How does intraarticular dexmedetomidine injection effect articular cartilage and synovium? An animal study.

BACKGROUND: Intraarticular injections are widely used to provide pain relief after arthroscopic procedures and minimize the use of opioids. Dexmedetomidine has been proven to potentiate pain relief and postpone the demand for the first analgesic drug when it is used intraarticularly following arthroscopic knee procedures. However, the effects of dexmedetomidine on articular structures have not yet been evaluated. Our aim was to determine the effects of intraarticular dexmedetomidine injection on articular structures such as cartilage and synovium. DESIGN: Animal study. METHODS: Twenty adult rats (Sprague-Dawley) were enrolled in the study. Following appropriate aseptic and anesthetic conditions, dexmedetomidine (100 mcg/ml) (0.25 ml) was injected into the right knee joint (the study group) and normal saline solution (0.25 ml) into the left knee joint (the control group) of the rats. Four rats were sacrificed from each group on days 1, 2, 7, 14, and 21, and knee joint samples were obtained. Histologists evaluated the articular and periarticular regions and the synovium using histological sections, and a five-point scale was used to grade the inflammatory changes in a blinded manner. RESULTS: The groups were found to be similar in terms of median congestion scores, edema and inflammation scores, subintimal fibrosis, neutrophil activation and cartilage structure at each of the time intervals. CONCLUSION: In our placebo-controlled, in vivo trial, the intraarticular use of dexmedetomidine seemed to be safe with respect to the studied histopathological parameters. However, complementary studies investigating the histopathological effects, analgesic dosage and adverse effects of dexmedetomidine on damaged articular structure models are needed.

Procaine and saline have similar effects on articular cartilage and synovium in rat knee.

BACKGROUND: Intra-articular local anaesthetics are widely used for providing postoperative analgesia and decreasing the need for opioids. Procaine has proven positive effects in carpal tunnel syndrome and chondromalacia patella. However, the effect of procaine on articular cartilage has not yet been studied. The aim of this study was to evaluate the effects of intra-articular procaine injection on the articular cartilage and the synovium. METHODS: Twenty adult Sprague-Dawley rats were enrolled in the study. After providing anaesthesia and aseptic conditions, 0.25 ml of 10% procaine was injected to the right knee joint, and 0.25 ml of normal saline (as control group) was injected to the left knee joint. Knee joint samples were obtained from four rats in each group after appropriate euthanasia on days 1, 2, 7, 14 and 21. The histological sections of the articular and periarticular regions and the synovium were evaluated by two histologists, and inflammatory changes were graded according to a five-point scale in a blinded manner. The apoptosis of chondrocytes was determined by the caspase-3 indirect immunoperoxidase method. RESULTS: There were no significant differences in inflammation between procaine and saline groups at any of the time intervals. Slight inflammatory infiltration due to injection was seen in both groups on the 1st day. Haemorrhage was observed in both groups at days 1 and 2, and the difference between groups was not found to be significant. No significant difference was detected in the percentage of apoptotic chondrocytes between groups at any of the time intervals. CONCLUSIONS: Injection of procaine seems safe to use intra-articularly based on this in vivo study on rat knee cartilage. However, further studies investigating both the analgesic and histopathological effects of procaine on damaged articular cartilage and synovium models are needed.