The rapid recovery study: Cyclobenzaprine's effect on recovery following joint arthroplasty.

INTRODUCTION: Skeletal muscle relaxants have previously not been examined in multimodal anesthesia regimens following joint arthroplasty. We sought to evaluate cyclobenzaprine's effect on postoperative opioid consumption as well as surgical recovery following joint arthroplasty.

MATERIALS AND METHODS: In this retrospective cohort study, 471 patients undergoing 554 joint arthroplasty procedures were evaluated. Patients were divided into cohorts who did and did not receive cyclobenzaprine postoperatively, and postoperative opioid consumption and functional recovery measures were recorded in each cohort.

RESULTS: In the unadjusted model, the cyclobenzaprine cohort experienced a 1.11 increase in pain scores on postoperative day zero (95% CI (0.60, 1.62), p < 0.0001). After adjusting for age, sex, BMI, CCI, perioperative MME, laterality, procedure, anesthesia, pre-op opioid use, pre-operative other controlled substance uses and pre-op benzodiazepine use, the cyclobenzaprine cohort's pain scores were 1.08 units higher at rest (95% CI (0.59, 1.56), p < 0.0001) and 1.25 units higher with activity on postoperative-day-zero (95% CI (0.78, 1.72), p < 0.0001). Both cohorts experienced statistically insignificantly different changes in mobility scores between postoperative day zero and postoperative day one, range of motion at 6 and 12 weeks, and readmission in <90 days. Postoperative morphine milliequivalents were insignificantly different between cohorts after controlling for pain in all models (base model mean ratio: 1.06, 95% CI (0.87,1.29), p = 0.5599) (Full model mean ratio: 1.09, 95% CI (0.91,1.30), p = 0.3608).

CONCLUSIONS: Cyclobenzaprine shows utility in a multimodal anesthetic approach after joint arthroplasty in patients with higher baseline pain.