DIFFERENT ASPECTS OF THE CYCLOPS LESION FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION - A MULTIFACTORIAL ETIOPATHOGENESIS

After anterior cruciate ligament (ACL) reconstruction using a patellar tendon autograft, 65 patients underwent second-look arthroscopy in con junction with hardware removal. In 23 patients, hypertrophic tissue wa s found in the anterior part of the knee. This tissue presented differ ent aspects, from a well-synovialized nodule to a more disorganized fi brous tissue according to patients' complaints. Endoscopic resection o f this offending tissue was generally sufficient to obtain a satisfact ory result. In patients presenting a loss of extension, the notch freq uently had to be enlarged. We have found a multifactorial pathogenesis to be likely: the nodule is a natural fibroproliferative tissue proce ss originating either from drilling debris from the tibial tunnel or f rom remnants of the ACL stump and, more rarely, from broken graft fibe rs. Sometimes, when the graft is malpositioned, the scar tissue can re sult from repeated graft impingement on the notch at terminal extensio n. Formation of this aberrant tissue should be prevented by proper pos itioning of the graft, by enlargement of the narrowed notch in chronic cases, by using drills of increasing diameters to avoid production of osteocartilaginous fragments, by meticulous resection of all drilling debris and ACL remnants around the tibial tunnel, and by enlarging th e notch roof if any contact with the graft is present when the knee is fully extended intraoperatively.