Abstract
Rapidly destructive arthrosis is a rare syndrome characterized by narrowing of the joint space and rapid joint destruction within 6~12 months. A 62-year-old woman with anaplastic lymphoma kinase rearranged non-small-cell lung cancer presented with both knee pain and varus deformity. She was treated with crizotinib 500 mg/day for more than 2 years, with partial tumor response. Initial plain radiography showed Kellgren and Lawrence (K-L) grade 1. After 10 months, varus deformity was worsened and plain radiography aggravated to K-L grade 4 despite conservative treatment including activity modification. Diffuse synovitis with massive joint effusion and destruction of anterior cruciate ligament, medial meniscus, medial collateral ligament, and lateral collateral ligament were shown in magnetic resonance imaging. The patient was diagnosed with rapidly destructive arthrosis of knee and underwent a both total knee arthroplasty.