Short-Term Clinical Outcomes of a Conical Prosthesis Used in Revision Total Hip Arthroplasty.

ABSTRACT

INTRODUCTION: Although primary total hip arthroplasty (THA) stem designs have evolved from conventional lengths to shorter lengths, revision stems have not undergone a similar change. Tapered, conical prostheses have performed well in primary THA, however their use in revision THA has not been thoroughly investigated. Our purpose was to report the short-term radiographic and clinical outcomes of the Wagner Cone Prosthesis® (Zimmer Biomet, Warsaw, Indiana) in revision THA. MATERIALS AND METHODS: An institutional review board approved retrospective study was performed to identify all revision THAs with minimum one-year clinical and radiographic follow up between January 1, 2007 and December 31, 2018, which used a short conical tapered stem to reconstruct the femur. Demographic, surgical, and radiographic variables were collected for each patient. RESULTS: Fifteen hips that fit inclusion criteria were identified. Implant survivorship was 93.3% with a mean follow up of 33.6 months. Radiographic analysis revealed mean subsidence of 2.57mm ± 4.31mm and a limb-length difference of 0.69mm ± 12.4mm longer than the contralateral side. Furthermore, pedestal sign was observed on preoperative radiographs of six patients, none of whom suffered periprosthetic fracture or femoral cortex perforation upon insertion of the conical prosthesis. CONCLUSION: Our findings suggest that the Wagner Cone Prosthesis® is as a useful implant for revision THA. In our sample, it had excellent survivorship, impressive postoperative radiographic measurements obtained from most recent follow up, minimal mean subsidence, and minimal complication rates. Further prospective studies with longer follow up are needed to determine the efficacy of this stem in revision THA.