Transverse Subtrochanteric Shortening Osteotomy in Total Hip Arthroplasty for Severe Hip Developmental Dysplasia

Thirty-five total hip arthroplasties (33 patients) were performed in cases of Crowe grade III or IV hip dysplasia using subtrochanteric shortening osteotomy with two kinds of femoral stem: monoblock and modular type. All acetabular components were used with a cementless cup. The average patient age was 47.8 years, and the average follow-up time was 5.1 years. Acetabular reconstruction was performed using autogenous femoral head in 11 hips. Radiologically, hip centres were nearly normalised with vertical heights of 10.6mm elevation and horizontal lengths of 1.7mm compared with uninvolved sites. Leg length discrepancies were improved from 4.7 to 1.5cm. Early post-operative complications included two non-unions at the osteotomy site, one dislocation after monoblock stem, one case of peroneal nerve palsy and one subsidence occurring after modular stem placement. The non-union fractures were managed with bone grafts and modular stems. The dislocation was managed with closed reduction and an abduction brace. The peroneal nerve patient was managed with an ankle stop brace. Late complications included cup loosening, but there was no loosening in the femoral stem. The average Harris Hip Score was improved from 36 to 82.4. These data demonstrate that a cementless modular femoral stem is the more useful device for treating hip dysplasia patients.