Do Pain Coping and Pain Beliefs Associate With Outcome Measures Before Knee Arthroplasty in Patients Who Catastrophize About Pain? A Cross-sectional Analysis From a Randomized Clinical Trial

Background Pain-coping strategies and appraisals are responses to the pain experience. They can influence patient-reported and physical performance outcome measures in a variety of disorders, but the associations between a comprehensive profile of pain-coping responses and preoperative pain/function and physical performance measures in patients scheduled for knee arthroplasty have not been examined. Patients with moderate to high pain catastrophizing (a pain appraisal approach associated with an exaggerated focus on the threat value of pain) may represent an excellent study population in which to address this knowledge gap.

Questions/purposes We asked the following questions among patients with high levels of pain catastrophizing who were scheduled for TKA: (1) Do maladaptive pain responses correlate with worse self-reported pain intensity and function and physical performance? (2) Do adaptive pain-coping responses show the opposite pattern? As an exploratory hypothesis, we also asked: (3) Do maladaptive responses show more consistent associations with measures of pain, function, and performance as compared with adaptive responses?

Methods A total of 384 persons identified with moderate to high levels of pain catastrophizing and who consented to have knee arthroplasty were recruited. The sample was 67% (257 of 384) women and the mean age was 63 years. Subjects were consented between 1 and 8 weeks before scheduled surgery. All subjects completed the WOMAC pain and function scales in addition to a comprehensive profile of pain coping and appraisal measures and psychologic health measures. Subjects also completed the Short Physical Performance Battery and the 6-minute walk test. For the current study, all measures were obtained at a single point in time at the preoperative visit with no followup. Multilevel multivariate multiple regression was used to test the hypotheses and potential confounders were adjusted for in the models.

Results Maladaptive pain responses were associated with worse preoperative pain and function measures. For example, the maladaptive pain-coping strategy of guarding and the pain catastrophizing appraisal measures were associated with WOMAC pain scores such that higher guarding scores (β = 0.12, p = 0.007) and higher pain catastrophizing (β = 0.31, p < 0.001) were associated with worse WOMAC pain; no adaptive responses were associated with better WOMAC pain or physical performance scores. Maladaptive responses were also more consistently associated with worse self-reported and performance-based measure scores (six of 16 associations were significant in the hypothesized direction), whereas adaptive responses did not associate with better scores (zero of 16 scores were significant in the hypothesized direction).

Conclusions The maladaptive responses of guarding, resting, and pain catastrophizing were associated with worse scores on preoperative pain and performance measures. These are pain-related responses surgeons should consider when assessing patients before knee arthroplasty. TKA candidates found to have these pain responses may be targets for treatments that may improve postoperative outcome given that these responses are modifiable. Future intervention-based research should target this trio of maladaptive pain responses to determine if intervention leads to improvements in postsurgical health outcomes.

Level of Evidence Level I, prognostic study.