To assess the evolution of anterior cruciate ligament mucoid degeneration and to correlate these findings with clinical instability and ligament tear.

278 patients (175 male, 103 female, mean age 57,9 years) with magnetic resonance images diagnosis of anterior cruciate ligament mucoid degeneration were followed up at one, two, five and seven years, recording the location (the anteromedial and the posterolateral bundle) and distribution (proximal, middle and distal) and size of lesion. Moreover these pattern were correlated with clinical instability and partial/complete disruption of the ligament.

328 knee MR examinations identified only proximal (19%), middle portion (6%) and distal (22%) mucoid impairment; diffuse involvement was recorded in 53%. In all patients both bundles were involved. The one year follow−up examinations didn’t show any change in 90% of ligament; in the remaning 10% with partial mucoid involvement was reported a progression from distal, middle or proximal to diffuse involvement. The two and seven years follow-up exams detected a complete and diffuse mucoid impairment in all cruciate anterior ligaments with decreased trasversal size...

The mucoid degeneration of the ACL increased in extention over short time and decreased in size over long time, without signs of clinical knee instability and rupture.

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