A new anterior total hip arthroplasty reduction technique for patients who require leg lengthening.

Background: When performing anterior total hip arthroplasty (THA) for patients who require leg lengthening, surgeons often encounter difficulties during reduction due to soft tissue tightness. The purpose of this study was to introduce a new THA reduction technique for these patients.

Methods: Between October 2018 and September 2019, 545 THAs were performed. In 15 hips (2.8%), reduction was not achieved with a traditional technique. The preoperative diagnosis was Crowe grade II in 4 hips, Crowe grade III in 4 hips, Crowe grade IV in 1 hip, and sequelae of Legg-Calvé-Perthes disease in 6 hips. All procedures were performed using a direct anterior approach. The new reduction technique was to use a lever hooked on the acetabular teardrop as a counter force against the preserved muscles. The lever was connected to the impactor with a wire and the counterforce was transmitted to the impactor.

Results: Reduction was achieved in all cases without shortening osteotomy or muscle release. The mean lengthening of the operated limb was 30 mm (range 13-59 mm). Neither sciatic nor femoral nerve palsy were observed.

Conclusion: We developed a new anterior THA reduction technique for patients who require leg lengthening. When the centre of the femoral head was reduced to the superior edge of the cup with the traditional technique, reduction was safely achieved with this technique.