[Operative therapy of benign and semimalignant bone tumors].

The difficulties in treating bone tumors involve mainly: (1) assurance of benignity, (2) possibility of malignant degeneration, (3) tendency to recur locally, (4) problems arising from topography (spine tumors, joint destruction, growth disturbances, deformities, marked vascularization, pathological fractures), (5) malignant degeneration (mainly after radiation therapy, which is generally not indicated) and (6) tendency to recur (50% and more), particularly after inadequate treatment. The "therapy" of benign bone tumors ranges from simple observation to "en bloc" resection with extensive replacement by bone grafts and corresponding osteosynthetic techniques.