Abstract
It is known that excessive varus alignment of the femoral stem in total hip replacement (THR) creates a sub-optimal biomechanical environment which is associated with increased rates of revision surgery and component wear. Little is known regarding the effect of femoral stem alignment on patient functional outcome.
Methods
Retrospective study of primary THR patients at the RNOH. Alignment of the femoral stem component in-situ was measured subjectively by a consultant musculoskeletal radiologist in both coronal and sagittal planes using post-operative anterior-posterior and lateral pelvic radiographs. Each THR was grouped into valgus, minor-valgus, neutral, minor-varus or varus coronal plane alignment and posterior, minor-posterior, neutral, minor-anterior or anterior sagittal plane alignment. Patient reported functional outcome was assessed by Oxford Hip Score (OHS) and WOMAC questionnaires. Data analysed using a linear regression model.
Results
90 THRs were studied in 87 patients (55 Female). Mean age at THR=62 (22-86). Mean follow-up=17 months (11-39 months). Median OHS=16, WOMAC=8. Coronal plane alignment of the femoral stem was not associated with any change in OHS (p>0.05) or WOMAC score (p>0.05). Sagittal plane alignment of the femoral stem was not associated with any change in OHS (p>0.05) or WOMAC score (p>0.05).
Conclusion
Although it is known that alignment of the femoral stem on sagittal and coronal planes has a direct effect on survivorship of the prosthesis, our study does not demonstrate any relationship between femoral stem alignment and functional outcome in patients undergoing primary THR.
