S Bright, Sarah Girling, T O'Neill, J F Innes
An 11-week-old, domestic shorthair cat was presented for evaluation of a congenital right tarsal deformity. The cat was non-weightbearing lame on the right hindlimb. There was severe tarsal hyperextension and concurrent spasticity/contracture/shortening of the gastrocnemius muscle-tendon. The cat was otherwise healthy. Radiographically there was luxation of the proximal intertarsal joint and talocrural hyperextension. Treatment with 10 mu/kg botulinum toxin A (Botox; Allergan) intramuscular injections directly into the gastrocnemius muscle and passive physiotherapy marginally improved the range of motion in the talocrural joint. Definitive surgical treatment with partial tarsal arthodesis produced an excellent clinical outcome. This case report demonstrates the successful treatment of a severe congenital tarsal abnormality and also documents the first clinical use of botulinum toxin in a feline patient.