October 2004 Bulletin

Point of View

Orthopaedic surgeons and bone densitometry

Mary I. O’Connor, MD Ann Babbitt, MD

Evaluation of bone density continues to be important in musculoskeletal health. The evolution of bone densitometry has resulted in differences in technologies, acquisition techniques, reference databases, reporting methods, and terminology. These differences may have adverse effects on patient care and the exchange of scientific information.

The International Society for Clinical Densitometry (ISCD) is a not-for-profit multidisciplinary professional society. Its mission is to enhance both knowledge about and the quality of bone densitometry and to provide guidelines for densitometry testing. Currently, 80 percent of ISCD members are physicians and 20 percent are densitometry technologists. More than 30 disciplines are represented, including: nephrologists, endocrinologists, radiologists, rheumatologists, gynecologists, densitometry technologists, and nurses.

The ISCD reflects an optimal approach to the care and diagnosis of patients with metabolic bone disease across a broad span.

ISCD Recommendations

The ISCD periodically holds Position Development Conferences, a process whereby a panel of experts makes recommendations based on reviews of the scientific literature by the ISCD’s Scientific Advisory Committee. On Nov. 1, 2003, the ISCD approved a series of guidelines on indications for bone mineral density (BMD) testing, scoring, equipment, and diagnosing. Guidelines relevant to orthopaedic surgeons are shown in the box accompanying this article.

Orthopaedic surgeons should recognize the need for BMD testing in all adults with fragility fractures and in those adults with secondary contributors to low bone density.

Central dual energy X-ray absorptiometry (DXA) is the “state-of-the-art” diagnostic test for bone density quantitation. DXA evaluates BMD in the posteroanterior spine L1-L4 and the femoral neck, trochanter and total hip region to determine bone density. Peripheral testing has value in estimating fracture risk, but can be misleading in clinical settings.

In postmenopausal women and in men who are older than 50 years, the diagnosis of osteoporosis is based on clinical criteria (if the patient has had a fragility fracture) and/or the World Health Organization’s criteria of a DXA T-score of 2.5 or less in the spine, hip (except Ward’s area) or 33 percent radius. Fracture or low bone density or both can indicate osteoporosis. In patients younger than 50 years of age, the terms “low bone density” or “low bone strength” are more appropriate to describe the predisposition to bone fragility.

Densitometry is an essential tool to help us identify and quantify susceptibility to fracture in our patients. This quantification of bone mass will more accurately and specifically direct our prevention and treatment recommendations for individuals with low bone strength.

More information is available in the Journal of Clinical Densitometry (Volume 7, Number 1, 2004) and at the ISCD Web site: http://www.iscd.org/

Ann Babbitt, MD, is an orthopaedist in private practice in South Portland, Maine. She can be reached at ababbitt@maine.rr.com Mary I. O’Connor, MD, is chair of the AAOS Women’s Health Issues Committee. She can be reached at oconnor.mary@mayo.edu

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