Objective: To investigate the effects of intra articular tramadol injection on articular cartilage and synovium in rat knee joint.
Methods: After Animal Ethical Committee approval, a total of 20 Sprague-Dawley rats were used and divided into 4 groups. Each group was composed of 5 rats. 0.2 ml of tramadol HCl was injected into the right knee joints and left knee joints of all the rats were considered as control. Control side joints received saline injection. Rats were sacrificed with ketamin on 1st, 7th, 14th and 21st days and knee joints were removed. Obtained tissue samples were decalcified and were dyed with Hematoxylin-eosin and Masson’s trichrome stain and examined by light microscopy for the presence of inflammation in periarticular area and synovia.
Results: Congestion of synovial veins and perivascular cell infiltration were observed in tramadol group on days 1 and 7 (P < 0.05). The inflammation process was replaced by fibrosis on day 14 and fibrosis was significantly decreased on day 21.
Conclusion: Intra articular tramadol should be used cautiously, keeping in mind that it may cause synovial inflammation in early phases and fibrosis in late phases.