[Insufficiency fractures in rheumatology. Case report and overview]

Stress fractures occur as insufficiency fractures, with a prevalence of 0.8% in patients with rheumatological illness. The main sites of insufficiency fractures are the pelvis and sacrum, parts of the tibia and fibula that are close to the joints, and the calcaneus and hip. Since the painful symptoms overlap with the clinical picture of the painful joint diseases and because of the low sensitivity of conventional diagnostic X-ray, insufficiency fractures are not diagnosed directly or their diagnosis is delayed. The high sensitivity of computer tomography, skeletal scintigraphy and nuclear magnetic resonance imaging should be exploited in the diagnosis of insufficiency fractures. The case report presented describes insufficiency fractures of the distal right tibia and fibula in an elderly female patient with rheumatoid arthritis being treated with long-term glucocorticoids. In addition to advanced age, female gender, immobility and rheumatoid arthritis requiring long-term cortisone, there are further risk factors for insufficiency fractures: fluoride treatment over many years in the past, hypovitaminosis D3, renal failure. The DXA bone density values of the neck of the femur and the lumbar vertebrae do not show any osteoporosis, and the calcium concentration in the serum is low; phosphate is raised and parathormone is normal; osteocalcin, beta crosslaps and alkaline phosphatase are raised. Bone biopsy specimens taken from the iliac crest and the proximal femur and investigated for the purpose of differential diagnosis revealed renal osteopathy with secondary hyperparathyroidism and osteomalacia. In elderly patients with kidney failure, the possibility of renal osteopathy must be considered as the possible cause of reduced bone quality with a raised risk of insufficiency fractures, even when the parathormone levels are normal. In view of the frequency of osteopathies in rheumatological patients, osteology is of enormous significance in rheumatology.