Cornell University College of Veterinary Medicine, Department of Clinical Sciences, Ithaca, New York, USA.
Cornell University College of Engineering, Department of Biomedical Engineering, Ithaca, New York, USA.
Vet Surg. 2022 Aug;51(6):952-962. doi: 10.1111/vsu.13816. Epub 2022 Jun 7.
To determine whether proximal sesamoid bone (PSB) microdamage and fracture toughness differ between Thoroughbred racehorses sustaining PSB fracture and controls.
Cadaveric case-control.
Twenty-four Thoroughbred racehorses (n = 12 PSB fracture, n = 12 control).
Proximal sesamoid bones were dissected, and gross pathological changes and morphological measurements were documented. High-speed exercise history data were evaluated. Microdamage was assessed in fracture, fracture-contralateral limb (FXCL) and control PSBs using whole bone lead uranyl acetate (LUA) staining with micro-CT imaging or basic fuchsin histological analysis. Fracture toughness mechanical testing was carried out in 3-point-bending of microbeams created from PSB flexor cortices. Data were analyzed using ordinal logistic and linear regression models.
Microdamage was detected most commonly in the articular subchondral region of PSBs via LUA micro-CT and basic fuchsin histology. There were no differences in microdamage between FXCL and control PSBs. Fracture toughness values were similar for FXCL (1.31 MPa√m) and control (1.35 MPa√m) PSBs. Exercise histories were similar except that horses sustaining fracture spent a greater percentage of their careers in rest weeks.
Microdamage was detected in the articular region of PSBs but was not greater in horses sustaining catastrophic PSB fracture. Fracture toughness of PSB flexor cortices did not differ between FXCL and control PSBs.
Although uncommon, microdamage is localized to the articular region of Thoroughbred racehorse PSBs. Catastrophic PSB failure is not associated with lower PSB flexor cortex fracture toughness.
确定发生籽骨骨折（PSB）与未发生 PSB 骨折的纯种赛马之间，其 PSB 微损伤和断裂韧性是否存在差异。
尸体病例对照研究。
24 匹纯种赛马（n=12 匹 PSB 骨折，n=12 匹对照）。
解剖 PSB，记录大体病理变化和形态学测量结果。评估高速运动史数据。使用全骨硝酸铅（LUA）染色联合微 CT 成像或碱性品红组织学分析，评估骨折、骨折对侧肢（FXCL）和对照 PSB 中的微损伤。在 3 点弯曲试验中对 PSB 屈肌腱皮质制成的微梁进行断裂韧性力学测试。使用有序逻辑回归和线性回归模型进行数据分析。
LUA 微 CT 和碱性品红组织学最常显示 PSB 的关节下骨软骨区有微损伤。FXCL 和对照 PSB 的微损伤无差异。FXCL（1.31 MPa√m）和对照 PSB（1.35 MPa√m）的断裂韧性值相似。运动史相似，但发生骨折的马在休息周的职业生涯百分比更大。
PSB 的关节区存在微损伤，但未发生灾难性 PSB 骨折的马的微损伤并不更严重。PSB 屈肌腱皮质的断裂韧性在 FXCL 和对照 PSB 之间无差异。
虽然罕见，但纯种赛马的 PSB 微损伤局限于关节区。灾难性 PSB 失败与 PSB 屈肌腱皮质较低的断裂韧性无关。
