Comparative efficacy of corticosteroid and platelet rich plasma intraarticular injection on the adhesive capsulitis of rats

The aim of this experimental study is to compare the clinical and histopathological effects and the benefits of intraarticular injection of Corticosteroid (CS) and Platelet Rich Plasma (PRP) on the treatment of Frozen Shoulder. 48 adult Sprague-Dawley (S-Dawley) rats were divided equally into 3 groups. The Frozen Shoulder model was obtained following internal fixation of the rats' shoulders with sutures, followed by 8 weeks of immobilization. At the 8th week, all sutures were removed, and the first group was injected intraarticularly with saline solution, the second group with CS, and the third with PRP. The skin was re-sutured afterwards. At the 10th . Week all three groups were sacrificed. The shoulders that were operated on (left shoulder) were excised en-bloc including the forearm, the humerus, the clavicle and the scapula. The remaining shoulders of the sacrificed subjects were randomly divided into two groups of which the first was separated for the examination range of joint motion, and the second group was separated for histopathological examination. Subsequently, two groups were made, comprised of sacrificed subjects randomly selected from all three groups. The first group for the examination of range of joint motion, the second for histopathological examination. After comparing all groups, although there is a minor clinical differene , rats which have been injected with CS have better results on Adduction (add.), Abduction (abd.) and total range of motion (ROM) compared to the other two groups. PRP has better ROM results compared to the control group but rather poor results compared to CS group. However, statistically there was no significant difference between these mean values. The histopathological evaluation has showed that the rats in CS and PRP groups have significantly decreased synovial inflamation, fibrosis, type 3 collagen deposition, adhesion of the Subscapular bursa rather to those in the control group. However, there was no significant statistical difference in vascular proliferation although there was a slight decrease in clinical evaluation. vii The histopathological evaluation of CS and PRP groups has shown that vascular proliferation and type 3 collagen deposition on the CS applied rats was more efficient compared to the PRP applied group and they were both equally effective on the 3 other parameters, however there was no significant statistical difference between them. Consequently, clinical evaluation has shown that the results of CS have been found to be more effective compared to PRP. Keywords: frozen shoulder, adhesive capsulitis, corticosteroids, platelet rich plasma, animal model.