Chronic Pain Diagnosis Before Total Knee Arthroplasty Leads to Higher Readmission Risk, Lower Patient-Reported Outcome Measures, and Dissatisfaction at One Year: An Analysis of 13,894 Patients.

BACKGROUND

Patients who have chronic pain may experience worse outcomes after total knee arthroplasty (TKA), yet its impact on postoperative metrics remains unclear. This study evaluated the prevalence of chronic pain diagnoses and their association with health care utilization, patient-reported outcome measures, and satisfaction.

METHODS

A retrospective analysis of 13,894 primary unilateral TKAs performed from 2016 to 2022 at a tertiary center was conducted. Chronic pain diagnoses were identified via International Classification of Diseases, 9th Revision (338.2, 338.4) and 10th Revision (G89.2, G89.4) codes. Outcomes were compared using multivariable logistic regression. The patient-reported outcome measures included Knee injury and Osteoarthritis Outcome Score (KOOS) Pain, Physical Function Shortform, Joint Replacement (JR), and Veterans RAND 12-Item Mental Component Score. Minimal clinically important difference and patient acceptable symptom state thresholds were assessed.

RESULTS

Chronic pain was present in 23.4% (3,258 of 13,894) of patients. These patients had higher odds of 90-day readmission (OR [odds ratio] 1.27, 95% CI [confidence interval]: 1.1 to 1.46; P < 0.001) but were less likely to have a length of stay ≥ two days (OR 0.85, 95% CI: 0.76 to 0.95; P = 0.004). There was no significant association found with nonhome discharge (P = 0.301). Patients who had chronic pain had increased odds of failing to reach minimal clinically important difference in KOOS JR (OR 1.2, 95% CI: 1.0 to 1.43; P = 0.049) and Veterans RAND 12-Item Mental Component Score (OR 1.15, 95% CI: 1.03 to 1.29; P = 0.01). They were also more likely to fail patient acceptable symptom state thresholds in KOOS Pain (OR 1.25; P < 0.001), Physical Function Shortform (OR 1.22; P < 0.001), and JR (OR 1.28; P < 0.001). In addition, chronic pain patients had higher odds of dissatisfaction at one year (OR 1.17, 95% CI: 1.04 to 1.32; P = 0.011).

CONCLUSIONS

Chronic pain was independently associated with increased 90-day readmission risk and poorer postoperative outcomes, including failure to reach clinically relevant pain relief, functional improvement, and satisfaction. These findings highlight the need for targeted preoperative optimization strategies for chronic pain patients undergoing TKA.

LEVEL OF EVIDENCE: III (prospective).