cholecalciferol and Tibial-Fractures

A 93 year-old woman with Paget's disease of bone had been treated with etidronate without interruption during 20 years. The daily dose was usual (5mg/kg/day) but this prescription had never been stopped by her physicians. Two fractures had already occurred in pagetic (right tibia) and non pagetic bones (right fibula) within the last 2 years, and she presented rib fractures, another right tibia fracture and right femur fracture during hospitalization time. X-rays films showed major osteolysis of left ulna and right tibia. Blood samples and technetium bone scan brought no evidence for sarcoma or lytic evolution of the disease. A transiliac bone biopsy on non pagetic bone site confirmed the diagnosis of osteomalacia (increased osteoid parameters), with secondary hyperparathyroidism (hook resorption). In Paget's disease of bone, continuous treatment by etidronate may induce generalized osteomalacia, and increase the risk of fracture in both pagetic and non-pagetic bones. Whereas physicians and pharmaceutical industry try to improve the observance of those drugs, this striking observation also points out that a prescription always needs to be updated.

Topics: Aged, 80 and over; Alkaline Phosphatase; Biopsy; Bone Density Conservation Agents; Calcification, Physiologic; Calcium Carbonate; Cholecalciferol; Etidronic Acid; Female; Femoral Fractures; Fibula; Fractures, Spontaneous; Humans; Hyperparathyroidism, Secondary; Iatrogenic Disease; Osteitis Deformans; Osteolysis; Osteomalacia; Parathyroid Hormone; Radionuclide Imaging; Rib Fractures; Tibial Fractures; Ulna; Vitamin D

The benefits of vitamin D3 on fracture healing have been commonly demonstrated in vitamin-D3-depleted animal models. The aim of this study was to examine the effects of a single high dose of vitamin D3 on fracture healing in a healthy animal model, which has not been previously reported. Twenty healthy young adult guinea pigs were randomly divided into groups as 'control' and 'vitamin D', and their right tibias were fractured with digital manipulation. Guinea pigs in vitamin D group were injected intramuscularly with 50,000 i.u./kg of vitamin D3. The animals were killed at 7, 14, 21 and 28 days following fracture. Ultrastructural analysis of the harvested tibias revealed that a single high dose of vitamin D3 stimulated fracture healing. The observed effects at the fracture zone in a healthy animal model included advancement of blood supply, acceleration of synthesis and organization of collagen fibres, acceleration of the proliferation and differentiation of osteoprogenitor cells, and activation of the mineralization of the matrix.

Topics: Animals; Bony Callus; Cholecalciferol; Female; Fracture Healing; Guinea Pigs; Tibial Fractures

One-day-old chicks were depleted of vitamin D. At 3 weeks their right tibiae, and those of a control group given vitamin D3, were fractured and pinned. After fracture the controls were kept on vitamin D3. Another group was left vitamin D-deficient. The remaining depleted chicks, divided into four groups, were given vitamin D3, 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] or a combination of 24,25(OH)2D3 and 1,25(OH)2D3. The callus obtained after 9 and 14 days was subjected to torsional stress. The callus of chicks given vitamin D continuously showed the greatest resistance, whereas that of vitamin D-deficient chicks showed the smallest resistance. Repletion with either vitamin D3 or its metabolites increased the strength of the callus. Repletion with the combination of 24,25(OH)2D3 and 1,25(OH)2D3 produced the most marked results, in that the callus was even stronger than that of chicks replete with vitamin D3. It is concluded that 24,25(OH)2D3 is essential for bone formation in addition to the known active vitamin D metabolite 1,25(OH)2D3, and the possible clinical implications of these findings are discussed.

Topics: 24,25-Dihydroxyvitamin D 3; Animals; Body Weight; Bony Callus; Calcitriol; Calcium; Chickens; Cholecalciferol; Dihydroxycholecalciferols; Male; Phosphates; Stress, Mechanical; Tibial Fractures; Wound Healing