Younger Age, Postoperative Pain, Catastrophizing Are Risk Factors for Persistent TKA Pain

The authors of a systematic review and meta-analysis published in Pain Medicine found that persistent pain following total knee arthroplasty (TKA) was associated with younger age, acute postoperative pain, and pain catastrophizing.

According to the study authors, “Pain and consequent functional limitations are the primary indication for knee replacement, and patients anticipate that surgery will provide relief; however, approximately 25% of patients report persistent post-surgical pain after TKA with higher rates after revision surgery.”

Therefore, the investigators searched publication databases through April 2021 for cohort and case-control studies of persistent postsurgical pain after total knee replacement. A total of 30 studies comprising 26,517 patients were included in this analysis.

The studies were conducted in Europe (n=12), North America (n=10), Asia (n=5), Australia (n=2), and New Zealand (n=1). The median duration of the studies was 13 months, and persistent pain was defined as postsurgical pain lasting at least 3 months following TKA.

The studies included a median sample size of 350 patients, the median proportion of women among the study populations was 67%, and the median age of study participants was 68 years.

One-quarter of patients reported experiencing persistent postsurgical pain with a visual analogue scale (VAS) pain severity of 6.1 cm.

The most robust predictors for persistent pain were younger age (absolute risk increase [ARI], 4% per 10-year decrease from 80 years; P =.015), moderate to severe (≥4-points on a 10-point scale) acute postoperative pain (ARI, 29.5%; P <.001), and pain catastrophizing (ARI, 29.5%; P <.001).

The predictors with moderate support for their association with persistent pain risk included preoperative pain (ARI, 35%; P =.010), female sex (ARI, 6.7%; P=.001), non-White ethnicity (ARI, 9.5%; P=.039), and diabetes mellitus (ARI, 11%; P =.026).

In sensitivity analyses that imputed missing information, the significant relationships between persistent pain and non-White ethnicity and diabetes mellitus were attenuated.

The findings of this analysis may have been biased by combining data collected from different follow-up durations (3 months vs 7 years).

These data indicate that pain catastrophizing, acute postoperative pain, and younger age may be predictors of persistent pain following TKA. More rigorous studies are needed to confirm these findings.