Purpose: The occurrence of thigh pain following cementless total hip arthroplasty (THA) may be dependent on multiple factors, which may differ with design of the prosthesis. Thus, this study aimed to investigate the frequency of thigh pain following cementless THA using a short, tapered-wedge stem to identify risk factors for thigh pain.
Methods: This retrospective cohort study analysed 222 joints of patients who underwent THA with a short, tapered-wedge stem. Thigh pain was evaluated using a questionnaire during each follow-up visit, and the clinical and radiographic assessments were compared.
Results: Thigh pain occurred in 37 patients (16.7%) during the follow-up period. The pain started two to 24 months after THA. Multivariate analysis demonstrated that higher University of California, Los Angeles, activity rating (odds ratio 7.2; 95% confidence interval (CI) 3.0-17.2); Dorr type C femoral bone shape (odds ratio 1.5; 95% CI 1.1-2.0); and stem tip-cortical bone contact (odds ratio 8.2; 95% CI 2.3-29.4) were significant risk factors of thigh pain following THA. Post-operatively, cortical hypertrophy at Gruen zone 4 was significantly found in patients with thigh pain (p value = 0.032).
Conclusion: Risk factors of pain following THA with short, tapered-wedge stem were high activity level, Dorr type C femoral bone shape, and stem tip contacting the distal bone surface. Moreover, post-operative cortical hypertrophy at the distal stem tip significantly increased the incidence of thigh pain. Therefore, we must pay attention to the aforementioned factors to avoid post-operative thigh pain when using a short, tapered-wedge stem.
Keywords: Femoral bone shape; Physical activity; THA; Thigh pain.