Fractures in Thoroughbred racing and the potential for pre-race identification of horses at risk.

Risk rates for and predisposing factors to fractures occurring in Thoroughbred racing that have been published in peer reviewed journals are documented. The potential for currently available techniques to identify horses at increased risk for fracture is discussed on the bases of principles, practicalities, advantages, disadvantages and current data. All are reviewed in light of justifiable decision making and importance of fractures to horseracing's social license.

Arthroscopically guided lag screw fixation of subchondral bone cysts in the medial femoral condyle in Thoroughbred racehorses: description of technique and comparative results.

OBJECTIVE: To describe an arthroscopically guided technique for lag screw placement across subchondral bone cyst (SBC) in the medial femoral condyle (MFC) and to compare postoperative racing performance with corticosteroid injection and cyst debridement. STUDY DESIGN: Retrospective cohort study. ANIMALS: One hundred twenty-three horses with 134 MFC SBCs undergoing treatment at a single referral hospital in the UK between January, 2009, and December, 2020. METHODS: Sex, age, limb affected, radiographic cyst dimensions, preoperative and postoperative lameness, surgical technique (lag screw placement, cyst debridement, intralesional corticosteroid injection), and, where applicable, screw positioning were recorded retrospectively. A ratio was calculated using measurements from preoperative and postoperative radiographs. Outcome was assessed by resolution or improvement in lameness, reduction in cyst size, and starting one race after treatment. Outcome data was compared between treatment groups. RESULTS: Twenty-six of 45 (57.8%) horses that underwent transcondylar screw placement raced postoperatively, at a median of 403 days between surgery and first postoperative race. There was no difference between treatment groups with regard to racing or preoperative and postoperative lameness. Cysts treated with transcondylar screw placement had a greater reduction in cyst size and a reduced period of convalescence in comparison with those that underwent debridement; the results were similar to those treated by intralesional corticosteroid injection. CONCLUSION: Postoperative racing rates were similar for all techniques. Convalescence was reduced for lag screw placement and corticosteroid injection compared to debridement. CLINICAL SIGNIFICANCE: The arthroscopically guided technique results in radiographically consistent screw placement and cyst engagement and offers a viable alternative to other treatments.

Comparison of radiography and CT for the evaluation of third carpal bone slab fractures in Thoroughbred racehorses.

Slab fractures of the third carpal bone (C3) are a common cause of lameness in Thoroughbred racehorses. Information on fracture morphology is commonly obtained from radiographs or CT. This retrospective, methods comparison aimed to explore the agreement between radiography and CT for imaging C3 slab fractures and discuss the contribution of the latter to clinical case management. Thoroughbred racehorses with a slab or incomplete slab fracture of C3 identified on radiographs that subsequently underwent CT examination were included. Fracture characteristics (location, plane, classification, displacement, comminution) and fracture length as a percentage of the proximodistal length of the bone, termed the proximodistal fracture percentage (PFP) were recorded independently from both modalities and then compared. Across all fractures (n = 82) radiographs and CT showed slight agreement on the presence of comminution (Cohen's Kappa (κ) 0.108, P 0.031) and moderate agreement on fracture displacement (K 0.683, P < 0.001). Computed tomography identified comminution in 49 (59.8%) and displacement in nine (11.0%) fractures that were not detected by radiographs. Half of the fractures were only seen on flexed dorsoproximal-dorsodistal oblique (DPr-DDiO) radiographs and therefore were of unknown length without additional CT imaging. Incomplete fractures that could be measured on radiographs (n = 12) had a median (IQR) PFP of 40% (30%-52%) on radiographs and 53% (38%-59%) on CT, a statistically significant difference (P = 0.026). Radiography and CT showed the poorest agreement when determining the presence of comminution. Additionally, radiography often underestimated the incidence of displacement, and fracture length, and resulted in more fractures being classified as incomplete when compared to CT.

Increased cartilage oligomeric matrix protein concentrations in equine digital flexor tendon sheath synovial fluid predicts intrathecal tendon damage.

OBJECTIVES: To evaluate digital flexor tendon sheath (DFTS) synovial fluid cartilage oligomeric matrix protein (COMP) concentrations as a molecular marker for intrathecal pathology. STUDY DESIGN: Case control study. ANIMALS: Horses (n=46) with DFTS tenosynovitis; 23 fresh cadaver horses. METHODS: DFTS synovial fluid samples were collected from clinical cases with noninfected DFTS tenosynovitis and from control DFTS. Clinical and surgical findings were recorded, and dissection of control limbs was performed to confirm the DFTS to be grossly normal. Synovial fluid COMP was quantified using a homologous competitive inhibition ELISA. RESULTS: Abnormalities were identified tenoscopically: intrathecal tendon/ligament tearing was identified in 37 cases and 9 had other lesions. In control horses, synovial fluid COMP was higher in younger horses. Clinical cases with intrathecal tendon/ligament tearing had higher synovial fluid COMP than either clinical cases with other lesions, or controls. In horses ≥5 years old, the sensitivity and specificity of the assay was high for diagnosing intrathecal tendon/ligament tearing. CONCLUSIONS: COMP concentrations in DFTS synovial fluid were significantly greater than those in normal horses with noninfected tenosynovitis caused by intrathecal tendon/ligament tearing, but not by other lesions.