Bilateral extensive steroid-associated osteonecrosis (SAON) of femur, tibia and patella: Successful early management with combined antiresorptive and anabolic bone agents

Abstract

Aim of the work

To present a case of bilateral extensive steroid-associated osteonecrosis (SAON) of femur, tibia and patella that was successfully managed with combined antiresorptive and anabolic bone agents.

Case presentation

A 38-year-old female patient encountered an aggressive coronavirus disease 2019 (COVID-19) infection and was given systemic steroids for six months. The patient then began to experience bilateral lower limb pain. Tenderness over the knee joint margins was found, as well as tenderness of the lower end of the femur, upper tibia, and patella on both sides. The initial plain x-ray of the lower limb bones revealed subtle areas of sclerosis at the proximal metaphysis of tibial bones. The patient did not improve despite stopping steroids and repeated courses of simple analgesics, and the pain became progressive and more intense, to the point where the patient was unable to bear any weight and became wheel chair bound. Magnetic resonance imaging (MRI) was done revealing extensive osteonecrotic lesions involving the distal metaphysis of the femur with posterior extension into the medial and lateral condyles abutting the articular surfaces. Two anti-osteoporotic drugs were used; alendronate, used weekly to inhibit osteoclastic activity and limit the progression of the osteonecrotic lesions and teriparatide, an anabolic agent that increases osteoblasts, resulting in new trabecular and cortical bone growth. Clinical improvement, pain and ambulation, occurred after one month of initiation of treatment and follow up MRI study after 10 months showed marked radiological improvement.

Conclusion

Combined antiresorptive and anabolic bone agents remarkably reversed SAON.