Objective

To evaluate thermal nociceptive thresholds (TNTs) before and after inducing a standardized radiocarpal bone osteochondral fracture (OCF) in horses.

Study design

Prospective, controlled, randomized, masked study.

Animals

A group of 10 Thoroughbred fillies aged 2 years.

Methods

Skin temperature and TNTs were measured on the skin over the triceps brachii muscle in both the thoracic limbs before (week 0) and weekly (weeks 1–8) after unilateral arthroscopic induction of a radiocarpal OCF (n = 4) or sham surgery (n = 6) followed by a standardized exercise programme. The contralateral, non-operated thoracic limb was used as a control within each horse. Percentage thermal excursion (%TE) defined as %TE = 100 ∗ (TNT – skin temperature)/(cut-off temperature – skin temperature) was calculated. Data were analysed with a mixed-effects model followed by Dunnett’s and Tukey’s tests for within and between-limbs comparisons, respectively; p < 0.05 was considered significant.

Results

Skin temperature in the control limb of OCF horses was significantly higher at week 7 than at week 0 (p = 0.0125). At week 1, TNTs and %TE values in operated limbs of OCF horses were significantly reduced compared with their baseline values at week 0 (p ≤ 0.0153) and their values in contralateral control limbs (p ≤ 0.0024) and operated limbs of sham-operated horses (p ≤ 0.0162). At week 2, TNTs and %TE values in operated limbs of OCF horses remained significantly reduced compared with values in operated limbs of sham-operated horses (p ≤ 0.0248).

Conclusions and clinical relevance

Creation of an OCF in a radiocarpal bone induced transitory (<2 weeks) ipsilateral heat hypersensitivity proximal to the surgery site (skin over the triceps brachii muscle) in horses. Surgically induced OCF may cause somatosensory abnormalities consistent with secondary thermal hyperalgesia.

中文翻译：

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马手术诱发的骨软骨骨折附近部位的热超敏反应

客观的

评估在马中诱导标准化的桡腕骨骨软骨骨折 (OCF) 前后的热伤害感受阈值 (TNT)。

学习规划

前瞻性、对照、随机、掩蔽研究。

动物

一组 10 头 2 岁的纯种母马。

方法

在单侧关节镜诱导桡腕 OCF（n  = 4）或假手术（n  = 6) 其次是标准化的锻炼计划。对侧、未手术的胸肢用作每匹马的对照。计算热偏移百分比 (%TE)，定义为 %TE = 100 *（TNT – 皮肤温度）/（临界温度 – 皮肤温度）。使用混合效应模型分析数据，然后分别进行 Dunnett's 和 Tukey's 检验以进行肢体内和肢体间的比较；p < 0.05 被认为是显着的。

结果

OCF 马对照肢体的皮肤温度在第 7 周显着高于第 0 周（p  = 0.0125）。在第 1 周，与第 0 周的基线值 ( p ≤ 0.0153) 及其对侧对照肢体 ( p ≤ 0.0024) 和假手术马的手术肢体的值相比，OCF 马的手术肢体的 TNT 和 %TE 值显着降低马 ( p ≤ 0.0162)。在第 2 周，与假手术马的手术肢体的值相比，OCF 马的手术肢体的TNT和 %TE 值仍然显着降低 ( p ≤ 0.0248)。

结论和临床相关性

在马的桡腕骨中产生 OCF，在手术部位（肱三头肌上的皮肤）近端引起短暂（<2 周）同侧热过敏。手术诱导的 OCF 可能导致与继发性热痛觉过敏一致的躯体感觉异常。