Purpose: Bipolar hemiarthroplasty (BH) is one of the commonly performed orthopedic procedures for the treatment of displaced fractures of the femoral neck. However, despite the common use of the BH, little has been written on preoperative planning for this operation. The purpose of this study was to assess the neglected subject which is about the cognition of the femoral head cartilage in planning a BH.
Methods: We reviewed a group of 62 consecutive patients in whom cemented BH had been performed by one surgeon. A total of 31 patients underwent BH with consideration of the femoral head cartilage thickness in preoperative planning. The anteroposterior radiographs of this group were compared to those of a group of 31 patients who underwent BH without consideration of the femoral head cartilage thickness in preoperative planning. We measured the limb length and offset with reference to the normal contralateral hip and the cartilage thickness of the hip joints postoperatively.
Results: There were significant reduction in the limb-length discrepancy (LLD) (mean 0.4 mm lengthening compared with 1.6 mm shortening; P < 0.001) and improvement of the femoral offset ratios of the operated hips to the normal contralateral hips (mean 99.9% compared with 96.8%; P = 0.032) in the group of patients with consideration of the femoral head cartilage thickness in preoperative planning.
Conclusions: The femoral head cartilage should be considered when determining the level of femoral neck resection in order to reduce postoperative LLD when planning a bipolar hemiarthroplasty. Accurate and careful preoperative planning can result in balanced hip reconstruction by equalizing limb lengths and restoring the offsets.