Bilateral Snapping Knee in a Patient with Rheumatoid Arthritis Accompanied by Sjögren's Syndrome - A Case Report

We experienced a rare case in which a bilateral snapping knee was caused by rheumatoid arthritis accompanied by Sjögren's syndrome (SS), and the symptoms were resolved by arthroscopic surgery.

A 43-year-old Asian male presented at another hospital with finger, shoulder, and knee pain and was diagnosed with rheumatoid arthritis accompanied by SS. Two months later, he developed the snapping phenomenon in both knees and presented at our hospital. The patient was positive for rheumatoid factor, anti-Smith antibody, and anti-SS-A antibody. Arthroscopy revealed a hard scar-like tissue in the lateral patellofemoral joint in both knees. The scar-like tissue was excised arthroscopically. Post-operatively, the snapping phenomenon and pain during flexion of the bilateral knee joints had been resolved.

In the present case, rheumatoid arthritis accompanied by SS caused inflammation of the knee joints and degeneration of the articular capsules, and snapping of the bilateral knees was caused by impingement of the scar tissue in the patellofemoral joints.