Reasons for performing study: The centrodistal (CD) and tarsometatarsal (TMT) joints are often injected individually with a corticosteroid to resolve lameness caused by osteoarthritis (OA). There are no data available regarding diffusion of methylprednisolone (MP) from the TMT joint to the CD joint.
Hypothesis: A therapeutic concentration of MP diffuses into the CD joint after methylprednisolone acetate (MPA) is administered into the TMT joint.
Objective: To measure the concentration of MP in the CD joint after MPA was administered into the TMT joint.
Methods: MPA was administered into a TMT joint of 16 horses. At different times, the ipsilateral CD joint of these horses was injected with a small amount of saline and recovered saline was measured for concentration of MP using high performance liquid chromatography.
Results: Six hours after administration of MPA into the TMT joint, a therapeutic concentration of MP was found in all 10 CD joints sampled at this time.
Conclusions: Horses with pain arising from the distal 2 joints of the hock can be treated by administering MPA into the TMT joint alone.
Potential relevance: Administering MPA into the TMT joint only, to treat OA of the distal 2 hock joints, reduces the difficulties and risks associated with centesis of the CD joint.