[Persistent polyarticular synovitis after treatment with alendronate]

A 62-year-old, previously healthy woman diagnosed with post-menopausal osteoporosis received alendronate 70 mg/week. One week after the first dose, she developed polyarticular synovitis in the hands, feet and knees. We suspect this to be an adverse reaction to alendronate. At follow-up after 14 months, the patient still had residual synovitis, mainly in the hands and finger joints, despite continued low-dose prednisolone therapy. Two additional cases of synovitis associated with bisphosphonate therapy have been reported in the literature. The pathophysiology behind this phenomenon is unknown.