To assess the histological findings of anterior cruciate ligament (ACL) degeneration in an arthritic knee and its correlation with the gross appearance of the ACL, the patient's age and the functional status of the knee.

Histological evaluations of the ACL were carried out on 80 patients who had total knee arthroplasty. Five types of ACL degeneration were noted; 1) mucoid degeneration, 2) liquefaction, 3) hyaline degeneration, 4) calcification, and 5) fissuring. A scoring system for the level of ACL degeneration was made. Each type of degeneration was scored and the degree of ACL degeneration was graded by summing each score. The correlation between ACL degeneration and patient's age, gross appearance, and functional evaluation of knee by Knee Society Score (KSS) was analyzed. The gross appearance of the ACL was classified as normal, abnormal (thinned or hypertrophied), and tear.

The scores for the histological degeneration of the ACL ranged from 2 to 10, and there was no correlation between the patient's age and the scores (p>0.05). The gross appearance of the ACL was "nor-mal" in 19 cases, "abnormal" in 57, and "tear" in 4 with an average score of histological degeneration in 3.47 (2-6), 5.95 (3-10), and 9.0 (8-10) respectively. The score for the histological degeneration of the ACL was correlated with the gross appearance of the ACL and a functional evaluation by the KSS (p<0.05).

The degree of ACL degeneration was not closely related to the patient's age but there was some relationship with the gross degenerative changes in the ACL and the functional loss of the knee.