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Fig. 1 Representative images of tests used in the diagnosis of osteoporosis. A–B, A vertebral fracture assessment on a DXA scan would show vertebral height and any deformities. C, DXA scan of a hip.
Courtesy of Allison Hahr, MD

AAOS Now

Published 12/1/2015
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Andrew D. Bunta, MD

Meeting the Bone Health Challenge

Now that we, as orthopaedic surgeons, have agreed to do something about the bone health of our patients—in particular, older adult fracture patients—it's time to consider how we can become involved.

First, we must decide whether to take an advocacy role, to actively coordinate care, or to personally involve the orthopaedic team in ensuring proper bone health care. Many avenues are open to different practice settings, as previously noted. (See "Bone Health and the Challenge to Orthopaedic Surgeons," AAOS Now, October 2015.) The easiest and most pertinent way for any orthopaedic practice to become involved in improving bone health involves assessing and educating hospitalized fracture patients. Although an astute, committed hospital nursing staff can do this, a better response is a dedicated Advanced Practice Provider (APP) such as nurse practitioner, or physician assistant employed by the hospital or by the orthopaedic surgeon or group practice.

Such a program can identify the most at-risk population—older adults (50 years or older) with fragility fractures. In particular, hip fracture patients are most at risk for another devastating fracture. Starting with these patients enables the surgeon to develop an evaluation methodology and provide appropriate treatment to the most vulnerable fracture patients. Basic information regarding bone health issues could certainly be addressed with patients and their families.

The program can later expand to evaluating other inpatient fracture patients and then to fracture patients treated as outpatients under current national guidelines. Meanwhile, the orthopaedic surgeon can initiate and refine a referral system to other osteoporosis specialists (if desired). Or, an orthopaedist or group practice may provide its own evaluation and treatment of fracture patients, using an APP working with them in an outpatient setting.

The osteoporosis disease process
Historically, the most common descriptive terms associated with osteoporosis—namely postmenopausal and "senile"—might indicate that osteoporosis is a disease of older people. But a more recent understanding of this disease and its etiology has given rise to more appropriate classifications: primary and secondary, with their associated subgroups.

Primary osteoporosis includes both postmenopausal and premenopausal females and older males. Primary osteoporosis in males may have some basis in testosterone decline, just as postmenopausal cases in females are related to estrogen decline. Premenopausal disease may be associated with eating disorders and athletic amenorrhea, which can disturb normal sex hormone production, thus leading to increased fracture risk in younger women. As the clinical and basic science research worlds continue to elucidate genetic factors and mutations associated with this and numerous other disease processes, a clearer understanding of the role of family and hereditary relationships in osteoporosis may emerge.

Also included in primary osteoporosis groups are the following:

  • conditions associated with inflammatory disease processes, such as rheumatoid arthritis and systemic lupus erythematosus
  • endocrine abnormalities such as hyperparathyroidism, hyperthyroidism and, more recently, diabetes mellitus
  • cases associated with transplant patients

Secondary forms of osteoporosis are associated with conditions that usually do not manifest primarily as skeletal diseases. These include the following:

  • celiac disease and malabsorption syndromes
  • glucocorticoid-induced osteoporosis
  • lowered bone mass associated with estrogen inhibition drugs, such as aromatase inhibitors for breast cancer and androgen deprivation drugs used in prostate cancer patients

Basic evaluation
With this background, we can now consider the basic evaluation required during an initial orthopaedic intervention, such as fracture surgery or nonsurgical fracture management in some cases. Reasonable initial laboratory testing includes a complete blood count, basic chemistry panel (including a calcium level), and a 25-OH vitamin D value. These studies, which are now readily available in most hospital laboratories, are necessary as part of a preoperative evaluation of most surgical patients with fragility fractures.

Many individuals have deficient or insufficient vitamin D levels, which are easily treatable. So it seems sensible to identify this condition early, although there is clearly no harm in giving fracture patients 1000 IU to 2000 IU of vitamin D3 if serum levels are not readily available.

A comprehensive chemistry panel, including liver function tests, and/or a renal chemistry panel, including albumin and phosphorus levels, may be ordered for patients with extensive comorbidities. This is usually done by the evaluating medical or geriatric service.

Whether to initially order other laboratory studies that may have some bearing on the etiology of the osteoporosis associated with a patient's fracture has long been debated. Today, osteoporosis specialists such as endocrinologists, rheumatologists, and geriatricians, as well as many orthopaedic surgeons, believe that a more extensive workup (Table 1) can be postponed for 4 to 8 weeks following the fracture. At that time, the values of specialized tests are more reliable as the patient's inflammatory stress response to the initial injury eases.

Often, if hospital reimbursements are based on specific diagnosis-related group (DRG) payment levels, there may be reluctance by both hospitals and physicians to add more costs to any given hospitalization episode. The practical solution is to leave more extensive laboratory workups to a later date.

Imaging
Dual-energy X-ray absorptiometry, or DXA, evaluates bone density, but bone strength is a function of bone density and bone quality. Quantitative computerized tomography (QCT) can evaluate quality, but is often not readily available. As technology improves and QCT becomes less costly, it will probably play a larger role in diagnosing and treating osteoporosis.

Fig. 1 Representative images of tests used in the diagnosis of osteoporosis. A–B, A vertebral fracture assessment on a DXA scan would show vertebral height and any deformities. C, DXA scan of a hip.
Courtesy of Allison Hahr, MD

The classic diagnosis of osteoporosis requires a DXA scan T-score of –2.5 standard deviations or below (compared to a population of gender-matched, healthy 30-year olds), in either the lumbar spine or hip region. Nevertheless, there are numerous caveats to using absolute DXA values to make the diagnosis. Expert interpretation is necessary because arthritic changes in the spine or hip, for example, can falsely elevate values.

More important, most fragility fractures actually occur in patients with low bone mass and a DXA value of –1.0 to –2.4, defined as the osteopenic range. Many experts, including a task force from the American Society of Bone and Mineral Research, now support the necessity of pharmacologically treating all older patients with hip fragility fractures, presuming them to have osteoporosis as defined by the fracture occurrence.

This approach is valid, even without a DXA scan result, due to the devastating natural history of hip fractures in older adults and the strong likelihood for a future fracture. Thus, a threshold to treat may have a basis in more than absolute DXA T scores.

Obtaining a concurrent vertebral fracture assessment (VFA) by DXA is important, if it can be performed on the scanner for the routine DXA scan. Although the routine scan will estimate bone density, the VFA DXA will provide an actual lateral image of the thoracic and lumbar spine.

VFA DXA images can identify both clinical and asymptomatic compression fractures. Realizing the increased likelihood of further spinal compression fractures once that fragility fracture cascade has begun, clinicians can make better decisions and clearer treatment recommendations to patients and their families after a VFA.

This evaluation stage also includes the fracture risk assessment tool, or FRAX, developed by Professor John A. Kanis of the University of Sheffield and popularized by the World Health Organization. This online tool assists in defining which patients need pharmacologic treatment and will be discussed in a future article.

The appropriate age for obtaining initial DXA scans and the frequency of repeating DXA evaluations is under debate. The International Society of Clinical Densitometry (ISCD) supports ordering DXA screening studies for women age 60 or 65 years and men age 70 years. It also strongly recommends a DXA for any adult (age 50 or older) with a fragility fracture.

As for the frequency of studies, the ISCD supports current guidelines for Medicare patients, which cover bone density testing every 24 months, when ordered by a physician for a woman at risk for osteoporosis, or more frequently if medically necessary. These guidelines would also apply to the following patients:

  • women or men with a fragility fracture history
  • those with radiographs that indicate possible osteoporosis or vertebral fractures
  • those taking or initiating the use of glucocorticoid drugs
  • patients with primary hyperparathyroidism
  • those being monitored during osteoporosis drug therapy

A preoperative DXA scan and VFA for older patients who plan to have elective spine surgery with instrumentation or joint replacement surgery would also meet the medical necessity requirement. Although some experts have advocated annual DXA scanning follow-up for patients undergoing pharmacologic treatment for osteoporosis, many support testing every 2 years. However, the initiation of osteoporosis drug therapy or the start of a new agent or combination of agents to treat osteoporosis should trigger a follow-up DXA in 1 year to evaluate the patient's early response to the treatment protocol. Thereafter, bone density testing at 2-year intervals is appropriate.

A future article will cover dietary and lifestyle suggestions as well as basic pharmacologic treatment alternatives for patients. In addition, the important subject of bone mass accrual in the early decades of life will be addressed.

Andrew D. Bunta, MD, is an associate professor in the department of orthopaedic surgery at the Northwestern University Feinberg School of Medicine.

Editor's note: This is the second in a series of articles on osteoporosis and bone health. AAOS Now invites readers to share their experiences, pearls, and frustrations in the management of bone quality issues; email them to aaoscomm@aaos.org

Bottom Line

  • Orthopaedic surgeons can meet the bone health challenge in a variety of ways.
  • Osteoporosis may be either primary or secondary.
  • Basic evaluation studies include a complete blood count, basic chemistry panel (with calcium level), and a 25-OH vitamin D value, as well as DXA and VFA.
  • All older patients with hip fractures should be presumed to have osteoporosis as defined by the fracture occurrence and probably should be treated pharmacologically.

Additional Information:
Bone Health and the Challenge to Orthopaedic Surgeons