Insufficiency fracture
Insufficiency fractures are a type of stress fracture, which are the result of normal stresses on abnormal bone. Looser zones are also a type of insufficiency fracture. They should not be confused with fatigue fractures which are due to abnormal stresses on normal bone, or with pathological fractures, the result of diseased, weakened bone due to focal pathology such as tumors (both malignant and benign).
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Epidemiology
In general, they are seen in the elderly, more frequently in women 2.
Pathology
They are most often seen in the setting of osteoporosis, although any process which weakens bone is a risk factor. Long-term bisphosphonate use has also been associated with insufficiency fractures 5.
Etiology
Osteoporosis is the most common cause of insufficiency fractures, although there are many more 7-9:
- disrupted bone mineral homeostasis: osteoporosis, hyperparathyroidism, diabetes mellitus, osteomalacia
- bone remodeling: Paget disease, osteopetrosis
- collagen formation: Marfan syndrome, fibrous dysplasia
- medications: glucocorticoids, chemotherapy
- radiation therapy
Location
-
vertebral (crush or wedge) fractures: very common
- marrow edema is limited to the vertebral body; extension of abnormal signal into the pedicles suggests an underlying lesion
- sacrum: Honda sign
- neck of femur
- proximal third femur (see article: bisphosphonate-related proximal femur fractures) 5
- pubic rami
- sternum3
- fibula 6
- tibia 6
Radiographic features
Early diagnosis is best made with bone scan or MRI, as plain films may initially appear normal.
Plain radiograph
- initially normal
- periosteal reaction progressing to callus formation in diaphyseal fractures
- linear sclerosis and cortical thickening more frequent in metaphyseal and epiphyseal fractures 2
MRI
MRI is as sensitive as bone scanning, with the added benefit of higher specificity, both in isolating the exact anatomic location and in distinguishing fractures from tumors or infection.
- T1: low marrow signal
- T2: high marrow signal with extension into adjacent soft tissues
- C+ (Gd): enhancement can be intense
Nuclear medicine
On bone scan, there is increased activity at the site of the 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.
Related Radiopaedia articles
Fractures
-
fracture
- terminology
- fracture location
- diaphyseal fracture
- metaphyseal fracture
- physeal fracture
- epiphyseal fracture
- fracture types
- avulsion fracture
- articular surface injuries
- complete fracture
- incomplete fracture
- infraction
- compound fracture
- pathological fracture
- stress fracture
- fracture displacement
- fracture location
- fracture healing
-
skull fractures
- base of skull fractures
- skull vault fractures
-
facial fractures
- fractures involving a single facial buttress
- alveolar process fractures
- frontal sinus fracture
- isolated zygomatic arch fractures
- mandibular fracture
- nasal bone fracture
- orbital blow-out fracture
- paranasal sinus fractures
- complex fractures
- dental fractures
- fractures involving a single facial buttress
-
spinal fractures
- classification (AO Spine classification systems)
-
cervical spine fracture classification systems
- AO classification of upper cervical injuries
- AO classification of subaxial injuries
- Anderson and D'Alonzo classification (odontoid fracture)
- Levine and Edwards classification (hangman fracture)
- Roy-Camille classification (odontoid process fracture )
- Allen and Ferguson classification (subaxial spine injuries)
- subaxial cervical spine injury classification (SLIC)
- thoracolumbar spinal fracture classification systems
- three column concept of spinal fractures (Denis classification)
- classification of sacral fractures
-
cervical spine fracture classification systems
- spinal fractures by region
- spinal fracture types
- classification (AO Spine classification systems)
- rib fractures
- sternal fractures
-
upper limb fractures
- classification
- Rockwood classification (acromioclavicular joint injury)
- AO classification (clavicle fracture)
- Neer classification (clavicle fracture)
- Neer classification (proximal humeral fracture)
- AO classification (proximal humeral fracture)
- AO/OTA classification of distal humeral fractures
- Milch classification (lateral humeral condyle fracture)
- Weiss classification (lateral humeral condyle fracture)
- Bado classification of Monteggia fracture-dislocations (radius-ulna)
- Mason classification (radial head fracture)
- Frykman classification (distal radial fracture)
- Mayo classification (scaphoid fracture)
- Hintermann classification (gamekeeper's thumb)
- Eaton classification (volar plate avulsion injury)
- Keifhaber-Stern classification (volar plate avulsion injury)
- upper limb fractures by region
- shoulder
- clavicular fracture
-
scapular fracture
- acromion fracture
- coracoid process fracture
- glenoid fracture
- humeral head fracture
- proximal humeral fracture
- humeral neck fracture
- arm
- elbow
- forearm
- wrist
-
carpal bones
- scaphoid fracture
- lunate fracture
- capitate fracture
- triquetral fracture
- pisiform fracture
- hamate fracture
- trapezoid fracture
- trapezium fracture
- hand
- shoulder
- classification
- lower limb fractures
- classification by region
- pelvis
- hip
- Pipkin classification (femoral head fracture)
- Garden classification (hip fracture)
- American Academy of Orthopedic Surgeons classification (periprosthetic hip fracture)
- Cooke and Newman classification (periprosthetic hip fracture)
- Johansson classification (periprosthetic hip fracture)
- Vancouver classification (periprosthetic hip fracture)
- femoral
- knee
- Schatzker classification (tibial plateau fracture)
- Meyers and McKeevers classification (anterior cruciate ligament avulsion fracture)
- tibia/fibula
- Watson-Jones classification (tibial tuberosity avulsion fracture)
- ankle
- foot
- Berndt and Harty classification (osteochondral lesions of the talus)
- Sanders CT classification (calcaneal fracture)
- Hawkins classification (talar neck fracture)
- Myerson classification (Lisfranc injury)
- Nunley-Vertullo classification (Lisfranc injury)
- pelvis and lower limb fractures by region
- pelvic fracture
- sacral fracture
- coccygeal fracture
-
hip
- acetabular fracture
- femoral head fracture
-
femoral neck fracture
- subcapital fracture
- transcervical fracture
- basicervical fracture
-
trochanteric fracture
- pertrochanteric fracture
- intertrochanteric fracture
- subtrochanteric fracture
- thigh
- mid-shaft fracture
- bisphosphonate-related fracture
- knee
- avulsion fractures
- Segond fracture
- reverse Segond fracture
- anterior cruciate ligament avulsion fracture
- posterior cruciate ligament avulsion fracture
- arcuate complex avulsion fracture (arcuate sign)
- biceps femoris avulsion fracture
- iliotibial band avulsion fracture
- semimembranosus tendon avulsion fracture
- Stieda fracture (MCL avulsion fracture)
- patellar fracture
- tibial plateau fracture
- avulsion fractures
- leg
- tibial tuberosity avulsion fracture
- tibial shaft fracture
- fibular shaft fracture
- Maisonneuve fracture
- ankle
- foot
- tarsal bones
- metatarsal bones
- phalanges
- classification by region
- terminology