Clinical, biomechanical and morphological assessment of anterior cruciate ligament Kevlar®-based artificial prosthesis in rabbit model (original) (raw)
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Biomechanical evaluation of a bioactive artificial anterior cruciate ligament
Advances in biomechanics and applications, 2014
This study aimed to assess the biomechanical performance of a new generation of artificial ligament, which can be considered "bioactive" and "biointegrated," implanted in sheep. Thirty sheep were implanted: 15 sheep received the artificial ligament grafted with a bioactive polymer (grafted) and 15 received the artificial ligament without a bioactive polymer (non-grafted). The animals were sacrificed 3 or 12 months after implantation. The knee kinematics, namely flexion-extension, anterior drawer, and varusvalgus tests, were evaluated using a fully characterized custom-made device. Afterward, the specimens were tested under uniaxial tension until failure. The flexion-extension showed significant differences between (grafted or non-grafted) artificial and native ligaments 3 months after implantation. This difference became non-significant 12 months postoperatively. The anterior tibial drawer was significantly increased 3 months after implantation and remained significantly different only for non-grafted ligament 12 months after implantation. Twelve months after implantation, the differences between grafted and non-grafted ligament biomechanical properties were significant in terms of stiffness. In terms of load to failure, grafted ligaments seem to have had slightly better performance than non-grafted ligaments 12 months postoperatively. Overall these results suggest that grafted artificial ligaments have slightly better biomechanical characteristics than non-grafted artificial ligaments 12 months after implantation in sheep.
International Orthopaedics, 2013
Purpose The purpose of this study was to evaluate in a sheep model the biomechanical performance of augmented and nonaugmented primary repair of the anterior cruciate ligament (ACL) following transection at the femoral end during a 12month postoperative observation. Methods Forty sheep were randomly assigned to nonaugmented or augmented primary ACL repair using a polyethylene terephthalate (PET) band. At two, six, 16, 26 and 52 weeks postoperatively four sheep in each group were sacrificed and biomechanical testing performed. Results Compared with nonaugmented primary ACL repair, the PET-augmented repair demonstrated superior biomechanical results from 16 weeks postoperatively onwards in terms of anterioposterior (AP) laxity, tensile strength and ligament stiffness. The augmentation device works as a stress shield during the ligament healing process. The nonaugmented ACL repair also resulted in ligament healing, but the biomechanical properties were at a significantly lower level. Conclusion These results support the previously reported histological findings following augmented primary ACL repair. This animal study on the healing capacity of the ACL may provide some important contributions to how primary healing in certain types of ruptures can be achieved.
Biomechanical study of ACL reconstruction grafts
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2015
There are no published studies describing the strength quadrupled gracilis tendon alone and quadrupled semitendinosus tendon alone in the configuration used for anterior cruciate ligament (ACL) reconstruction. The primary objective was to compare the mechanical properties of grafts used for ACL reconstruction during a tensile failure test. The secondary objective was to evaluate the effect of uniform suturing on graft strength. Fifteen pairs of knees were used. The mechanical properties of five types of ACL grafts were evaluated: patellar tendon (PT), sutured patellar tendon (sPT), both hamstring tendons (GST4), quadrupled semitendinosus (ST4) and quadrupled gracilis (G4). Validated methods were used to perform the tensile tests to failure and to record the results. Student's t-test was used to compare the various samples. The maximum load to failure was 630.8N (± 239.1) for the ST4, 473.5N (± 176.9) for the GST4, 413.3N (± 120.4) for the sPT and 416.4N (± 187.7) for the G4 cons...
Knee Surgery, Sports Traumatology, Arthroscopy, 2012
Purpose The structural properties of the healing ligament are the determining factor for the stability of the reconstruction before, during, and after osseous integration of anterior cruciate ligament grafts. Over the course of ligamentization, the stability of synovialized grafts seems lower than that of non-synovialized patellar tendon grafts. Methods In an animal study on 42 sheep, 21 nonsynovialized grafts (patellar tendon) and 21 synovialized grafts (flexor digitorum superficialis tendon) were performed to replace the anterior cruciate ligament. After 6, 12, and 24 weeks, 7 animals from each group were euthanized and investigated. Anteroposterior stability of the knee was assessed. After removal of all other soft tissues, the ACL was loaded to failure. Histology and histological analysis of the intra-articular graft region was then performed.
American Journal of Sports Medicine, 1996
This investigation determined the effect that anterior cruciate ligament graft elongation at the time of surgical reconstruction has on the long-term biomechanical behavior of the graft and knee joint. We chose the canine model for anterior cruciate ligament reconstruction, using the medial third of the patellar tendon with attached proximal bone block. Elongation of the graft was measured immediately after graft fixation during passive knee flexion using the Hall effect transducer. The dogs were divided into either Group 1 (graft elongation behavior within the 95% confidence limits of the normal anterior cruciate ligament) or Group 2 (graft elongation behavior more than the 95% confidence limits of the normal anterior cruciate ligament). All of the dogs were sacrificed 18 months postoperatively, and we evaluated anteroposterior load displacement (i.e., anteroposterior laxity) of the knee and the structural properties of the graft. The anteroposterior laxity behavior of the reconstructed knees in Group 2 was significantly more than that of Group 1. Group 2 had significantly less linear stiffness of the graft than Group * Presented at the 20th annual meeting of the AOSSM, Palm Desert,
Plastic and elastic biomechanical properties of anterior cruciate ligament autografts
BMC musculoskeletal disorders, 2024
Background Anterior cruciate ligament (ACL) rupture is a common orthopedic injury, occurring in roughly 68.6 per 100,000 persons annually, with the primary treatment option being ACL reconstruction. However, debate remains about the appropriate graft type for restoring the native biomechanical properties of the knee. Furthermore, plastic graft elongation may promote increased knee laxity and instability without rupture. This study aims to investigate the plastic properties of common ACL-R graft options. Methods Patellar tendon (PT), hamstring tendon (HT), and quadriceps tendon (QT) grafts were harvested from 11 cadaveric knees (6 male and 5 female) with a mean age of 71(range 55-81). All grafts were mechanically tested under uniaxial tension until failure to determine each graft's elastic and plastic biomechanical properties. Results Mechanically, the QT graft was the weakest, exhibiting the lowest failure force and the lowest failure stress (QT < HT, p = 0.032). The PT was the stiffest of the grafts, having a significantly higher stiffness (PT > QT, p = 0.0002) and Young's modulus (PT > QT, p = 0.001; PT > HT, p = 0.041). The HT graft had the highest plastic elongation at 4.01 ± 1.32 mm (HT > PT, p = 0.002). The post-yield behavior of the HT tendon shows increased energy storage capabilities with the highest plastic energy storage (HT > QT, p = 0.012) and the highest toughness (HT > QT, p = 0.032). Conclusion Our study agrees with prior studies indicating that the failure load of all grafts is above the requirements for everyday activities. However, grafts may be susceptible to yielding before failure during daily activities. This may result in the eventual loss of functionality for the neo-ACL, resulting in increased knee laxity and instability.
The Knee, 2007
A composite carbon fibre polyester scaffold class ligament (ABC-Active Biosynthetic Composite Ligament, Surgicraft Ltd., Redditch) has been used for primary reconstruction of the torn anterior cruciate ligament at Mayday University Hospital since 1985. A cohort of patients followed up until 1996 showed a high incidence of early failure of the implant due to rupture and stretching. This led to a detailed mode of failure analysis and as a result the surgical technique was modified and new instrumentation was introduced in 1992 leading to a substantial improvement in early and mid-term survivorship. However, from 1996 onwards a large number of patients was lost to follow-up and therefore in 2000 a second cohort of patients was recalled for retrospective review. All the patients in this cohort had undergone surgery after 1992 and following the introduction of new instrumentation and alteration in surgical technique. Review of the results in the second cohort showed a very low initial failure rate (0% in the first 3 years), but with an increasing incidence of failure (27.9%) noted between 5 and 7 years post-operatively.
Synthetic grafts for anterior cruciate ligament rupture: 19-year outcome study
The Knee, 2010
Artificial ligaments for ACL replacement have been widely used in the 1980s and early 1990s in orthopaedic surgery. Synthetic devices have been utilized either as a prosthetic material or as an augmentation for a biological ACL graft substitute. The initial enthusiasm surrounding the introduction of synthetic graft materials stemmed from their lack of donor morbidity, their abundant supply and significant strength of these devices. The disadvantages in long-term follow-up were found to be cross-infections, immunological responses, tunnels osteolysis, femural and tibial fractures, foreign-body synovitis and knee osteoarthritis. A total of 126 patients were treated with artificial ACL substitution with polyethylene terephthalate (PET) synthetic ligaments in our Institute between 1986 and 1990. Of the original group, 51 sportsmen aged 15 to 40 were followed-up at a mean of 19 years (range 17.5 to 20.6 years) after surgery. Assessment was made with KOOS and IKDC score, Tegner activity scale, clinical examination, KT-1000 arthrometer, and X-ray evaluation. Of the 51 patients followed-up, 27.5% were found to have ruptured their PET ligaments and 100% presented degenerative osteoarthritis at the X-ray evaluation according to Ahlbäck radiological classification of arthritis. The objective evaluation showed functional impairment in 29.4% with an average reduction of 3 points in the Tegner activity scale. The osteoarthritis observed in all patients prompted us to avoid the diffusion of this surgical technique. Although in theory well-conceived, studies have yet to substantiate the function of these augmentation devices or to show clinical better results than those achieved with isolated autograft or allograft ACL substitutes.