Sex‐specific biomechanics and morphology of the anterior cruciate ligament during skeletal growth in a porcine model

Author(s):  
Danielle Howe ◽  
Stephanie G. Cone ◽  
Jorge A. Piedrahita ◽  
Bruce Collins ◽  
Lynn A. Fordham ◽  
...  
2021 ◽  
Author(s):  
Danielle Howe ◽  
Stephanie G. Cone ◽  
Jorge A. Piedrahita ◽  
Bruce Collins ◽  
Lynn A. Fordham ◽  
...  

Pediatric anterior cruciate ligament (ACL) injuries are on the rise, and females experience higher ACL injury risk than males during adolescence. Studies in skeletally immature patients indicate differences in ACL size and joint laxity between males and females after the onset of adolescence. However, functional data regarding the ACL and its anteromedial and posterolateral bundles in the pediatric population remain rare. Therefore, this study uses a porcine model to investigate the sex-specific morphology and function of the ACL and its bundles throughout skeletal growth. Hind limbs from male and female Yorkshire pigs aged early youth to late adolescence were imaged using magnetic resonance imaging to measure the size and orientation of the ACL and its bundles, then biomechanically tested under anterior-posterior drawer using a robotic testing system. Joint laxity decreased (p<0.001) while joint stiffness increased (p<0.001) throughout skeletal growth in both sexes. The ACL was the primary stabilizer against anterior tibial loading in all specimens, while the functional role of the anteromedial bundle increased with age (p<0.001), with an earlier shift in males. ACL and posterolateral bundle cross-sectional area and ACL and anteromedial bundle length were larger in males than females during adolescence (p<0.01 for all), while ACL and bundle sagittal angle remained similar between sexes. Additionally, in situ ACL stiffness correlated with cross-sectional area across skeletal growth (r2=0.75, p<0.001 in males and r2=0.64, p<0.001 in females), but not within age groups. This study has implications for age and sex-specific surgical intervention strategies and suggests the need for human studies.


2009 ◽  
Vol 37 (8) ◽  
pp. 1554-1563 ◽  
Author(s):  
Braden C. Fleming ◽  
Kurt P. Spindler ◽  
Matthew P. Palmer ◽  
Elise M. Magarian ◽  
Martha M. Murray

Background The outcome of anterior cruciate ligament (ACL) reconstruction is variable, and many patients have increased joint laxity postoperatively. Hypothesis Placement of a collagen-platelet composite (CPC) around the graft at the time of ACL reconstruction decreases postoperative knee laxity and improves the structural properties of the graft compared with standard ACL reconstruction. Study Design Controlled laboratory study. Methods Thirteen immature pigs underwent unilateral ACL reconstruction with a bone–patellar tendon–bone allograft. In 6 pigs, a standard allograft was used to reconstruct the ACL. In 7 pigs, a CPC was placed around the allograft. After 15 weeks of healing, the animals were euthanized, and the anterior-posterior (AP) knee laxity and structural properties of the graft were measured. Qualitative histology of the grafts was also performed. Results The AP laxity values of the reconstructed knees, normalized to the contralateral control, were significantly reduced by 28% and 57% at 60° and 90° of knee flexion, respectively, with the addition of CPC (P <. 001). Significant improvements in the graft structural properties were also found; the normalized yield (P =. 044) and maximum failure loads (P =. 025) of the CPC group were 60% higher than the standard ACL-reconstructed group. Although cellular and vessel infiltration were observed in the grafts of both groups, regions of necrosis were present only in the standard ACL-reconstructed group. Conclusion These data demonstrate that the application of CPC at the time of ACL reconstruction improves the structural properties of the graft and reduces early AP knee laxity in the porcine model after 15 weeks of healing. Clinical Relevance Application of a CPC to an ACL graft at the time of surgery decreased knee laxity and increased the structural properties of the graft after 15 weeks of healing.


2015 ◽  
Vol 15 (01) ◽  
pp. 1550006 ◽  
Author(s):  
ZHENG LI ◽  
JIANKANG HE ◽  
XIANG LI ◽  
WEIGUO BIAN ◽  
WENYOU ZHANG ◽  
...  

Silk was widely investigated as a promising scaffold material in ligament tissue engineering. Although a variety of silk scaffolds were developed for the regeneration of anterior cruciate ligament (ACL) in vitro and in vivo, more investigations should be performed in large animals to translate these findings into clinical applications. The aim of this study is to evaluate the feasibility of using silk-based ACL scaffolds to regenerate damaged ACLs in porcine model. The microstructural organization, tissue regeneration as well as ligament-bone interface of silk implants were evaluated with scanning electron microscopy, micro-computerized tomography, histological and immunohistochemical staining at three and six months postoperatively. The results demonstrated that silk fibers in the ACL scaffolds organized in parallel similar with collagen fibers in native ligaments, which facilitated and guided the penetration of newly regenerated tissue into the pores among silk fibers. Collagen production especially collagen I in silk implants significantly increased from three to six months, and was gradually close to the level of native ligaments. At implant-bone interface, indirect ligament-bone insertion was observed at three months and substantial Sharpey's fibers formed at six months. The results indicated that the silk-based ACL scaffold provides a promising tissue engineering approach for ACL regeneration.


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