Short versus Long-Leg Hip Spica After Closed Reduction in Developmental Dysplasia of the Hip: A Retrospective Comparative Study

PURPOSE: Closed reduction (CR) is a standard treatment for developmental dysplasia of the hip (DDH) after failed conservative treatment. After CR, the affected hip is held in the reduced position by a spica cast that typically extends below the knee (long). Above knee (short) spica cast is an alternative technique utilized by some pediatric orthopedic surgeons. We aimed to compare short versus long spica cast after CR in terms of success rate and complications. METHODS: Patients who underwent CR with short or long hip spica cast over a 3-year period (2016–2019) were evaluated for the success (sustainability of the reduction) and complications. The acute and long-term success were recorded retrospectively. Acute success was defined as concentric reduction of the hip confirmed by intraoperative arthrogram and immediate postoperative CT scan. Long-term success was defined as maintained reduction at 12 months’ post reduction. RESULTS: Forty-seven patients were included in our study. Long spica casts were used in 24 patients and short ones in the remaining 23. The overall acute and long-term success rates were 83% and 66%, respectively. The acute success rate of long spica was 87.5%, while short spica achieved 78.2%. On the long term, the success rate of short spica was higher than long one (73.9% vs 58.3%). Cox regression analysis showed that the type of cast (short vs long spica) was not correlated with acute success (P = 0.405), long-term success (P = 0.263), residual dysplasia (P = 0.405), or avascular necrosis (P = 0.053). CONCLUSION: CR in DDH is an important line of management in the younger patient population and can save them an invasive open surgery later in life. A short leg spica could represent an easier and likely as successful alternative to the traditional long spica. More prospective future research is needed to validate our observational findings. LEVEL OF EVIDENCE: III.