Histological study on remodeling and maturation of hamstring autograft in postoperative patients / 中华骨科杂志

ABSTRACT

Objective To probe into the remodeling and maturity process along with extension of time in anterior cruciate ligament (ACL) reconstruction with hamstring autograft in order to confirm the date of maturity postoperatively. Methods Thirty-three patients after arthroscopic ACL reconstruction with hamstring autograft, were undergone second-look arthroscopical surgery. Meantime, biopsy specimens were obtained from the mid-zone of the hamstring graft. As a control group, specimens of normal ACL were obtained from total knee replacement of four cases, and specimens of semitendinous tendons obtained from ACL reconstruction of the four cases. The interval from initial reconstruction to second-look arthroscopy ranged from 2 to 36 months(mean 11.9 months). Patients were divided into different groups by postoperative time such as 1-, 4-, 7-, 10-, 13-, 18- and 25- month group. Thirty-three specimens were ordinarily sliced up into longitudinal sections. The sections were stained with hematoxylin and eosin so that cell and collagen fibrils were observed under light microscope, then compared the results with those of control group. Results Under microscopical observation, it was showed that tissue of hamstring graft was remodeled from more blood vessels and cellular amount to normal one, and from an irregular orientated crimp pattern of collagen to regular orientated crimp pattern of collagen in a time-dependent manner. Decreasing cellular amount, changing cell type, and a regular orientated crimp pattern of collagen of the hamstring graft were observed in 7- month group primarily, comparing with the original ACL. However, there existed a slower process in the other groups that are older than that of 7- month. Conclusion There are well histological features in the process of remodeling and maturation of the hamstring autograft after operation following extension of time, such as better survival of early period, and remodel of vessels and collagen. The process of remodeling and maturation in the hamstring autograft is similar to BPB autograft. The maturation period of the hamstring autograft after ACL reconstruction in human patients appears between 7 month and 9 month postoperatively.