Arthroscopic Management of Dysplastic Hip Deformities: Predictors of Success and Failures With Comparison to an Arthroscopic FAI Cohort

Background: Reports regarding arthroscopy for mild hip dysplasia have conflicting results. Hypothesis: Arthroscopy for borderline/mild hip dysplasia would lead to improved outcomes but be inferior to arthroscopy for femoroacetabular impingement (FAI). Study Design: Cohort study; Level of evidence, 3. Methods: A total of 88 hips (77 patients, 71% female; mean age, 33.9 years) with dysplastic radiographic findings were retrospectively reviewed at a mean follow-up of 26.0 months after hip arthroscopy. Specific procedures included labral repair (76%), labral debridement (23%), capsular repair/plication (82%), and femoral osteochondroplasty (72%). Radiographic parameters included lateral center-edge angle, neck-shaft angle, Tönnis angle, extrusion index, femoral head lateralization, and break in the Shenton line. Pre- and postoperative function were evaluated prospectively with the modified Harris Hip Score (mHHS), 12-Item Short Form Health Survey, and visual analog scale for pain. The results of the dysplastic cohort were compared with an age-matched cohort of 231 hips without radiographic dysplasia that underwent arthroscopic FAI correction during the study period (mean follow-up, 22.7 months). Results: The mean lateral center-edge angle was 20.8° (range, 8.7°-24.5°), and the mean Tönnis angle was 11.0° (range, 0°-22.2°). At the time of final follow-up, the dysplastic cohort demonstrated a mean mHHS of 81.3 with a mean 15.6-point improvement in mHHS, compared with 88.4 and 24.4 points, respectively, in the FAI cohort (P = .00044). The dysplastic cohort had 60.9% good/excellent results and 32.2% failures, compared with 81.2% good/excellent results and 10.5% failures for the FAI cohort (P < .01). Failure was defined as an mHHS ≤70 or eventual pelvic/femoral osteotomy or total hip arthroplasty. Dysplastic hips that underwent capsular plication and labral repair had greater good/excellent results (73%) and mean latest mHHS (85), as well as lower failure rates (18%) compared with the remainder of the dysplastic cohort (P < .05). Grade 4 chondral defects were predictive of lower scores (P = .02). There were no other statistically significant differences for outcomes regarding sex, age, or radiographic parameters (P > .05). There were no iatrogenic subluxations/dislocations. Conclusion: Arthroscopic management of mild to moderate acetabular dysplasia had inferior good/excellent results and higher failure rates when compared with an FAI cohort; therefore, isolated ar