Bilateral Spontaneous Bisphosphonate Insufficiency Fractures of the Proximal Tibia and Unilateral Distal Femur: A Case Report and Recommendation

Abstract

Bisphosphonate insufficiency fractures of the proximal femur have been increasingly described in literature. Bilateral proximal tibial fractures due to non-traumatic loading in patients with low bone density and on long term Bisphosphonate treatment are very rare and under reported in orthopaedic literature. We present a 77 years old Caucasian female with spontaneous onset of pain in both knees prior to presenting to casualty then to our fracture clinic. The patient is known to have Rheumatoid arthritis (RA) and has been on Bisphosphonate treatment for over 24 months following DEXA scan proven osteoporosis. Plain radiographs showed subtle linear areas of sclerosis bilaterally in her proximal tibiae. Magnetic resonance imaging (MRI) confirmed the presence of insufficiency fractures in these areas as well as her right distal femur. These fractures were treated successfully with activity modification and a hinge knee brace. This rare presentation in a rheumatoid patient with osteoporosis and long-term bisphosphonate treatment highlights the importance of being vigilant and having a high index of suspicion for these atypical fractures around the knees and not to relate symptoms to the inflammatory process associated with rheumatoid arthritis. We think that these insufficiency fractures around the knees are under diagnosed and often confused with the inflammatory process. We would like to raise awareness and recommend MRI scan in any patient with long-term bisphosphonate treatment and a new onset of pain around the knee.