An Electron Microscopic Study on Remodelling of Donor Site of Patellar Tendon Used for ACL Reconstruction

Song, Eun Kyoo; Lee, Keun Bae; Seo, Hyoung Yeon

Abstract

An electron microscopic study was conducted in order to investigate the healing and maturation process of central one third of donor site patellar tendon which was used for endoscopic anterior cruciate ligament reconstruction. 17 patients among 118 consecutive series, which underwent ACL reconstruction from January 1990 to March 1995, were involved in this study according to various followup periods. At 6 months follow-up, hypercullular and randomly arranged fibrohlasts had abundant cytoplasm with marked irregular cytoplasmic borders and short cytoplasmic extensions. Thc, nuclei of fibroblasts had prominent nuclear indentation with chromatin condensation along the nuclear mernbrane and prominent nucleolus. The cytoplasm contained irregularly dilated rough endoplasmic reticulum, Golgi complex, and pinocytic vesicles. Intercellular space were occupied by newly-formed, immature col)agen fibrills without distinct parallel arrangement, and the diameter of collagen fibrils was unifoimly small. At 12 months, fibroblast and collagen fibrils showed a little matured findings except the small diameter of collagen fibrils. At 24 months, irregular-shaped fibroblasts were still present, which contained folded nuclei, ahundant cytoplasm with large amount of rough endoplasmic reticulum and Golgi complex. Collagen fihril showed also a unimodal distribution pattern with small diameter, however had a tendency to have a regular parallel arrangement. These finding suggest that the donor site of a patellar tendon was still quite different from normal patellar tendon in electron microscopic morphology even at 24 months postoperative follow-up regardless of considerable maturation of regular parallel arrangement pattern of collagen fibril.