Establishing an optimal central sensitization inventory cut-off value affecting postoperative outcomes of osteotomy around the knee.

Background: Central sensitization has a significant effect on pain after osteotomy around the knee (OAK). The central sensitization inventory (CSI) score is considered disease specific, and the appropriate cut-off values for OAK are unclear. The purpose of this study was to establish the optimal CSI cut-off value affecting the postoperative outcomes of OAK based on the postoperative knee injury and osteoarthritis outcome score (KOOS).

Methods: Patients who underwent OAK for medial compartment knee osteoarthritis were included. The postoperative KOOS symptoms, pain, and activities of daily living (ADL) were categorized into two groups (score ≥80 each for symptoms, pain, and ADL, and score <80 for any of the three) and were used as factors to calculate receiver operating characteristic curves and the area under the curve with the CSI score. Cut-off values were calculated using the Youden index and the threshold value closest to the upper left corner. Subsequently, logistic multivariate analysis was performed using the KOOS and the obtained CSI cut-off values and other variables.

Results: A total of 173 patients were included in this study. The area under the curve of the model was 0.801 (95 % confidence interval, 0.74-0.87), and a CSI score of 12 was determined as the cut-off value. Logistic multivariate analysis based on the cut-off value showed that only the CSI score (odds ratio, 9.79; 95 % CI, 4.47-21.4; P < 0.01) was significant.

Conclusions: The optimal CSI cut-off value affecting the postoperative outcomes of OAK calculated using the postoperative KOOS was 12, which was supported by multivariate analysis results. Central sensitization assessment with an appropriate cut-off value would allow a more personalized treatment approach and may contribute to a better postoperative outcome.