Postoperative healing and complications based on anterior cruciate ligament reconstruction graft type

Injury to the anterior cruciate ligament (ACL) is a devastating injury to athletes of all ages. The current gold standard treatment following complete rupture of the ACL is reconstruction of the torn ligament with autograft or allograft tendon. Commonly used tendon grafts include patellar tendon, hamstring tendon, and quadriceps tendon. Although ligaments and tendons have similar collagen and proteoglycan compositions, they maintain a unique composition and arrangement of cells to serve their unique biomechanical needs. Therefore, following ACL reconstruction (ACLR), the implanted tendon tissue undergoes a process of remodeling which is termed "ligamentization". The process of ligamentization is divided into three main phases, which include the early healing phase, the proliferative phase, and the maturation phase. Following the process of ligamentization, the graft tissue closely mimics the appearance of ligament tissue on an ultrastructural level. Successful outcome following ACLR is contingent upon adequate remodeling of the tissue as well as healing of the graft within the bone tunnels in the femur and tibia. Choice of graft has individual implications regarding their associated risk of complications, failure, and infection. The purpose of this review is to summarize the process of ligamentization and graft healing and to discuss how graft type influences the rate and types of complications, failures, and infections.