Partial tarsal arthrodesis and botulinum toxin A injection for correction of tarsal arthrogryposis in a cat

Abstract

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.

Surgical correction of a bilateral congenital tarsal hyperextension deformity in a cat

“…We recommend surgical correction for the cases in which conservative management failed and the deformity is inflexible. Partial tarsal arthrodesis with a laterally applied 1.5 mm / 2.0 mm diameter seven-hole veterinary cuttable plate in a 15-week-old cat was reported to be successful (7). Similarly, pantarsal arthrodesis with a transarticular external fixation demonstrated excellent long-term functional efficacy for both of the limbs in our study.…”

“…Also, Boute and colleagues reported that the tibio-tarsal joints of all three kittens could be flexed to an angle of approximately 135° (6). Interestingly, we could not obtain even a slight improvement in our case, in both standing or under deep sedation, similar to the right hindlimb of the kitten reported by Bright and colleagues (7). Because of that, partial tarsal arthrodesis was performed in that unilateral case.…”

“…tion of tarsal hyperextension deformity in kittens with the exception of one other report (7). Bright and colleagues recommended passive physiotherapy supported by intra-muscular botulinum toxin for treatment of the gastrocnemius muscle-tendon spasticity (7). Reports by veterinarians and non-veterinarians document that in some affected kittens, the tarsus remained in the extended position despite attempted non-surgical treatment (2-7).…”

“…A variety of congenital limb anomalies have been reported in cats including limb agenesis, ectrodactyly, polydactyly, syndactyly, micromelia, amelia, peromelus ascelsus, congenital elbow luxation, radial hemimelia, carpal agenesis, proximal femoral dysplasia, and patellar aplasia (1). Recently, a new type of hindlimb anomaly characterized by severe tarsal hyperextension was reported; it is known as "twisted leg deformity" by amateur cat owners and congenital tarsal hyperextension or tarsal arthrogryposis in scientific reports (2)(3)(4)(5)(6)(7). The deformity is usually bilateral but unilateral cases have also been described (2)(3)(4)(5)(6)(7).…”

“…Recently, a new type of hindlimb anomaly characterized by severe tarsal hyperextension was reported; it is known as "twisted leg deformity" by amateur cat owners and congenital tarsal hyperextension or tarsal arthrogryposis in scientific reports (2)(3)(4)(5)(6)(7). The deformity is usually bilateral but unilateral cases have also been described (2)(3)(4)(5)(6)(7). The deformity is reported to arise at the level of the proximal intertarsal joint.…”