Comparison of intraarticular and oral corticosteroid treatment in a rat model of frozen shoulder

In this experimental study, it was aimed to compare the contribution of oral and intraarticular corticosteroid treatments to healing in frozen shoulder disease at clinical and histopathologic level. Eighty adult Sprague-Dawley rats included in the study were divided into 5 equal groups. The frozen shoulder disease model is developed by immobilizing shoulders of animals except sham group for 8 weeks, by internal fixation with sutures. At the eighth week, sham and control groups were sacrificed to collect data for healthy and diseased shoulders. Also at the eighth 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 remaining groups were sacrificed on the tenth week. After sacrification, half of the shoulder joints taken with scapulothoracic disarticulation as "en bloc" were used for joint range of motion measurement and the other half was used for histopathological examination. Control (disease model) group shoulder range of motion in all directions were lower than sham (healthy) group (P <0.01). In natural course and intraarticular steroid groups there was a significant increase in the direction of abduction compared to the disease model (P <0.05). But it was understood that in all directions the level of healing was not as good as the healthy values (P <0.01). It was found that this improvement in abduction obtained by intraarticular treatment was higher than natural course and oral steroid treatment (P <0.01). It was shown that there was no improvement in the oral steroid group compared to the disease model and no superiority to the natural course (P> 0.05). Histopathologically, there was no statistically significant difference (P> 0.05) between the groups in terms of the obliteration of axillary pouch, decreased synovial ruffled structure, decreased number of capillary vessels, presence of severe fibroblastic proliferation and severe collagen accumulation which was found in the immobilized group. It was also found that immobilization caused thickening in the capsule and this thickening did not reduce with treatment (P <0.05). As a result, in frozen shoulder disease intraarticular steroid injection was found to be effective in increasing the range of motion compared to oral steroid treatment. These findings confirm clinical trials. Key words: frozen shoulder, adhesive capsulitis, corticosteroid, animal model