ACL healing is dependent on an intact synovial lining. For this reason, surgical repair is usually necessary. During the evolution of anterior cruciate ligament (ACL) reconstruction surgery, several different sources of grafts have been used (Pearsall, 2000). The most commonly used tissues are autologous semitendinous/gracilis tendons, central one-third patellar tendons, and allograft patellar tendons. The central 1/3 autologous patellar tendon is considered by many to be the graft of choice, but the incidence of knee pain has been reported in a large number of cases, and due to technical factors such as tunnel angle and graft length, many of these grafts cannot be secured at the joint level, resulting in non-anatomic graft fixation. In an effort to improve this situation, while causing minimal damage to the tissue of harvest, the use of semitendinous/gracilis tendons (hamstrings) diminishes post-surgical knee pain because the patellar mechanism is not violated. However, pain is still experienced in some patients.
Hamstring tendinous grafts have evolved from a single-strand semitendinous graft to a quadruple-strand semitendinous/gracilis tendon graft, where both the semitendinous and gracilis tendons are folded in half and combined (Fu, Bennett, Lattermann and Ma, 1999, 821). The dimensions of the round, 10 mm quadruple semitendinous/gracilis tendon graft is more comparable with the intact ACL, and its tensile load is as high as 4108 N. It provides a multiple-bundle replacement graft that better approximates the function of the two-bundle ACL. The disadvantages are the concern over tendon healing within the osseous tunnels and the lack of rigid bony fixation.
After transplantation, tendon grafts undergo biologic transformation before they form a strong fibrous tissue (Fu, Bennett, Lattermann and Ma, 1999, 821). The tendon initially undergoes inflammation and necrosis, then revascularization and repopulation with ...