Diaphyseal fractures are among the most common serious injuries treated by orthopedic surgeons. The number of fractures increases with age in boys during puberty, while in girls, the number of fractures decreases towards puberty. The most frequent fractures occur in the radius. The immature skeleton differs from the adult skeleton in many ways that must be taken into account because these characteristics directly affect the diagnosis and treatment of musculoskeletal injuries. Children have a greater ability of bone remodeling. Diaphyses tolerate angulations up to a certain age, but much less so later, requiring surgical treatment. We distinguish several types of fractures: transverse, spiral, oblique, those with a triangular fragment, and comminuted. Symptoms of fractures include limb deformity, pathological mobility, crepitus of bone fragments, and limb dysfunction. With such a clinical picture, the diagnosis of a bone fracture can be made already at the stage of first medical aid and later confirmed by X-ray diagnostics. There are three basic principles of fracture treatment: reposition, retention of fragments, and early functional mobilization (rehabilitation). Treatment may vary depending on the severity of the fracture and the child's age. The surgical approach includes various methods of fixation of broken bone parts, such as internal pins or nails connected to an external frame (external fixator). In children, the ESIN method of osteosynthesis is most commonly used. Non-surgical or conservative procedures typically involve different types of plaster splints with or without extension (where a stretching force is applied).