A pathological fracture is a bone break caused by an underlying disease that has weakened the bone. Unlike a traumatic fracture from a major force, this type of break can happen during routine, low-impact activities. The fracture itself is a complication of a separate health issue that has compromised the bone’s internal structure.
Underlying Causes of Bone Weakening
A primary cause is cancer that has spread, or metastasized, to the bone from other areas like the breast, lung, or prostate. These cancerous cells can disrupt the normal bone remodeling process, creating lesions that weaken the skeletal structure. Primary bone cancers, such as osteosarcoma, though less common, also directly destroy healthy bone tissue, leading to structural failure.
Metabolic bone diseases are another major cause. Osteoporosis is a widespread condition that leads to decreased bone mineral density and mass, making bones porous and fragile. This systemic weakening makes fractures more likely, particularly in the spine, hip, or wrist. Other metabolic conditions like Paget’s disease of bone cause disorganized bone remodeling, resulting in bone that is enlarged and structurally unsound. Osteomalacia, a softening of the bones due to severe vitamin D deficiency, also impairs bone strength.
Non-cancerous, or benign, growths can also lead to pathological fractures. Simple bone cysts, which are fluid-filled sacs, and conditions like fibrous dysplasia, where fibrous tissue replaces normal bone, can expand within the bone. This expansion gradually thins the hard outer layer of the bone, known as the cortex, creating a focal point of weakness.
Infections within the bone, a condition called osteomyelitis, can cause significant damage. The bacterial invasion and subsequent inflammation can destroy bone tissue, leading to a localized area of weakness. If left untreated, this erosion of the bone can progress to the point where a fracture occurs with minimal stress.
Symptoms and Diagnostic Process
A key indicator of a pathological fracture is pain in the affected bone that begins before the break happens. The fracture itself may be triggered by a seemingly harmless activity, such as stepping off a curb, coughing, or turning over in bed. Following the break, symptoms are similar to other fractures and include intensified pain, swelling, bruising, and an inability to move the affected limb.
The diagnostic process begins with a patient history and physical examination. An X-ray is the first imaging tool used, as it can reveal both the fracture and any underlying abnormalities in the bone, such as a lesion or area of thinning. This initial image helps the physician understand the nature of the bone’s failure.
Further imaging is required for a more detailed understanding of the bone’s condition. A CT scan provides a more intricate view of the bone, while an MRI evaluates surrounding soft tissues and the extent of any tumor or infection. A definitive diagnosis of the cause requires a biopsy, where a small sample of abnormal bone tissue is removed and analyzed to identify cancer cells, infection, or other disease markers.
Treatment Strategies
Managing a pathological fracture requires addressing both the broken bone and the underlying disease. The first priority is to stabilize the fracture to relieve pain and restore function. Orthopedic treatment varies based on the fracture’s location and severity and can include non-surgical methods like casting or bracing for support.
Surgical intervention is often necessary to provide stable internal fixation. Surgeons may use metal rods, plates, and screws to hold the bone fragments in place, allowing them to heal. If a joint is severely damaged by both the fracture and the disease, such as in the hip, a complete joint replacement may be the most effective solution. This stabilization is designed to be durable, as the bone’s natural healing potential may be compromised by the disease.
Treating the root cause is necessary for healing and preventing future fractures. For metastatic cancer, treatment may involve radiation therapy or chemotherapy. If osteoporosis is the cause, medications like bisphosphonates are prescribed to increase bone density. When a benign growth is responsible, surgery may remove it, while osteomyelitis requires a long course of antibiotics.
Recovery and Long-Term Outlook
The recovery period focuses on regaining strength and mobility. Physical therapy helps restore the range of motion and function to the affected limb or area. Rehabilitation exercises are tailored to the individual’s needs and the specific surgical repair performed.
The long-term outlook is determined not by the fracture, but by the underlying condition that caused it. The prognosis for a fracture caused by a benign bone cyst is positive once the cyst is treated and the bone heals. Conversely, the outlook for a fracture resulting from advanced, metastatic cancer is linked to the prognosis of the cancer itself.