Assistant Professor, Equine Surgery Colorado State University Fort Collins, Colorado
Outcomes After Surgical Repair of Third Carpal Bone Slab Fractures of Both Radial and Intermediate Facets in Racing Quarter Horses. Nelson B1, Lawless S1, McIlwraith W1, McIlwraith W2. 1Colorado State University, Fort Collins, CO; 2Equine Medical Center, Cypress, CA.
Outcomes after surgical repair of slab fractures of the third carpal bone involving both radial and intermediate facets (C3-bifacet) in racing Quarter Horses (QHs) are unknown. Study objectives were to describe the pre- and intraoperative characteristics of C3-bifacet slab fractures and to report the long-term outcomes after internal fixation. Case records of racing QHs with C3 slab fractures between 2008 and 2020 were collected. Inclusion criteria required arthroscopic-guided repair of C3-bifacet slab fractures in QHs. Single facet C3 fractures, fractures in other breeds, or those repaired with other methods were excluded. Outcomes were obtained by standardized questionnaire to trainers/owners. Of 22 QHs with C3-bifacet slab fractures, 91% (n = 20) were collapsing and 91% had avulsion of the medial palmar intercarpal ligament. Articular cartilage erosion and osteochondral fracture of the radial carpal bone was observed in 91% (20/22) and 41% (9/22) cases, respectively. At 5.5 ± 3.9 years after surgery, 86% (19/22) were alive and used for breeding or retirement. Of 18 horses with follow-up > 1 year after surgery, 39% (n = 7) resumed non-racing activity. C3-bifacet slab fractures in racing QHs are commonly collapsing. Higher QH racing speeds towards the end of the race may explain the higher concurrent injuries sustained than is recognized in other racing breeds. Cases were referred specifically for surgical repair. Horses with fractures considered too severe for repair were not included. Questionnaire responses are susceptible to recall bias. Horses with C3-bifacet slab fractures that are repaired have a favorable prognosis for retirement and breeding and potentially low-level activity.