Mucoid degeneration of the anterior cruciate ligament: Management and outcome

Background: Mucoid degeneration (MD) is a rare pathological affection of the anterior cruciate ligament (ACL). Mucinous material within the substance of ACL produces pain and limited motion in the knee. This series describes the clinicoradiological presentation of patients with mucoid ACL, partial arthroscopic debridement of ACL and outcomes. Materials and Methods: During a period of 3 years, 11 patients were included based upon the clinical suspicion, magnetic resonance imaging (MRI) findings, arthroscopic features and histopathologic confirmation of MD of ACL. Result: Six patients were male and five were female with median age of 40 years (range 21-59 years). All patients complained of knee pain with median duration of 5 months (range 1-24 months). All patients had painful deep flexion with 63.6% (N = 7) reporting trivial trauma before the onset of symptoms. MRI revealed MD of ACL in all with associated cyst in three patients. Partial debridement of ACL was done in ten and complete in one patient. None of them required notchplasty. Histopathology confirmed the diagnosis in all of them. At the mean followup of 13.81 months (range 6-28 months), all patients regained complete flexion and none complained of instability. Conclusion: Prior knowledge of condition with high index of suspicion and careful interpretation of MRI can establish the diagnosis preoperatively. It responds well to partial debridement of ACL and mucinous material without development of instability.