Bone mass increases in youth and peaks for most people in their early 20s. With increasing age, however, bone loss surpasses bone growth. A variety of risk factors can predispose a patient to the weakening and eventually fragile bones characteristic of osteoporosis. In the presence of osteoporosis, fracture risk is high, and an initial fracture is a major risk factor for another. Weakened bones lead to instability and an increased risk of falling. In patients with distal radius fractures, 34% of women and 17% of men have osteoporosis. When normal or low-energy force is the mechanism, the osteoporotic injury is called a “fragility fracture.” Hand surgeons are often the first to see a patient with osteoporosis, after a fragility fracture. Therefore, hand surgeons should be alert to osteoporosis and refer appropriately.
Pathophysiology
- Collagen type 1 fibrils wind together and link with non-collagenous proteins, which help prevent shearing. Hydroxyapatite crystals within the collagen structure add strength.
- In osteoporotic bone, linkage of collagen fibrils and non-collagenous proteins is reduced, weakening the structure.
- Larger hydroxyapatite crystals make bones more brittle and prone to fracture.
Related Anatomy
- Osteoporosis-related fractures are most common in the hip, wrist, or spine.
- The most common cause of hip fractures in the elderly is falling, which can lead to disability and increased risk of death within the first year of injury.
Incidence and Related Conditions
- Incidence is expected to greatly increase with the aging of worldwide populations.
- Related conditions include celiac disease, inflammatory bowel disease (IBD), cancer, lupus, and rheumatoid arthritis (RA)
- Patients at highest risk are white and Asian women—particularly those in pre- (aged <45 y) or post-menopause (~30% of women).
- Other risk factors: family history, small body frame and underweight, hormone levels (hyperthyroid, parathyroid, adrenals; hypotestosterone, estrogen), gastrointestinal surgery that affects nutrient absorption, low calcium intake, lifestyle choices (eg, alcohol abuse, tobacco use, lack of exercise)
Differential Diagnosis
- Bone marrow diseases (eg, multiple myeloma)
- Connective tissue diseases (eg, Ehlers-Danlos syndrome, osteogenesis imperfecta)
- Endocrinopathies (eg, Type I diabetes mellitus)
- Paget disease
- Parathyroid adenoma
