Predicting Persistent Unclear Pain Following Primary Total Knee Arthroplasty.

Chronic post-surgical pain can be a considerable issue for patients undergoing primary total knee arthroplasty. According to the literature, persistent knee pain is experienced by up to 44% of patients. Most studies on total knee arthroplasty (TKA) outcomes have mainly investigated the biomechanics or function of the operated knee, but chronic pain has never been a primary issue. In recent years several possible predictors of chronic postsurgical pain have been investigated and eventually identified. A younger age, female gender, psychological distress, preoperative pain duration and intensity were all reported to influence chronic postoperative pain rates after total knee arthroplasty. Recently, it has also been hypothesized that preoperative signs of centrally driven hyperalgesia and distorted pain modulation may predict persistent knee pain in some patients. Despite the considerable number of patients suffering from chronic postsurgical pain after TKA, available data is scarce, and well controlled prospective studies are lacking. Predictors of chronic postsurgical pain after total knee arthroplasty have yet to be identified. Thus, this article is aimed at reviewing current knowledge on persistent pain after knee arthroplasty.