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The following is a summary of “Predictors of subacute postoperative pain after total knee arthroplasty: A secondary analysis of two randomized trials,” published in the July 2024 issue of Pain by Springborg et al. 

Identifying high-pain responders undergoing total knee arthroplasty enhances personalized pain management strategies.

Researchers conducted a retrospective study assessing predictors of pain before and during the perioperative period following total knee arthroplasty on days 2 to 7.

They involved 227 patients from 2 RCTs with pain outcomes measured as mean pain during walking on days 2–7, specifically on days 2, 4, and 7. Multivariable linear and logistic regressions were conducted in 2 stages. Preoperative factors (demographics, comorbidities, pain catastrophizing, preoperative pain) were analyzed while adjusting for trial intervention and site. Subsequently, perioperative variables and postoperative 24-hour walking pain were incorporated into the model.

The results showed the initial model for mean pain (days 2-7) identified preoperative pain as the sole predictor (R-squared 0.097). Incorporating postoperative variables revealed postoperative pain at 24 hours (R-squared 0.248) as the significant predictor, with recruitment site also influencing results. Similar findings were observed in the separate day analysis. The optimal sensitivity (60%) and specificity (74%) for high subacute postoperative pain (days 2-7) prediction was achieved with a 24-hour postoperative walking pain with a VAS score cutoff of 45.5.

Investigators concluded that postoperative walking pain at 24 hours was a better predictor of subsequent pain than preoperative pain for patients undergoing total knee arthroplasty.

Source: onlinelibrary.wiley.com/doi/abs/10.1002/ejp.4703