Abstract
Background:
Patients with developmental dysplasia of the hip (DDH) have a greater risk of acetabular labral tearing and joint instability, which predispose them to developing osteoarthritis. The arthroscopic management of DDH, however, remains controversial.
Hypothesis:
Specific clinical characteristics and radiographic parameters correlate with and predict a worsened clinical outcome after hip arthroscopic surgery for DDH.
Study Design:
Case control study; Level of evidence, 3.
Methods:
Of patients with DDH who underwent an arthroscopic procedure between March 2009 and June 2011, there were 28 hips in 28 patients (6 male and 22 female) that met the inclusion criteria. The mean patient age was 28.4 years. Clinical and radiographic follow-up evaluations up to a minimum of 2 years after surgery were performed for all patients. Failure of the procedure was defined as conversion to subsequent surgery or having a Tönnis osteoarthritis grade of 2 and modified Harris Hip Score (mHHS) that remained <85, and success was defined as patients who did not need subsequent surgery and had an mHHS >85. Univariate analysis and Cox hazard proportional analysis were performed on the 2 subpopulations.
Results:
There were 9 patients in the failure group (including 3 hips with T nnis grade 2) and 19 patients in the success group. In 22 of 28 patients, the mean mHHS significantly improved from 61.6 ± 18.8 (range, 12.0-85.0) preoperatively to 94.3 ± 7.0 (range, 73.7-100.0) at final follow-up, and the mean Non-Arthritic Hip Score (NAHS) improved from 56.2 ± 13.9 (range, 35.0-81.3) preoperatively to 92.7 ± 9.5 (range, 65.0-100.0) at final follow-up (P < .001, Wilcoxon signed-rank test). Univariate analysis showed that a broken Shenton line was significantly more prevalent in the failure group compared with the success group (8/9 [89%] vs 3/19 [16%] patients, respectively; P < .001). High-grade cartilage delamination (Multicenter Arthroscopy of the Hip Outcomes Research Network [MAHORN] grades 3-5) was significantly higher in the failure group than in the success group (8/9 [89%] vs 3/19 [16%] patients, respectively; P < .001). The median femoral neck-shaft (FNS) angle in the failure group was significantly higher than that in the success group (139° vs 134°, respectively; P = .01). Further, Cox hazard proportional analysis of the failure group showed that the predictors for a poor clinical outcome were the presence of a broken Shenton line, FNS angle >140°, center-edge (CE) angle <19°, body mass index (BMI) >23 kg/m2, acetabular cartilage damage (MAHORN grades 3-5), and cartilage damage of the femoral head (International Cartilage Repair Society grades 2-4). The most important predictors for a poor clinical outcome at the time of surgery were a broken Shenton line and an FNS angle >140°.
Conclusion:
Patients with a broken Shenton line, FNS angle >140°, CE angle <19°, or BMI >23 kg/m2 at the time of surgery are not good candidates for the arthroscopic management of DDH.
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