Abstract
Aims
Medial unicompartmental knee arthroplasty (UKA) is undertaken in patients with a passively correctable varus deformity. Our hypothesis was that restoration of natural soft tissue tension would result in a comparable lower limb alignment with the contralateral normal lower limb after mobile-bearing medial UKA.
Patients and Methods
In this retrospective study, hip-knee-ankle (HKA) angle, position of the weight-bearing axis (WBA) and knee joint line obliquity (KJLO) after mobile-bearing medial UKA was compared with the normal (clinically and radiologically) contralateral lower limb in 123 patients.
Results
Postoperatively, HKA angle was restored to within ±3° of the contralateral lower limb in 87% of patients andWBA passed within ±1 Kennedy and White's tibial zone of the contralateral normal lower limb in 95% of patients. The difference in the mean KJLO between the two groups was not significant (p=0.05) and the KJLO was within ±3° of the contralateral normal lower limb in 96% of patients.
Conclusion
Lower limb alignment & knee joint line obliquity after mobile-bearing medial UKA were comparable to the unaffected contralateral limb in most patients.
Clinical Relevance
Comparison with the contralateral normal lower limb is a reliable method to evaluate and validate limb mechanical alignment after mobile-bearing medial UKA.
