University Hospital of Botucatu Medical School, Paulista State University, Botucatu, Brazil.
School of Medicine, University of São Paulo, São Paulo, Brazil.
Am J Sports Med. 2019 Mar;47(3):721-728. doi: 10.1177/0363546518818819. Epub 2019 Jan 14.
Corticosteroid injections in or around tendons for the treatment of athletic injuries are a common practice among orthopaedic surgeons and are apparently efficacious in the short term, although controversies persist related to local complications.
This study evaluated short-term (48 hours) biomechanical, biochemical, and histological alterations after a single injection of betamethasone into the normal tendons of rabbits.
Controlled laboratory study.
A total of 72 New Zealand White rabbits were randomly divided into 2 groups: the test group-in which 36 animals underwent 1 intratendinous injection of betamethasone (1.4 mg / 0.2 mL) in the right calcaneal tendon; the control group-in which the right calcaneal tendon of 36 animals was injected with saline (placebo control group) and the left calcaneal tendon was left untreated for normal standards (normal control). Forty-eight hours later, animals were euthanized and tendons were harvested. Metalloproteinase (MMP1 and MMP2) and interleukin (IL1 and IL6) expression levels, biomechanical resistance (load × elongation parameters), and histomorphometry (hematoxylin and eosin and picrosirius red stains for collagen fibers, tenocytes, and inflammatory cells) were analyzed in the tendons.
The test group had a significant reduction in MMP2 expression as compared with the control groups ( P = .027). Regarding the other parameters, there were no additional significant differences between the groups.
A single injection of corticosteroid into normal calcaneal tendons did not trigger acute local morphological, structural, or biomechanical injuries at 48 hours, but it did promote a significant decrease in MMP2 levels. Additional studies are needed with increased duration of follow-up, various doses, and multiple injections and in tendinopathic models.
Some previous studies demonstrated early structural changes in tendons after a single corticosteroid injection, which was not corroborated by the present study. Metalloproteinase decrease is usually associated with a reduction in collagen degradation, which would be protective for the healing process. More studies are necessary to confirm the possible beneficial effect of these results in the long term and for tendinopathies.
在治疗运动损伤时，在肌腱内或周围注射皮质类固醇是骨科医生的常用方法，尽管与局部并发症相关的争议仍在持续，但这种方法在短期内显然是有效的。
本研究评估了单次注射倍他米松后正常兔肌腱的短期（48 小时）生物力学、生化和组织学变化。
对照实验室研究。
将 72 只新西兰白兔随机分为 2 组：实验组（36 只动物）右跟腱内注射倍他米松（1.4mg/0.2mL）；对照组（36 只动物）右跟腱注射生理盐水（安慰剂对照组），左跟腱不作处理作为正常标准（正常对照组）。48 小时后处死动物并取肌腱。分析肌腱的金属蛋白酶（MMP1 和 MMP2）和白细胞介素（IL1 和 IL6）表达水平、生物力学阻力（载荷×伸长参数）和组织形态计量学（苏木精和伊红以及胶原纤维、腱细胞和炎症细胞的苦味酸天狼星红染色）。
与对照组相比，实验组 MMP2 表达显著降低（P=0.027）。对于其他参数，组间无其他显著差异。
单次注射皮质类固醇到正常跟腱在 48 小时内不会引发急性局部形态、结构或生物力学损伤，但会显著降低 MMP2 水平。需要进行更多具有更长随访时间、不同剂量和多次注射以及肌腱病模型的研究。
一些先前的研究表明，单次皮质类固醇注射后肌腱会出现早期结构变化，但本研究并未证实这一点。金属蛋白酶的减少通常与胶原降解减少相关，这对愈合过程是有保护作用的。需要更多的研究来证实这些结果在长期和肌腱病方面的可能有益效果。
