Impact of pre-operative recreational marijuana use on outcomes two years after orthopaedic surgery.

PURPOSE

The purpose of this study was to investigate the relationship between recreational marijuana use and patient-reported outcomes two years after orthopaedic surgery. We hypothesized that pre-operative recreational marijuana use would be associated with less pain, better function, and better mental health measures two years after orthopaedic surgery.

METHODS

Patients were retrospectively analyzed from a prospective orthopaedic registry at a single urban institution. A total of 1710 patients completed the pre-operative assessment and 1103 patients (64.5%) completed the two-year follow-up questionnaires. The cohort was then divided into two groups based on reported preoperative recreational marijuana usage, and statistical analysis was performed to determine if marijuana use was associated with two-year outcomes. Multivariable analysis was used to control for confounding variables.

RESULTS

Marijuana use was reported by 47 (4.3%) patients. Significantly worse scores for two-year PROMIS Anxiety (53.2 vs. 49.2, p = 0.005), PROMIS Depression (51.1 vs. 46.5, p = 0.001), Met Expectations (63.1 vs. 74.4, p = 0.024), Surgical Satisfaction Questionnaire-8 (71.7 vs. 80.4, p = 0.005), and Numeric Satisfaction Scale (75.6 vs. 83.1, p = 0.041) were associated with marijuana use. Marijuana users also had less improvement of Numeric Pain Scores at the operative site (- 1.8 vs. - 2.7, p = 0.037) and greater decrease in Marx activity scores for lower extremities (- 12.3 vs. - 3.9, p = 0.024). Marijuana use was not an independent predictor of any outcome measure in the multivariable analysis.

CONCLUSION

Marijuana use was associated with worse mental health scores, lower activity level, less pain relief, and worse satisfaction two years after orthopaedic surgery. However, after controlling for confounding variables, marijuana use was not predictive of any two-year outcome measure.

STUDY DESIGN

Cross-sectional study.