Mucoid Degeneration of Posterior Cruciate Ligament - A Case Study

Introduction: Mucoid degeneration of the cruciate ligament is a well-known entity, but symptomatic lesions are rare. It is even rarer to find symptomatic posterior cruciate ligament mucoid degeneration than the anterior cruciate ligament.

Case report: A 63-year-old male presented to our hospital complaining of posterior knee pain was induced when the knee approached full flexion without episodes of trauma, despite conservative treatment over the preceding 8 months, his symptoms persisted. Physical examination of the right knee revealed on terminal flexion and cross-leg sitting pain get exaggerated. Right knee ROM 0-110° and a further terminal flexion was limited and painful. On ligament examination, posterior sagging and Lachman test were negative, and no clinical finding indicative of ligament insufficiency was noted. Magnetic resonance imaging showed a diffusely thickened posterior cruciate ligament with increased signal intensity on the T2-weighted sequence. A intact PCL fibers were observed with continuous margins from origin to insertion. Based on the patient's history and the magnetic resonance imaging findings, we suspected mucoid degeneration of the posterior cruciate ligament as the cause of the patient's symptoms. Since conservative treatment had failed to relieve the symptoms, arthroscopic treatment was indicated. Arthroscopic examination revealed yellowish crumbly tissues along the thickened posterior cruciate ligament. Tension and bulk of the posterior cruciate ligament were well preserved. Curettage of degenerative tissue and decompression of the posterior cruciate ligament resulted in symptom relief without instability of the knee joint. We did a notchplasty of the medial wall and roof to accommodate the posterior cruciate ligament and avoid impingement.

Conclusions: Arthroscopic decompression of the posterior cruciate ligament may relieve knee pain and facilitate early return with good functional results.