Osteonecrosis of the jaw (ONJ) and atypical femoral fracture (AFF) in an osteoporotic patient chronically treated with bisphosphonates

The aim of the study is to report the rare association of two complications of long-term treatment of osteoporosis with bisphosphonates in the same Caucasian elderly patient. A female patient of Italian descent, age 87 years, consulted in February 2013. She had a history of osteoporosis and had taken alendronate weekly for 7 years (1999-2006). Due to low back pain, an orthopedist had indicated i.v. zoledronic acid, 5 mg/year for 3 years (2006-2008). She received occasional supplements of ergocalciferol. In 2009, she suffered a fall and sustained a subtrochanteric fracture of the left femur. She was operated on and recovered uneventfully. In 2012, she consulted a dentist due to loose teeth. She underwent the removal of a molar and was given a denture. She had discomfort when using the prosthesis, and developed an ulceration in the gum of the mandible, which exposed the bone and did not heal for 2 months. After radiologic studies, the diagnosis was osteonecrosis of the jaw. She improved after surgical debridement and local and systemic antibiotics. In early 2013, laboratory tests were normal except for a slight elevation of serum PTH and CTX-I. Calcitriol 0.25 mcg/day was prescribed; after 3 months serum calcium, phosphate, PTH, and CTX-I showed no variation. Two years later, she experienced acute low back pain after a fall; MRI showed recent crushing of D12, and chronic deformities of D11 and L1. Bone densitometry of her right hip (DXA) showed a T-score of -2.3 at the femoral neck. An X-ray film of the right femur showed diffuse thickening of both cortices. She was treated with nasal calcitonin and analgesics. After the back pain subsided, she was treated with s.c. denosumab. Although the association of ONJ and AFF was known in cancer patients treated with high doses of bisphosphonates, it is very rare in patients with osteoporosis receiving these drugs at usual doses. Only three cases have been reported, all in oriental women. This appears to be the first reported case in a Caucasian woman.