Evaluation of the diffusion of corticosteroids between the distal interphalangeal joint and navicular bursa in horses.

The study evaluates the diffusion of corticosteroids between the distal interphalangeal joint and navicular bursa in horses to confirm if injections of methylprednisolone acetate (MPA) or triamcinolone acetonide (TA) into these areas reach clinically effective concentrations.

Methodology

• A total of 32 healthy horses were used in this study.
• The horses were divided into four groups. Groups 1 and 2 had injections of MPA and TA into the distal interphalangeal joint (DIPJ) respectively. In contrast, groups 3 and 4 received MPA and TA injections into the navicular bursa respectively.
• The corticosteroid’s concentrations that spread into the adjoining synovial structure were measured to determine the diffusion intensity.

Results

• The results indicated that the injection of MPA into the DIPJ in group 1 produced a mean concentration of 0.24 micrograms of methylprednisolone/mL in the navicular bursa.
• Group 2, which received TA in the DIPJ, showed a concentration of 0.124 micrograms of Triamcinolone/mL in the navicular bursa.
• Following injection of MPA into the navicular bursa, group 3 displayed a concentration of 0.05 micrograms of methylprednisolone/mL in the DIPJ.
• Last but not least, group 4 exhibited a concentration of 0.091 micrograms of Triamcinolone/mL in the DIPJ after injection of TA into the navicular bursa.

Conclusions

• The outcome of the study demonstrated that a therapeutically effective concentration of methylprednisolone or triamcinolone diffused between the DIPJ and navicular bursa subsequent to the intra-articular or intrabursal injection.
• This implies that inflammation in the navicular bursa could be mitigated by injection of MPA or TA into the DIPJ.