Abstract
PURPOSE: Unicompartmental knee arthroplasty (UKA) effectively alleviates pain and restores function in end-stage knee osteoarthritis. However, the relationship between post-operative knee skin temperature and systemic inflammatory responses remains poorly characterized. This study aimed to: (1) quantify changes in knee skin temperature and temperature difference for 6 months post-UKA, (2) analyze correlations between temperature difference and serum inflammatory markers, (3) determine whether prolonged thermal alterations represent a normal healing response or potential early warning sign of complications. METHODS: This study included 100 individuals who underwent UKA for primary osteoarthritis. Bilateral Knee skin temperatures were measured via infrared thermography preoperatively and at post-operative days (PODs) 1, 3, 5 and months 1, 3, 6, with strict ambient temperature control (20 ± 1.0°C). Concurrently, erythrocyte sedimentation rate (ESR), white blood cell count (WBC) and serum C-reactive protein (CRP) were assessed. Functional recovery was quantified using Hospital for Special Surgery (HSS) knee score. RESULTS: A total of 100 patients participated in the study. Bilateral knee skin temperature and temperature difference peaked at POD 3 following UKA, with gradual normalization occurring over 6 months. The patient's CRP and WBC demonstrated progressive elevation until POD 3, while ESR exhibited delayed onset of increase. Subsequent measurements showed divergence in marker resolution: CRP and WBC levels initiate decline by POD 5, whereas ESR peaked at POD 5 following UKA. All inflammatory markers returned to preoperative levels during follow-up. CONCLUSION: The skin temperature of the operated knee showed a rapid increase on the first POD following UKA, peaked on POD 3, and gradually returned to normal levels by 6 months after UKA. Moreover, there is a significant correlation between changes in temperature difference and serum inflammatory markers. Normal surgical reaction may cause this alteration. LEVEL OF EVIDENCE: Level III.