Preoperative Narx Overdose Risk Scores ≥200 associated with worse 1-year PROMs and satisfaction after unicompartmental knee arthroplasty.

BACKGROUND: The NarxCare Overdose Risk Score (ORS) is an algorithm-derived measure of prescription drug use incorporating dose, duration, and type of narcotics, sedatives, and stimulants. While elevated ORS has been linked to increased healthcare utilization after total knee arthroplasty (TKA), its relationship with patient-reported outcomes (PROMs) following unicompartmental knee arthroplasty (UKA) is unknown. This study examined whether higher preoperative ORS is associated with worse 1-year PROMs after UKA.

METHODS: This retrospective cohort study included 726 patients undergoing primary unilateral UKA from November 2018 to December 2023 with complete 1-year PROMs. Outcomes included KOOS Pain, KOOS Physical Function Shortform (PS), and Joint Replacement (JR) scores. Achievement of clinically meaningful improvement was defined using minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) thresholds. Baseline ORS was categorized as 0, 1-199, or ≥200. Multivariable logistic regression adjusted for demographics and clinical covariates assessed associations between ORS and 1-year outcomes.

RESULTS: Preoperatively, 43.8% had ORS 0, 29.9% had ORS 1-199, and 26.9% had ORS ≥200. Patients with ORS ≥200 had higher odds of dissatisfaction at 1 year (OR 1.62, 95% CI 1.00-2.61, p = 0.048) and failing to reach the PASS threshold for KOOS Pain (OR 1.53, 95% CI 1.03-2.28, p = 0.035). ORS was not significantly associated with MCID achievement in any KOOS domain.

CONCLUSION: Preoperative ORS ≥200 was independently associated with worse perceived pain improvement and greater dissatisfaction after UKA. Surgeons may use this readily available EMR score to identify at-risk patients, guide counseling, and optimize modifiable prescription drug exposures before surgery.