Abstract
Introduction
This study assessed outcomes of total knee joint replacements (TKJR) in patients who had undergone previous periarticular osteotomy compared with unicompartmental knee replacement (UKR). Establishing a difference in the results of total knee joint replacements following these operations may be an important consideration in the decision-making and patient counselling around osteotomy versus UKR for the management of single-compartment osteoarthritis.
Method
Using data from the New Zealand Joint Registry, we identified 1,895 total knee joint replacements with prior osteotomy and 1,391 with prior UKR. Revision rates and patient-reported outcomes, as measured by the Oxford Knee Score (OKS), between these two groups were compared. Adjusted hazard ratios were also calculated to compare the groups.
Results
The revision rate for total knee joint replacement following osteotomy was significantly lower than TKJR following UKR (0.88 per 100 component years versus 1.38 per 100 component years, respectively). Adjusted hazard ratio calculations found that those with TKJR with prior UKR had more than double the risk of requiring revision than those with prior osteotomy. Additionally, there was a statistically significant difference in the mean adjusted OKS scores between the two groups, with improved outcomes in the group with prior osteotomy.
Conclusion
Our findings suggest that total knee joint replacement following periarticular osteotomy have a lower risk of revision and improved OKS when compared to those with prior UKR. Previous studies assessing New Zealand Joint Registry have not found a statistically significant difference between the two groups however, these results are no longer in keeping with more contemporary literature. Our study confirms the New Zealand population to be comparable with international studies with TKJR after osteotomy performing significantly better compared with prior UKR.
