LIGHT AND ELECTRON-MICROSCOPIC STUDY OF REMODELING AND MATURATION PROCESS IN AUTOGENOUS GRAFT FOR ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

We evaluated the remodeling process of autogenous patellar tendon graf t for anterior cruciate ligament (ACL) reconstruction by means of ligh t microscopic (LM) and electron microscopic (EM) examinations from the biopsy specimens obtained at the time of second-look arthroscopy. Twe nty-one patients were examined at various times postoperatively (from 6 weeks to 15 months, mean 9.5 months), and the results were cor-relat ed with the morphology of normal patellar tendon and normal ACL. Our s tudy showed that the graft was revascularized in the early postoperati ve period, fibroblastic remodeling took place, and the graft obtained gross similarity to the original ACL on their arthroscopic and LM appe arances at approximately 1 year postoperatively. However, EM study sho wed that at both approximately 6 months and 1 year postoperatively the grafts consisted equally of active fibroblasts with a higher cytoplas m-to-nucleus ratio compared with normal ACL. Collagen fibrils of these grafts were of uniformly small diameter compared with normal patellar tendon and ACL. Our results with ultrastructural study suggest that t he grafts were still immature even at 1 year postoperatively.