The Outcomes of Patients With Hyperuricemia After Total Knee Arthroplasty: A Retrospective Cohort Study.

OBJECTIVE

Hyperuricemia, characterized by elevated serum uric acid levels without acute gout symptoms, may influence postoperative outcomes after total knee arthroplasty (TKA). This study aimed to evaluate the impact of hyperuricemia on postoperative inflammatory responses, complications, and mid-term functional outcomes in patients undergoing primary TKA.

METHODS

This was a retrospective cohort study. We identified all patients who had undergone primary TKA from April 1, 2015, to March 30, 2016. Patients were grouped by uric acid level. The knee society score (KSS) and hospital for special surgery knee score (HSS) before the surgery and 6 years after the surgery were recorded. Statistical analyses included t-tests, chi-square tests, and regression analyses to assess the influences of uric acid levels on C-reactive protein (CRP) levels, body temperature, functional scores, and local inflammatory response. The influence of the uric acid level on the local inflammatory response was also analyzed.

RESULTS

Of the 614 patients, 140 had hyperuricemia, and 474 had normal uric acid levels. The hyperuricemia group had a higher unplanned readmission rate (11.4% vs. 5.7%, p < 0.05) and longer hospital stay (10.75 vs. 9.54 days, p = 0.002). CRP levels were significantly greater in the hyperuricemia group (OR = 34.64, 95% CI: 27.99-41.30, p < 0.001), and the incidence of the local inflammatory response was greater (42.1% vs. 9.5%, p < 0.01). The diagnostic accuracy for uric acid in the local inflammatory response was 0.742 (AUC). Improvements in the KSS clinical score (p < 0.01), KSS functional score (p < 0.01), and HSS score (p < 0.01) were lower in the hyperuricemia group.

CONCLUSIONS

Hyperuricemia is associated with significantly elevated postoperative CRP levels, a higher unplanned readmission rate, and substantially poorer mid-term functional outcomes after TKA. These patients also demonstrate increased inflammatory complications. These findings support preoperative uric acid screening to identify high-risk patients for targeted management.

CLINICAL RELEVANCE: Level III.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05476367.