The histologic and ultrastructural features of callus in the different phases of the fracture healing process in a patient affected by osteopetrosis, autosomic dominant form (adult form) are analysed. In the initial phase (10 days) a completely normal fracture callus can be observed, showing cartilaginous and fibrobiastic cells together with a rich vascular supply. 20 days after trauma repair tissue can still be regarded as normal. Occasional mononucleated cells are observed, which might belong to a pre- osteoclastic series. One year after trauma bone still appears immature, showing very little haversian pattern and a primitive vascular organisation. Microcracks and occasional areas of cartilaginous tissue can be seen. Very few cells are observed. No osteoclastic cells and only very few, at times picnotic, osteocytes can be identified. These findings support the hypothesis that osteopetrosis affects primitively bone remodelling. Osteocytes' alterations could be due to bone remodelling defects caused by the maturation deficiency of the osteoclasts. These alterations cannot be observed in the initial phases, but only at later stages: this supports the hypothesis of a progressive defect in bone resorption which doesn't affect the initial bone apposition. Final result of such a healing process is the formation through physiologic stages of a biomechanically inadequate pathological tissue.
Histologic and ultrastructural findings of fracture healing in osteopetrosis [La risposta dell'osso osteopetrosico al trauma fratturativo: Rilievi istologici ed ultrastrutturali]
ZANOLI, Gustavo Alberto
1998
Abstract
The histologic and ultrastructural features of callus in the different phases of the fracture healing process in a patient affected by osteopetrosis, autosomic dominant form (adult form) are analysed. In the initial phase (10 days) a completely normal fracture callus can be observed, showing cartilaginous and fibrobiastic cells together with a rich vascular supply. 20 days after trauma repair tissue can still be regarded as normal. Occasional mononucleated cells are observed, which might belong to a pre- osteoclastic series. One year after trauma bone still appears immature, showing very little haversian pattern and a primitive vascular organisation. Microcracks and occasional areas of cartilaginous tissue can be seen. Very few cells are observed. No osteoclastic cells and only very few, at times picnotic, osteocytes can be identified. These findings support the hypothesis that osteopetrosis affects primitively bone remodelling. Osteocytes' alterations could be due to bone remodelling defects caused by the maturation deficiency of the osteoclasts. These alterations cannot be observed in the initial phases, but only at later stages: this supports the hypothesis of a progressive defect in bone resorption which doesn't affect the initial bone apposition. Final result of such a healing process is the formation through physiologic stages of a biomechanically inadequate pathological tissue.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
