Pain catastrophizing as a predictor for postoperative pain and opiate consumption in total joint arthroplasty patients.

Background: Pain catastrophizing has been suggested as a prospective risk factor for poor postoperative pain outcomes in total joint arthroplasty (TJA). However, results from the previous studies have been mixed and have not controlled for postoperative opiate analgesic intake. This study investigates pain catastrophizing and postoperative pain intensity in TJA patients, adjusting for analgesic intake. We hypothesized that "pain catastrophizers" would exhibit higher pain scores and increased analgesic requirements postoperatively.

Methods: In this prospective cohort study, patients were defined as catastrophizers (PCS > 30), or non-catastrophizers (PCS ≤ 30). The primary outcome was the visual analog scale (VAS) pain score at 3-month follow-up. Secondary outcomes included length of stay (LOS) for the index hospitalization, total daily opiate analgesic intake, and VAS pain scores on postoperative days 0, 1, 2, and 3 through discharge. Multivariable regression was used to control for total daily morphine equivalent dose consumed during the stay in addition to other clinical and demographic factors.

Results: There were 87 patients in the "non-catastrophizing" and 36 in the "catastrophizing" groups. There was no clinically significant difference in VAS pain scores between groups at 3-month follow-up. Patients with a length of stay (LOS) ≥ 3 postoperative days differed in VAS pain scores ("non-catastrophizers" = 5.08 vs. "catastrophizers" = 7.13; p = 0.002) and were 2.4 times more likely to be catastrophizers than non-catastrophizers (p = 0.042). There were no differences in the remaining secondary outcomes.

Conclusion: The pain catastrophizing scale is a poor predictor of postoperative pain at 3-month follow-up. However, it may be a risk factor for increased LOS.