The human bone is remarkably resilient and can often withstand significant trauma without breaking. Many medical conditions can weaken bones to the point that they are unable to even adequately support the weight of the body, however. When this happens, normally tough bones can fracture spontaneously. The resulting breakage is called a pathologic fracture.
A pathologic fracture is almost always a sign of a serious underlying medical problem. Conditions that have progressed enough to affect the thickness or shape of the bone are generally very difficult to treat. In many patients, especially elderly women, osteoporosis is to blame.
Throughout a person's life, their bones are simultaneously growing and being reabsorbed by the body. In healthy individuals, these dual processes happen at roughly the same speed. Osteoporosis occurs when the absorption of the minerals in bones far outpaces the ability of the bones to regenerate.
Generally, by the time osteoporosis has weakened bones enough for a pathological fracture to occur, treatment options are limited. Bisphosphonates can help strengthen bones to some degree, but a complete reversal of bone density loss is highly improbable. More often, the focus of osteoporosis treatment is preventing further bone loss and relieving pain. Special care is taken to prevent injuries from falls and other situations that could increase the risks of additional broken bones.
Ostomalacia also results from an imbalance in the speed of bone growth and reabsorption, but this condition primarily affects bone growth. Unlike the brittle bones created by osteoporosis, bones in a patient with osteomalacia can become so soft that they bend. Pressure on the ends of these bones can result in a pathologic fracture at the arc of the bow. Regardless of the underlying cause of the osteomalacia, lack of vitamin D is always the direct cause of the bone damage. Supplements of the vitamin can prevent further injury, but will not fix the damage that has already occurred.
Any change in the shape or density of a bone, including those changes caused by bone tumors, can increase the possibility of a pathologic fracture. As such, both benign and malignant bone tumors have been responsible for spontaneous broken bones. Unlike malignant tumors, however, benign bone tumors generally do not cause reduction in bone density and are, therefore, much less likely to weaken bones.
A pathologic fracture can take longer to heal than normal fractures. The same conditions that caused the weakened bones often affect natural bone reconstruction as well. Physical therapy is often prescribed with the hope that increased muscle strength in the affected area will help ease the burden on the bone.