Comparison of canine femoral implant templating for total hip arthroplasty on 25 sets of craniocaudal extended and caudocranial flexed hip radiographs

Abstract

Objective: To determine whether radiographic templating of femoral stem size for total hip arthroplasty (THA) using extended and flexed hip radiographs are interchangeable. Study design: Retrospective radiographic study. Sample population: A total of 25 dogs evaluated as THA candidates. Methods: Hip-extended and hip-flexed radiographs were templated for femoral stem implant size by three surgeons. A fourth investigator measured femoral length, canal flare index (CFI), and osteoarthritis scores for each projection and recorded implant size from surgical records. Templated stem sizes from each projection were compared with the implanted stem sizes using Bland–Altman analysis. Descriptive statistics were reported based on data distribution. Results: Templated femoral stem size differed between surgeons (p =.014); the median (IQR) stem size was #9 (8–10) for one surgeon, compared to #8 (7–9) for the other surgeons. Templated stem sizes on extended and flexed radiographs were #8 (7–9) and #9 (7–9), respectively (p