Pelvic insufficiency fractures in the elderly.

Insufficiency fractures are a subgroup of stress fractures which occur when normal or physiological stresses are placed on weakened bone. Occurrences of these fractures in the pelvis are difficult to detect clinically and the appropriate radiological investigation is necessary for diagnosis. Osteoporosis is the main underlying cause of these fractures. The clinical and radiological features of three elderly patients with varying presentations of pelvic insufficiency fractures are described. Together with images from three other patients, the radiological spectrum of these fractures is illustrated. The current literature on this subject is reviewed. Plain radiographs are usually unhelpful or may be misleading. Isotope bone scans are the most sensitive modality, demonstrating complete or partial H-shaped sacral uptake, parasymphyseal uptake, or a combination of both. CT is useful for confirming these fractures and excluding malignant disease. Patients invariably improve with bed rest. Awareness of this entity should lead to utilisation of the appropriate imaging modalities for its diagnosis, the proper patient management and avoidance of unnecessary invasive procedures.