(Kiosk 2) Transient Osteoporosis in an Adult with Knee Pain: A Case Report

Case Diagnosis: 49-year-old male with left knee pain

Case Description or Program Description: Patient with insidious onset of left knee pain without trauma or inciting incident. X-ray demonstrated early degenerative changes. He was provided a home exercise program for lower extremity strengthening and a hinged patellar J brace. He underwent an ultrasound guided knee aspiration and steroid injection without relief. Given no improvement, he underwent further workup with magnetic resonance imaging (MRI), which showed extensive subchondral edema and subchondral fractures. He underwent a dual x-ray absorptiometry scan, which was normal. He was followed with multiple MRI’s with and without contrast, demonstrating evolving subchondral fractures and bone edema in different stages of healing. Computed Tomography revealed aggressive nonspecific patchy osteopenia without periostitis or gross cortical destruction.

Setting: Outpatient clinic at university hospital

Assessment/Results: His case was discussed with orthopedic oncology and presented at tumor board, and was thought to be consistent with transient migratory osteoporosis. He was treated with 6 months of limited weight bearing, time off work, non-weightbearing range of motion and strengthening exercises, as well as calcium and vitamin D supplementation. Repeat MRI 6 months later demonstrated interval resolution of pathology.

Discussion (relevance): Transient osteoporosis (TO) is characterized by gradual onset of joint pain, usually in the absence of trauma or injury. Literature regarding this diagnosis remains limited. A systematic review in 2008 revealed a total of 63 patients with TO, with the hip being the most affected joint, followed by knee, ankle, and foot. Since then, most of the published research has been limited to case reports.

Conclusions: TO is a rare and poorly understood condition that is usually self-limited but may cause significant pain and functional impairment both during and after pathologic processes have resolved. Further research is needed to better understand the pathogenesis and determine effective treatment options for TO.