Mucoid degeneration of the anterior cruciate ligament: Partial arthroscopic debridement and outcomes

BackgroundMucoid degeneration of the anterior cruciate ligament (ACL) is a common pathology but is often unknown and underdiagnosed. Mucinous material within the substance of ACL produces pain and limited motion in the knee. The purpose of this study was to diagnose mucoid degeneration of ACL and to assess the effectiveness of arthroscopic treatment in these patients.Materials and methodsBetween 2011 and 2014, 13 patients were diagnosed to be suffering from mucoid degeneration of ACL on the basis of magnetic resonance imaging (MRI), histopathology, and arthroscopy findings. All the patients had clinical symptoms of central knee pain behind patella and were unable to extend knees fully because of pain without instability. The aim of surgery was to remove as much of the degenerative mass as possible without having to sacrifice the entire ACL. Thus, the remaining ACL consisted of some intact anteromedial or posterolateral portion of the ACL interspersed with degenerate ACL tissue. Copious debridement of mucoid hypertrophied lesions of the ACL was performed.ResultsMean follow-up was of 8.4 months (range 6–12 months) and all except one patient had a full range of painless motion. All patients have resumed their normal daily activities. None complained of any instability. Postoperatively, 12 knees showed complete pain relief and 1 showed pain improvement by at least 4 Visual Analogue Scale (VAS) grades and preoperative average International Knee Documentation Committee (IKDC) score 8 was 36.39 which improved postoperatively to the average 73.18.ConclusionsMucoid degeneration of the ACL should be suspected in patients presenting pain on terminal extension or flexion without preceding trauma. Prior knowledge of condition with high index of suspicion and careful interpretation of MRI can establish the diagnosis preoperatively. Arthroscopic debridement with or without notchplasty gives excellent functional results.