Pengaruh Injeksi Intra-Artikular Dexamethasone untuk Pencegahan Perburukan Kontraktur Arthrogenik pada Fleksi Lutut Tikus di Fase Remobilisasi

Abstract

Abstract Background: Prolonged joint immobilization commonly results in arthrogenic contracture, characterized by irreversible limitations in passive range of motion (PROM) due to capsular fibrosis. This study aimed to investigate whether a single intra-articular dexamethasone injection could prevent progression of arthrogenic contracture during the critical remobilization phase in a rat knee model. Methods: This study used an experimental posttest-only control group design with 24 male Wistar rats. All rats underwent 4 weeks of knee immobilization using K-wires. On day 28, the K-wires were removed, and the rats were divided into three groups: a dexamethasone group (single intra-articular injection of 0.3 mg/kg), a saline group (0.9% NaCl injection), and a control group (no injection). Passive range of motion (PROM) was measured at baseline, after immobilization, and following injection and myotomy. Histopathological evaluation of the posterior joint capsule included measurements of thickness, length, and inflammatory cell count. Data were analyzed using ANOVA followed by post-hoc testing. Results: The dexamethasone group demonstrated a significantly greater mean PROM after injection (130.13 ± 4.94°) compared with the 0.9% NaCl group (111.88 ± 5.02°) and the control group (105.38 ± 7.13°) (p < 0.001). Superior PROM was also maintained after myotomy. Histopathological analysis revealed that dexamethasone significantly decreased posterior capsule thickness and inflammatory cell infiltration, while increasing capsule length, consistent with reduced arthrofibrosis. Conclusion: A single intra-articular dexamethasone injection effectively improved PROM and mitigated arthrofibrotic changes in a rat model of joint contracture. This suggests that localized dexamethasone administration could be a promising prophylactic strategy to prevent the progression of arthrogenic contracture. Keywords: Joint contracture, Dexamethasone, Arthrofibrosis.