69.13 Pathological fractures

Two kinds of fracture can occur without major trauma: (1) Fractures m which normal bone is subjected to unaccustomed, frequently repeated normal movements, as in fatigue fractures of the tibia (81.8), and march fractures of the metatarsals (83.11). (2) Fractures in which the bone is abnormal. Under the age of 20 the common causes are a chondroma (in a finger or toe) or a bone cyst at the end of a long bone, and osteomyelitis (7.2). Over the age of 40 the common causes are a secondary carcinoma (in the spine, pelvis, humerus, or femur), or osteoporosis (in the spine or femoral neck).

PATHOLOGICAL FRACTURES

X–RAYS Benign lesions typically have a smooth margin, and malignant ones a ragged gnawed appearance.

BIOPSY if you decide to biopsy the lesion, take tissue from the border of the lesion and try to get normal and abnormal bone in the same specimen.

TREATMENT Most pathological fractures unite, many of them at the normal speed, so that you can treat most of them in the same way as fractures through normal bone. Even fractures through secondary metastases may unite. If a fracture takes place through a bone cyst, it may unite. If it does not, refer the patient.

If a fracture takes place through a sarcoma, this may be an indication for amputation.