What is the role for partial arthrodesis of the carpus and tarsus?

PARTIAL CARPAL ARTHRODESIS

Introduction

Compromise to the canine carpal palmar fibrocartilage and ligaments most commonly occur due to traumatic hyperextension injury often sustained from a jump or fall. An inherited degeneration has also been reported in breeds such as the Shetland Sheep Dog and Border Collie. Carpal hyperextension injuries may affect the antebrachiocarpal, middle carpal or carpometacarpal joints either in isolation or concurrently, with concurrent middle carpal and carpometacarpal injury being most common (Parker & others 1981). In the case where antebrachiocarpal palmar support is not compromised, partial carpal arthrodesis, comprising fusion of the middle carpal and carpometacarpal joints has been advocated to re-establish palmar stability and limb function. Partial carpal arthrodesis carries the biomechanical advantage over pancarpal arthrodesis of maintained antebrachiocarpal motion during gait with typically 76^o or approximately 50% of carpal flexion being maintained postoperatively (Andreoni & others 2010). Techniques described for management of middle carpal or carpometacarpal hyperextension injuries include immobilisation in a flexion cast (Slocum & Devine 1982) (which the author would not advocate) or partial carpal arthrodesis via intramedullary (IM) pinning (Slocum & Devine 1982, Willer & others 1990), a dorsally applied T-plate (Smith & Spagnola 1991), dorsal twin DCP plating (Denny & Barr, 1991) and cross pinning (Haburjak 2003). Medial plating has also been described in a small series of cats (Mathis & Voss, 2014). Early reports of management by coaptation cannot be advocated as this predictably results in unsatisfactory clinical results with persistence of hyperextension as do attempts at primary ligament repair or augmentation techniques utilising wire or autogenous fascia. [...]