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Artificial
Ligaments for Reconstruction Therapy
In 1903, Frederich Lange of Munich performed the
first ACL replacement, using braided silkattached to the semitendinous
as a ligament substitute. Whether he knew it or not, Lange had just
implanted the first artificial ligament. Unfortunately, the ligament
failed and artificial ligaments were not used for about half a century.
An artificial ligament is a ligament manufactured from various materials to simulate the properties of a ligament. Since the first artificial ligament in 1903 made of silk, it has been determined that synthetic polymers are the best materials to create artificial ligaments. Some of the materials being used in artificial ligaments are:
- Polyester
- Polyethylene
- Nylon
- Polytetrafluoroethylene
- Polystyrene
- Gore-Tex
- Stryker Dacron
When choosing which material to create the ligament from, designers must take into account the mechanical properties of the material, specifically tensile strength, minimal creep, elasticity, resiliency, and crimp. High strength fibers exhibit the strength desired by the ligament but are usually too stiff which leads to damage in the surrounding tissue. Less stiff polymers, such as polyester and nylon, exhibit good crimp morphology. (24)
Though this sounds very appetizing, no one uses prosthetic ligaments for ligament reconstruction therapy in athletes anymore. Most surgeons stay clear of it even in the general population. Overall, there has never been a high long-term success rate with prosthetic ligaments. On study of 855 ACL ligaments over a 15-year period found that there was a 40-78% failure rate. (23) Another report found that around 80% of knees which had been reconstructed using Dacron prosthetic ligaments had developed significant osteoarthritic symptoms at a 9 year follow up. (23) Right now, these ligaments are causing more trouble than they are solving, so most surgeons would rather use the reliable methods, autologous or allogeneic grafts. A second study on Dacron prosthesis yielded similar results. In this 5 year study, 16% of the prosthesis had been removed due to abrasion and arthritis with rupture of the prosthesis. Overall there was a 43% complication rate which is much higher than the rate with autologous and allogeneic ligaments.
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