Keeping you up-to-date on recent headlines in orthopedics.

Hip fracture rates decline in Canada . . . Standardized rates of hip fracture have steadily declined in Canada since 1985, with a more rapid decline between 1996 and 2005 and a more marked decrease among individuals age 55 to 64 years, according to a report in the August 26 issue of the Journal of the American Medical Association (JAMA). Osteoporosis is a common bone-thinning disease that predisposes individuals to fractures, according to background information in the article. "Because the prevalence of osteoporosis increases with age, the global burden of osteoporosis is projected to rise markedly over the next few decades as the number of elderly individuals increases," the authors write. "The incidence of hip fractures is an index of osteoporosis burden and the potential impact of preventive efforts in the population." William Leslie, MD, of the University of Manitoba (Winnipeg, Manitoba), and colleagues analyzed nationwide hospitalization data from the Canadian Institute for Health Information for 1985 to 2005. A total of 570,872 individuals were hospitalized for hip fracture during this time period.
Over the 21 years, age-adjusted rates of hip fracture declined 31.8% in females and 25% in males. The largest percentage decrease was observed among individuals age 55 to 64 years; hip fracture rates decreased by almost one-half in females and about one-third in males in this age range. Detailed analyses identified a more rapid decline beginning around 1996. "For the overall population, the average age-adjusted annual percentage decrease in hip fracture rates was 1.2% per year from 1985 to 1996 and 2.4% per year from 1996 to 2005," the authors write. The authors noted that the decline began before the widespread availability of bone density testing or pharmacological treatments for osteoporosis, and there is little evidence to suggest that improvements in physical activity, calcium intake, vitamin D status or prevention of falls are responsible. "Overweight and obesity are epidemic in modern societies and may contribute to reduced fracture rates," they write.

Scientists uncover immune system's role in bone loss . . . A new University California, Los Angeles (UCLA) study sheds light on the link between high cholesterol and osteoporosis and identifies a new way that the body's immune cells play a role in bone loss. Published Aug. 20 in the journal Clinical Immunology, the research could lead to new immune-based approaches for treating osteoporosis. Affecting 10 million Americans, the disease causes fragile bones and increases the risk of fractures, resulting in lost independence and mobility. Scientists have long recognized the relationship between high cholesterol and osteoporosis, but pinpointing the exact mechanism connecting the two has proved elusive. "We've known that osteoporosis patients have higher cholesterol levels, more severe clogging of the heart arteries and increased risk of stroke. We also knew that drugs that lower cholesterol reduce bone fractures, too," explained Rita Effros, professor of pathology at the David Geffen School of Medicine at UCLA. "What we didn't understand was why." In the study, UCLA researchers focused on low-density lipoprotein (LDL), the so-called "bad" cholesterol. They examined how high levels of oxidized LDL affect bone and whether a type of immune cell called a T cell plays a role in the process. Using blood samples from healthy human volunteers, the team isolated the participants' T cells and cultured them in a dish. Half of the T cells were combined with normal LDL the rest was combined with oxidized LDL. The scientists stimulated half of the T cells to mimic an immune response and left the other half alone. The resting and the activated T cells emitted a chemical that stimulates cells whose sole purpose is to destroy bone. Called RANKL, the chemical is involved in immune response and bone physiology. The T cells switched on the gene that produces RANKL. The chemical also appeared in the animals' bloodstream, suggesting that the cellular activity contributed to their bone loss. The next step will be exploring methods to control T cell response to oxidized LDL in an effort to develop immune-based approaches to prevent or slow bone loss, Effros says. The study was funded by the National Institute on Aging, the National Institute of Allergy and Infectious Diseases and the National Heart, Lung and Blood Institute.

Access to America's Orthopaedic Services Act of 2009 introduced in the Senate . . . The Access to America's Orthopaedic Services Act of 2009 (AAOS Act), S. 1548, was recently introduced in the U.S. Senate by Senators Benjamin Cardin (D-Maryland) and Richard Burr (R-North Carolina). S. 1548 compliments legislation already introduced in the House of Representatives by Representatives Gene Green (D-Texas) and Michael Burgess, MD (R-Texas). "Congress has a responsibility to act to increase educational and training efforts, identify gaps in access to care, and help standardize accreditation for specialized care and transplants" Senator Cardin said. The American Association of Orthopaedic Surgeons (AAOS; Rosemont, Illinois) has long championed this legislation, which will bring greater awareness and promote research and new surgical methods to orthopedic surgeons. "This is an important development for the orthopedic community and our patients," said AAOS Council on Advocacy Chair, Peter Mandell, MD. "We commend Senators Cardin and Burr for their leadership on improving the ability of patients to access affordable, quality orthopaedic care." The budget-neutral AAOS Act offers solutions to lowering the cost of treating bone and joint conditions — with a current annual domestic price tag of $849 billion. "The effects of musculoskeletal disease can be physically debilitating and very painful for patients. It also costs our nation billions of dollars each year in treatment and care. As a large number of Americans get older, good bone health will need to be a top priority for our country. I'm pleased to work with the AAOS and Senator Cardin on this important legislation," said Burr. "Bone loss, joint pain, and debilitating trauma are among the many forms of musculoskeletal diseases and conditions that are the leading causes of disability in the United States today. Such problems account for more than one-half of all chronic conditions in people over 50 years of age. Despite such widespread affliction, there is an inherent lack of awareness in the public and the medical community about bone and joint health. It's costing us billions of dollars each year in medical and hospital costs, work loss, and outright pain," said Cardin.

Navigation-assisted bone tumor surgery may lead to better resection, function . . . Performing bone tumor resection using a navigation system can improve the accuracy of the surgical resection and help preserve limb function, according to researchers from Korea. "Under navigated guidance, three-dimensional anatomy of the tumor and the surrounding normal tissue can be visualized during surgery," said Hwan-Seong Cho, MD. "Precise control of the resection margin is possible, enabling us to achieve the resection margin determined preoperatively. In selected patients, this technique can be helpful in increasing the accuracy of surgical resection and in reducing the functional impairment." Cho and his colleagues studied patients with a total of 11 primary bone tumors or solitary bone metastases who underwent bone tumor resection and joint preservation limb surgery using a navigation system at Seoul National University College of Medicine since 2005. Preoperatively, the patients had malignant fibrous histiocytoma of bone, high-grade chondrosarcomas, Ewing's sarcomas, osteosarcomas, and solitary bone metastases from rectal or thyroid cancers. Surgeons used a navigation system during four internal hemipelvectomies, two partial sacrotomies and five joint preserving limb salvage procedures. They performed joint preserving limb surgery if the following conditions were met: the tumor was located in the metaphyseal region; the preoperative chemotherapy was estimated to be effective as evidenced by imaging studies; and the remaining epiphysis was expected to be more than 1 cm long after tumor resection with a 1 cm to 2 cm-surgical margin. The navigation system took a mean time of almost 51 minutes to set-up, and the investigators followed the patients for a mean of 18.5 months. The investigators discovered that the mean registration error was less than 1 mm. "The distances from the tumor to the resection margins on the pathologic examination were in accordance with those of the preoperative plans," Cho said. The patients had a mean Musculoskeletal Tumor Society functional score of 28 points, and the investigators found no cases of local recurrence at the latest follow-up.

— Compiled by Holland Johnson, MDD