Application of Growth Factors for Enhancement of Mechanical Strength of Grafted Tendon Following Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) injury is a relatively common knee injury during sports activities (Uhorchak, 2003). A torn ACL usually occurs through a twisting force being applied to the knee whilst the foot is firmly planted on the ground or upon landing (Boden, 2000). The traditional surgical treatment for ACL rupture is ACL reconstruction by an autogenous tendon graft. However, fibroblasts of the tendon graft are necrotized immediately after transplantation of an autogenous tendon graft, and, then, extrinsic fibroblasts infiltrate in the graft (Amiel, 1986; Arnoczky, 1982; Kleiner 1986). During this process, the grafted tendon weakens in the early phase after ACL reconstruction surgery, even if the grafted tendon is subjected in the mechanically physiological condition (Jackson 1991). In addition, a case report of histology of patellar tendon graft 18 months after ACL reconstruction suggested that the cell infiltration into a core portion of the graft occurs very slowly after ligament reconstruction (Delay, 2002). The slow graft maturation may result in graft failure during the postoperative rehabilitation period. It has been known that growth factors enhance proliferation, migration, and matrix synthesis of cells in vitro (Deie, 1997; DesRosiers, 1996; Kobayashi, 2000; Marui, 1997; Scherping, 1997; Schmidt, 1995). The authors conducted a series of animal experimental studies for the application of growth factors to ligament reconstruction. We will review our recent experimental studies that intended to enhance mechanical strength of grafted tendon after ligament reconstruction using growth factors.