Validation of standing cone beam computed tomography for diagnosing subchondral fetlock pathology in the Thoroughbred racehorse.

BACKGROUND: Subchondral bone pathology is common in Thoroughbred racehorses and believed to precede more serious injury. Early identification of pathology is critical to allow for intervention. OBJECTIVES: To determine interobserver variability of fetlock subchondral bone lesions using cone beam and fan beam computed tomography (CBCT, FBCT) and to validate a robotics-controlled CBCT to identify fetlock subchondral bone pathology in the Thoroughbred racehorse. STUDY DESIGN: Prospective cohort study. METHODS: FBCT and CBCT images were acquired of 25 metacarpo-/metatarsophalangeal joints of Thoroughbred racehorses. Images were analysed for subchondral bone lesions commonly identified in Thoroughbred fetlocks by an imaging specialist and surgery specialist. Interobserver and intermodality equivalence were determined with a Pearson correlation analysis and Bland-Altman equivalence test. RESULTS: Interobserver FBCT correlation was significant (P < .05) for 19 of 25 variables (Pearson R mean 0.77). Concordance was significant for all 25 variables (Bland Altman average difference 0.28 ± 0.21 mm). Interobserver CBCT correlation was significant for 21 of 25 variables (Pearson R mean 0.73). Concordance was significant for all variables (Bland Altman average difference 0.07 ± 1.90 mm). Intermodality (FBCT vs CBCT) correlation and concordance was significant for all variables as interpreted by the radiologist (Pearson R mean of 0.72, Bland Altman average difference 0.21 ± 0.47 mm). Intermodality correlation was significant for 19 of 25 variables as interpreted by the surgeon (Pearson R mean of 0.72). Concordance was significant for all variables (Bland Altman average difference 0.49 ± 0.52 mm). MAIN LIMITATIONS: Neither FBCT nor CBCT images were compared with other imaging modalities/histopathology; limited number of cases included; inconsistent agreement of small lesions in specific categories. CONCLUSIONS: Standing CBCT is a valid diagnostic modality to identify subchondral bone lesions in Thoroughbred fetlocks. This technology may provide valuable information regarding the development and progression of fetlock pathology and yield insight into predisposing factors leading to more severe pathology.

Epiglottopexy for the treatment of epiglottic retroversion in 2 horses.

OBJECTIVE: To report an epiglottopexy technique for the treatment of epiglottic retroversion (ER) in 2 horses. STUDY DESIGN: Case report. ANIMALS: A 2-year-old thoroughbred gelding and a 6-year-old standardbred gelding, both with ER. METHODS: Epiglottic retroversion was diagnosed via exercising endoscopic examination in both horses. Epiglottopexy technique was performed in both cases. RESULTS: Both horses returned to previous racing class within 1 year after surgery. Repeat exercising endoscopy of 1 horse 6 months postoperatively revealed resolution of the ER. CONCLUSION: Epiglottopexy should be considered for treatment of ER in the equine athlete. CLINICAL SIGNIFICANCE: Previously reported surgical techniques for ER in the equine athlete have not resulted in horses returning to previous performance level. The technique reported here resulted in both horses achieving athletic status.

Surgical site infection associated with equine orthopedic internal fixation: 155 cases (2008-2016).

OBJECTIVE: To determine the prevalence of surgical site infection (SSI) after internal fixation and to identify risk factors for SSI and nonsurvival. STUDY DESIGN: Retrospective study. ANIMALS: One hundred fifty-five horses with long bone fractures or arthrodesis treated by internal fixation at 1 hospital between 2008-2016. METHODS: Signalment, diagnosis, surgical repair, surgeon, surgical time, antimicrobial use, SSI onset, bacterial identification, and adjunct treatments were recorded. Perioperative variables were analyzed to identify risk factors associated with outcomes. RESULTS: Surgical-site infection was reported in 22 of 155 (14.2%) horses, which is lower than what has been previously reported (P = .003). Horses with fetlock arthrodesis or ulnar fracture were more likely to develop SSI. Local prophylactic antimicrobial therapy was associated with an increased risk of SSI. Horses with SSI were 12 times (P < .0001) less likely to survive to discharge than horses without SSI. Horses with a fetlock or carpal arthrodesis or those with radial/humeral/femoral fractures were less likely to survive. No association was identified between open fractures, open reduction and internal fixation, or surgical times and SSI. CONCLUSION: The prevalence of SSI in this population was lower than what has been previously reported. Horses with fetlock or carpal arthrodesis or radial/humeral/femoral fractures were at increased risk for SSI and/or nonsurvival to discharge. A protective role of local antimicrobial therapy for SSI could not be established. CLINICAL RELEVANCE: The impact of SSI on outcomes of cases of equine internal fixation remains substantial. Identification of cases at higher risk of SSI should influence surgical technique, postoperative management, and early intervention when SSI is suspected. Additional investigation is warranted regarding local antimicrobial therapy.

Pancarpal and partial carpal arthrodesis with 3 locking compression plates in 6 horses.

OBJECTIVE: To report the outcome of horses after pancarpal or partial carpal arthrodesis with 3 locking compression plates (LCP). STUDY DESIGN: Case series. ANIMALS: Six horses ranging in age from 8 months to 16 years and weighing 227-580 kg with severe carpal pathology including acute fractures, chronic osteoarthritis, and chronic angular limb deformity. METHODS: Pancarpal or partial carpal arthrodesis was performed with 3 LCP. Autologous cancellous bone grafts were used in 5 of 6 cases to facilitate joint arthrodesis. RESULTS: External coaptation was maintained for 4 to 6 weeks after surgery. Radiographic follow-up was available in all 6 cases, all of which reached arthrodesis and pasture soundness by 4-5 months postoperatively. One case required implant removal at 6 months because of implant exposure through the skin but returned to pasture soundness after removal. CONCLUSION: Carpal instability due to acute fractures or chronic disease was successfully stabilized with 3 short LCP, leading to pasture soundness in all 6 horses. CLINICAL SIGNIFICANCE: The use of 3 short LCP should be considered as a strategy to facilitate pancarpal or partial carpal arthrodesis by providing superior stability without placement of implants in the diaphysis of the radius and third metacarpus.