Acquired flexural deformity of the metacarpophalangeal joint in five horses associated with tendonous damage in the palmar metacarpus.

Five cases of acquired flexural deformity of the metacarpophalangeal joint (MCPJ) in older horses and ponies were studied. The mean age of affected horses was 14-8 years. Four deformities developed following desmitis of the accessory ligament of the deep digital flexor tendon (ALDDFT) and superficial digital flexor tendon (SDFT) and one following tendonitis of the SDFT alone. All cases were markedly lame and demonstrated variable degrees of flexural deformity. Ultrasonographic examination was performed on all cases which revealed extensive adhesion formation between the ALDDFT and SDFT and reduced cross-sectional area of the deep digital flexor tendon in each case. A variety of treatments were unsuccessfully employed to treat this condition. The prognosis for acquired flexural deformity of the MCPJ in old horses following tendonous damage in the palmar metacarpus is likely to be poor.