Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University Medical Centre, Ulm, Germany.
Knee Surg Sports Traumatol Arthrosc. 2019 Jun;27(6):1708-1716. doi: 10.1007/s00167-018-5185-y. Epub 2018 Oct 5.
This systematic review intends to give an overview of the current knowledge on how allografts used for the reconstruction of cruciate ligaments and menisci are integrated and specifically perform regarding their biomechanical function.
Two reviewers reviewed the PubMed and Central Cochrane library with focus on the biomechanical integration of tendon ligament and meniscus allografts. The literature search was conducted in accordance with the PRISMA statement for reporting systematic reviews and meta-analyses.
The analysed literature on tendon allografts shows that they are more vulnerable to overstretching in the phase of degradation compared to autografts as the revascularization process starts later and takes longer. Therefore, to avoid excessive graft loads, allografts for cruciate ligament replacement should be selected that exhibit much higher failure loads than the native ligaments to counteract the detrimental effect of degradation. Further, placement techniques should be considered that result in a minimum of strain differences during knee joint motion, which is best achieved by near-isometric placement. The most important biomechanical parameters for meniscus allograft transplantation are secure fixation and proper graft sizing. Allograft attachment by bone plugs or by a bone block is superior to circumferential suturing and enables the allograft to restore the chondroprotective biomechanical function. Graft sizing is also of major relevance, because too small grafts are not able to compensate the knee joint incongruity and too large grafts may fail due to extrusion. Only adequate sizing and fixation together can lead to a biomechanically functioning allograft. The objective assessment of the biomechanical quality of allografts in a clinical setting is challenging, but would be highly desirable for monitoring the remodelling and incorporation process.
Currently, indicators like ap-stability after ACL reconstruction or meniscal extrusion represent only indirect measures for biomechanical graft integration. These parameters are at best clinical indicators of allograft function, but the overall integration properties comprising e.g. fixation and graft stiffness remain unknown. Therefore, future research should e.g. focus on advanced imaging techniques or other non-invasive methods allowing for in vivo assessment of biomechanical allograft properties.
本系统综述旨在概述用于重建交叉韧带和半月板的同种异体移植物的整合方式，以及其在生物力学功能方面的具体表现。
两名审查员对 PubMed 和中央 Cochrane 图书馆进行了审查，重点关注肌腱韧带和半月板同种异体移植物的生物力学整合。文献检索符合 PRISMA 声明，用于报告系统评价和荟萃分析。
分析的肌腱同种异体移植物文献表明，与自体移植物相比，同种异体移植物在降解阶段更容易过度拉伸，因为再血管化过程开始较晚且持续时间较长。因此，为了避免移植物过度负荷，应选择用于交叉韧带置换的同种异体移植物，其失效负荷应远高于天然韧带，以抵消降解的不利影响。此外，应考虑采用在膝关节运动过程中产生最小应变差异的放置技术，这通过近乎等长的放置可最佳实现。同种异体半月板移植的最重要生物力学参数是固定牢固和适当的移植物尺寸。通过骨栓或骨块进行同种异体移植物附着优于环形缝合，可使同种异体移植物恢复软骨保护的生物力学功能。移植物尺寸也非常重要，因为太小的移植物无法补偿膝关节不匹配，而太大的移植物可能会因挤出而失效。只有适当的尺寸和固定才能使同种异体移植物具有生物力学功能。同种异体移植物生物力学质量的客观评估在临床环境中具有挑战性，但对于监测重塑和整合过程非常可取。
目前，ACL 重建后 ACL 稳定性或半月板挤出等指标仅代表生物力学移植物整合的间接指标。这些参数充其量只是同种异体移植物功能的临床指标，但总体整合特性（例如固定和移植物刚度）仍未知。因此，未来的研究应侧重于先进的成像技术或其他允许对生物力学同种异体特性进行体内评估的非侵入性方法。
