Short-Term Treatment With Teriparatide Restores Independent Ambulation in a Patient With Glucocorticoid-Induced Osteonecrosis of the Knees and Ankles

Teriparatide is a well-established treatment for osteoporosis. It is emerging as a promising treatment for osteonecrosis of the jaw and may be superior to alendronate for treating glucocorticoid-induced osteonecrosis of the femoral head and reduce collapse progression. However, few studies have investigated its efficacy in treating steroid-induced osteonecrosis affecting other sites such as the knee and ankle. Osteonecrosis treatment at these sites in early stages is limited to protected weight bearing and pain management. Surgical management is required for advanced stages. This case describes an unusual presentation of steroid-induced osteonecrosis in the bilateral lower extremities and illustrates the potential benefit of teriparatide as an alternative to surgery in managing this debilitating condition. A 25-year-old male with a history of a heart transplant for viral myocarditis was admitted to the hospital for severe bilateral lower extremity pain. His post-transplant course was complicated by giant cell myocarditis, treated with a prednisone taper from 80 mg to 7.5 mg daily over the course of one year. MRI showed diffuse osteonecrosis in the distal femora, medial femoral condyles, bilateral proximal tibias, left distal tibia, and bilateral ankles. A bone density test showed only mildly low bone mass with Z-scores of -0.8 at the right femur, -1.3 at the left femur and -1.3 at the lumbar spine. Due to progressive osteonecrosis on imaging and a decline in functional status over the next two months, following a discussion of risks, benefits and alternatives, he was started on daily teriparatide injections. Prior to therapy, he was using a walker and had difficulty ambulating more than a few feet. Within a month of teriparatide initiation, he reported improvement in both pain and mobility, and was able to walk independently into clinic. MRI two months later demonstrated no new lesions and significant improvement in previously necrotic areas. Our case highlights the importance of considering osteonecrosis at atypical locations in patients on chronic glucocorticoid therapy. It also demonstrates a promising role for teriparatide in treating steroid-induced osteonecrosis atypical sites and without concurrent osteoporosis.