UC Davis

OBJECTIVE: To describe the outcome of metacarpophalangeal (MCPJ) and proximal interphalangeal joint (PIPJ) arthrodesis using a locking compression-distal femur plate (LCP-DFP) in Thoroughbred racehorses with traumatic disruption of the suspensory apparatus (TDSA) at risk of PIPJ subluxation. STUDY DESIGN: Multicenter retrospective study. ANIMALS: Twenty-six Thoroughbred racehorses. METHODS: Records of Thoroughbred racehorses with TDSA that had undergone MCPJ and PIPJ arthrodesis using an LCP-DFP at three referral hospitals between 2020 and 2024 were reviewed for inclusion. The preoperative data collected included signalment, affected limb, and type of injury. All postoperative complications were recorded. Long-term outcomes were obtained from medical records and telephone interviews. RESULTS: Nine females, 14 geldings, and three intact males with TDSA were treated via double arthrodesis using an LCP-DFP. The most common postoperative complications included support limb laminitis, incisional drainage, implant infection with osteomyelitis, and distal interphalangeal joint subluxation. No horses developed PIPJ subluxation. Twenty (76.9%) horses developed short-term complications. Thirteen (50%) horses survived long term (>6 months, range 6-32 months) and were reported to be pasture sound without receiving any analgesic or antiinflammatory medication. CONCLUSION: Metacarpophalangeal and PIPJ arthrodesis using an LCP-DFP in racehorses resulted in a stable construct with no horses developing subluxation of the PIPJ joint postoperatively. Arthrodesis using an LCP-DFP was associated with a fair prognosis for pasture soundness. CLINICAL SIGNIFICANCE: Application of an LCP-DFP may prevent subluxation of the PIPJ; however, the prognosis is still affected by the high prevalence of other complications and associated mortality among horses that suffer TDSA.