Published 7/1/2009

Second Look

If you missed these Headline News Now items the first time around, AAOS Now gives you a second chance to review them. Headline News Now—the AAOS thrice-weekly, online update of news of interest to orthopaedic surgeons—brings you the latest on clinical, socioeconomic, and political issues, as well as important announcements from AAOS.

Surgical treatment for spondylolisthesis more effective
study in the Journal of Bone & Joint Surgery—American (June 1, 2009) finds that patients treated surgically for degenerative spondylolisthesis and associated spinal stenosis tend to have greater pain relief and function at 4-year follow-up than those treated nonsurgically. The randomized study of 607 surgical candidates from 13 centers found that 66 percent of the patients randomized to receive surgery received it by 4 years, and 54 percent of those randomized to receive nonsurgical care received surgery by 4 years. In the observational cohort, 97 percent of those who chose surgery received it and 33 percent of those who chose nonsurgical care eventually received surgery as well. An as-treated analysis found that previous clinically relevant advantages of surgery at 2 years continued to be maintained at 4 years.

Percutaneous vertebroplasty after vertebral compression fractures
Percutaneous vertebroplasty in treatment of chronic vertebral compression fractures is associated with reduction in back pain and overall health improvement, according to a
study in the Journal of Bone & Joint Surgery—British (JBJS-B) (June 2009). A prospective study of 30 consecutive patients who received percutaneous vertebroplasty for 62 vertebral compression fractures between August 2002 and August 2005 found an immediate, significant, and lasting reduction in average and worst back pain. Asymptomatic leakage of cement was found in 47 of 58 (81 percent) of treated vertebrae, and two minor complications occurred.

No need for imaging for low-back pain
study in the Archives of Internal Medicine (May 25, 2009) finds that although rapid imaging for uncomplicated low-back pain is rarely indicated, many elderly Medicare patients receive imaging services within a month of getting a diagnosis of low-back pain. An analysis of claims for 35,039 Medicare fee-for-service beneficiaries found that 28.8 percent of patients underwent imaging within 28 days, and an additional 4.6 percent underwent imaging between 28 and 180 days. The most common form of initial imaging was radiographs (88.2 percent). White patients received higher levels of imaging than patients of other races. Compared with no incentives, clinical quality–based incentives were associated with less advanced imaging; incentive combinations that included satisfaction measures were associated with more rapid and advanced imaging.

Reducing hip fracture rates
According to
data presented at the European Symposium on Calcified Tissue (ESCT), daily doses of both vitamin D and calcium can reduce the rate of hip fracture in older people. Researchers reviewed data from seven randomized trials covering 68,500 patients aged 47 to 107 years. At approximately 16-month follow-up, the rate of hip fracture was reduced by 20 percent among subjects who took vitamin D (10ug; 400 IU) and calcium (1,000 mg) together, regardless of age, gender, and fracture history. Fracture rate in other bones was reduced by 10 percent.

Heartburn medications linked to hip fracture
Data presented
at the Digestive Disease Week 2009 meeting shows that certain acid-reducing heartburn drugs may be linked to increased risk of hip fractures. An analysis of data from nearly 40,000 patients taking acid-reducing drugs and more than 130,000 controls found increased risk of hip fracture among patients taking proton pump inhibitors and histamine-2 receptor antagonists. Patients aged 50 to 59 years who had been on proton pump inhibitors for more than 2 years displayed the greatest increase in fracture risk.

MOM hips associated with reduced T lymphocytes
study in JBJS-B (June 2009) finds significant differences in the levels of metal ions in the blood of patients with metal-on-metal (MOM) hip replacements. A cross-sectional study of 164 patients (101 men, 63 women) with either MOM hip resurfacing (n=106), or ceramic-on-ceramic or metal-on-polyethylene hip replacements (n=58) found reduced peripheral blood counts of T-lymphocytes in particular and B-lymphocytes when compared with control patients who had hip replacements that did not produce metal wear debris. All patients were younger than 65 years of age and had a preoperative diagnosis of osteoarthritis with no pre-existing immunologic disorders. Circulating levels of metal ions, especially cobalt, explained the variation in absolute lymphocyte counts for almost all lymphocyte subsets.

PE uncommon with aspirin prophylaxis after TJR
At 90 days postoperative, pulmonary embolism (PE) had developed in only 3 of 4,253 total joint replacement (TJR) patients (2,050 total knees, 2,203 total hips) between November 2002 and November 2007. Overall, 4,060 patients received aspirin only as chemical prophylaxis; 46 were mistakenly given low molecular weight heparin initially, which was stopped and changed to aspirin; 136 received no chemoprophylaxis; and 11 patients received warfarin because of a previous history of pulmonary embolism. The
study appeared in JBJS-B (May 2009).

TZDs can increase fracture risk in diabetes patients
Data presented at the 69th Scientific Sessions of the American Diabetes Association finds that type-2 diabetes patients taking the thiazolidinediones (TZDs) pioglitazone or rosiglitazone are at a greater risk of bone fracture than similar patients who do not take TZDs. An analysis of patient records of 69,047 patients taking TZDs from January 2006 to July 2008 and 75,352 controls found that both male and female patients taking TZDs had higher fracture rates than controls. No difference in fracture risk was found between patients taking rosiglitazone and those taking pioglitazone.

Fracture rates increase after bariatric surgery
Data presented at the annual meeting of the Endocrine Society show that patients who have bariatric surgery experience extensive bone turnover and loss of bone density and have an increased risk of fractures afterward. A review of 97 patients who underwent bariatric surgery from 1985 to 2004 at a single facility found that 21 patients experienced 31 fractures at mean follow-up of 7 years. When compared with overall local fracture incidence rates, the standardized incidence ratio for the first fracture at any site was 1.8, and was highest at the foot and hand, although fractures also occurred at the hip, wrist, spine, and humerus.

Portal administration of anesthetic
study in JBJS-B (May 2009) finds that administration of bupivacaine around arthroscopic portals may be as effective in relieving pain as intra-articular injection. The authors randomized 137 knee arthroscopy patients to receive 20 mL of 0.5 percent bupivacaine by injection either into the joint or around the portals. They found no statistical difference in pain relief between the groups and suggested that the portal technique could be used to avoid possible chondrotoxic effects of intra-articular bupivacaine injections.

Torn gloves increase risk of SSI
A Swiss
study in the Archives of Surgery (June 2009) finds that surgical gloves that develop holes during a procedure may increase risk of surgical site infection (SSI) in patients who are not given prophylactic antibiotics. Of 4,417 surgical procedures performed at a single facility during 2000 and 2001, 677 involved known glove perforations. Researchers found 188 instances of SSI, including 51 (7.5 percent) in procedures performed with perforated gloves and 137 (3.9 percent) in procedures where gloves remained intact. If antimicrobial prophylaxis was used, glove perforation was not associated with surgical site infection after other, related factors were considered.

PET scans can diagnose prosthetic knee joint infection
Data presented at the annual meeting of the Society of Nuclear Medicine show that positron emission tomography (PET) scans can accurately detect infections in prosthetic knee joints more than 90 percent of the time. Fluorodeoxyglucose-PET imaging in patients after clinical evaluation and laboratory data proved inconclusive for infection correctly diagnosed 8 of 9 cases of infection and 38 of 41 cases absent of infection, for a 92 percent accuracy rate.

Postfracture complications linked to increased mortality
In a retrospective cohort
study published online in the Journals of Gerontology Series A, researchers found that, among 195 long-term care residents (153 women, 42 men) with hip fractures (1999–2006), postfracture complications were associated with increased mortality after hip fracture. Overall, 76.9 percent of participants had died at median follow-up of 1.4 years. Male nursing home residents were nearly twice as likely to die compared with female residents. Mortality was 70 percent greater among residents with a pressure ulcer or pneumonia within 6 months of hip fracture.

Hyperkyphosis may predict increased mortality
study published in the Annals of Internal Medicine (May 19, 2009) finds that hyperkyphosis may predict an increased risk for death, independent of underlying spinal osteoporosis and the extent and severity of vertebral fractures among older, white women. The prospective cohort study of 610 women (age range = 67 to 93 years) from four clinical centers across the United States found that, in age-adjusted models, each standard deviational increase in degree of kyphosis carried a 1.14-fold increased risk for death. On stratification by prevalent vertebral fracture status, only women with prevalent fractures were at increased mortality risk from hyperkyphosis, independent of age, self-reported health, smoking, spine bone mineral density, number of vertebral fractures, and severe vertebral fractures.

Three genes associated with Paget’s Disease
Presenters at ESCT
have found three additional genes associated with Paget’s disease. Researchers examined 750 patients with Paget’s disease and found that 104 had a family history of the condition. In an analysis of those patients and 1,000 healthy controls, three genes were found to have an association with Paget’s disease. Previously, only one gene had been linked to the disorder.

Genetics and osteoporosis
German researchers say they have identified a molecular mechanism that regulates the equilibrium between bone formation and bone resorption. Their
study, published online in the EMBO Journal, found two different forms of a gene switch—a short isoform that enhances the proliferation and activity of the osteoclasts and a long isoform that suppresses the formation of osteoclasts. An imbalance in the ratio between the long and short forms may play a role in the development of osteoporosis.

Women underestimate fracture risk
Research presented at the ESCT finds that women at high risk of fracture often underestimate their vulnerability. A
review of 25,334 European women participating in the Global Longitudinal Registry of Osteoporosis in Women trial found that 64 percent of those with a history of fracture considered their risk of future fracture to be lower than other women of the same age. Among women diagnosed with osteoporosis, more than half believed that they were not at increased risk for fracture. Further, 75 percent of nearly 18,000 women with a high FRACTURE Index considered themselves not to be at greater risk for fracture than other women their age.

Exercise good for low back pain
Research presented
at the annual meeting of the American College of Sports Medicine finds that patients with chronic nonspecific low back pain (CLBP) who exercise 4 days per week may show greater improvement in outcome measures than those who exercise only 2 or 3 days per week. In a randomized trial, all rehabilitation groups showed significant improvement over the control group at 12 weeks; patients who exercised 4 days per week demonstrated the greatest improvement in outcome measures—especially in pain and quality of life.