High-Level Athletes With Borderline Hip Dysplasia Achieve Favorable Outcomes and Return to Sport Rates Following Primary Hip Arthroscopy: Minimum 5-Year Outcomes Comparison to a Propensity-Matched Control Group

Sport Participation Is Associated with Superior 10-Year Patient Acceptable Symptom State Achievement Following Contemporary Hip Arthroscopy for Femoroacetabular Impingement

BACKGROUND

Sport participation has been associated with favorable outcomes following hip arthroscopy (HA) for femoroacetabular impingement (FAI) at short- and mid-term follow-up; however, few studies have evaluated the 10-year outcomes in this population. The purpose of this study was to compare patient-reported outcome measures (PROMs), the achievement of clinically significant outcomes, and reoperation-free survivorship between patients with and without regular preoperative sport participation who underwent HA for FAI and had a minimum of 10 years of follow-up.

METHODS

Data were prospectively collected for patients who underwent primary HA for FAI between January 2012 and September 2013. Patients who participated in weekly sport participation at the time of surgery ("athletes") were matched 1:1 to patients who denied sport participation ("nonathletes"), controlling for age, sex, and body mass index (BMI). Preoperative and 10-year postoperative PROMs were collected, including the Hip Outcome Score Activities of Daily Living (HOS-ADL) and Sports (HOS-Sports) subscales, the modified Harris hip score (mHHS), and the visual analog scale for pain (VAS Pain) and satisfaction (VAS Satisfaction). Patient acceptable symptom state (PASS) achievement and reoperation-free survivorship were compared between the groups.

RESULTS

Sixty-four athletes were matched to 64 nonathletes of similar age, sex, and BMI (p ≥ 0.411). In the athlete group, 85.9% were recreational-level athletes. The groups had similar preoperative PROMs, except for the HOS-ADL subscale, where the athlete group demonstrated a higher preoperative score (67.8 ± 16.7 versus 59.9 ± 21.1, p = 0.029). Both groups demonstrated a significant improvement in all PROMs (p < 0.001) at the minimum 10-year follow-up10.3 ± 0.4 years). At the time of the final follow-up, the athlete group demonstrated significantly higher scores across all of the measured PROMs (p ≤ 0.036). Athletes showed a higher cumulative PASS achievement compared with nonathletes for the HOS-ADL subscale (73% versus 50%, p = 0.033), the HOS-Sports subscale (85% versus 61%, p = 0.010), the mHHS (69% versus 43%, p = 0.013), and the VAS Pain (78% versus 51%, p = 0.006). Reoperation-free survivorship frequencies were 87.5% and 82.8%, respectively (p = 0.504).

CONCLUSIONS

Athletes who underwent contemporary HA for FAI showed superior PROMs and PASS achievement compared with nonathletes at the 10-year follow-up. Athletes and nonathletes showed reoperation-free survivorship frequencies of 87.5% and 82.8%, respectively.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Primary and Revision Hip Arthroscopy in Borderline Hip Dysplasia Shows Comparable Outcomes at a Minimum 5-Year Follow-Up

PURPOSE

To compare patient-reported outcomes (PROs), achievement of clinically significant outcomes, and reoperation-free survivorship between primary and revision hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) in propensity-matched borderline hip dysplasia (BHD) patients at a minimum 5-year follow-up.

METHODS

Patients with BHD, characterized by a lateral center-edge angle 18° to 25°, who underwent HA for FAIS with capsular repair by a single surgeon between January 2012 and June 2018 with a minimum 5-year follow-up were identified. Cases of revision HA were propensity-matched 1:2 to cases of primary HA, controlling for age, sex, and body mass index. A 1:2 ratio was chosen to maximize the number of included patients. Collected PROs included Hip Outcome Score-Activities of Daily Living and Sport Subscales, International Hip Outcome Score 12, modified Harris Hip Score, and Visual Analog Scale for Pain. Achievement of minimal clinically important difference, patient acceptable symptom state, and substantial clinical benefit for any measured PRO was compared between groups along with reoperation-free survivorship using Kaplan-Meier analysis.

RESULTS

Thirty-six revision HA hips (34 patients) were propensity-matched to 72 primary HA hips (70 patients). The groups were similar in age (31.5 ± 10.3 years vs 30.5 ± 11.2, P = .669), sex (69.4% female vs 70.8%, P = .656), and body mass index (25.7 ± 4.0 vs 25.5 ± 3.7, P = .849). The revision group showed a greater prevalence of prolonged preoperative pain (50.0% vs 27.8%, P = .032) compared with the primary group. A significant improvement in all PROs was observed for both groups with comparable PROs preoperatively and at the 5-year follow-up between groups (P ≥ .086). The revision and primary groups showed comparable minimal clinically important difference (95.0% vs 95.7%, P ≥ .999), patient acceptable symptom state (80.0% vs 83.6%, P = .757), and substantial clinical benefit (62.5% vs 70.7%, P = .603) achievement for any PRO. Comparable reoperation-free survivorship was observed (P = .151).

CONCLUSIONS

Propensity-matched patients with BHD undergoing primary and revision hip arthroscopy for FAIS achieved similar minimum 5-year PROs, clinically significant outcomes, and reoperation-free survivorship.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

Are Women Less Likely to Return to Sport Compared to Men Following Hip Arthroscopy. A Systematic Review and Meta-analysis

OBJECTIVE: To compare return-to-sport outcomes between females/women/girls and males/men/boys undergoing hip arthroscopy and explore social and structural determinants of health that may influence return to sport. DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: CINAHL, Cochrane Central Register of Controlled Trials, Embase, Medline, SPORTDiscus, and Web of Science from inception to February 2024. STUDY SELECTION CRITERIA: Studies were included if they assessed return to sport after hip arthroscopy and analyzed the influence of sex/gender on return-to-sport outcomes, or reported sex- or gender-stratified return-to-sport rates. DATA SYNTHESIS: We used a random effects model to calculate pooled odds ratios and conducted meta-regressions to compare return-to-sport outcomes between females/women/girls and males/men/boys. RESULTS: Forty-five studies were included, with all pooled results deemed as very low-certainty evidence. Compared to males/men/boys, females/women/girls had inferior return to sport at the same or higher level between 1 and 3 years postoperatively (pooled OR = 0.53; 95% CI: 0.34, 0.81; P = .004), and at any level of sport at >3 years postoperatively (pooled OR = 0.46; 95% CI: 0.25, 0.86; P = .014). Sports participation decreased over time, with ~5.5% to 10% lower proportions observed in females/women/girls compared to males/men/boys. The reporting of determinants of returning to sport was minimal, precluding further exploration of their effects. CONCLUSION: Females/women/girls had lower odds of return to sport, especially during longer follow-up periods, than males/men/boys. The lack of reporting of social and structural determinants of health influencing return-to-sport outcomes makes the reasons for this disparity unclear. J Orthop Sports Phys Ther 2025;55(3):1-13. Epub 10 February 2025. doi:10.2519/jospt.2025.12813.

Painful Borderline Acetabular Dysplasia: What's New?

Developmental dysplasia of the hip (DDH) is a complex static-dynamic condition resulting in chronic joint instability and osteoarthritis. Borderline acetabular dysplasia refers to slightly abnormal patterns in the acetabular shape and coverage that are not within the dysplastic range. However, they can predispose to mechanical dysfunction and hip instability. Diagnosis and treatment remain controversial topics in hip preservation, with little current comparative literature to guide accurate diagnosis and treatment decision-making. Historically, the diagnosis of borderline DDH relied on assessments of the acetabular anatomy on anteroposterior pelvic radiography, most commonly the lateral central-edge angle (LCEA), with normal values ranging from 20 to 25° or, in some more recent studies, 18 to 25°. Surgical treatment decision-making debates the use of isolated hip arthroscopy or periacetabular osteotomy, considering the difficulty in determining a fundamental mechanical diagnosis (instability versus femoroacetabular impingement) in subjects with borderline DDH. Therefore, for effective surgical decision-making, the evaluation of additional bone anatomy characteristics, instability, and patients' features is essential.

Return-to-sports criteria used by professional team physicians in elite athletes after hip arthroscopy - a qualitative study

OBJECTIVES

The purpose of this study was to explore currently utilized readiness to Return to Sport (RTS) criteria after Hip Arthroscopy (HA) used in elite athletes to gain novel insights into the RTS decision-making process of professional team physicians. The authors hypothesized that even among this group of highly specialized physicians, there exists variability of measures and criteria used to determine RTS after HA.

METHODS

A total of 15 qualitative semi-structured interviews with professional team physicians were conducted by a single trained interviewer. The interviews were used to identify team physician concepts and themes regarding the criteria used to determine RTS after HA. Themes and sub-themes were identified using a general inductive analysis and a coding process. A hierarchical approach in coding helped to link themes.

RESULTS

Four key themes and several subordinate themes were identified from the interviews that seem to influence the return to sports decision. The most important RTS criteria were muscle strength (especially symmetric hip strength and muscle bulk with low side-to-side variance compared to the contralateral side) followed by pain-free sport-specific activity (pain-free drill skills and play at a lower level), physical examination (with major emphasis on the absence of hip pain with a painless hip range of motion compared to the contralateral side), and functional testing (including full squats, Ober test, FABER test, and pain-free FADIR position).

CONCLUSION

Besides objective findings, including muscle strength, we identified time after surgery as well as subjective findings, including absence of pain and feedback of clinical team members that influence RTS decision after HA. We showed that even among specialized professional team physicians, the main criteria to RTS in these categories were not consistent necessitating the further development of specific RTS guidelines.

Risk Factors for Failure of Hip Arthroscopy in Patients With Borderline Dysplasia Include a Tönnis Angle ≥15°, Age ≥40 to 42 Years, Female Sex, Anterior Wall Index <0.35, Labral Debridement, and Preexisting Hip Osteoarthritis: A Systematic Review

PURPOSE

To systematically review the literature to determine potential risk factors for failure of hip arthroscopy (HA) in patients with borderline hip dysplasia (BHD).

METHODS

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines by searching PubMed, the Cochrane Library, and Embase to identify English-language clinical studies reporting on patients with BHD undergoing HA from 2003 to 2023. The search terms used were (borderline OR mild) AND hip AND (arthroscopy OR dysplasia) AND failure. The primary outcomes assessed were risk factors reported by each study for failure of a HA-only approach in patients with BHD.

RESULTS

Fourteen studies (8 Level III, 6 Level IV) met inclusion criteria, totaling 749 hips. Patient age ranged from 29.8 to 39.2 years, with a mean follow-up ranging from 24.0 to 144.0 months. The overall percentage of female patients ranged from 11.8% to 100.0%. Overall, the clinical failure rate ranged from 0 to 53.3%, and the reoperation rate ranged from 0 to 44.0%. The predominant predictors of poor outcomes after HA alone included Tönnis angle ≥15°, age ≥40 to 42 years at surgery, and female sex. Other risk factors for failure were preoperative clinical arthritis, grade 3 or 4 articular cartilage changes to the femoral head or acetabulum, an anterior wall index <0.35, and labral debridement. Revision procedures performed included revision HA (n = 88, 0-28.0%), total hip arthroplasty (n = 55, 0%-23.7%), and endoscopic shelf acetabuloplasty (n = 5, 0%-11.0%). One study included an additional 9 patients converting to either periacetabular osteotomy or total hip arthroplasty without distinguishing between the two.

CONCLUSIONS

For patients with BHD, Tönnis angle ≥15°, age ≥40 to 42 years at surgery, female sex, anterior wall index <0.35, labral debridement, and pre-existing hip osteoarthritis are common risk factors for treatment failure following isolated HA.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Primary Hip Arthroscopy in Patients With Acetabular Dysplasia: A Systematic Review of Published Clinical Outcomes at Minimum 5-Year Follow-up

BACKGROUND

Hip arthroscopy in patients with borderline hip dysplasia has satisfactory outcomes at short-term follow-up; however, the data on midterm outcomes are inconsistent, and failure rates are high in some studies, limiting understanding of the role and utility of hip arthroscopy in this patient cohort.

PURPOSE

To provide an up-to-date, evidence-based review of the clinical outcomes of primary hip arthroscopy in patients with frank or borderline hip dysplasia at ≥5-year follow-up and report the failure rate and progression to total hip arthroplasty in this cohort.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive literature search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they evaluated outcomes of primary hip arthroscopy in patients with lateral center-edge angle (LCEA) <25° at ≥5-year follow-up. Risk of bias assessment was performed using the methodological index for non-randomized studies scoring system. Level of evidence was determined using criteria from the Oxford Centre for Evidence-Based Medicine.

RESULTS

Nine studies were included in this review. Patients with LCEA <25° demonstrated satisfactory clinical outcomes, high patient satisfaction, and significant postoperative improvements in patient-reported outcomes (PROs) at follow-up ranging from a ≥5 to 10 years. Studies comparing patients with dysplasia to those without did not demonstrate significant differences in preoperative, postoperative, or delta PROs or in failure, reoperation, or revision rates. There was no overall significant correlation between outcomes and LCEA stratification.

CONCLUSION

Hip arthroscopy in carefully selected patients with LCEA <25° can be successful at mid- to long-term follow-up and may provide clinical outcomes and failure rates comparable with patients with normal LCEA, understanding that this is a singular, 2-dimensional radiographic measure that does not differentiate instability from impingement or combinations thereof, warranting future studies delineating these differences. These findings suggest that hip dysplasia may not be an absolute contraindication for isolated hip arthroscopy and may serve as a viable intervention with consideration of staged future periacetabular osteotomy (PAO). Importantly, this review does not suggest that hip arthroscopy alters the natural history of dysplasia; therefore, patients with dysplasia should be counseled on the potential utility of PAO by appropriate hip preservation specialists.

The Use of Combined Hip Arthroscopy and Periacetabular Osteotomy for Hip Dysplasia Is Increasing and Has Low Complication Rates

Purpose

To analyze the annual use of hip arthroscopy (HA) and Bernese periacetabular osteotomy (PAO) for the treatment of hip dysplasia (HD), as well as postoperative outcomes, including ipsilateral reoperations.

Methods

International Classification of Diseases, Ninth and Tenth Revision, codes were used to query the PearlDiver Mariner database from January 2010 through January 2022 to identify patients aged 10 to 59 years who had a presenting diagnosis of HD and subsequently underwent (1) HA; (2) PAO; or (3) combined HA and PAO (HA-PAO, defined as PAO on the same day or within 28 days after HA). We analyzed annual rates for each treatment, as well as rates of postoperative emergency visits, readmissions, and 5-year ipsilateral secondary operations (determined via Kaplan-Meier analysis).

Results

There were 32,068 patients who underwent surgical treatment of HD. For HA, PAO, and HA-PAO, there were 29,700, 2,083, and 285 patients, respectively. All operations had the greatest percent-increase from 2015 to 2016. HA and HA-PAO peaked in 2021, whereas PAO peaked in 2019. For HA, PAO, and HA-PAO, most cases were performed in female patients and patients aged 30 to 49 years, 10 to 19 years, and 10 to 29 years, respectively. The 5-year incidence of ipsilateral secondary operations, which include revision HA, PAO, or conversion to total hip arthroplasty, was 9.2% (95% confidence interval 8.6%-9.8%) in the HA group and 6.5% (95% confidence interval 4.1%-8.8%) in the PAO group. Combining HA with PAO resulted in so few secondary operations that Kaplan-Meier analysis was infeasible. The PAO cohort had the greatest 30-day emergency visit and 90-day readmission rates, with infection as the most common cause for readmission.

Conclusions

HA is more frequently performed than PAO for hip dysplasia. HA-PAO is increasing at the greatest rate, demonstrating fewer complications and reoperations.

Level of Evidence

Level III, retrospective comparative trial.

No Difference in Patient-Reported Outcomes for Periacetabular Osteotomy and Hip Arthroscopy With Capsular Plication in the Setting of Borderline Hip Dysplasia: A Propensity-Matched Multicenter Study With Minimum 5-Year Follow-Up

PURPOSE

To compare minimum 5-year patient-reported outcome measures after hip arthroscopy (HA) and periacetabular osteotomy (PAO) for borderline hip dysplasia.

METHODS

Hips with a lateral center-edge angle (LCEA) between 18° and less than 25° that underwent either PAO or HA were selected from 2 institutions. The exclusion criteria were as follows: LCEA less than 18°, Tönnis osteoarthritis grade greater than 1, prior hip surgical procedures, active inflammatory disease, Workers' Compensation, and concomitant surgery. Patients underwent propensity matching based on age, sex, body mass index, and Tönnis osteoarthritis grade. Patient-reported outcome measures included the modified Harris Hip Score, as well as calculation of the minimal clinically important difference, patient acceptable symptom state, and maximum outcome improvement satisfaction threshold. Preoperative radiographic predictors included comparison of the Femoro-epiphyseal Acetabular Roof index and ligamentum teres lesions.

RESULTS

A total of 28 PAO patients underwent propensity matching to 49 HA patients. The 2 groups were similar in terms of mean age, sex, preoperative body mass index, and LCEA. The PAO group had a longer mean follow-up period (95.8 months vs 81.3 months, P = .001). The mean Femoro-epiphyseal Acetabular Roof index was significantly lower preoperatively in the HA group (P < .001). The 2 groups showed similar and significant improvements in the mean modified Harris Hip Score from preoperatively to latest follow-up (P < .001). The relative risk of subsequent surgery in the PAO group was 3.49 (P = .024), mostly attributed to hardware removal (25%). The revision rate was 3.6% in the PAO group and 8.2% in the HA group (P = .65). One patient in the PAO group required revision HA for intra-articular adhesions. Three of the patients requiring revision in the HA group underwent PAO because of persistent pain, and one underwent revision HA alone. Conversion to total hip arthroplasty was required in 1 patient in the HA group and no patients in the PAO group.

CONCLUSIONS

Both PAO and HA with capsular plication provide borderline hip dysplasia patients with clinically significant improvements and low revision rates at a minimum of 5 years postoperatively.

LEVEL OF EVIDENCE

Level III, retrospective, comparative therapeutic trial.

Outcomes and Return-to-Sports Rates in Patients With Borderline Hip Dysplasia After Periacetabular Osteotomy: A Case Series With 5-Year Follow-up

BACKGROUND

The optimal surgical approach in patients with borderline hip dysplasia (BHD) remains controversial. Both hip arthroscopy and periacetabular osteotomy (PAO) are commonly employed in this patient population. Those who participate in sports want to resume and maintain sports activities after surgery, and the ability to do so plays an important role in the choice of a treatment method. To our knowledge, no previous study has assessed return-to-sports rates and activity levels in patients with BHD after PAO.

PURPOSE

To assess return-to-sports rates and postoperative activity levels as measured by the University of California, Los Angeles (UCLA), activity scale as well as patient-reported outcome measures. Also to assess changes in sports activity both qualitatively and quantitatively as well as underlying reasons for these changes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We conducted a retrospective analysis of prospectively collected data from 55 hips in 52 patients with BHD who underwent PAO between January 2015 and June 2017. Return-to-sports rates, UCLA activity scores, International Hip Outcome Tool-12 scores, Subjective Hip Value scores, Hip disability and Osteoarthritis Outcome Score subscores, sports practiced, frequency and duration of sports activity, and postoperative changes as well as underlying reasons were recorded.

RESULTS

The mean follow-up was 62.8 ± 9.0 months. The return-to-sports rate among preoperatively active patients was 92.5%. Most patients resumed sports activity after 6 months (50%) or after 3 to 6 months (37.5%). The UCLA activity score improved significantly (from 5.2 ± 2.4 to 7.0 ± 1.8; P < .001). The International Hip Outcome Tool-12, Subjective Hip Value, and Hip disability and Osteoarthritis Outcome Score scores also improved significantly (all, P < .001). Changes in sports activity occurred in 34.5% of cases after PAO. Significantly more patients engaged in low-impact sports postoperatively. Participation in high-impact sports did not decrease significantly. Reasons for changes were both hip related and non-hip related. Quantitatively, patients were able to significantly increase both the frequency (P = .007) and duration (P = .007) of sports activity.

CONCLUSION

The return-to-sports rate in patients with BHD after PAO was high at over 92%. Most patients returned to sports after a period of 6 months or 3 to 6 months. Overall, activity levels and hip function improved after PAO. A number of patients adjusted their sports activity after PAO. Although more patients engaged in low-impact sports, participation in high-impact sports was maintained postoperatively. The results of this study may help both patients and orthopaedic surgeons in deciding on the best surgical procedure in the setting of BHD.

Lateral Center-edge Angle of 18° (Bone-Edge): Threshold for Hip Arthroscopy Treatment in Patients with Borderline Developmental Dysplasia of the Hip?

OBJECTIVE

Hip arthroscopy for the treatment of symptomatic borderline developmental dysplasia of the hip (BDDH) has been controversial. The purpose of this study was to retrospectively analyze minimum 2-year outcomes of BDDH after arthroscopic surgery and explore the criteria and thresholds of the lateral center-edge angle (LCEA) in arthroscopic surgery for BDDH.

METHODS

Data were retrospectively collected from patients aged 18-50 who underwent arthroscopic surgery for BDDH and had an LCEA 18-25° between September 2016 and June 2020. The consistency of interobserver and intraobserver measurements of bone-edge LCEA was analyzed. Patients were divided into two groups based on LCEA (18-20°and 20-25°) and the results of arthroscopy compared between groups. Patient-reported outcome (PRO) scores, consisting of the modified Harris hip score (mHHS), the visual analogue scale (VAS) and the international hip outcome tool-12 (IHOT-12), the minimal clinically important difference (MCID) and patient acceptable symptom status (PASS) were calculated.

RESULTS

In 52 patients with ≥2-year follow-up, female patients accounted for 71.2% and the mean age was 30.8 ± 8.4 years (range: 18 to 49 years). There was a high level of agreement when measuring the bone-edge LCEA definition of BDDH (Kappa = 0.921). Interobserver repeatability (ICC = 0.909, 95%CI: 0.847-0.947) and intraobserver repeatability (ICC = 0.944, 95%CI: 0.905-0.968) were excellent for bone-edge LCEA measurements. In addition to LCEA and Tönnis angle, there were no significant differences in α angle, neck stem angle, femoral anteversion angle, medial joint space, Tönnis grade of osteoarthritis, acetabular retroversion (8 sign), Cam deformity and anterior inferior iliac spine (AIIS) morphology between the two groups (p > 0.05). Intraoperative findings and procedures showed no statistical difference between groups (p > 0.05). The mean follow-up time was 44.4 ± 11.0 months (range: 25 to 64 months). Postoperative VAS, mHHS and IHOT-12 scores in the LCEA 18-20° group and the LCEA 20-25° group were significantly improved compared with those before surgery, and there was no statistically significant difference in the percentage of MCID and PASS (mHHS and iHOT-12) between the groups (p > 0.05).

CONCLUSION

Patients in the LCEA 18-20° group and the LCEA 20-25° group achieved favorable outcomes after arthroscopic surgery. LCEA 18° (bone-edge) should be the threshold for hip arthroscopic surgery in BDDH patients without obvious hip instability.

Periacetabular Osteotomy in Athletes With Symptomatic Hip Dysplasia Allows for Participation in Low-, Moderate-, and High-Impact Sports, With Greater Than 70% Return to Sport for Competitive Athletes: A Systematic Review

PURPOSE

To systematically review the literature and report the rate of return to sport (RTS) in athletes following periacetabular osteotomy (PAO) for symptomatic hip dysplasia.

METHODS

A literature search of the PubMed, Embase, and Cochrane Library databases was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for clinical studies reporting on athletes undergoing PAO surgery for symptomatic hip dysplasia. A quality assessment was performed using the Methodological Index of Non-Randomized Studies (MINORS) grading system. Data collection included study characteristics, demographics, radiographic measurements, rate and timing of RTS, baseline and most recent patient-reported outcomes (PROs), and subsequent surgeries.

RESULTS

Six studies met inclusion criteria with 341 patients undergoing PAO. There were 2 level III and 4 level IV studies, with an average MINORS score of 11. Preoperative and postoperative lateral center edge angles ranged from 8° to 18° and 23° to 41.3°, respectively. One study reported solely on dancers with a 63% rate of RTS at 1 year postoperatively. Two other studies reported RTS of 80% and 82% for multiple sports, with slightly lower rates (73% and 78%) in competitive athletes. Three studies demonstrated a comparable distribution of sports participation, from the preoperative to postoperative period, in low-impact (61.4% to 72.1% and 63.7% to 85.7%), moderate-impact (10.3% to 21.0% and 4.3% to 25.4%), and high-impact (8.5% to 17.6% and 5.1% to 10.8%) sports. Three studies reported time to RTS after PAO, ranging from 8.8 to 12.8 months. Of the 3 studies noting reasons for not returning to sport, concerns related to the operative hip ranged from 36.4% to 67%. Of the studies that reported both preoperative and postoperative PROs, improvements in all values were observed, with modified Harris Hip Scores and Hip Disability Osteoarthritis Outcome Scores at most recent follow-up ranging from 81 to 95 and 72 to 93, respectively.

CONCLUSIONS

In athletes with symptomatic hip dysplasia undergoing PAO, postoperative participation in low-, moderate-, and high-impact sports was observed, with greater than 70% RTS for competitive athletes. These findings suggest that PAO, with appropriate indications, is an efficacious treatment option in this active patient population with severe dysplasia.

LEVEL OF EVIDENCE

Level IV, systematic review of level III and IV studies.

Editorial Commentary: Most Patients With Borderline Hip Dysplasia Do Well After Hip Arthroscopy: Could Instability Be the Problem for Those Who Do Poorly?

Borderline hip dysplasia (BHD) is often defined based on the lateral center edge angle. While patients with frank hip dysplasia often require bony realignment with periacetabular osteotomy and/or derotational femoral osteotomy, patients with BHD represent an "in-between" group of patients. While many, perhaps even most, patients with BHD will have successful outcomes after hip arthroscopy alone, some will be unresponsive to an arthroscopic-only approach and require the same surgical treatments as those with frank dysplasia. A variety of radiographic and arthroscopic parameters can be used to assess the degree of instability in patients with BHD. It may be that patients with "borderline" hip dysplasia combined with hip instability are more likely to fail an arthroscopic-only approach but to date we still do not have a great algorithm for determining which patients with BHD should undergo bony treatment with periacetabular osteotomy. It is important for future studies to continue to seek out characteristics of BHD patients that predict failure of an arthroscopic-only approach. This will not only allow for optimal initial surgical treatment in "at-risk" patients with BHD but will also improve success rates in BHD patients selected for hip arthroscopy as initial surgical treatment.