Diagnosis and Treatment of Osteoporosis

What Orthopaedic Surgeons Need to Know

Elizabeth G. Matzkin, MD; Marlene DeMaio, MD; Julia F. Charles, MD, PhD; Corinna C. Franklin, MD

Disclosures

J Am Acad Orthop Surg. 2019;27(20):e902-e912. 

In This Article

Diagnosis

Because osteoporosis is unlikely to be symptomatic before the first fracture, accurate risk assessment is essential (Table 3).[11–13] As in most cases, the first step in diagnosis and assessment of osteoporosis is a detailed history and physical examination to elicit whether the patient has any relevant risk factors. Important points in the history include previous fractures, diseases associated with bone loss, chronic diseases, exercise, medications, alcohol and tobacco use, falls and fall risk, diet, and family history. For females, the number of pregnancies, lactation, menstrual history, and onset of menopause should be recorded. Menopause before age 40 years is considered early. Surgical history should include inquiring about oophorectomy or castration and parathyroid or adrenal procedures. Physical examination should include height and weight with assessment of loss of height. The spine should be inspected for kyphosis. The neurologic examination should include balance and mobility.[14] Sarcopenia and lower extremity muscle mass should be noted.[14] Signs of secondary osteoporosis should be noted, including hypogonadism, hyperthyroidism, diabetes mellitus, malnutrition, and liver disease.

With regard to laboratory testing, serum calcium and 25-hydroxyvitamin D may be checked. Other tests can help identify causes of secondary osteoporosis and include thyroid and parathyroid studies, complete blood count, urine calcium, protein electrophoresis, and testosterone (in men).[8,10]

The mainstay of testing for osteoporosis is DXA. DXA measures the areal BMD at the proximal femur and lumbar spine and compares it to the BMD of age-matched reference controls and of young adults. A typical DXA report includes the BMD of the intertrochanteric and trochanteric regions of the femur, the femoral neck, and lumbar vertebrae 1 to 4, as well as the T and Z scores for each region. The T score compares the patient's BMD to that of a young adult population (an average 30-year-old woman); the Z score compares the patient's BMD to an age, sex, and race or ethnicity-matched reference population. Both are reported as SDs from the mean BMD of the reference population. Indications for BMD testing are shown in Table 4.[12,13,15,16]

The World Health Organization defines osteoporosis as a T score below −2.5 in postmenopausal women and men older than 50 years. Osteopenia is defined as a T score between −1.0 and −2.5.[8,17] Osteoporosis can also be diagnosed on fracture criteria, that is a low trauma hip or spine fracture, regardless of BMD. In premenopausal women and men aged <50 years, osteoporosis cannot be diagnosed on densitometric criteria alone, and the Z score of −2.0 or lower is used to categorize these patients as having low bone density for chronologic age.[11]

High-resolution peripheral quantitative CT is an emerging technology that is able to evaluate the microarchitecture of bone. High-resolution peripheral quantitative CT evaluates distal skeletal sites and is able to provide details such as volumetric BMD of both cortical and trabecular bone. Studies continue to determine its applicability to clinical practice.[18]

A BMD is recommended for all women aged 65 years and older and postmenopausal women younger than 65 years with increased risk determined by a formal clinical risk assessment. Data are not sufficient to recommend routine screening for men to prevent osteoporotic fractures.[12] Higher-risk men including those aged 70 years or older and those aged 50 to 69 years with associated risk factors (eg, low body weight, previous fracture, smoking) should be considered for BMD testing.[15] The prevalence of osteoporosis in US white men does not approach that of 65-year-old women until age 80 years.[19]

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