Preoperative factors associated with patient satisfaction after modified kinematically aligned total knee arthroplasty in varus knees

Purpose

Kinematically aligned-total knee arthroplasty (KA-TKA) has recently attracted significant interest because it delivers better clinical outcomes than mechanically aligned (MA)-TKA. However, the optimal preoperative factors that maximize the effectiveness of KA-TKA remain controversial. Therefore, we aimed to determine the preoperative factors that are appropriate for and might benefit from modified KA-TKA, based on patient-reported outcome measures (PROMs).

Methods

The relationships between postoperative satisfaction and other variables in 84 patients with varus-type osteoarthritis of the knee who underwent primary modified KA-TKAs were investigated using stepwise multiple regression analysis. Patients were assigned to groups that were satisfied or dissatisfied with their outcomes after KA-TKA according to the 2011 Knee Society Scores. The cutoff for preoperative advanced activities scores (AASs) for excellent satisfaction were determined by analyzing receiver operating characteristic (ROC) curves. The variables correlated with excellent satisfaction were identified using logistic regression models.

Results

A preoperative variable relevant to patient satisfaction was AAS (β ​= ​0.465). The results of the ROC curve analysis revealed eight optimal cut-offs for preoperative AASs that predicted excellent satisfaction, with a sensitivity and specificity of 0.700 and 0.625, respectively. Logistic regression analysis revealed that AASs significantly contributed to excellent patient satisfaction (odds ratio, 1.181; p ​= ​0.001).

Conclusions

Individuals who were highly active preoperatively were good candidates for KA-TKA. This modified kinematically aligned surgical technique can satisfy the demands of highly active patients.