Comparison of efficacy of Oral versus Intra-articular Corticosteroid Application in the treatment of Frozen Shoulder: An experimental study in rats

Abstract

Objective: The aim of this study was to compare clinical and histopathological effects of oral versus intraarticular corticosteroid application in a rat model of frozen shoulder. Methods: In this study, eighty adult Sprague-Dawley rats were used. The animals were divided into 5 equal groups. The frozen shoulder model was created by immobilizing animals’ shoulders with internal fixation with sutures for 8 weeks. At the 8th week, sham (n: 16) and control (n: 16) groups were sacrificed to collect data for healthy and affected shoulders. Also, at the 8th week, 50 mg/ kg methylprednisolone was started for the oral treatment group, and a single dose of 0.5 mg/kg triamcinolone acetonide was injected for the intraarticular treatment group. The effect of additional steroid treatment was expected for 2 weeks, then all remaining treatment and natural course groups were sacrificed on the 10th week. Results: After sacrification, specimens taken as “en bloc” scapulothoracic disarticulation were randomly divided into two groups for a range of motion measurement and histopathological examination. The control (frozen shoulder model) group's shoulder range of motion in all directions was lower than the sham (healthy) group (P 0.05). Histopathologically, no statistically significant difference was observed between the groups for signs of frozen shoulder which was found in the immobilized group (P > 0.05). Histopathologically, immobilization was found to cause thickening of the capsule that cannot be resolved by treatment. (P < 0.05). Conclusion: In frozen shoulder disease, intraarticular steroid injection seems to be superior in increasing the range of motion than oral steroid treatment.