JOA - 2026-06-01 - Journal Article
Central Sensitization Elevates the Minimal Clinically Important Difference of Brief Pain Inventory Scores After Total Knee Arthroplasty.
Xu C, Chang X, Wang S, Bao H, Yao S, Ma J
Topics
Key Takeaway
Central sensitization raises the anchor-based BPI MCID threshold from 9.8 to 15.3 points after TKA, and CS patients are significantly less likely to achieve that threshold at one year.
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Summary
This study asked whether preoperative central sensitization status, determined by the Central Sensitization Inventory, alters the MCID of the Brief Pain Inventory after primary TKA. In 296 prospectively enrolled patients, anchor-based MCIDs for total BPI score were 15.3 points (95% CI 10.65–20.03) in the CS group versus 9.8 points (95% CI 5.82–13.94) in the non-CS group, with ROC-derived cutoffs of 14.5 (AUC 0.88) and 10.6 (AUC 0.88), respectively. CS patients achieved clinically meaningful pain relief at significantly lower rates than non-CS patients (P<0.05).
Key Limitation
The Central Sensitization Inventory is a self-report screening tool, not a neurophysiologic diagnosis, so CS group classification may include patients with other pain-amplifying conditions, inflating the apparent MCID elevation attributable to true central sensitization.
Original Abstract
BACKGROUND
Central sensitization (CS) is a recognized risk factor for increased pain and reduced satisfaction after total knee arthroplasty (TKA). However, its effect on the minimal clinically important difference (MCID) of patient-reported outcome measures has not been established. This study aimed to assess the influence of CS status on the MCID of the Brief Pain Inventory (BPI) in TKA patients.
METHODS
We prospectively enrolled 296 unilateral TKA patients who completed 1-year follow-up. Preoperatively, CS status was determined by the Central Sensitization Inventory. Pain severity and interference were measured with the BPI before surgery and at one year postoperatively. The MCIDs for BPI were calculated separately for each group using anchor-based and distribution-based approaches. Receiver operating characteristic curve analysis was employed to derive MCID cutoff values for the BPI total score and each subscale.
RESULTS
By the anchor-based method, MCIDs for total BPI score were 15.3 points (95% confidence interval 10.65 to 20.03) in the CS group and 9.8 (95% confidence interval 5.82 to 13.94) points in the non-central sensitization (NCS) group. The receiver operating characteristic analysis yielded optimal cutoffs of 14.5 points (area under the curve = 0.88) for CS patients and 10.6 points (area under the curve = 0.88) for NCS patients. The CS patients had significantly lower MCID achievement rates than NCS patients (P < 0.05).
CONCLUSIONS
Preoperative CS elevates BPI MCID thresholds and decreases the likelihood of achieving clinically meaningful pain relief after TKA. These findings help explain persistently lower satisfaction in CS patients and support applying CS-specific MCID standards when evaluating postoperative outcomes.