Definition
- Fracture through bone weakened by pre-existing pathology (usually tumor—primary or metastatic, infection, metabolic disease).
- Occurs with minimal or no trauma.
Common Causes
- Metastatic disease (breast, prostate, lung, kidney, thyroid)
- Primary bone tumors (e.g., myeloma, lymphoma)
- Infection (osteomyelitis)
- Metabolic bone disease (e.g., Paget, osteomalacia)
Imaging Features
- Fracture at site of bone lesion (lytic/blastic/mixed)
- Often ill-defined margins; possible soft tissue mass
- May have periosteal reaction or abnormal marrow signal on MRI
- May see multiple lesions if metastatic/myeloma
Pathological Fracture vs. Fatigue Fracture #VS
| Feature |
Pathological Fracture |
Fatigue Fracture |
| Location |
At site of underlying lesion (any bone) |
Predictable stress areas (shaft, metaphysis) |
| Bone Quality |
Abnormal (tumor, infection, etc.) |
Normal (overuse/repetitive microtrauma) |
| Preceding Lesion |
Present (tumor, cyst, infection) |
Absent |
| Pattern |
Often lytic/blastic, destructive, may be comminuted |
Usually simple, linear, transverse, no destruction |
| History |
Often older/adult, history of malignancy |
Young/athletic, repetitive use |
| Soft Tissue Mass |
May be present |
Rare |
Mirel’s Scoring System
Radiographic qualitative evaluation for impending pathological fracture risk
| Variable |
1 point |
2 points |
3 points |
| Site |
Upper limb |
Lower limb |
Peritrochanteric |
| Pain |
Mild |
Moderate |
Functional (severe) |
| Lesion type |
Blastic |
Mixed |
Lytic |
| Size |
<1/3 diameter |
1/3–2/3 diameter |
>2/3 diameter |
- Total Score:
- ≤7: Low risk
- 8: Borderline
- ≥9: High risk (consider prophylactic fixation)
- Always suspect pathological fracture if:
- Fracture occurs with minimal trauma in abnormal bone
- Unusual location/pattern (e.g., diaphyseal in elderly)
- Known malignancy or systemic symptoms
- Key step: Look for underlying lesion on imaging
- Don’t confuse fatigue fracture (healthy bone, overuse) with pathological fracture (diseased bone, minimal trauma)
