Osteoporosis continues to be a major health condition plaguing the aging population. The major manifestation of osteoporosis, the development of fragility fractures, is a burden both clinically and economically on patients and the nation’s health care system, with up to half of all American women sustaining a fragility fracture in their older years. The high frequency of injuries to the distal radius and proximal humerus should lead upper extremity surgeons to take pause and recognize the magnitude of impact these fractures have on their patient population. Recommended interventions span a spectrum of aggressiveness and have various financial implications.
Key points
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Osteoporosis is a silent and painless disease until a fracture occurs from a low-energy injury.
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The goal of treatment is early diagnosis and prevention.
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Diagnosis is made through bone mineral density testing, most commonly through dual-emission x-ray absorptiometry (DEXA) scanning.
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The Fracture Risk Algorithm (FRAX) tool (World Health Orgainziation Collaborating Centre for Metabolic Bone Diseases, University of Sheffield, UK) uses clinical grounds to assess one’s 10-year fragility fracture risk.
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Prevention is provided through avoiding alcohol and tobacco, performing regular weight-bearing exercises, dietary supplementation, and pharmacologic management when indicated.
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DEXA scanning is indicated in women aged 65 years and older and men aged 70 years and older. Testing can be performed earlier in postmenopausal women of any age or men with higher risk profiles.
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Adequate daily calcium intake consists of at least 1200 mg and vitamin D of 800 to 1000 IU, each per day. Dietary supplementation should be used accordingly.
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Pharmacologic management is indicated in those who have incurred a hip or vertebral fracture or in those with a DEXA scan T-score of less than or equal to −2.5 standard deviations (osteoporosis) at the femoral neck or spine.
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Pharmacologic management is also indicated in those with a DEXA scan T-score of between −1.0 and −2.5 standard deviations (osteopenia) with a FRAX 10-year fracture probability of more than 20%.
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Current Food and Drug Administration–approved pharmacologic agents for osteoporosis prevention and treatment include bisphosphonates, parathyroid hormone, calcitonin, and hormone therapy.
Introduction and epidemiology of fragility fractures
Osteoporosis is a silent and painless disease until a fracture occurs with minimal trauma (ie, a fragility fracture) ( Fig. 1 ). The mainstay of treatment is detection and prevention. Osteoporosis is endemic in aging patients, with up to 50% of all men and women aged 80 years and older meeting the diagnostic criteria. By definition, osteoporosis is diagnosed and quantified by bone mineral density. However, deficient bone mineral density (BMD) in itself is not as great a burden on patients and the American health care system as its manifestation in a fragility fracture because BMD is only a surrogate parameter for an impending fracture (comparable with blood pressure for stroke). Osteoporosis poses a major health problem both clinically and economically because it currently has no cure and leads to an alarming increase in bone’s propensity to fracture.
The World Health Organization defines a fragility fracture as a fracture caused by injury that would be insufficient to fracture normal bone: the result of reduced compressive and/or torsional strength of bone. These injuries are most often seen in the hip, distal forearm, proximal humerus, or vertebrae (compression) as result of low-energy trauma (ie, a fall from a height of less than 1 m). These low-energy mechanisms represent 53% of all fractures in patients aged 50 years or older and 80% in patients aged 75 years and older. Nearly half of all American women will sustain a fragility fracture in their lifetime, and distal radius fractures are particularly considered to be a harbinger of future fragility fractures because they are frequently the first to occur as osteoporosis develops. The distal radius fracture is the most frequently diagnosed fracture in women, and the mean age of women with fractures of the distal radius is 64 years old. Women who are 60 years of age with a residual life expectancy of more than 21 years have a 17% chance of incurring a fracture of the distal radius and an 8% chance of incurring a fracture of the proximal humerus.
Risk factors for distal radius fractures include family history of fragility fracture of the hip or distal radius, obesity in men, early menopause in women, and less menopausal discomfort during menstruation. Protective factors have been shown to include moderate daily activity level, late menopause, and hormone replacement therapy. No effect on risk has been noted with body mass index in women, smoking habits, oral contraceptive use, medical comorbidities, education level, visual capacity, hand dominance, or physical activity level described other than moderate (which was found to be protective); the lack of impact of these factors is noteworthy because several of them have a significant effect on osteoporosis risk.
Introduction and epidemiology of fragility fractures
Osteoporosis is a silent and painless disease until a fracture occurs with minimal trauma (ie, a fragility fracture) ( Fig. 1 ). The mainstay of treatment is detection and prevention. Osteoporosis is endemic in aging patients, with up to 50% of all men and women aged 80 years and older meeting the diagnostic criteria. By definition, osteoporosis is diagnosed and quantified by bone mineral density. However, deficient bone mineral density (BMD) in itself is not as great a burden on patients and the American health care system as its manifestation in a fragility fracture because BMD is only a surrogate parameter for an impending fracture (comparable with blood pressure for stroke). Osteoporosis poses a major health problem both clinically and economically because it currently has no cure and leads to an alarming increase in bone’s propensity to fracture.
The World Health Organization defines a fragility fracture as a fracture caused by injury that would be insufficient to fracture normal bone: the result of reduced compressive and/or torsional strength of bone. These injuries are most often seen in the hip, distal forearm, proximal humerus, or vertebrae (compression) as result of low-energy trauma (ie, a fall from a height of less than 1 m). These low-energy mechanisms represent 53% of all fractures in patients aged 50 years or older and 80% in patients aged 75 years and older. Nearly half of all American women will sustain a fragility fracture in their lifetime, and distal radius fractures are particularly considered to be a harbinger of future fragility fractures because they are frequently the first to occur as osteoporosis develops. The distal radius fracture is the most frequently diagnosed fracture in women, and the mean age of women with fractures of the distal radius is 64 years old. Women who are 60 years of age with a residual life expectancy of more than 21 years have a 17% chance of incurring a fracture of the distal radius and an 8% chance of incurring a fracture of the proximal humerus.
Risk factors for distal radius fractures include family history of fragility fracture of the hip or distal radius, obesity in men, early menopause in women, and less menopausal discomfort during menstruation. Protective factors have been shown to include moderate daily activity level, late menopause, and hormone replacement therapy. No effect on risk has been noted with body mass index in women, smoking habits, oral contraceptive use, medical comorbidities, education level, visual capacity, hand dominance, or physical activity level described other than moderate (which was found to be protective); the lack of impact of these factors is noteworthy because several of them have a significant effect on osteoporosis risk.
The definition and pathophysiology of osteoporosis
The World Health Organization defines osteoporosis as a BMD T-score less than −2.5, or a score more than 2.5 standard deviations less than the reference standard (the reference standard often used is the mean score for Caucasian women aged 20–29 years), as measured by dual-emission x-ray absorptiometry (DEXA). This score, thought to represent overall bone strength and subsequent risk of fracture, primarily integrates bone density and bone quality. The features contributing to this include trabecular microarchitecture, intrinsic material properties of bone tissue, and repair of microdamage to bone; all of these features have been shown to suffer as osteoporosis begins to develop.
The theory regarding the underlying process behind osteoporosis is still evolving. The disease involves both bone quality and quantity, rooted largely in unregulated bone remodeling. Remodeling causes transient weakness at areas of resorption but is physiologically necessary to repair areas of microdamage. When occurring in this physiologic capacity, the process is called targeted remodeling and is rarely pathologic. If, however, the bone is serving as a calcium reservoir in order to achieve calcium homeostasis in the serum or is being excessively remodeled for reasons other than to repair areas of microdamage, the term stochastic remodeling is used and the bone can become weaker over time. Higher remodeling activity leads to both excessive bone resorption by osteoclasts as well as a disproportionately high fraction of bone mass existing as unmineralized collagen matrix, which is weaker and less resistant to bending. In this context, attempts to slow stochastic remodeling are gaining traction as an increasing area of interest in osteoporosis prevention efforts. In addition to the declining quality of tissue, the pathologic process also involves changing bone microarchitecture, as osteoporotic trabeculae decrease in number, size, and thickness. The microhardness of bone, referring to its intrinsic strength, resistance to bending, and toughness, has been shown to be significantly less in osteoporotic tissue as result of these processes.
The relationship between menopause and the onset of osteoporosis has been well established. The link is largely based on estrogen’s inhibitory effect on osteoclasts. At menopause, occurring at approximately 51 years of age for most women, the relative estrogen deficiency that develops lifts this inhibitory effect, and the increased number, lifespan, and activity of osteoclasts leads to more and deeper bone remodeling sites. Up to 12% of bone mass is lost within the 5 to 7 years following the onset of menopause. Estrogen withdrawal also stimulates T cells to produce cytokines, such as tumor necrosis factor and interleukin-1, which stimulate osteoclast activity and inhibit osteoblasts. The rate of bone remodeling increases, beginning with osteoclastic resorption followed by osteoblastic laying down of new bone collagen matrix to be mineralized. As these steps accelerate, a larger proportion of bone is in the premineralized state, leading to overall weakening. This remodeling rate has been shown to double during early menopause and triple within 10 to 15 years after menopause, leading to profound clinical consequences.
Evaluation and indications for treatment
Osteoporosis screening has become increasingly popular in recent decades, especially since measures to prevent osteoporosis-related fractures now exist. The United States Preventive Services Task Force has established a grade B recommendation that all women aged 65 years and older, without previous known fractures or reasons for secondary osteoporosis, should obtain a DEXA scan of the hip and lumbar spine to establish a baseline BMD score ( Table 1 ). The evidence currently does not exist to support the same recommendation for men. If osteoporosis or osteopenia is found on a DEXA scan, some experts also recommend a limited workup for other systemic causes of (secondary) osteoporosis (eg, multiple myeloma, endocrine disorders, malabsorption syndromes, liver disorders, osteomalacia, hyperparathyroidism, and so forth), which can be ruled out by basic blood tests and serum electrophoresis. Baseline calcium and vitamin D levels should also be measured.
| Normal | BMD is within 1 standard of deviation of a normal young adult (T-score at −1.0 and more) |
| Osteopenia | BMD is between 1.0 and 2.5 standard deviation less than a normal young adult (T-score between −1.0 and −2.5) |
| Osteoporosis | BMD is more than 2.5 standard deviations less than that of a normal young adult (T-score less than −2.5) |
Once these studies have been completed, criteria have been established to assess the strength of bone and its subsequent susceptibility to fracture. Tools such as the Fracture Risk Algorithm (FRAX) tool estimates a patient’s 10-year risk of sustaining both a hip fracture and major fracture of an upper extremity or vertebral compression based on BMD and weighted clinical risk factors. It is based on the theory that although bone mass is a key component of the risk of fracture, other factors contribute to this risk, including liability to fall, presence of arthritic or skeletal conditions, and so forth, which operate independently of BMD. A comprehensive assessment of all these factors should be used in calculating the global risk of fracture. The input parameters are weighted according to a multivariate algorithmic model built based on meta-analyses studying the clinical impact of each of the risk factors. It is an accessible and self-explanatory questionnaire that is available online for no cost.
Box 1 lists the parameters included in the FRAX tool. Of note, several of these criteria have been shown to influence the risk of fracture in a dose-dependent manner, whereas the available FRAX tool includes them in a binomial (yes/no) capacity. Currently, the tool has not been developed in sufficient detail to accommodate these specific modifications, and the clinician must use his or her judgment when interpreting the fracture probability obtained from the calculation tool. For example, a patient with 3 previous fractures has a higher probability of subsequent fracture than a patient with a history of only one previous fracture, despite the tool’s failure to accommodate for this difference.
| Age | Rheumatoid arthritis |
| Sex | >3 Alcohol drinks per day |
| Race | Secondary osteoporosis |
| Weight | Smoking status |
| Height | Parent with hip fracture |
| Previous fracture | Femoral neck BMD score |
| Glucocorticoid Use |
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