful Clinical Outcomes Is Unaffected by Capsulotomy Type During Arthroscopic Treatment of Femoroacetabular Impingement Syndrome: Results From the Multicenter Arthroscopic Study of the Hip (MASH) Study Group

BACKGROUND

Capsule management has emerged as an important topic in the field of hip arthroscopy. The 2 most popular techniques are interportal capsulotomy and T-type capsulotomy, but few studies have compared outcomes between these 2 techniques.

PURPOSE

To compare 2-year (±2 months) patient-reported outcomes (PROs) between patients who underwent interportal versus T-type capsulotomy during arthroscopic labral repair for femoroacetabular impingement syndrome (FAIS).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective review of a large multicenter registry of patients undergoing arthroscopic hip preservation surgery for FAIS was performed. Data from 9 surgeons across 9 sites between January 2014 and February 2018 were included in the study. Baseline demographic data, preoperative PROs, and minimum 2-year postoperative PROs including Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sports Subscale (HOS-SS), modified Harris Hip Score, and International Hip Outcome Tool-12 (iHOT-12) were recorded. Patients were divided into 2 groups based on whether interportal or T-type capsulotomy was performed according to the senior surgeon's preference and training, and all capsulotomies were then routinely repaired. The 2 groups were matched 1:1 by age, sex, and body mass index (BMI). Achievement of minimal clinically important difference (MCID), Patient Acceptable Symptomatic State (PASS), and substantial clinical benefit (SCB) was compared for the HOS-ADL, HOS-SS, and iHOT-12 between the 2 groups.

RESULTS

The final analysis included 658 of 1483 eligible patients with a mean ± SD age of 32.6 ± 11.6 years and BMI of 24.0 ± 3.7; of these, 329 patients were treated via interportal capsulotomy, and 329 patients were treated via T-type capsulotomy. Female patients comprised 66.3% of the study population. Capsulotomy type was not a predictor of 2-year postoperative PROs on multivariate linear regression analysis when adjusted for covariates. Chi-square analysis showed no statistical difference in achievement of MCID, PASS, and SCB between the interportal and T-type groups for HOS-ADL (80.3%, 75.8%, 52.7% and 77.1%, 71.7%, 53.6%, respectively; P > .01 for all), HOS-SS (83.6%, 72.5%, 51.5% and 81.7%, 68.4%, 49.2%, respectively; P > .01 for all), and iHOT-12 (87.5%, 72.0%, 50.5% and 80.0%, 64.7%, 45.6%, respectively; P > .01 for all).

CONCLUSION

Arthroscopic management of FAIS resulted in significant clinical improvement that was independent of capsulotomy type when the capsulotomy included repair.

Prevalence of Anterior Inferior Iliac Spine Dysmorphism and Development of a Novel Classification System: An Anatomic Study of 1,797 Cadaveric Specimens

Purpose: Subspine impingement occurs due to a morphologically abnormal anterior inferior iliac spine (AIIS), capable of causing impingement against the distal femoral neck. The purpose of this investigation was to determine the prevalence of AIIS dysmorphism based on specimen sex, race, and age, while introducing a novel anatomic-based classification system.

Methods: A total of 1,797 adult cadaveric specimens (n = 3,594 hemipelvises) were analyzed. AIIS with the potential for subspine impingement (SSI) was recorded in each specimen by two independent authors. Specimens with AIIS dysmorphism were then reexamined to determine SSI subtype using a novel descriptive anatomic classification system.

Results: AIIS dysmorphism was present in 6.4% (n = 115 of 1,797 specimens) of specimens and 5.2% (n = 186 of 3,594) of hemipelvises. Dysmorphism was significantly more common in male specimens (p = 0.04) and African–American specimens (p = 0.04). No significant overall difference in prevalence was appreciated based on specimen age (p = 0.89). Subtype classification found that 67% of hemipelvises possessed a columnar type AIIS, 30% were bulbous and 3% hook type. Males possessed a significantly higher prevalence of columnar type AIIS dysmorphism (p < 0.001). No significant overall differences in anatomic classification were appreciated based on race (p = 0.12) or when analyzed based on age (p = 0.34).

Conclusion: AIIS dysmorphism was present in 6.4% of the 1,797 cadaveric specimens evaluated. African-American and male specimens possessed significantly higher prevalence of AIIS dysmorphism, with no significant difference based on specimen age. Columnar type AIIS dysmorphism was most common. Anatomic classification was not significantly different based on specimen race or age.

Level of Evidence: Case Series, Level IV.

Approach to the Patient With Failed Hip Arthroscopy for Labral Tears and Femoroacetabular Impingement

There has been an exponential increase in the diagnosis and treatment of patients with femoroacetabular impingement, leading to a rise in the number of hip arthroscopies done annually. Despite reliable pain relief and functional improvements after hip arthroscopy in properly indicated patients, and due to these increased numbers, there is a growing number of patients who have persistent pain after surgery. The etiology of these continued symptoms is multifactorial, and clinicians must have a fundamental understanding of these causes to properly diagnose and manage these patients. Factors contributing to failure after surgery include those related to the patient, the surgeon, and the postoperative physical therapy. This review highlights common causes of failure, including those related to residual bony deformity as well as capsular deficiency, and provides a framework for diagnosis and treatment of these patients.

Running with Femoral Acetabular Impingement: Operative Vs Nonoperative Treatment

A 31-year-old female lawyer presents with right hip pain starting approximately 3 years ago and worsening over the past 2 to 3 months. She is an avid runner, running 20 to 30 miles weekly, and noticed that her pain started after a running program training for the marathon. Her pain is primarily over the lateral aspect of her hip with some radiation into the groin. The pain is made worse with impact exercises such as running and made better with walking and cycling. She has done physical therapy for the past 3 months without any significant improvement. She has not had any injections or taken anti-inflammatories because of a history of gastric ulcer disease. On physical examination she has mild tenderness over her right greater trochanter and her range of motion tests are full in terms of flexion, internal rotation, and external rotation. She has a positive FADIR (flexion-adduction-internal rotation) impingement that causes both groin and lateral hip pain. Radiograph of the right hip revealed preservation of the joint space and an anterior cam lesion with reduced offset at the femoral head neck junction. Magnetic resonance imaging (MRI) of the right hip revealed a tear at the anterior superior labrum at the 1 to 2 o'clock position along with subjacent bone marrow edema in the femoral head that is likely reactive. Computed tomography (CT) scan of the right hip confirmed a combined cam and pincer type femoral acetabular impingement of the right hip with overcoverage of the femoral head. There was 15° of femoral anteversion and the coronal lateral center of edge angle (LCEA) is 34°. Dr. Peter Moley argues that a focused rehabilitation program to restore strength and motor control of the deep hip stabilizers will provide optimal functional recovery. Dr. Jakub Tatka argues that right hip arthroscopy with labral repair and possible osteochondralplasty are indicated in order to prevent early hip arthritis and prevent long-term sequela of femoral acetabular impingement.

Survivorship Following Hip Arthroscopy: Lessons Learned from a Comprehensive Database

PURPOSE OF REVIEW

Hip arthroscopy and its indications continue to expand. Understanding the durability of hip arthroscopic procedures remains important not only for counseling patients, but also for determining the success of certain procedures or in certain populations. Survivorship is defined as the proportion of hip arthroscopy patients who have not yet gone on to periacetabular osteotomy (PAO), total hip arthroplasty (THA), and/or revision surgery. The purpose of this review is to summarize the recent literature pertaining to survivorship after certain hip arthroscopic procedures and certain special populations.

RECENT FINDINGS

There is yet to be level 1 evidence published with relation to survivorship following hip arthroscopy. The best evidence in the recent literature is contained in just rew long-term prospective studies demonstrating good to excellent survivorship following hip arthroscopy for femoroacetabular impingement (FAI). Unfortunately, the follow-up for other conditions treated by hip arthroscopy is more limited. In summary, hip arthroscopy indications continue to expand. The most common indication for surgery is FAI, and its recently published long-term survivorship demonstrates excellent durability. Other hip arthroscopic procedures, including labral reconstruction, adjunctive procedures such as capsular closure, and special populations such as athletes, also demonstrate excellent survivorship in shorter term follow-up. Further prospective research is needed to further define survivorship of various hip conditions, associated procedures, and special populations commonly treated with hip arthroscopy.

Identifying the Most Successful Procedures in Hip Arthroscopy

Hip arthroscopy for femoral and acetabular pathologies has increased dramatically. However, there is little literature analyzing procedures as predictors of revision arthroscopy or arthroplasty. From February 2008 to November 2015, patients undergoing hip arthroscopy for a labral tear with minimum 2-year follow-up and between 18 and 60 years old were retrospectively reviewed. Those with previous surgeries, Tönnis grade greater than 1, and previous hip conditions were excluded. Follow-up was obtained for 1118 patients (1249 hips; 81.7%) with a mean age of 38.7 years (range, 18.0-60.0 years), mean body mass index of 26.4 kg/m² (range, 16.3-48.9 kg/m²), and mean follow-up of 50.2 months (range, 24.0-111.9 months). A total of 122 (9.8%) patients converted to total hip arthroplasty (mean, 35.3 months; range, 1.4-95.2 months). Multivariate analysis for predictors of total hip arthroplasty found age at surgery (hazard ratio, 1.064/y; P<.05), body mass index (nonlinear; P<.05), labral debridement (HR, 1.558; P=.03), and notchplasty (HR, 2.128; P<.05), with trochanteric bursectomy (HR, 0.367; P<.05) identified as associated with higher survivorship. A total of 124 (9.9%) patients underwent revision hip arthroscopy at a mean of 21.7 months (range, 0.10-83.3 months). Multivariate analysis for predictors of revision surgery found workers' compensation (HR, 3.352; P<.05), capsular repair (HR, 1.950; P<.05), and femoral head microfracture (HR, 2.844; P=.04) to be significant, with age at date of surgery (HR, 0.973/y; P<.05) and femoral head chondroplasty (HR, 0.241; P=.05) associated with higher survivorship. Understanding risk factors for conversion to total hip arthroplasty or revision is paramount during discussions with patients. [Orthopedics. 2020;43(3):173-181.].

Outcomes of periacetabular osteotomy for borderline hip dysplasia in adolescent patients

Treatment of borderline acetabular dysplasia (lateral center edge angle ≥18°) remains controversial, and there is a paucity of literature focusing on outcomes in adolescent patients. The purpose of this study was to evaluate the outcomes of a periacetabular osteotomy (PAO) as surgical management of borderline acetabular dysplasia in adolescent patients. We performed a retrospective review of prospectively collected data and included patients ≤ 21 years of age that underwent PAO for borderline acetabular dysplasia. All patients had a minimum of 1-year follow-up. Outcomes were assessed using modified Harris Hip Scores (mHHS), Hip Outcome Scores (HOS) and international Hip Outcome Tool (iHOT-33). Descriptive and univariate statistical analyses were performed. This study included 33 adolescent patients (35 hips) with symptomatic, borderline acetabular dysplasia. The majority of patients was female (32 patients, 97%); half of all patients reported a history of hip pain for over 1 year; and seven patients had previous hip arthroscopy. In addition to PAO, seven hips (20%) underwent a concurrent hip arthroscopy at the time of surgery. There were significant improvements in mean mHHS, HOS-activities of daily living (ADL), HOS-Sport and iHOT-33 scores after surgery (P < 0.01). Minimal clinically important difference in outcome scores was achieved for over 90% of patients at a minimum of 1-year follow-up. Borderline acetabular dysplasia is a major cause of hip pain in adolescent patients. Patients with symptomatic borderline acetabular dysplasia report a significant benefit after a PAO to correct structural hip instability.

Outcomes of Revision Hip Arthroscopic Surgery: A Systematic Review and Meta-analysis

BACKGROUND

While the indications for primary hip arthroscopic surgery in treating femoroacetabular abnormalities continue to be defined, the indications and outcomes for revision hip arthroscopic surgery remain ambiguous. However, revision hip arthroscopic surgery is performed in 5% to 14% of patients after their index procedure. While patient-reported outcomes (PROs) generally improve after revision procedures, the extent of their improvement is not well defined.

PURPOSE

To determine the outcomes and efficacy of revision hip arthroscopic surgery in patients who remain symptomatic after their index procedure.

STUDY DESIGN

Meta-analysis and systematic review.

METHODS

The terms "hip arthroscopy,""revisions,""outcomes," and "femoroacetabular impingement" were searched in PubMed, Web of Science, Scopus, Cochrane Library, and Google Scholar. After screening, 15 studies were included for review. In addition to hip-specific metrics, functional outcome measures were included. Pooled estimates and 95% CIs were calculated using inverse variance methods.

RESULTS

A total of 4765 hips in 4316 patients were identified. The most common indication for revision surgery was inadequate bony resection during the index procedure. Meta-analysis showed that all PROs improved significantly from baseline to final follow-up after revision hip arthroscopic surgery. Notably, the modified Harris Hip Score (mHHS) increased a mean of 17.20 points after revision hip arthroscopic surgery, the Hip Outcome Score-Activities of Daily Living (HOS-ADL) improved by 13.98, and the visual analog scale (VAS) for pain decreased by 3.16. However, when compared with primary hip arthroscopic surgery, the mean PRO scores after revision hip arthroscopic surgery were lower. After revision hip arthroscopic surgery, the rates of conversion to total hip arthroplasty ranged from 0% to 14.3%, and the rates of further arthroscopic revision ranged from 2% to 14%.

CONCLUSION

Inadequate bony resection represents the most common indication for revision hip arthroscopic surgery. PROs improve significantly after revision hip arthroscopic surgery but remain lower than those of patients undergoing primary hip arthroscopic surgery.

Application of Machine Learning for Predicting Clinically Meaningful Outcome After Arthroscopic Femoroacetabular Impingement Surgery

BACKGROUND

Hip arthroscopy has become an important tool for surgical treatment of intra-articular hip pathology. Predictive models for clinically meaningful outcomes in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) are unknown.

PURPOSE

To apply a machine learning model to determine preoperative variables predictive for achieving the minimal clinically important difference (MCID) at 2 years after hip arthroscopy for FAIS.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were analyzed for patients who underwent hip arthroscopy for FAIS by a high-volume fellowship-trained surgeon between January 2012 and July 2016. The MCID cutoffs for the Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sport Specific (HOS-SS), and modified Harris Hip Score (mHHS) were 9.8, 14.4, and 9.14, respectively. Predictive models for achieving the MCID with respect to each were built with the LASSO algorithm (least absolute shrinkage and selection operator) for feature selection, followed by logistic regression on the selected features. Study data were analyzed with PatientIQ, a cloud-based research and analytics platform for health care.

RESULTS

Of 1103 patients who met inclusion criteria, 898 (81.4%) had a minimum of 2-year reported outcomes and were entered into the modeling algorithm. A total of 74.0%, 73.5%, and 79.9% met the HOS-ADL, HOS-SS, and mHHS threshold scores for achieving the MCID. Predictors of not achieving the HOS-ADL MCID included anxiety/depression, symptom duration for >2 years before surgery, higher body mass index, high preoperative HOS-ADL score, and preoperative hip injection (all P < .05). Predictors of not achieving the HOS-SS MCID included anxiety/depression, preoperative symptom duration for >2 years, high preoperative HOS-SS score, and preoperative hip injection, while running at least at the recreational level was a predictor of achieving HOS-SS MCID (all P < .05). Predictors of not achieving the mHHS MCID included history of anxiety or depression, high preoperative mHHS score, and hip injections, while being female was predictive of achieving the MCID (all P < .05).

CONCLUSION

This study identified predictive variables for achieving clinically meaningful outcome after hip arthroscopy for FAIS. Patient factors including anxiety/depression, symptom duration >2 years, preoperative intra-articular injection, and high preoperative outcome scores are most consistently predictive of inability to achieve clinically meaningful outcome. These findings have important implications for shared decision-making algorithms and management of preoperative expectations after hip arthroscopy for FAI.

Arthroscopic anterior inferior iliac spine decompression does not alter postoperative muscle strength

PURPOSE

The purpose of this study was to assess the additional effect of anterior inferior iliac spine (AIIS) decompression on knee extensor and hip flexor strength and compare functional outcomes after arthroscopic FAI correction with and without AIIS decompression.

METHODS

Sixty patients who underwent arthroscopic FAI correction surgery were divided into two groups matched for AIIS morphology: 31 patients who underwent arthroscopic FAI surgery only (without AIIS decompression) (FAI group) (AIIS Type I; n = 5, Type II; n = 26, Type III; n = 0) and 29 patients who underwent arthroscopic FAI surgery with AIIS decompression (AIIS group) (AIIS Type I; n = 5, Type II; n = 24, Type III; n = 0). Knee extensor and hip flexor strength were evaluated preoperatively and at 6 months after surgery. Patient-reported outcome (PRO) scores using the modified Harris hip score (MHHS), the nonarthritic hip score (NAHS) and iHOT-12 were obtained preoperatively and at 6 months after surgery.

RESULTS

In the AIIS group, there was no significant difference between knee extensor strength pre- and postoperatively (n.s.). In the AIIS group, hip flexor strength was significantly improved postoperatively compared to preoperative measures (p < 0.05). In the FAI group, there were no significant improvements regarding muscle strength (n.s.). While there were no significant differences of preoperative and postoperative MHHS and NAHS between both groups (MHHS; n.s., NAHS; n.s.), the mean postoperative iHOT-12 in the FAI group was inferior to that in the AIIS group. (p < 0.01). The revision surgery rate for the AIIS group was significantly lower compared with that in the FAI group (p < 0.05).

CONCLUSION

Anterior inferior iliac spine decompression, as a part of an arthroscopic FAI corrective procedure, had a lower revision surgery rate and did not compromise knee extensor and hip flexor strength, and it improved clinical outcomes comparable to FAI correction without AIIS decompression. AIIS decompression for FAI correction improved postoperative PRO scores without altering the muscle strength of hip flexor and knee extensor.

LEVEL OF EVIDENCE

III.

Preoperative Predictors of Achieving Clinically Significant Athletic Functional Status After Hip Arthroscopy for Femoroacetabular Impingement at Minimum 2-Year Follow-Up

PURPOSE

To identify predictors of achieving clinically significant sport function in athletic patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS).

METHODS

Data were analyzed for all patients who treated for FAIS between 2012 to 2016 and reported being athletes, including recreational and competitive athletes. All patients had a minimum of 2-year follow-up with patient-reported athletic function in the form of the Hip Outcome Score-Sport Specific (HOS-SS), visual analog score-pain, and patient satisfaction. Achieving clinically significant sports function was defined as either reaching the minimally clinical important difference (MCID) or the patient acceptable symptomatic state (PASS) for HOS-SS at 2-year follow-up. An exploratory factor analysis was used to determine specific domains for the predictor variables and to reduce the redundancy in these variables. A logistic regression analysis was used to identify significant predictors of achieving clinically significant sports function [corrected].

RESULTS

Of 780 qualifying patients, 626 completed the 2-year minimum follow-up (80%), with a mean age and body mass index of 31.6 ± 11.9 years and 24.6 ± 8.6, respectively. A total of 500 patients (86.5%) achieved high functional status, with 77.9% achieving MCID HOS-SS and 68.7% achieving PASS HOS-SS. Logistic regression analysis identified increased the α angle (odds ratio [OR] 0.976; P = .027), preoperative pain duration (OR 0.729; P = .011), and body mass index (BMI) (OR 0.919; P = .018), as well as the presence of femoral chondral defects (OR 0.769; P = .013), as negative predictors for achieving MCID. Negative predictors for achieving PASS HOS-SS included the presence of a preoperative limp (OR 0.384; P = .013), anxiety or depression (OR 0.561; P = .041), and increased BMI (OR 0.945; P = .018) and preoperative pain duration (OR 0.987; P < .001).

CONCLUSIONS

Several predictors of achieving clinically significant sport function performance exist, including a history of anxiety or depression, BMI, preoperative α angle, limp, femoral chondral damage, *and preoperative symptom duration. Our results suggest there are both modifiable and nonmodifiable preoperative factors that have the potential to predict achieving high athletic function after hip arthroscopy for FAIS.

LEVEL OF EVIDENCE

IV, Case Series.

A Novel Approach to Lower-limb Axial Alignment Analysis: A CT Study

To analyze the torsion of the lower extremities in a healthy cohort and to determine the contribution of different segments of the femur and tibia to the torsion of both bones.

METHODS

In this cross-sectional study, 32 patients with nonjoint or bone-related symptoms were analyzed by CT angiography. Lower-limb torsion, femoral torsion, proximal femoral torsion, femoral shaft torsion, distal femoral torsion, tibial torsion, proximal tibial torsion, and distal tibial torsion were measured.

RESULTS

The median total limb torsion was 25° external torsion, with the median femoral torsion being -9° and the median tibial torsion 30°. Both femoral metaphyses had internal torsion, with the internal torsion of the proximal metaphysis being approximately three times greater than that of the distal femoral metaphysis. The shaft was found to compensate with an external torsion of approximately two-thirds of the internal torsion of both femoral metaphyses. The proximal metaphysis of the tibia accounted for approximately one-third of the external torsion, with the segment from the distal to the tibial tubercle accounting for the remaining two-thirds of the tibial torsion.

CONCLUSIONS

The diaphysis and distal metaphysis are the major contributors to external torsion of the tibia, whereas the proximal metaphysis is the major contributor to the internal torsion of the femur.

Outcomes for Surgical Treatment of Femoroacetabular Impingement in Adults

PURPOSE OF REVIEW

To assess the outcomes of modern techniques for arthroscopic surgery in the treatment of femoroacetabular impingement.

RECENT FINDINGS

While initially approached by means of open surgical hip dislocation, recent literature has shown generally good outcomes of arthroscopic treatment for femoroacetabular impingement. Modern advances in hip arthroscopy technique and implants now allow for labral repair or reconstruction when indicated. Arthroscopic treatment of femoroacetabular impingement results in significant improvements in patient pain and function, with low complication rates and high patient satisfaction. A majority of improvements in these patients occur within 1 to 2 years post-operatively. Hip arthroscopy for femoroacetabular impingement yields the best results in patients without significant arthritis or hip dysplasia.

Surgical Treatment for FAI: Arthroscopic and Open Techniques for Osteoplasty

PURPOSE OF REVIEW

To review the relevant literature and techniques regarding arthroscopic and open treatment of femoroacetabular impingement (FAI). To discuss both the senior authors' preferred method of arthroscopic and open treatment of FAI.

RECENT FINDINGS

Routine treatment of FAI has moved away from open techniques and is more focused arthroscopic methods. Arthroscopic treatment of FAI has more recently focused on differing techniques of hip access and capsular management. Open techniques still have a role in FAI, but indications for open management are focused on cases with more severe pathology. While arthroscopic techniques have shown better outcomes in the short term and higher return to play, it is not without risk and is a procedure with a steep learning curve. In cases of complex joint pathology, such as FAI coupled with dysplasia or Legg-Calve-Perthes, arthroscopy may be not indicated and an open approach preferred. We outline various techniques for both arthroscopic and open treatment of FAI and their outcomes when possible.

A T-capsulotomy provides increased hip joint visualization compared with an extended interportal capsulotomy

The purpose of this study was to compare the cross-sectional area (CSA) of joint visualization between extended interportal and T-capsulotomies. Twenty fresh-frozen cadaveric hips were dissected to their capsuloligamentous complexes and fixed in a custom apparatus in neutral hip position. Ten hips underwent sequential interportal capsulotomies at lengths of 2, 4, 6, and 8 cm. Ten hips underwent sequential T-capsulotomies starting from a 4 cm interportal capsulotomy, creating a 2 cm T-capsulotomy (Half-T), and finally a 4 cm T-capsulotomy (Full-T). Following each sequential capsule change in both groups, a high-resolution digital photograph was taken to measure the visualized intra-articular cross-sectional area (CSA). Independent t-test was used to compare CSA interportal and T-capsulotomy groups. Analysis demonstrated a statistically significant increase in CSA visualization with each sequential increase in interportal capsulotomy length up to 6 cm (2cm: 0.6 ± 0.2 cm²; 4cm: 2.1 ± 0.5 cm² (p<0.001); 6cm: 3.6 ± 1.0 cm² (p=0.001)), and no difference at 8cm (4.2 ± 1.2 cm² (p=0.20)). For the T-capsulotomy group the average CSA visualization significantly increased from 3.2 ± 0.9 cm2 for the Half-T to 7.1 ± 1.0 cm² for the Full-T (p<0.001). The Half-T CSA visualization was not statistically different from the 6 cm capsulotomy (p=0.4) and the 8cm capsulotomy (p=0.05). The Full-T had significantly superior CSA visualization area as compared to the 6 cm and 8 cm interportal capsulotomies (p<0.001 for both). In conclusion, T-capsulotomy resulted in improved cross-sectional area of joint visualization compared to an extended (8cm) interportal capsulotomy in a cadaveric model. Surgeons must weigh the benefits of greater visualization from T-capsulotomy that may help to avoid residual FAI while ensuring to completely repair the capsulotomy to avoid iatrogenic instability.

Survivorship and Outcome of Hip Arthroscopy for Femoroacetabular Impingement Syndrome Performed With Modern Surgical Techniques

BACKGROUND

Hip arthroscopy for femoroacetabular impingement syndrome (FAIS) is a rapidly growing field in sports surgery; however, factors associated with poor outcomes and identification of predictor models of inferior clinical outcomes is unclear.

PURPOSE

To analyze predictors of clinical failure and inferior clinical outcomes among patients undergoing hip arthroscopy for treatment of FAIS.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were collected and analyzed from consecutive patients who underwent primary hip arthroscopy with routine capsular closure for the treatment of FAIS from a single fellowship-trained surgeon between January 2012 and November 2015. Baseline data, postoperative patient-reported outcomes, and rates of clinical failure and inferior clinical outcomes were recorded at 2 years postoperatively. Clinical failure was defined by revision hip arthroscopy or conversion to total hip arthroplasty. Inferior clinical outcome was defined as not reaching the minimal clinically important difference (MCID) or patient acceptable symptomatic state for Hip Outcome Score-Activities of Daily Living. A multivariate logistic regression analysis was used to identify significant predictors of clinical failure and inferior clinical outcome.

RESULTS

Out of 1161 eligible patients, 935 (80.5%) completed 2-year postoperative patient-reported outcomes. The mean ± SD age and body mass index were 33.3 ± 12.3 years and 25.4 ± 8.2 kg/m², respectively. The overall clinical failure rate was 3.6% (n = 34), including 23 cases (2.5%) of revision hip arthroscopy and 11 cases (1.2%) of conversion to total hip arthroplasty. Predictors of clinical failure were lower preoperative International Hip Outcome Tool score ( P = .016), chronic preoperative pain ( P = .001), and chondromalacia in the affected hip ( P = .04). The inferior clinical outcome group, consisting of those who failed to reach the MCID for Hip Outcome Score-Activities of Daily Living, included 256 patients (27.4%). Predictors of inferior clinical outcomes were Tönnis grade >1 ( P = .01), workers' compensation ( P < .001), and increased body mass index ( P = .02).

CONCLUSION

This study demonstrates that 73% of all patients treated for symptomatic FAIS with primary hip arthroscopy and routine capsular closure achieved the MCID. Clinical failure is predicted by a number of modifiable and nonmodifiable factors, including chronic preoperative pain and presence of chondromalacia. The current study updates the midterm failure rates and outcomes achievable with hip arthroscopy for FAIS.

Hip Arthroscopy for Femoroacetabular Impingement and Labral Tears in Patients Younger than 50 Years: Minimum Five-year Outcomes, Survivorship, and Risk Factors for Reoperations

INTRODUCTION

There is a paucity of literature on mid-term outcomes for hip arthroscopy for femoroacetabular impingement and labral tears.

METHODS

Inclusion criteria were age at surgery <50 years and documented preoperative patient-reported outcomes. Patients with a Tönnis grade >0 or previous ipsilateral hip conditions were excluded.

RESULTS

Of 407 eligible cases, 327 hips (295 patients) had minimum 5-year follow-up. Mean age was 32.4 years. All mean patient-reported outcomes and visual analog scale improved at follow-up (P < 0.001). Mean satisfaction was 7.9. Thirty-eight hips (11.6%) required secondary arthroscopy at a mean of 25.1 months. Survivorship at minimum 5 years was 92.4%. The complication rate was 7.0%.

CONCLUSIONS

Hip arthroscopy for management of femoroacetabular impingement and labral tears in patients aged <50 demonstrates favorable and safe mid-term outcomes. Several risk factors for conversion to total hip arthroplasty in this age group warrant cautious patient selection for arthroscopy.

Clinical outcomes and causes of arthroscopic hip revision surgery

Hip arthroscopic surgery has become a common technique during the past decade, leading to an increased number of arthroscopic hip revision surgeries. This study aimed to evaluate the clinical outcomes in a series of revision hip arthroscopies to analyse the causes of reoperation in the short to medium-term follow-up. We retrospectively analysed 22 patients who underwent arthroscopic hip revision surgery in our institute. All patients accepted a detailed physical examination and obtained radiographs to measure the centre edge angle, the alpha angle and the offset. Three-dimensional computed tomography was used to evaluate the deformities. The modified Harris Hip Score, visual analogue scale and patient self-reported satisfaction were collected and analysed preoperatively and postoperatively. Our results demonstrated that the modified Harris Hip Score improved from 52.8 to 81.6, and the visual analogue scale decreased from 5.0 to 1.1. Patient self-reported satisfaction was 8.5. In conclusion, patients who underwent arthroscopic hip revision surgery exhibited significant improvement in patient-centred outcomes in the short- to medium-term follow-up, and the outcomes indicated the effectiveness of revision surgery. Residual femoroacetabular impingement and extra-articular impingement are common reasons for arthroscopic hip revision surgery. Misdiagnosis of osteoid osteoma and relapse of synovial chondromatosis are also important reasons for revision.

Anterior Inferior Iliac Spine Morphology: Comparison of Symptomatic Hips With Femoroacetabular Impingement and Asymptomatic Hips

OBJECTIVE

The objective of our study was to compare anterior inferior iliac spine (AIIS) morphology in symptomatic hips with femoroacetabular impingement (FAI) and in asymptomatic hips, determine the prevalence of impingement morphology in patients with a radiographic "crossover" sign, and identify potential risk factors for having impingement morphology.

MATERIALS AND METHODS

For this retrospective study, we identified consecutive symptomatic hips with FAI (n = 54) and asymptomatic hips (n = 35) in patients who underwent CT from 2015 to 2017. Two radiologists blindly and independently evaluated 3D CT images of each hip and graded the AIIS morphology according to the Hetsroni classification scheme. The prevalence of AIIS morphology types was calculated. Associations of AIIS morphology types with symptoms and the crossover sign were evaluated with a chi-square test. A multivariable logistic regression determined risk factors for abnormal AIIS morphology (i.e., type 2 or 3).

RESULTS

There was no difference in the prevalence of AIIS morphology types for symptomatic hips with FAI versus asymptomatic hips (p = 0.44) or for hips with a positive versus those with a negative crossover sign (p = 0.21). There was moderate interobserver agreement (κ = 0.44) and good-to-excellent intraobserver agreement (κ = 0.67 and 0.90) for grading AIIS morphology. Age, sex, femoral version, acetabular version, alpha angle, lateral center edge angle, and the crossover sign were not significant risk factors for abnormal AIIS morphology in patients with FAI (p = 0.11-0.79).

CONCLUSION

There is no difference in AIIS morphology between symptomatic hips with FAI versus asymptomatic hips or between hips with and those without the radiographic crossover sign. Age, sex, and other FAI parameters are not risk factors for developing AIIS impingement morphology.

Trends of hip arthroscopy in the setting of acetabular dysplasia

Hip arthroscopy is increasingly utilized in the treatment of symptomatic intra-articular hip pathology. Unaddressed development dysplasia of the hip (DDH) is thought to be associated with failure after hip arthroscopy. The aims of this study were (i) to identify the prevalence of previous failed hip arthroscopy in patients undergoing a periactebaular osteotomy (PAO) for the treatment of symptomatic acetabular dysplasia, (ii) report on the temporal trend of failed ipsilateral hip arthroscopy in patients undergoing PAO and (iii) to determine clinical and radiographic characteristics associated with utilization of isolated hip arthroscopy in patients with acetabular dysplasia. We identified 139 patients undergoing PAO who had a history of a prior ipsilateral hip arthroscopy. A comparison group of 1505 patients with a diagnosis of acetabular dysplasia, who underwent PAO alone without any prior ipsilateral surgery during the study period was used. Clinical characteristics, radiographic and intraoperative findings were compared between cohorts. From 2008 to 2015, the rate of previous failed hip arthroscopy in patients undergoing subsequent PAO increased steadily until 2013 with a maximum of 12%. Patients in the study group had mild dysplasia with significantly higher LCEA (17.2° versus 11.3°; P < 0.001) and ACEA (15.6° versus 10.8°; P < 0.001), a lower acetabular inclination (14.0° versus 19.0°; P < 0.001). The findings illustrate a constant increase in the rate of failed hip arthroscopy in the setting of acetabular dysplasia from 2008 till 2013. Female sex and mild dysplasia were associated with use of isolated hip arthroscopy in the setting of acetabular dysplasia.

Preoperative Depression Is Negatively Associated With Function and Predicts Poorer Outcomes After Hip Arthroscopy for Femoroacetabular Impingement

PURPOSE

(1) To determine the prevalence of depression in patients undergoing hip arthroscopy for the treatment of femoroacetabular impingement (FAI) syndrome and (2) to determine whether depression has a statistically significant and clinically relevant effect on preoperative and postoperative patient-reported outcome scores.

METHODS

Consecutive subjects undergoing hip arthroscopy for FAI syndrome were retrospectively reviewed. The Beck Depression Inventory-II (BDI-II), Hip Outcome Score (HOS), and 33-item International Hip Outcome Tool (iHOT-33) were administered preoperatively and postoperatively. Clinically relevant differences were defined by the minimal clinically important difference, substantial clinical benefit, and patient acceptable symptom state. Comparisons between preoperative and postoperative scores were completed. The Spearman correlation coefficient (r) was used to determine the degree of correlation between the BDI-II score, HOS, and iHOT-33 score preoperatively and postoperatively.

RESULTS

We analyzed 77 patients (72.7% female patients; mean age, 35.2 ± 12.5 years). Depressive symptoms were reported as minimal (75.3%), mild (11.7%), moderate (6.5%), or severe (6.5%). Patients with minimal or mild depression had a superior HOS Activities of Daily Living (Δ17.3 preoperatively [P < .001] and Δ37.8 postoperatively [P < .001]), HOS Sport-Specific Subscore (Δ12.8 preoperatively [P = .002] and Δ52.1 postoperatively [P < .0001]), and iHOT-33 score (Δ15.4 preoperatively [P < .0001] and Δ51.3 postoperatively [P < .0001]) compared with patients with moderate or severe depression. There was a weak to moderate negative correlation between the BDI-II score and iHOT-33 score (r = -0.4614, P < .0001 preoperatively; r = -0.327, P < .0001 at 1 year), HOS Activities of Daily Living (r = -0.531, P < .0001 preoperatively), and HOS Sport-Specific Subscore (r = -0.379, P < .0017 at 1 year).

CONCLUSIONS

Most patients undergoing hip arthroscopy for FAI have minimal depressive symptoms with the overall prevalence higher than the general population. Patients with minimal or mild depressive symptoms have statistically and clinically better preoperative and postoperative patient-reported outcomes, are more likely to obtain substantial clinical benefit from surgery, and are more likely to reach a patient acceptable symptom state after surgery than patients with moderate to severe depressive symptoms.

LEVEL OF EVIDENCE

Level III, case-control study.

Surgical Trends in Arthroscopic Hip Surgery Using a Large National Database

PURPOSE

To assess the practice trends in hip arthroscopy, including femoroplasty, acetabuloplasty, and labral repair Current Procedure Terminology, 4th edition (CPT-4), codes that have been implemented since many of the previous studies were published, without concerns for Hawthorne or observer effect as can be seen during a board collection window, and in a larger volume of patients with a more comprehensive database than previous published data.

METHODS

The MarketScan Commercial Claims and Encounters database was searched using CPT-4 codes to identify patients who underwent any arthroscopic hip procedure from 2008 to 2013. Patients identified were characterized by gender, age group, and year of the initial procedure. Regression analysis was used to evaluate differences in surgical trends between individual patient groups delineated by age and gender. The Cochran-Armitage trend test was used to identify significant differences in surgical trends seen yearly.

RESULTS

A total of 62,782 arthroscopic hip procedures in 31,569 surgeries in 27,997 patients were identified and included from 2008 through 2013. The number of surgeries in the database increased every year. After changes to CPT coding in 2011, femoroplasty became the most common procedure in 2012, comprising 28% of all procedures performed in 2013. Patients ages 40 to 49 underwent the most procedures (7,467, 27%). Females were more likely to undergo any arthroscopic procedure during the study period (.068% vs .041%, P < .0001). A total of 2,754 patients (10%) underwent a second surgery during the study period. A total of 1,625 patients (6%) underwent a total hip arthroplasty following an arthroscopic procedure during the study period.

CONCLUSIONS

Arthroscopic hip procedures continue to increase, with femoroplasty, labral repair, and acetabuloplasty being the 3 most common procedures performed. Females are more likely to undergo any procedure, and labral repair is now performed more commonly than labral debridement.

LEVEL OF EVIDENCE

Level IV, cross-sectional study.

Are Results of Arthroscopic Labral Repair Durable in Dysplasia at Midterm Follow-up? A 2-Center Matched Cohort Analysis

BACKGROUND

Studies assessing dysplasia's effect on hip arthroscopy are often limited to the short term and unable to account for demographic factors that may vary between dysplastic and nondysplastic populations.

PURPOSE

To determine the midterm failure rate and patient-reported outcomes of arthroscopic labral repair in the setting of dysplasia and make subsequent failure and outcome comparisons with a rigorously matched nondysplastic control group.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Primary arthroscopic labral repair cases at 2 centers from 2008 to 2011 were reviewed. Patients with lateral center edge angle (LCEA) <25° were matched to nondysplastic controls by age, sex, laterality, body mass index (BMI), Tönnis grade, and capsular repair per a 1:2 matching algorithm. Groups were compared with a visual analog scale (VAS) for pain, modified Harris Hip Score (mHHS), and Hip Outcome Score-Sports Specific Subscale (HOS-SSS) to determine predictors of outcome and failure.

RESULTS

Forty-eight patients with dysplasia (mean LCEA, 21.6°; range, 13.0°-24.9°; n = 25 with capsular repair) were matched to 96 controls (mean LCEA, 32.1°; range, 25°-52°; n = 50 with capsular repair) and followed for a mean of 5.7 years (range, 5.0-7.7 years). Patients achieved mean VAS improvements of 3.3 points, mHHS of 19.5, and HOS-SSS of 29.0 points ( P < .01) with no significant differences between the dysplasia and control populations ( P > .05). Five-year failure-free survival was 83.3% for patients with dysplasia and 78.1% for controls ( P = .53). No survival or outcomes difference was observed between patients with dysplasia who did or did not have capsular repair ( P ≥ .45) or when comparing LCEA <20° and LCEA 20° to 25° ( P ≥ .60). BMI ≤30 was associated with increased revision surgery risk ( P < .01). Age >35 years ( P < .05) and Tönnis grade 0 radiographs ( P < .01) predicted failure to reach minimal clinically important differences.

CONCLUSION

With careful selection and modern techniques, patients with dysplasia can benefit significantly and durably from arthroscopic labral repair. The dysplastic cohort had outcomes and failure rates similar to those of rigorously matched controls at midterm follow-up. Subanalyses comparing LCEA <20° and LCEA 20° to 25° are presented for completeness; however, this study was not designed to detect differences in dysplastic subpopulations. BMI ≤30 was associated with increased revision risk. Age >35 years and Tönnis grade 0 radiographs predicted failure to achieve minimal clinically important differences.

Minimal Clinically Important Difference and Substantial Clinical Benefit After Revision Hip Arthroscopy

PURPOSE

To define minimal clinically important difference (MCID) and substantial clinical benefit (SCB) in revision hip arthroscopy.

METHODS

The modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS), and the international Hip Outcome Tool (iHOT-33) were administered to revision hip arthroscopy patients. At 1 year postoperatively, patients graded their hip function based on anchor responses. SCB was defined as both a net change and an absolute value. Receiver operating characteristic analysis with area under the curve was used to confirm psychometric values. A distribution-based method was used for MCID.

RESULTS

Forty-nine patients were included with a mean age of 29.7 (±8.6) years. The most common indication for revision hip arthroscopy was residual femoroacetabular impingement (FAI; N = 34; 69.4%) followed by capsular management (N = 8; 16.3%). At 1-year follow-up, 34 patients reported feeling improved. Outcome score change corresponding to MCID and SCB net change for the mHHS, HOS Activities of Daily Living (ADL), HOS Sports, and iHOT-33 was 7.9/23.1, 7.9/16.2, 13.1/25.0, and 12.8/25.5, respectively. A higher proportion of patients with residual FAI achieved MCID compared with patients with other diagnoses. On the preoperative HOS ADL, HOS Sports, and iHOT-33, patients scoring below 67.7 (0.78), 55.6 (0.81), and 35.7 (0.73) were significantly more likely to achieve SCB postoperatively. Thirty-four patients (73.9%) were classified as receiving physical function improvement, and on the HOS Sports, MCID was achieved by 65% whereas 43% met the SCB criteria.

CONCLUSIONS

MCID values ranged from 7.9 on the mHHS and the HOS ADL to 13.1 on the HOS Sports. SCB net change ranged from 16.2 on the HOS ADL to 25.2 on the iHOT-33, whereas absolute SCB ranged from 82.4 on the iHOT-33 to 84.7 on the mHHS. Residual FAI and capsular management were the most common indications for revision surgery with patients who underwent surgery for the former found to be most likely to achieve clinically significant improvement.

LEVEL OF EVIDENCE

Level IV, case series.

Self-reported Mental Disorders Negatively Influence Surgical Outcomes After Arthroscopic Treatment of Femoroacetabular Impingement

Background

Femoroacetabular impingement (FAI) is responsible for hip pain and dysfunction, and surgical outcomes depend on multiple factors. The presence of mental disorders negatively influences outcomes of multiple orthopaedic conditions, although the impact on FAI surgery is unclear.

Hypothesis

The authors hypothesized that a preoperative self-reported history of mental disorders would negatively influence patient-reported outcome measures after FAI surgery.

Study Design

Cohort study; Level of evidence, 3.

Methods

A matched-cohort study was performed by reviewing a prospectively collected database of cases of arthroscopic management of FAI with a single surgeon over a 2-year period. Demographics and radiographic parameters were recorded for all patients. Patients completed the Hip Outcome Score-Activity of Daily Living Subscale (HOS-ADL), Hip Outcome Score-Sport-Specific Subscale (HOS-SSS), and modified Harris Hip Score (mHHS) prior to surgery and 2 years after surgery. Unpaired and paired t tests were used to compare results between and within cohorts at baseline and follow-up. Statistical significance was defined as P < .05.

Results

The cohort included 301 patients, with 75 and 226 patients reporting and not reporting a history of mental disorders, respectively. Before treatment, all patient-reported outcome measures were significantly lower among patients reporting a history of mental disorders (P < .01 for HOS-ADL, HOS-SSS, and mHHS). Patients in both groups demonstrated significant improvements (P < .0001) in HOS-ADL, HOS-SSS, and mHHS when preoperative outcome measures were compared with follow-up. Patients with reported mental disorders had significantly lower scores after surgery as compared with patients without mental disorders (P < .0001 for HOS-ADL, HOS-SSS, and mHHS).

Conclusion

The presence of a reported mental disorder is associated with lower patient-reported outcomes before and after surgical management of FAI. Statistically significant and clinically relevant improvements were observed for patients who reported mental disorders. The magnitude of these improvements was not as large as that for an age- and sex-matched control group without a self-reported mental disorder.

Defining the Learning Curve for Hip Arthroscopy: A Threshold Analysis of the Volume-Outcomes Relationship

BACKGROUND

Hip arthroscopy has emerged as a successful option for the treatment of femoroacetabular impingement and related hip disorders, but the procedure is technically challenging.

PURPOSE

To define the learning curve through which surgeons become proficient at hip arthroscopy.

STUDY DESIGN

Cohort study; level of evidence, 3.

METHODS

The authors identified hip arthroscopy procedures performed by surgeons through a New York State database (Statewide Planning and Research Cooperative System) and followed those cases for additional hip surgery (total hip arthroplasty, hip resurfacing, or ipsilateral hip arthroscopy) within 5 years of the original procedure. Career volume for each case was calculated as the number of hip arthroscopy procedures that the surgeon had performed. Volume strata were identified via the stratum-specific likelihood ratio method. A Cox proportional hazards model was used to measure the effect of surgeon career volume on risk of additional hip surgery, adjusting for the following patient characteristics: age, sex, race/ethnicity, insurance type, and concurrent diagnosis of hip osteoarthritis.

RESULTS

Among 8041 hip arthroscopies performed by 251 surgeons, 989 (12.3%) cases underwent additional hip surgery within 5 years. Four strata of surgeon career volume associated with distinct frequencies of reoperation were identified: cases in the lowest stratum (0-97) had the highest frequency of additional surgery (15.4%). Frequencies declined for cases in the medium (98-388), high (389-518), and highest (≥519) strata (13.8%, 10.1%, and 2.6%, respectively). There was an increased risk of subsequent surgery in each stratum when compared with the highest stratum (hazard ratio [95% CI]: low volume, 3.22 [2.29-4.54]; medium, 3.40 [2.41-4.82]; high, 2.81 [1.86-4.25]; P < .0001 for all). Patients with a diagnosis of hip osteoarthritis had increased risk of subsequent hip arthroplasty or resurfacing (2.46 [2.09-2.89], P < .0001) . Risk also increased with age: 30 to 39 vs ≤29 years (5.12 [3.29-8.00], P < .0001), 40 to 49 vs ≤29 years (11.30 [7.43-17.190], P < .0001), ≥50 vs ≤29 years (18.39 [12.10-27.96], P < .0001). Increased age and osteoarthritis were not risk factors for revision hip arthroscopy.

CONCLUSION

The learning curve for hip arthroscopy was unexpectedly demanding. Cases performed by surgeons with career volumes ≥519 had significantly lower risk of subsequent hip surgery than those performed by lower-volume surgeons.

Fluoroscopy Learning Curve in Hip Arthroscopy-A Single Surgeon's Experience

PURPOSE

To determine if (1) absorbed radiation dose and (2) fluoroscopy time decreased with experience over the first 100 cases of a single surgeon's hip arthroscopy practice.

METHODS

Subjects who underwent hip arthroscopy for symptomatic femoroacetabular impingement and labral injury were eligible for analysis. Inclusion criteria included the first 100 subjects who underwent hip arthroscopy by a single surgeon (December 2013 to December 2014). Subject demographics, procedure details, fluoroscopy absorbed dose (milligray [mGy]), and time were recorded. Subjects were categorized by date of surgery to one of 4 possible groups (25 per group). One-way analysis of variance was used to determine if a significant difference in dose (mGy) or time was present between groups. Simple linear regression analysis was performed to determine the relation between case number and both radiation dose and fluoroscopy time.

RESULTS

Subjects underwent labral repair (n = 93), cam osteoplasty (n = 90), and pincer acetabuloplasty (n = 65). There was a significant (P < .001 for both) linear regression between case number and both radiation dose and fluoroscopy time. A significant difference in mGy was observed between groups, group 1 the highest and group 4 the lowest amounts of radiation (P = .003). Comparing individual groups, group 4 was found to have a significantly lower amount of radiation than group 1 (P = .002), though it was not significantly lower than that of group 2 (P = .09) or group 3 (P = .08). A significant difference in fluoroscopy time was observed between groups, group 1 the highest and group 4 the lowest times (P = .05). Comparing individual groups, group 4 was found to have a significantly lower fluoroscopy time than group 1 (P = .039). Correction for weight, height, and body mass index all revealed the same findings: significant (P < .05) differences in both dose and time across groups.

CONCLUSIONS

The absorbed dose of radiation and fluoroscopy time decreased significantly over the first 100 cases of a single surgeon's hip arthroscopy practice learning curve.

LEVEL OF EVIDENCE

Level IV, therapeutic, retrospective, noncomparative case series.

Early Functional Outcomes of Periacetabular Osteotomy After Failed Hip Arthroscopic Surgery for Symptomatic Acetabular Dysplasia

BACKGROUND

Persistent acetabular dysplasia is a common reason for the failure of hip arthroscopic surgery; however, the effect of prior hip arthroscopic surgery on functional outcomes after subsequent periacetabular osteotomy (PAO) is unknown. Hypothesis/Purpose: The purpose of this study was to (1) compare demographic and radiological findings in patients who had and had not undergone previous hip arthroscopic surgery before PAO for symptomatic acetabular dysplasia and (2) compare the short-term, hip-specific patient-reported outcomes in these same patient populations. It was hypothesized that prior hip arthroscopic surgery is associated with worse early functional outcomes in PAO.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective cohort study design was utilized. Patients undergoing PAO were enrolled from a single-center, prospective hip preservation registry from March 2011 to April 2015. Patients with a minimum of 1-year clinical follow-up with preoperative and postoperative outcome scores undergoing PAO were eligible for inclusion (n = 93 patients; mean clinical follow-up, 24 months [range, 11-58 months]). The study group consisted of patients undergoing PAO for symptomatic hip dysplasia after prior hip arthroscopic surgery (PREVSCOPE group; 22 patients, 25 hips). Patients undergoing PAO without prior hip arthroscopic surgery (PAOALONE group; 71 patients, 85 hips) were included as a comparison group. Demographic and radiological variables were recorded. Postoperative functional outcome scores (modified Harris Hip Score [mHHS], Hip Outcome Score [HOS], and International Hip Outcome Tool [iHOT-33]) were recorded at 6 months and annually postoperatively.

RESULTS

There were no demographic differences between the 2 groups at baseline. Acetabular version, femoral version, Tönnis grade, preoperative lateral center edge angle, and intraoperative procedures were not different between the 2 groups. At 1-year follow-up from the last hip surgical procedure, the mean (±SD) mHHS (73 ± 14 vs 86 ± 14, respectively; P < .001), HOS-Activities of Daily Living (84 ± 12 vs 93 ± 11, respectively; P = .007), HOS-Sport (62 ± 25 vs 85 ± 18, respectively; P < .001), and iHOT-33 (62 ± 21 vs 79 ± 20, respectively; P = .004) were decreased in the PREVSCOPE group versus the PAOALONE group. At last follow-up (mean, 18 months from the last hip surgical procedure), the mHHS and HOS-Sport were lower in the PREVSCOPE group versus the PAOALONE group. There was no difference in complication or reoperation rates between the 2 groups.

CONCLUSION

Failed hip arthroscopic surgery before PAO for symptomatic hip dysplasia is associated with lower hip-specific functional outcomes within the first 1 year of follow-up despite similar baseline demographic and radiological characteristics. These differences persisted in certain outcome scores (mHHS, HOS-Sport) at last follow-up but were less pronounced than at 1 year.

Outcomes for Arthroscopic Treatment of Anterior Inferior Iliac Spine (Subspine) Hip Impingement

BACKGROUND

Femoroacetabular hip impingement (FAI) is now well recognized; however, anterior inferior iliac spine (AIIS; or subspine) impingement is a form of hip impingement that is underrecognized and can be an important source of hip disability and functional limitation.

PURPOSE

To investigate the outcomes after arthroscopic treatment of AIIS/subspine-related hip impingement in the absence of FAI surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A prospective institutional hip preservation registry was reviewed to identify patients who underwent arthroscopic AIIS decompression without concurrent treatment of FAI. Primary outcome tools captured in the registry included the modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS), and the International Hip Outcome Tool-33 (iHOT-33). Patients with minimum 1-year follow-up were included. Meaningful outcome improvement was determined per minimal clinically important difference (MCID). Statistical analyses were primarily descriptive.

RESULTS

Thirty-three patients with a mean follow-up of 19.1 months (range, 12-44 months) were identified. All patients were female, with a mean ± SD age of 26.1 ± 10.3 years. All patients were found to have an associated labral tear, and the mean acetabular version was increased at 2 and 3 o'clock (14.5° and 19.8°, respectively). Mean preoperative outcome scores on the mHHS, HOS ADL (activities of daily living), HOS sport, and iHOT-33 were 57.2 ± 15.3, 66.9 ± 18.8, 43.9 ± 23.6, and 33.5 ± 18.3, respectively. At final available follow-up, mean scores on these outcome measures were 79.5 ± 19.0, 86.8 ± 15.8, 70.4 ± 32.8, and 65.0 ± 31.0, respectively. By the 1-year follow-up, MCID had been achieved in the majority of patients across all 4 tools.

CONCLUSION

There is a paucity of outcomes evidence on AIIS/subspine-related hip impingement. This study demonstrates that isolated subspine impingement can be a cause of hip disability, even in the absence of FAI. Patients with isolated subspine impingement are more likely to be women and to present with low patient-reported outcome scores. However, meaningful outcome improvement can be achieved with arthroscopic AIIS decompression.

Arthroscopic Treatment of a Displaced Nonunion of the Anterior Inferior Iliac Spine Causing Extra-articular Impingement

This report describes a case of nonunion of an anterior inferior iliac spine (AIIS) apophyseal avulsion fracture with resultant subspine impingement combined with symptomatic femoroacetabular impingement (FAI). A 16-year-old male soccer player presented with a 6-month history of right groin pain exacerbated by kicking and running. The patient was diagnosed with a displaced nonunion of the AIIS apophysis avulsion fracture causing secondary extra-articular impingement beyond cam-type FAI by physical examination and radiological findings. The authors performed arthroscopic AIIS decompression, with concurrent FAI correction and labral repair and capsular closure. At 4 months after surgery, a radiograph and a computed tomography scan showed complete bony union of the AIIS apophyseal nonunion. Modified Harris Hip Sore and Nonarthritic Hip Score improved from 74.8 and 61, respectively, to 100 for both at final follow-up. The effectiveness of arthroscopic decompression of the AIIS as part of a comprehensive minimally invasive surgery including FAI correction and labral repair resulted in complete union of the AIIS and pain-free return to sport and bony union. [Orthopedics. 2017; 40(4):e725-e728.].

Preoperative Outcome Scores Are Predictive of Achieving the Minimal Clinically Important Difference After Arthroscopic Treatment of Femoroacetabular Impingement

BACKGROUND

There is increasing interest in defining meaningful improvement in patient-reported outcomes. Knowledge of the thresholds and determinants for successful femoroacetabular impingement (FAI) outcomes is evolving.

PURPOSE

To define preoperative outcome score thresholds and determine clinical/demographic patient factors predictive for achieving the minimal clinically important difference (MCID) after arthroscopic FAI surgery.

STUDY DESIGN

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

METHODS

A prospective institutional hip preservation registry was reviewed to identify patients undergoing arthroscopic FAI surgery. The modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS), and the international Hip Outcome Tool (iHOT-33) were administered at baseline and 1 year postoperatively. The MCID was calculated using a distribution-based method. Receiver operating characteristic (ROC) analysis was used to calculate cohort-based threshold values predictive of achieving the MCID. The area under the curve (AUC) was used to define predictive ability, with AUC >0.7 considered acceptably predictive. Multivariable analysis identified patient factors associated with achieving the MCID. Sensitivity analysis was performed to derive the MCID by an alternative anchor-based method.

RESULTS

There were 364 patients (mean [±SD] age, 32.5 ± 10.3 years), and 57.1% were female. The MCID for the mHHS, HOS-Activities of Daily Living (HOS-ADL), HOS-Sports, and iHOT-33 was 8.2, 8.3, 14.5, and 12.1, respectively. ROC analysis findings (threshold, percentage achieving the MCID, and strength of association) for these tools were as follows: mHHS (60.5, 77.2%, and 0.68, respectively), HOS-ADL (83.3, 68.1%, and 0.85, respectively), HOS-Sports (58.3, 65.9%, and 0.76, respectively), and iHOT-33 (53.9, 81.9%, and 0.65, respectively). The likelihood for achieving the MCID significantly declined above these thresholds. In multivariable analysis, a higher sagittal center-edge angle (CEA) (odds ratio [OR], 1.04; 95% CI, 1.01-1.08) was a positive predictor of achieving the MCID on the iHOT-33, while a higher Outerbridge grade for the acetabulum was a negative predictor (OR, 0.56; 95% CI, 0.32-0.99) on the mHHS. Sensitivity analysis confirmed these variables and identified relative femoral retroversion as another negative predictor (OR, 0.40; 95% CI, 0.17-0.94).

CONCLUSION

The HOS had excellent predictive ability for identifying patient thresholds of achieving the MCID; patients with preoperative scores below identified thresholds were most likely to achieve the MCID. Additionally, anterior acetabular undercoverage, chondral injuries, and relative femoral retroversion were clinically significant negative modifiers of outcomes. These findings have implications for managing preoperative expectations of FAI surgery.