The biomechanical differences of rotational acetabular osteotomy, Chiari osteotomy and shelf procedure in developmental dysplasia of hip

Background: Rotational acetabular osteotomy (RAO), Chiari osteotomy and shelf procedure are important treatments to delay the progression of osteoarthritis in developmental dysplasia of hip (DDH) patients, but their biomechanical differences are still unknown. This study was to evaluate the different biomechanical changes of hip joint after these three surgeries. Methods: Sixteen DDH models of 8 human cadaver specimens were reconstructed, and treated by different surgeries, and then strain around femoral head was evaluated by strain gauges. Results: Hip strain value of DDH model was decreased after treated by shelf procedure (Pleft = 0.016 and Pright = 0.021) and rotational acetabular osteotomy (P = 0.004), but not in Chiari osteotomy (P = 0.856). Moreover, the improved ratio of RAO treatment was better than shelf procedure (P = 0.015) and Chiari osteotomy (P = 0.0007), and the descendent range of shelf procedure was greater than Chiari osteotomy (P = 0.018). Conclusions: From biomechanics points, RAO was more effective in relieving hip joint stress compared with shelf procedure and Chiari osteotomy.