Long term radiological and clinical outcomes of femoral components placed in varus malposition after total hip arthroplasty

Introduction and Aim: Total Hip Arthroplasty is a frequently applied successful surgery used in the treatment of osteoarthritis. The cementless femoral stem can be applied in varus or valgus malposition. Varus malposition can cause anterior thigh pain, aseptic loosening of the femoral stem, subsidence and periprosthetic fracture. In our study, long-term clinical and radiological results of varus cementless femoral stems were examined. Material and Method: In this study, cementless total hip arthroplasty patients with at least 5 years of follow-up between December 2006 - December 2017 were evaluated. According to the femoral stem position measurement in the Pelvis AP X-ray taken on the first post-operative day, patients were divided into 3 categories as Varus, Neutral and Valgus. Varus group was further subdivided into 2 subgroups as 1°-3°varus and 3°≤ varus. The overall varus group and subgroups were compared with the neutral group in terms of survival, complications, revision, clinical and radiological aspects. Harris hip score, Oxford hip score and WOMAC score were evaluated in clinical evaluation. The position of the femoral stem, subsidence, Engh-Massin score, pedestal formation, cortical hypertrophy, leg length discrepancy, femoral medullary canal filling rates were compared in the radiological evaluation. Results: 96 cases with a mean follow-up of 11.2 years were compared. No significant difference was observed in terms of survival, complications, and revision between 63 varus group and 28 neutral group, including all varus subtypes. In clinical evaluation, no significant difference was observed in Harris and Oxford hip scores in the varus group and its subtypes. Radiologically, there were similar results in terms of leg length discrepancy, cortical hypertrophy and subsidence. Differences were observed in pedestal formation, femoral medullary canal filling rate and Engh-Massin scores. In the 3°≤ varus subgroup, the only diffrence from neutral group was lower femoral medullar canal filling rate. Conclusion: Varus cementless femoral component alignment does not lead to poor survival and clinical outcomes although radiological differences can be seen. Increased degrees of varus malposition leads to smaller femoral stem implantation.