What is an insufficiency fracture?

From the Guidelines

An insufficiency fracture is a type of stress fracture that occurs when normal forces are applied to bone that has decreased mineral density or weakened structure, as noted in the 2024 update of the ACR Appropriateness Criteria for stress fractures, including sacrum, excluding other vertebrae 1.

Definition and Causes

Insufficiency fractures develop gradually as the weakened bone fails under normal physiological stress, commonly affecting the spine, pelvis, sacrum, and lower extremities, particularly in individuals with osteoporosis, long-term steroid use, radiation therapy, or metabolic bone diseases.

• These fractures are distinct from fatigue fractures, which result from repetitive submaximal stress on normal bone, leading to accelerated bone remodeling 1.
• The weakened bone structure in insufficiency fractures can be due to various factors, including osteoporosis, which is characterized by low bone mineral density and poor bone quality, leading to reduced bone strength and increased risk of fracture 1.

Diagnosis and Treatment

Patients with insufficiency fractures typically experience localized pain that worsens with activity and improves with rest.

• Diagnosis involves imaging studies such as X-rays, MRI, or bone scans, with MRI being particularly sensitive for early detection, as highlighted in the 2024 update of the ACR Appropriateness Criteria for stress fractures, including sacrum, excluding other vertebrae 1.
• Treatment generally includes pain management with acetaminophen or NSAIDs, activity modification, protected weight-bearing with assistive devices like crutches or walkers, and addressing the underlying bone weakness through calcium and vitamin D supplementation, bisphosphonates, or other bone-strengthening medications.
• Most insufficiency fractures heal within 6-12 weeks with appropriate conservative management, though healing may be prolonged in severely compromised bone, emphasizing the importance of early diagnosis and treatment 1.

Prevention

Prevention of insufficiency fractures focuses on maintaining bone health through adequate nutrition, weight-bearing exercise, and appropriate medical management of conditions that affect bone strength.

• This is particularly important given the significant personal and economic burden of osteoporotic fractures, with an estimated 178 million new fractures occurring in 2019 and a direct cost of managing fragility fractures worldwide exceeding $100 billion USD 1.
• Addressing the "osteoporosis care gap" by ensuring that individuals at high fracture risk undergo assessment and treatment for osteoporosis is crucial in preventing insufficiency fractures and reducing the associated morbidity, mortality, and impact on quality of life 1.

From the Research

Definition of Insufficiency Fracture

An insufficiency fracture is a type of fracture that occurs when normal or physiological stress is exerted on weakened bone 2, 3, 4, 5. This type of fracture is often associated with osteoporosis, which is the most common cause of insufficiency fractures 2. Other conditions that can lead to insufficiency fractures include disorders that affect bone metabolism, collagen formation, and bone remodeling, as well as medications such as bisphosphonates and glucocorticoids 5.

Characteristics of Insufficiency Fractures

Some key characteristics of insufficiency fractures include:

• They occur with normal stress exerted on weakened bone 2, 4
• They are often associated with osteoporosis, particularly in postmenopausal women 2
• They can occur in various locations, including the pelvis, spine, and long bones 3, 4
• They may be mistaken for other conditions, such as pathological fractures or abuse 5
• They can be diagnosed using imaging modalities such as radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) scans 2, 3, 4

Risk Factors and Prevention

Some risk factors for insufficiency fractures include:

• Osteoporosis 2, 5
• Disorders that affect bone metabolism, collagen formation, and bone remodeling 5
• Medications such as bisphosphonates and glucocorticoids 5
• Prolonged immobilization and bed rest 4, 5
• Poor nutrition, including inadequate intake of protein, calcium, and vitamin D 5

Preventative measures for insufficiency fractures include:

• Optimizing nutrition to include an adequate intake of protein, calcium, and vitamin D 5
• Maintaining mobility and preventing long periods of bed rest 4, 5
• Treating underlying pre-disposing conditions, such as osteoporosis 5