MRI of anterior cruciate ligament healing

The purpose of this study was to evaluate using MRI the natural healing of the anterior cruciate ligament (ACL) when treated conservatively by early protective motion.

Consecutive acute complete intraligamentous ruptures of the ACL in 50 cases that were allowed to heal without surgery were evaluated before and after 3 month treatment by MRI, arthroscopy, and stress radiographs. Twenty-nine of the 50 patients were also reevaluated 11 months from the initial injury, of which 7 were reevaluated again 24 months from the initial injury by MRI. The MR appearance of the treated ACL was categorized into four grades depending on homogeneity, straight band, and size.

MR assessment of the ACL after 3 month treatment demonstrated a well defined normal-sized straight band in 37 cases (74%). There was a significant relationship between the 3 and 11 month MR evaluations (rs = 0.801, p <0.0001). There were also significant relationships between the MR and arthroscopic evaluations (rs = 0.455, p <0.005) and between the MR stress radiographic evaluations (rs = 0.348, p <0.025) after the 3 month treatment.

MRI can demonstrate ACL healing when treated conservatively with early protective mobilization.