Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, China.
Am J Sports Med. 2018 Nov;46(13):3227-3236. doi: 10.1177/0363546518799357. Epub 2018 Oct 4.
The semitendinosus tendon graft with an intact tibial insertion has a sustainable blood supply and might be beneficial for graft maturation after anterior cruciate ligament reconstruction (ACLR); however, its potential advantages for graft tendon-bone healing is still unclear.
Intact tibial insertion of the hamstring tendon can preserve enough blood supply to keep the harvested tendon alive, which can improve tendon-bone healing and the biomechanical strength of the graft.
Controlled laboratory study.
Sixty-four healthy New Zealand White rabbits underwent unilateral ACLR with a semitendinosus tendon autograft after random enrollment into 2 groups (study group, n = 32 rabbits with semitendinosus tendon-preserved tibial insertions; control group, n = 32 rabbits with free semitendinosus tendons). At weeks 3, 6, 12, and 24, 8 rabbits in each group were sacrificed to evaluate tendon-bone healing by histologic staining, micro-computed tomography (micro-CT) examination, and biomechanical test.
The grafts in the study group maintained a similar cell count with no signs of necrosis or hypocellularity across all time points, but the grafts in the control group underwent a characteristic stage of necrosis at weeks 3 and 6. Sharpey-like fibers were observed from postoperative 3 weeks at the tendon-bone interface in the study group, and a normal insertion-like structure was formed at week 12, which became more mature at week 24. In the control group, however, Sharpey-like fibers could not be observed until week 12, and a normal transition through cartilage from bone to tendon was not observed at any time point. Histologic scores of the tendon-bone interface in the study group were significantly higher than those in the control group at week 6 ( P = .04), week 12 ( P < .001), and week 24 ( P = .04). As compared with the control group via micro-CT, the study group had a significantly smaller bone tunnel area at week 6 ( P = .01) and larger bone volume/total volume at week 3 ( P = .0026) and week 6 ( P = .01). Also, the study group had a significantly higher failure load at weeks 12 and 24 (both P = .03) and a significantly higher stiffness at week 24 ( P < .001) versus the control group.
The semitendinosus tendon graft with an intact tibial insertion in ACLR would bypass the graft avascular necrosis stage, which improves tendon-bone healing and biomechanical strength.
An alive graft in ACLR could improve tendon-bone healing and the biomechanical strength of the graft, which might be beneficial to early and intensive rehabilitation after ACLR.
半腱肌腱保留完整的胫骨止点具有持续的血液供应，可能有利于前交叉韧带重建（ACLR）后移植物的成熟；然而，其对移植物肌腱-骨愈合的潜在优势仍不清楚。
半腱肌腱的完整胫骨止点可以保留足够的血液供应，使所采集的肌腱保持存活，从而改善肌腱-骨愈合和移植物的生物力学强度。
对照实验室研究。
64 只健康的新西兰白兔在随机分为 2 组（研究组，n = 32 只半腱肌腱保留胫骨止点的兔子；对照组，n = 32 只游离半腱肌腱的兔子）后接受单侧 ACLR 手术，使用半腱肌腱自体移植物。每组在 3、6、12 和 24 周时分别处死 8 只兔子，通过组织学染色、微计算机断层扫描（micro-CT）检查和生物力学试验评估肌腱-骨愈合情况。
研究组的移植物在所有时间点均保持相似的细胞计数，无坏死或细胞减少迹象，但对照组的移植物在第 3 周和第 6 周经历了特征性的坏死阶段。研究组在肌腱-骨界面处从术后 3 周开始出现Sharpey 样纤维，在第 12 周形成正常的插入样结构，在第 24 周变得更加成熟。然而，在对照组中，直到第 12 周才观察到 Sharpey 样纤维，并且在任何时间点都没有观察到从骨到肌腱的正常软骨过渡。研究组肌腱-骨界面的组织学评分在第 6 周（P =.04）、第 12 周（P <.001）和第 24 周（P =.04）显著高于对照组。与对照组相比，通过 micro-CT 观察，研究组在第 6 周时骨隧道面积明显较小（P =.01），第 3 周（P =.0026）和第 6 周时骨体积/总体积明显较大（P =.01）。此外，研究组在第 12 周和第 24 周时的失效负荷明显较高（均 P =.03），在第 24 周时的刚度明显较高（P <.001），与对照组相比。
ACL 中保留完整胫骨止点的半腱肌腱移植物可以绕过移植物的缺血性坏死阶段，从而改善肌腱-骨愈合和生物力学强度。
ACL 中的活移植物可以改善肌腱-骨愈合和移植物的生物力学强度，这可能有利于 ACLR 后的早期和强化康复。
