Radiographic sclerosis with intraoperative fragile bone in skeletal fluorosis: a case report

Introduction: Skeletal fluorosis is a rare toxic osteopathy characterized by massive bone fluoride fixation. The disease is an endemic problem in some parts of the world and is the result of the prolonged ingestion or inhalation of large amounts of fluoride. The radiographic presentation is mainly characterized by bone changes, with osteocondensation and ossification of many ligaments and interosseous membranes. Diagnoses: A 59-year-old woman with skeletal fluorosis underwent staged bilateral total knee arthroplasty. Preoperative radiographs showed increased bone density, thickened and fused trabecular, a thickened cortical bone, and a narrowed marrow cavity. Patient concerns: Severe osteoporosis combined with calcification of the capsule, ligaments, and tendons was found intraoperatively, which increased both exposure difficulty and periprosthetic fracture risk. Lessons: Skeletal fluorosis is not clinically obvious and is easily misdiagnosed. It is essential to evaluate bone quality and soft tissue flexibility preoperatively in patients from endemic areas. Special exposure procedures and release techniques are useful in these cases. It is recommended that clinicians fully appreciate that skeletal fluorosis can occur in the presence of preoperative radiographic sclerosis and intraoperative osteoporosis.