Insufficiency fracture
Updates to Article Attributes
Insufficiency fractures are a type of stress fracture, which are the result of normal stresses on abnormal bone. It should not be confused with fatigue fractures which are due to abnormal stresses on normal bone or with pathological fractures, a term usually restricted to focal bony abnormalities such as tumours and metastases.
Epidemiology
In general they are seen in elderly and more frequently in women 2.
Pathology
They are most frequently seen in the setting of osteoporosis, although any process which weakens bone is a risk factor. Long-term bisphosphonate use has been associated with insufficiency fractures 5.
Risk factors are those of osteoporosis as well as other abnormal bone conditions, including:
- osteoporosis: most common
- rheumatoid arthritis
- Paget's disease
- osteomalacia - milkman syndrome
- diabetes: classically causes calcaneal insufficiency avulsion
Common locations include:
- vertebral (crush or wedge) fractures: very common
- sacrum: H sign or Honda sign
- neck of femur
- proximal third femur (see article: bisphosphonate-related proximal femur fractures) 5
- pubic rami
- sternum 3
Radiographic features
Early diagnosis is best made with bone scan or MRI, as plain films may initially appear normal.
Plain film
- initially normal
- periosteal reaction progressing to callus formation in diaphyseal fractures
- linear sclerosis and cortical thickening more common in metaphyseal and epiphyseal fractures 2
MRI
MRI is as sensitive as bone scanning but is of higher specificity, both in isolating the exact anatomic location and in distinguishing fractures from tumours or infection.
-
T1
- low marrow signal
- enhancement can be prominent
- T2: high marrow signal with extension into adjacent soft tissues
Bone scan
Increased activity at site of fracture.
Treatment and prognosis
Treatment depends on the location and whether the fracture is complete or incomplete. Options therefore include:
- conservative management
- plaster cast
- internal fixation
- vertebroplasty
- kyphoplasty
Treatment of the underlying cause of bone weakness is also essential.
- +<li>diabetes: classically causes calcaneal insufficiency avulsion</li>
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