Resizing and Reshaping Anterior Cruciate Ligament Stump Tissue Does Not Compromise Cell Viability, and Infiltration Into Patellar Tendon Grafts Does Not Compromise Tensile Properties
Juliana Heimur D.O. , Mark Callanan M.D. , Jessi Truett Ed.D., B.C.B.A. , Achraf Cohen Ph.D. , Murilo Basso B.E. , Nick Carssow , Adam W. Anz M.D.
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引用次数: 0
Abstract
Purpose
To determine whether a technique to process anterior cruciate ligament (ACL) stump tissue for needle infiltration into tendon grafts for ACL reconstruction would affect the viability of the cells within the tissue or the tensile properties of infiltrated grafts.
Methods
ACL stump and Hoffa fat pad tissue was harvested from 13 ACL reconstruction patients and processed. Harvesting involved a standard arthroscopic shaver and an inline suction device. Processing involved 3 steps, 2 syringes, and 3 syringe transfer devices of decreasing size. After processing, tissue could pass through a needle for infiltration into ACL reconstruction tendon grafts. Tissue analysis was performed at each serial step of the processing technique and included cell counts and viability testing. Tensile testing involved 15 matched-pair cadaveric knees, from which bone–patellar tendon–bone (BPTB) grafts, stump tissue, and fat pad tissue were harvested. Harvested and processed tissue was infiltrated into BPTB grafts, and tensile biomechanical testing was performed.
Results
Unprocessed tissue showed average cell viability (ACV) of 72.8% during cell viability testing. After step 1 of the process, ACV was 66.4%; after step 2, ACV was 73.1%; and after step 3, ACV was 67.1%. There was no significant difference in cell viability between processing steps (P = .528). When un-infiltrated control grafts were compared with infiltrated grafts, expected significant differences were found for weight (6.55 ± 1.51 g vs 8.91 ± 0.98 g, P < .001), width (9.53 ± 1.35 mm vs 13.74 ± 2.04 mm, P < .001), thickness (5.2 ± 1.26 mm vs 10.78 ± 2.11 mm, P < .001), and Young’s modulus (94.55 ± 47.19 MPa vs 28.57 ± 16.37 MPa, P < .001). There were no significant differences in tensile failure load (536.65 ± 168.00 N vs 509.55 ± 139.31 N, P = .49), deformation at failure (9.34 ± 2.96 mm vs 9.28 ± 3.21 mm, P = .91), or stiffness (97.04 ± 32.34 N/mm vs 86.82 ± 24.37 N/mm, P = .11) between the groups.
Conclusions
A technique to process remnant ACL and fat pad tissue for infiltration does not affect the viability of cells within the tissue. Infiltration of tissue into BPTB graft increases overall volume and mass and does not significantly alter the graft’s tensile load to failure when compared with matched controls.
Clinical Relevance
Evaluation of the biomechanical properties of a graft injected with minimally manipulated biologic material obtained at the time of harvest may provide laboratory data on the procedure's safety and viability as a direct delivery method for ACL grafts. These data could contribute to future studies involving clinical application during ACL reconstruction.
目的探讨前交叉韧带(ACL)残端组织处理方法针刺入肌腱移植物重建前交叉韧带,是否会影响组织内细胞活力及浸润移植物的拉伸性能。方法收集13例前交叉韧带重建患者的前交叉韧带残端和Hoffa脂肪垫组织进行处理。采集包括一个标准的关节镜刮刀和一个内嵌吸装置。处理涉及3个步骤,2个注射器和3个注射器转移装置的尺寸递减。处理后的组织可以通过针浸润到ACL重建肌腱移植物中。在处理技术的每个系列步骤中进行组织分析,包括细胞计数和活力测试。拉伸试验涉及15对配对的尸体膝盖,从中获取骨-髌骨肌腱-骨(BPTB)移植物、残肢组织和脂肪垫组织。采集和处理的组织浸润到BPTB移植物中,并进行拉伸生物力学测试。结果细胞活力检测显示,处理后的组织平均细胞活力(ACV)为72.8%。经过步骤1处理,ACV为66.4%;步骤2后,ACV为73.1%;步骤3后ACV为67.1%。不同处理步骤间细胞活力无显著差异(P = .528)。未浸润对照移植物与浸润对照移植物相比,在重量(6.55±1.51 g vs 8.91±0.98 g, P < .001)、宽度(9.53±1.35 mm vs 13.74±2.04 mm, P < .001)、厚度(5.2±1.26 mm vs 10.78±2.11 mm, P < .001)和杨氏模量(94.55±47.19 MPa vs 28.57±16.37 MPa, P < .001)方面存在显著差异。拉伸破坏载荷(536.65±168.00 N vs 509.55±139.31 N, P = 0.49)、破坏变形(9.34±2.96 mm vs 9.28±3.21 mm, P = 0.91)、刚度(97.04±32.34 N/mm vs 86.82±24.37 N/mm, P = 0.11)组间差异均无统计学意义。结论人工前交叉韧带残馀组织和脂肪垫组织浸润处理不影响组织内细胞活力。与对照组相比,组织浸润到BPTB移植物中会增加移植物的总体体积和质量,并且不会显著改变移植物的拉伸负荷而导致失败。临床意义:在收获时,用最小操作的生物材料注射移植物,对其生物力学特性进行评估,可以为该程序的安全性和作为ACL移植物直接传递方法的可行性提供实验室数据。这些数据可以为未来ACL重建的临床应用研究做出贡献。