What is the definition of a pathological fracture?

Pathological Fracture Definition

A pathological fracture is a break in bone that occurs through an area weakened by pre-existing disease, resulting from minimal or no trauma that would not normally cause a fracture in healthy bone 1, 2.

Core Characteristics

The defining features of a pathological fracture include:

• Inadequate traumatic mechanism: The fracture occurs without sufficient force that would typically break normal bone, often during routine activities or minor falls 1, 2
• Pre-existing bone pathology: The bone has been structurally compromised by underlying disease processes before the fracture event 1
• Non-traumatic nature: These are fundamentally different from traumatic fractures in that the bone failure is due to abnormal bone quality rather than excessive force 3, 2

Underlying Causes

Pathological fractures result from various disease processes that weaken bone structure:

Malignant conditions:

• Metastatic carcinoma (most common in adults, particularly from breast, lung, prostate, colon primaries) 4
• Multiple myeloma (70-80% present with lytic skeletal lesions) 4
• Primary malignant bone tumors 1, 5

Benign conditions:

• Benign bone tumors (juvenile bone cysts, non-ossifying fibromas, giant cell tumors, aneurysmal bone cysts) 6, 5
• Metabolic bone diseases 3, 6
• Infections 6

Extrinsic factors:

• Prior radiation therapy 6
• Chemotherapy effects 6
• Chronic steroid use 6

Clinical Significance

Pathological fractures have profound implications for patient outcomes 4:

• They diminish functional capacity and quality of life significantly
• Can potentially reduce overall survival, particularly femoral fractures around the hip 4
• Often represent the first manifestation of undiagnosed underlying disease 3
• Dramatically alter activities of daily living, especially upper extremity fractures affecting feeding and personal hygiene 7

Critical Distinction from Other Fracture Types

It is essential to differentiate pathological fractures from insufficiency fractures (osteoporotic fractures from normal stress on abnormally weak bone) and stress fractures (abnormal repetitive stress on normal bone), as this distinction is crucial for correct treatment planning 2.

Common Anatomic Sites

The most frequent locations for pathological fractures in metastatic disease are 7, 4:

• Spine (most common overall)
• Femur (most common long bone)
• Humerus (second most common long bone, representing 16-39% of long bone pathological fractures)
• Pelvis and ribs