Alzola R, Easter C, Riggs C M, Gardner D S, Freeman S L
Oakham Veterinary Hospital, Oakham, Rutland, UK.
Oxtex Ltd, Witney, Oxfordshire, UK.
Equine Vet J. 2018 Sep;50(5):602-608. doi: 10.1111/evj.12810. Epub 2018 Feb 23.
Superficial digital flexor tendon (SDFT) injury is an important health and welfare concern in racehorses. It is generally diagnosed with ultrasonography, but predictive ultrasonographic features have not been reported.
To determine ultrasonographic features of forelimb SDFT injury at initial presentation in Thoroughbred racehorses that could predict a successful return to racing (completing ≥5 races).
Retrospective cohort study.
Digitised ultrasonographic images of 469 horses with forelimb SDFT injuries from the Hong Kong Jockey Club (2003-2014) were evaluated, using a previously validated ultrasonographic scoring system. Six ultrasonographic parameters were evaluated (type and extent of the injury, location, echogenicity, cross-sectional area and longitudinal fibre pattern of the maximal injury zone [MIZ]), as well as horse signalment, retirement date and number of races before and after injury. Data were analysed by generalised linear regression with significance at P<0.05.
Cases were divided into two groups: 1) For cases of SDFT tendonitis with core lesions, cross-sectional area at the MIZ was the most significant factor determining a successful return to racing (P = 0.03). If the lesion was <50% of the total cross-sectional area, horses had 29-35% probability of successfully racing again, but if it was ≥50% this decreased to 11-16%. 2) For cases of SDFT tendonitis without a core lesion, longitudinal fibre pattern at the MIZ best predicted a successful return to racing (P = 0.002); if the affected longitudinal fibre pattern was <75% of the total, horses had 49-99% probability of successfully return to racing, but if it was ≥75% this decreased to 14%.
Prognostic information may not be applicable to other breeds/disciplines.
This is the first study to describe ultrasonographic features of forelimb SDFT injuries at initial presentation that were predictive of successful return to racing. The outcomes will assist with early, evidence-based decisions on prognosis in Thoroughbred racehorses.
指浅屈肌腱（SDFT）损伤是赛马健康和福利方面的一个重要问题。通常通过超声检查进行诊断，但尚未有预测性超声特征的报道。
确定纯种赛马初次出现前肢SDFT损伤时的超声特征，这些特征可预测能否成功重返赛场（完成≥5场比赛）。
回顾性队列研究。
使用先前验证的超声评分系统，对香港赛马会（2003 - 2014年）469例前肢SDFT损伤马匹的数字化超声图像进行评估。评估了六个超声参数（损伤类型和范围、位置、回声性、最大损伤区[MIZ]的横截面积和纵向纤维模式），以及马匹的特征、退役日期和损伤前后的比赛场次。采用广义线性回归分析数据，显著性水平为P<0.05。
病例分为两组：1）对于伴有核心病变的SDFT肌腱炎病例，MIZ处的横截面积是决定能否成功重返赛场的最重要因素（P = 0.03）。如果病变面积小于总面积的50%，马匹再次成功参赛的概率为29 - 35%，但如果病变面积≥50%，则降至11 - 16%。2）对于无核心病变的SDFT肌腱炎病例，MIZ处的纵向纤维模式最能预测能否成功重返赛场（P = 0.002）；如果受影响的纵向纤维模式小于总数的75%，马匹成功重返赛场的概率为49 - 99%，但如果病变面积≥75%，则降至14%。
预后信息可能不适用于其他品种/赛事。
这是第一项描述初次出现时前肢SDFT损伤的超声特征并能预测成功重返赛场的研究。研究结果将有助于在纯种赛马预后方面做出基于证据的早期决策。
