Fractures of the tarsus or hock occur as a result of trauma or as a secondary complication of degenerative joint disease. The hock consists of 8 bones that form several different joints. As in the carpus, a wide range of locations and types of fractures can occur. Specific diagnosis depends on careful radiographic examination, including several oblique projections or better, CT.
Some of the more common fractures involve chips of the intermediate ridge and the medial or lateral malleolus of the tibia. These lesions must be distinguished from the osteochondritis dissecans complex. Slab fractures of the central and third tarsal bones are also seen, particularly in Standardbreds. Because these often are quite small and may not cause lameness, it is important to use intra-articular anesthesia to positively identify the site if the horse is lame. In many instances, a rest period (3–6 mo) is all that is required for full recovery, although with large chip fragments, arthroscopic removal is preferred. The talocrural joint is amenable to arthroscopy and surgery, with most involved areas being accessible. Slab fractures are amenable to lag screw fixation.
Fractures of the calcaneus are obvious and result in severe lameness. In most cases, these fractures must be treated by means of internal fixation; in severe cases, horses should be humanely destroyed.
Last full review/revision March 2012 by Stephen B. Adams, DVM, MS, DACVS; Joerg A. Auer, DrMedVet, Dr h c, MS, DACVS, DECVS; James K. Belknap, DVM, PhD, DACVS; Jane C. Boswell, MA, VetMB, CertVA, CertES (Orth), DECVS, MRCVS; Peter Clegg, MA, Vet MB, PhD, CertEO, DECVS, MRCVS; Andrew L. Crawford, BVetMed, CertES (Orth), MRCVS; Jean-Marie Denoix, DVM, PhD, Agregé; Marcus J. Head, BVetMed, MRCVS; C. Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, DACVS, DACVSMR; James Schumacher, DVM, MS, DACVS, MRCVS; John Schumacher, DVM, MS, DACVIM; Roger K. W. Smith, MA, VetMB, PhD, DEO, DECVS, MRCVS; Chris Whitton, BVSc, FACVSc, PhD