Remodeling of patellar tendon grafts augmented with woven polyester after anterior cruciate ligament reconstruction in humans

Abstract

Arthroscopic and histological evaluations of anterior cruciate ligament (ACL) grafts were made in 38 patients at various intervals after reconstruction was performed with patellar tendons (PTs) augmented with woven polyester. The interval between the surgery and the examinations ranged from 3 to 36 months (mean, 14.1 months). Biopsy specimens with woven polyester were removed from the anterior midportion of the graft 5mm in depth from the graft surface. Arthroscopically, all 38 grafts showed thick ligamentous tissues, but some polyester fibers had ruptured in 9 grafts. The transplanted grafts were arthroscopically very similar to normal ACL 12 months after reconstruction. Histologically, a marked inflammatory response to the woven polyester was observed in the first 4 months after the operation, but this decreased with time. Five of 6 grafts obtained 18–36 months postoperatively showed decreased cellularity, with longitudinally oriented fibrous bundles, suggesting approaching ligament maturity. The appearance of the fibroblasts in the grafts varied from patient to patient, with 13 of 37 grafts (35.1%) showing spindling fibroblasts, and 24 grafts (64.9%) oval ones. (The remaining graft consisted of mesenchynal cells). Clinically, postoperative KT 1000 arthrometer measurements showed that the mean injured-to-uninjured difference in anterior knee laxity was 1.7 ± 2.65mm. There was no chronic synovitis or effusion during the study period. These results suggest that grafts with PT augmented with woven polyester transform arthroscopically and histologically into a structure similar to that of normal ligaments after reconstruction, and may act as a substitute for the ACL. The advantage of woven polyester for the augmentation of PT grafts was that it allowed earlier mobilization and weight-bearing after reconstruction, without adverse effects on graft integrity.