Predictors for secondary procedures in walking DDH

BACKGROUND: Persistent or recurrent hip dysplasia and/or loss of reduction can complicate the treatment of developmental dysplasia of the hip (DDH) in walking children. In this study, we identify predictors for secondary procedures after open reduction of the hip in walking children with DDH. METHODS: We performed a retrospective study of walking children with idiopathic DDH treated with open reduction of the hip and followed up for >5 years. Perioperative factors were analyzed to investigate predictors of reoperation. Factors associated with the need for secondary procedures were identified. Acetabular remodeling was analyzed with a graphical plot of serial (0, 6 and 12 mo, and yearly) mean acetabular index and SD. RESULTS: There were 49 open reductions of the hip in 42 patients (34 female, 8 male) at a mean age of 31.3 months (range, 15.3 to 92.6 mo), with a mean follow-up of 9.7 years (5 to 16.9 y). Twelve (24%) patients had open reduction only, 15 (31%) had concurrent pelvic osteotomy, 4 (8%) had femoral osteotomy, and 18 (37%) had both femoral and pelvic osteotomy. Four (8%) patients required repeat open reduction at a mean of 5.1 months (range, 4 to 7.5 mo) after index surgery. Twenty-four (49%) patients had at least 1 secondary surgery for dysplasia at a mean of 3.2 years after index surgery. Six of the 24 (25%) had 2 and 2/24 (8.3%) had 3 additional operations. Of the 27 patients who did not have concurrent femoral osteotomy at index surgery, 19/27 (73%) required a secondary procedure; this significantly predicted the need for reoperation (P<0.001). Only 5/22 patients with femoral osteotomy at index surgery required a secondary procedure. Maximum acetabular remodeling was observed in the first 4 years after primary reduction, and the mean acetabular index remodeled from 43.9 to 20.3 degrees during this period. CONCLUSIONS: Forty-nine percent of the patients in this cohort required secondary procedures to treat hip dysplasia. Open reduction without concurrent femoral osteotomy strongly predicted the need for a secondary procedure. Maximum acetabular remodeling was observed in the first 4 years after open reduction. LEVEL OF EVIDENCE: Retrospective case series, level IV.