Maturation of autogenous tendon grafts in anterior cruciate ligament reconstruction of the human knee--an arthroscopic study.

Fifty-six arthroscopic observations on 53 knees at various intervals after anterior cruciate ligament (ACL) reconstruction using the autogenous quadriceps and patellar tendon were analyzed to clarify the morphological maturation process of the grafts in human patients. Arthroscopic observations of the grafts were divided into four types, except for one rerupture case. In type I, thick synovial tissue with abundant capillary blood vessels filled the intercondylar fossa. In type II, synovial tissue mass was decreased and ligamentous tissue showed through the thin synovial tissue. In type III, relatively thick synovial tissue with many folds and abundant capillary blood vessels enveloped thick ligamentous tissue. In type IV, thin synovial tissue with relatively few blood vessels enveloped thick ligamentous tissue. Correlation between these graded types and intervals after reconstruction was significant (chi-square test, p less than 0.001). These four types of arthroscopic findings are thought to represent four phases of the maturation process of autogenous grafts after ACL reconstruction in human patients.