Comparative study of the use of computer assisted navigation system for axial correction in medial unicompartmental knee arthroplasty.

摘要

I write you regarding the paper by Lim et al. [2] "Comparative study of the use of computer assisted navigation system for axial correction in medial unicompartmental knee arthroplasty". Navigation system has been developed to improve the accuracy of implantation of total knee replacement (TKR) [3]. Few systems have implemented an application to unicompartmental knee replacement (UKR) [1]. It is, therefore, important to get an objective evaluation of the systems. The present study compared two groups of navigated (30 cases) or non-navigated (21 cases) UKR implantation with a well-known navigation system, already validated for TKR. The authors analyzed the accuracy of implantation on post-operative X-rays, and they observed no significant difference between the groups. However, they did not provide any power analysis in their paper. This might be a relevant information, as the number of cases in each group is relatively small. Underpowered study has the risk not to detect a difference which actually exists.