The effect of intra-articular levobupivacaine on shoulder cartilage at different doses-experimental study.

BACKGROUND AND OBJECTIVES: In this study it was aimed to examine the histological and morphometric effects on cartilage structure of intra-articular application of levobupivacaine to the shoulder joint. METHODS: In twenty New Zealand adult male rabbits, 35 shoulders were used for the study and prepared in 5 groups of 7. These groups were defined as Groups L1, L2, L3 and L4 which were right shoulders administered with 0.25% and 0.5% levobupivacaine, Group C which were left shoulders as the control group and Groups S1 and S2 which were left shoulders administered with 0.9% saline. On the 2nd and 15th days the animals were killed, the glenohumeral joints were evaluated macroscopically then cartilage samples were taken. These samples were evaluated with Mankin score, and histomorphometrically by measuring the thickness of the cartilage between the superficial cartilage layer and the tidemark and the thickness of calcified cartilage between the tidemark and the subchondral bone. RESULTS: Macroscopically, on the 15th day the joint fluid was seen to have reduced in all the groups. After microscopic evaluation, the highest Mankin score (mean: 3.14±2.1/14) was in the L4 group (15th day 0.5% levobupivacaine) and was found to be statistically significant (p<0.05). No statistically significant difference was determined between the other groups. CONCLUSIONS: Histologically, as the highest Mankin score was in the L4 group, this indicates that in a single intra-articular injection of levobupivacaine a low concentration should be selected. LEVEL OF EVIDENCE: Level 5, animal study.