Abstract:

Objective To investigate the application of medial protrusion technique in total hip arthroplasty (THA) for developmental dysplasia hips (DDH). Methods The clinical data of 31 patients (38 hips) with DDH of Crowe typeⅡ-Ⅳundergoing THA were retrospectively analysed, and all patients were treated with medial protrusion technique in THA. The incidence of complications early after operation was observed, and Harris scores and radiological measurements were used for function evaluation after operation. Results Three cases of acetabular fractures were identified during operation. One case of posterior dislocation (3 months after operation), three cases of impingement syndrome and one case of cup displacement were found after operation. The mean distance of medial placement was 12 mm (5 to 20 mm), with a mean acetabular coverage of 85% (70% to 100%). The average inclination angle was 47.5°(42°to 65°), and valgus placement of acetabular components was found in 4 cases with inclination angle over 60°. The mean Harris score was 46.6 (38-77) before operation and 83.0 (65-92) after operation, and there were significant differences between them （P<0.05）. Conclusion The medial protrusion technique is effective in reconstruction of the hip rotator center in THA for DDH. However, precise preoperative planning and controllable operative techniques are required to decrease the incidence of complications early after operation.

Key words: medial protrusion technique, developmental dysplasia hip, total hip arthroplasty, complication