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Influence of component alignment on outcome for unicompartmental knee replacement
A Gulati1, R Chau, D J Simpson
1Nuffield Department of Orthopaedic Surgery, University of Oxford, OX3 7LD, UK.
The Knee
|December 2, 2008
Summary
The Oxford Unicompartmental Knee Replacement (UKR) demonstrates tolerance to component mal-alignment. Both femoral and tibial components showed no significant impact on outcomes within specific alignment ranges, suggesting flexibility in surgical positioning.
Area of Science:
- Orthopedic surgery
- Biomedical engineering
- Radiology
Background:
- Unicompartmental knee replacement (UKR) is an alternative to total knee replacement.
- Assessing the impact of surgical technique and component positioning on UKR outcomes is crucial for patient success.
Purpose of the Study:
- To evaluate how mal-alignment of femoral and tibial components affects the outcomes of Oxford Unicompartmental Knee Replacement (UKR).
Main Methods:
- A cohort of 211 medial UKR procedures performed with a minimally invasive approach were analyzed.
- Component alignment (sagittal and frontal planes) was measured using radiographs at a minimum 4-year follow-up.
- Oxford Knee Score (OKS) and radiolucency (RL) were compared across different component alignment groups.
Main Results:
- Most femoral components were within +/-10 degrees of ideal alignment; tibial components were within +/-5 degrees.
- No significant differences in OKS or RL were observed between alignment groups, including those at the extremes.
- The spherical design of the Oxford UKR's femoral component appears to contribute to its tolerance.
Conclusions:
- The Oxford UKR is tolerant to femoral component mal-alignment up to 10 degrees and tibial component mal-alignment up to 5 degrees.
- This suggests a degree of flexibility in component positioning during minimally invasive UKR surgery without compromising outcomes.