There is little evidence to suggest that postoperative knee pain, knee function, or various psychosocial factors influence long-term chronic pain following total knee replacement (TKR), according to findings from a systematic review published in the BMJ Open.
For this review, investigators screened 16,430 studies evaluating the association between patient-related risk factors and pain, 3 months and ≥6 months, respectively, after undergoing TKR.
A total of 14 studies (n=1168) were included in the final analysis. Self-reported pain severity in the replaced knee at ≥6 months after surgery was the study’s primary outcome. The included studies examined associations between postoperative pain outcomes and postoperative acute pain (first 3 months; n=737), knee function (n=835), and psychosocial factors (n=226).
More severe acute postoperative pain at 6 weeks and at 6 and 12 months after TKR was found to correlate with chronic pain in 2 of 5 studies (correlation factor, r=0.53 and r=0.35, respectively); however, this association was reduced in one study following adjustment for preprocedural pain.
In 4 studies that evaluated range of motion and ambulatory status at discharge, no association was found between knee function and postoperative pain. Psychosocial factors (eg, anxiety, catastrophizing, coping skills, depression, fear of movement, and social support) were not found to be associated with persistent postoperative pain, except in one study, which indicated an association between catastrophizing and night pain — but not global pain — and another study in which positive social support was linked with reduced chronic pain.
The investigators note that the heterogeneity of postoperative risk factors across studies and the lack of studies using a composite pain and function measure to assess outcomes present significant limitations in this review.
Despite the insufficient findings, the investigators suggest that identification of preoperative and postoperative factors may be useful to, “inform the development of comprehensive care packages to improve outcomes” in patients undergoing TKR.
Wylde V, Beswick AD, Dennis J, Gooberman-Hill R. Post-operative patient-related risk factors for chronic pain after total knee replacement: a systematic review. BMJ Open. 2017;7(11):e018105.