Making more use of MRI, degenerative lesions of the anterior cruciate ligament are more frequently diagnosed. Three separates entities are reported (mucoid degeneration, ganglion cyst and mucoid degeneration with ganglion cysts) but it is probably a continuum of the same degenerative process. In middle aged individuals, it would result of repeated microtrauma in the setting of a narrow intercondylar notch and/or increased posterior tibial slope. In the older patient, it would be part of a whole organ disease with the onset of osteoarthritis. Most cases are incidental findings. For symptomatic patients, a complete resection of the ligament is our first option when conservative treatment failed. It is effective for pain relief and motion recovery. Although it produces postoperative instability, secondary reconstruction is not always required.