Changes in third carpal bone articular cartilage after synovectomy in normal and inflamed joints.

The research investigated the effects of arthroscopic synovectomy, a surgical procedure that removes inflamed joint tissues, on the articular cartilage of horses’ carpal bones. The study showed that synovectomy in inflamed joints resulted in significant changes in cartilage, especially greater concentrations of newly synthesized proteoglycan (PG), leading to the suggestion that the procedure might not be beneficial to inflamed joints.

Study Design and Methodology

• The research team carried out an experiment on 16 carpi (wrist joints) from eight horses. They designed the study to observe effects of arthroscopic synovectomy at different times and in different conditions: normal and inflamed joints. The observation periods were set at 2 weeks (groups 3 and 4) and 6 weeks (groups 1 and 2) after the procedure.
• The team then evaluated the biochemical and biomechanical properties of both the dorsal (back) and palmar (front) parts of the articular cartilage. They used techniques such as radiolabeling, proteoglycan (PG) extraction, chromatography, electrophoresis, and indentation testing to achieve the evaluation.

Observations and Results

• Observations showed that synovectomy in inflamed joints resulted in the highest concentration of newly synthesized PG in the articular cartilage by 2 weeks. By contrast, in normal joints, significantly more new PG was synthesized in the articular cartilage by 6 weeks post surgery.
• Dorsal parts of the joints showed greater production of both newly synthesized and endogenous PG in some groups. Chromatographic profiles revealed early and late PG peaks.
• Electrophoresis of the late PG peak indicated a band positive to toluidine blue staining that moved with the human A1D1 PG monomer particularly in the two groups with the highest quantities of newly synthesized PG. This band was reactive with monoclonal antibody 1C6, a marker for the hyaluronic acid-binding region of aggrecan, a core component of articular cartilage.
• Among the several material properties evaluated, only the Poisson’s ratio, which suggests how much a material can be deformed by stress, was shown to be significantly decreased between groups over time. This decrease was most apparent in the thicker dorsal sites.

Conclusions

• The researchers concluded that arthroscopic synovectomy had a distinct effect on inflamed joints, leading to more significant changes in the articular cartilage than in normal joints.
• Although synovectomy is a common procedure to treat inflamed joints, the results suggest that it might have a negative impact on the articular cartilage in inflamed joints. This finding calls for more investigation into alternatives or improvements to the synovectomy procedure in treating inflamed joints.