人工股関節置換術における上方進入法の概説

抄録

Introduction: The superior approach (SA) in total hip arthroplasty (THA) is one of the muscle sparing posterior approaches. We describe this method and report the radiographic outcomes of the first 30 hip arthroplasties performed using a SA.

Methods: The method for THA: The patient was placed in the lateral decubitus position with the operative leg in approximately 60° of flexion, 40° of adduction, and 20° of internal rotation. The gluteus medius muscle was retracted anteriorly, and the piriformis muscle posteriorly, to exposure the hip capsule. The femoral canal was entered at the trochanteric fossa with a round chisel. The femoral broaches were performed before the femoral neck osteotomy. The femoral head was removed after the osteotomy. The acetabular cup was impacted with anteversion of the transverse acetabular ligament.

 The method for hip hemi-arthroplasty (HA): First, the outer head was placed in the acetabular fossa; second, the femoral stem was placed and the inner head was impacted. The outer and inner head were set up in the acetabular fossa.

Results: The SA group included 12 THAs and 18 HAs. In the THA group, the mean operative duration was 106±18 minutes, the mean varus angle of the stem was 0±1.5 degrees, the mean inclination of the cup was 45±8 degrees, the mean anteversion of the cup was 9±8 degrees and the mean limb length discrepancy was 6±4 mm. In the HA group, the mean duration was 60±17 minutes, the mean varus angle of the stem was 1±2 degrees and the mean limb length discrepancy was 0.5±4 mm.

 In four (33%) THAs, the piriformis muscles were resected and repaired. In all of the HAs, the piriformis and conjoint tendons were preserved.

Conclusion: The piriformis muscles were resected in some THAs, but the short rotators muscles were preserved in the HA procedures.