Şahin Hikmet, Akalın Yavuz, Çevik Nazan, Avci Özgür, Sağlıcak Harun, Öztürk Alpaslan
Department of Orthopaedic and Traumatology, Sivas Numune State Hospital, Sivas, Türkiye.
Department of Orthopedics and Traumatology, Heath Sciences University, Bursa Yüksek !htisas Research and Training Hospital, Bursa, Türkiye.
Acta Orthop Traumatol Turc. 2025 Apr 29;59(2):100-104. doi: 10.5152/j.aott.2025.24075.
Objective: The aim of this experimental study in a rat model was to investigate the biomechanical and histological effects of subacromial corticosteroid injections on the healing of the tendon-bone junction after repair in the rotator cuff tear model. Methods: A total of 48 rats were divided into 3 groups: the control group, the single-dose steroid group, and the 4-dose steroid group. The supraspinatus tendon was completely dissected from the footprint attachment site and repaired. Saline was injected into the subacromial area in the control group, while 0.6 mL-4.8 mg/kg of single-dose methylprednisolone was applied to the single-dose group, and the same dose was applied 4 times at 1-week intervals to the 4-dose steroid group. All animals were allowed unrestricted movement during this period, and all animals were sacrificed by cervical dislocation 4 weeks after the last dose in the 4-dose steroid group. Cell shape and the number of apoptotic cells were assessed histopathologically, and the fracture load, maximum stress, and energy absorption were assessed biomechanically. Results: There were no significant differences in terms of cell shape between the groups. There was a significant difference in the mean number of apoptotic cells in the control group and in the single-dose and 4-dose steroid groups (P=.028). There was a 36% reduction in the mean number of apoptotic cells in the steroid groups compared to the control group. In the biomechanical evaluation, no differences were found between the groups in terms of maximum tension or breaking load (n.s.). A significant difference was found when the 3 groups were compared in terms of energy absorption (P=.001). There was a significant difference in energy absorption between the control group and the steroid-treated groups, but there was also a significant difference between the single-dose group and the 4-dose group (P=.038). Conclusion: The administration of corticosteroids was found to have a negative effect on healing at the tendon-bone junction, but this effect did not vary with the number of steroid injections. From a biomechanical perspective, it was observed that the energy absorption at the surgical repair site was lower with corticosteroid administration, and this negative effect increased with the increasing number of injections.
本大鼠模型实验研究旨在探讨肩峰下皮质类固醇注射对肩袖撕裂模型修复后肌腱-骨结合部愈合的生物力学和组织学影响。方法：将48只大鼠分为3组：对照组、单剂量类固醇组和4剂量类固醇组。将冈上肌腱从足迹附着部位完全解剖并修复。对照组在肩峰下区域注射生理盐水，单剂量组应用0.6 mL - 4.8 mg/kg的单剂量甲基强的松龙，4剂量类固醇组以1周的间隔应用相同剂量4次。在此期间所有动物均可自由活动，4剂量类固醇组在最后一次给药后4周通过颈椎脱臼处死所有动物。通过组织病理学评估细胞形态和凋亡细胞数量，通过生物力学评估骨折负荷、最大应力和能量吸收。结果：各组之间在细胞形态方面无显著差异。对照组与单剂量和4剂量类固醇组的凋亡细胞平均数存在显著差异（P = 0.028）。与对照组相比，类固醇组的凋亡细胞平均数减少了36%。在生物力学评估中，各组在最大张力或断裂负荷方面未发现差异（无统计学意义）。当比较3组在能量吸收方面的差异时发现有显著差异（P = 0.001）。对照组与类固醇治疗组之间在能量吸收方面存在显著差异，但单剂量组与4剂量组之间也存在显著差异（P = 0.038）。结论：发现皮质类固醇给药对肌腱-骨结合部的愈合有负面影响，但这种影响并不随类固醇注射次数而变化。从生物力学角度观察到，皮质类固醇给药后手术修复部位的能量吸收较低，且这种负面影响随着注射次数的增加而增加。
