Intra-articular administration of analgesics is performed to ensure good perioperative pain management avoiding undesirable systemic effects. To evaluate the effect of intra-articular injection of tramadol on postoperative pain after arthroscopy in horses and to determine whether tramadol had a local effect. Before the in vivo study, an in vitro test was performed aiming to evaluate the viability of equine chondrocytes after exposure to various concentrations of tramadol. The concentration identified as most appropriate was used to treat the horses’ joints. Twelve horses affected by osteochondrosis were randomly assigned to two groups that were treated intra-articularly at the end of surgery with tramadol (4 mg/mL) and saline, respectively. At predetermined time-points a Composite Pain Scale was applied and blood samples were collected in order to define the extent of tramadol absorption into the systemic circulation. The Mann-Whitney test was used for statistical analysis. Serum of four out of six treated horses revealed traces of tramadol (range 10.6–19.3 ng/mL) sporadically between 0.5 and 4 hours post-treatment, while in the other two horses, no trace of drug was found. Findings suggested that any eventual effect was probably due to local action rather than systemic absorption. The pain scores obtained in tramadol-treated horses were lower between 1 and 6 hours post-administration, than those obtained in the control group, but the differences were not statistically significant. These preliminary results suggest that tramadol, at this concentration, is only mildly beneficial in the pain management of horses after arthroscopy.

关节内施用镇痛药以确保良好的围手术期疼痛管理，避免不良的全身作用。评价关节内注射曲马多对马关节镜检查后术后疼痛的影响，并确定曲马多是否具有局部作用。在进行体内研究之前，进行了一项体外试验，旨在评估暴露于各种浓度的曲马多后马软骨细胞的活力。确定为最合适的浓度用于治疗马关节。将受骨软骨病影响的十二匹马随机分为两组，分别在手术结束时进行关节内治疗，分别使用曲马多（4 mg / mL）和生理盐水。在预定的时间点，应用复合疼痛量表并收集血液样本，以确定曲马多吸收到体循环中的程度。使用Mann-Whitney检验进行统计分析。在接受治疗的六匹马中，有四只的血清在治疗后0.5至4小时间偶有痕量曲马多（10.6-19.3 ng / mL），而在其他两匹马中，未发现任何药物。研究结果表明，任何最终的影响都可能是由于局部作用而不是全身吸收所致。用曲马多治疗的马在给药后1至6小时的疼痛评分低于对照组，但差异无统计学意义。这些初步结果表明，曲马多在这种浓度下，