Osteoporosis and the Orthopaedic Surgeon: How to Prevent and Treat

John D. Kaufman, MD

Disclosures

Medscape Orthopaedics & Sports Medicine eJourn. 2001;5(2) 

In This Article

Who Needs Bone Density Testing?: Identifying Patients at Risk

Many factors increase the risk for osteoporosis, emphasizing a need for accurate predictive tools that can correctly target which populations are at risk. Understanding the basic mechanisms of bone loss is important to identifying some of the risk factors of osteoporosis, including fractures, genetics, and use of steroids.

Sirus Cooper, MA, DM, from the United Kingdom, discussed new types of risk factors. He reported on a study of 7086 families in whom risk factors were identified before and soon after birth. Three risk factors were identified: maternal tallness, below-average birth length, and children who grew in height at a rate below average. Each of these factors increased relative risk of hip fracture among these individuals once they reached adulthood.

Michael McClung, MD, of the Oregon Osteoporosis Center, examined the relationship between short-term changes in bone mineral density (BMD) and long-term BMD changes.[1] Using data from the EPIC study on 373 women, aged 45-59, he showed that BMD changes measured over 1 year generally provide a good prediction of the total BMD changes that will occur over the following 4 years. Based on this data, Dr. McClung suggested that women initially identified as "slow BMD losers" should be monitored via BMD tests at longer time intervals than women who have rapid bone loss after 1 year.

Robert Lindsey, MD, from the Helen Hays Hospital in New York, presented a paper on the effects of calcium and vitamin D on fracture incidence. Lindsey examined the control groups from several large clinical trials. These control subjects received only calcium and vitamin D. Of the 381 women who experienced an incident fracture, 19.2% of these women fractured again within 1 year. He concluded that patients taking only calcium and vitamin D who sustain a fracture are at immediate high risk for second fracture. A need for early pharmacologic therapy in these patients is needed to reduce the risk of subsequent fractures.

In a "meet the professor" session, Ken Faulkner, PhD, stressed the importance of looking at all risk factors, not just BMD, to accurately predict fracture risk. He recommended subtracting about 0.5 from the T-score for each risk factor to get a more accurate T-score for predicting fracture risk. In other words, if a patient had the risk factors of smoking and previous fracture, one would subtract 1.0 (0.5 + 0.5) from the measured T-score. If this patient had a measured T-score of -1.5 from a bone density test, then subtracting 1.0 from this would result in a revised score of -2.5. This T-score would call for more aggressive treatment.

Each of the speakers stressed the importance of recognizing that the first insufficiency fracture markedly increases the chance of future fractures. Vertebral fractures were also shown to be predictive of future fractures as well as an independent cause of increased mortality.[2] Unfortunately, many first fractures either go unrecognized or are not seen by clinicians as a reason to initiate treatment for future fracture prevention. Recent data from the Mayo Clinic show that only 5% of patients presenting with Colles' fractures receive evaluation and treatment for the underlying osteoporosis. Dan Baran, MD, noted that two thirds of all vertebral fractures are asymptomatic. As such, he stressed the importance of taking thorough patient histories and assessing any height loss in order to enable early diagnosis of vertebral fractures.

Genetics, as a risk factor for osteoporosis, is important in men and in women. Males with a family history of osteoporosis are likely to have below-average bone density. Eric Orwoll, MD,[3] from Portland, Oregon, a prominent researcher in this field, stressed the importance of not ignoring the risk of osteoporosis in men. He pointed out that osteoporosis in men is (1) common, accounting for 20% of all cases, (2) expensive, leading to a great economic burden, and (3) serious, as men with hip fractures have a higher mortality than women with hip fractures.

Men with low testosterone levels have an increased risk of osteoporosis.[4,5] Dr. P. Szulc and his colleagues from France measured estradiol levels in a cohort of 596 men, aged 51 to 85. They found that men with low levels of bioavailable estradiol were likely to have high bone turnover and low bone mineral density. Their data suggest that both androgen levels and estradiol levels may influence the development of osteoporosis in men.

Dr. L.E. Wehren and his colleagues from the University of Maryland examined why men have a higher mortality after hip fracture than women. They followed 804 community-dwelling men and women for 2 years following hip fracture. They found that the men were younger (79.5 vs 81.6 years old), had more baseline comorbidity, and had longer hospitalization (17.2 vs 14.3 days); however, men experienced fewer postoperative complications than women (1.4 vs 3.2). Men were more likely to have chest x-ray abnormalities (47.3% vs 37.3%) and lived a significantly shorter amount of time (517 vs 624 days) after fracture. Only 58% of the men were alive at 24 months compared with 77% of the women. They concluded that this increased vulnerability of men who fractured their hips is still not well understood and deserves further study.

Glucocorticoid-induced osteoporosis continues to be a major challenge in medicine.[6] Bone loss induced by steroids is rapid, but, fortunately, also reversible. Taking patients off glucocorticoids at any time in the course of their disease will significantly benefit their future outcome.

Even at low doses, glucocorticoids can significantly increase the risk of fracture. Studies show that even prednisone 2.5 mg daily, a so-called "safe dose," produces a 1.5-fold increase in the relative risk of fracture. Studies also show that fracture risk is extremely high in postmenopausal women and older men. As such, it is very important for clinicians treating their patients with glucocorticoids to access bone status at the beginning of treatment and introduce fracture prophylaxis early.

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