Comparison of Clinical and Radiological Outcomes of Three Modern Stem Designs in Total Hip Arthroplasty With Minimum Two-Year Follow Up

Introduction: Recent changes in stem design for total hip arthroplasty (THA) complicate the daunting task of the orthopaedic surgeon to choose the best stem for patients. The purpose of our study was to report the early- to mid-term clinical and radiological outcomes of three unique stem designs used for THA using primarily a posterolateral approach.

Materials and methods: A retrospective study was performed at a single healthcare system between January 2007 and March 2018 to identify THA patients who received a stem belonging to the Taplerloc® Complete Hip System (Zimmer-Biomet, Warsaw, Indiana). Stems were then stratified into full-length, standard profile, full-length, reduced distal profile, and short-length, standard profile cohorts. Demographic, radiological, and clinical outcome variables were collected for each patient and compared between stem cohorts.

Results: 538 THAs (248 full-length, reduced distal; 202 full-length, standard profile; 88 short-length, standard profile) were analyzed. One patient in the full-length, reduced distal cohort suffered a perioperative fracture following implantation of the stem. There were a total of 29 postoperative complications at most recent follow up, nine (3.6%) in the full-length, reduced distal group, 12 (5.9%) in the full-length, standard profile group, and eight (9.1%) in the short-length, standard profile group, with no difference in rates of complication between groups (p=0.136). No difference in complication rates was observed when only posterolateral cases were considered (p=0.05). Survivorship of each stem group was 99.6%, 98.5%, and 96.6%, respectively. Limb length discrepancy and stem subsidence were found to be similar between groups based on measurements taken at most recent clinical follow up.

Conclusion: Our findings suggest that shortened length and reduced distal profile features result in no added benefit regarding intraoperative and postoperative clinical or radiological outcomes.