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AAOS Now

Published 8/1/2010

Second Look— Clinical News and Views

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.

Ultrasound and “tennis elbow”
A study in the American Journal of Sports Medicine (AJSM) (June) finds that the size of intrasubstance tears and presence of a lateral collateral ligament tear on ultrasound can be used to guide treatment for lateral elbow tendinopathy. The authors examined 62 elbows (34 right, 28 left) in 62 patients (30 male, 32 female) with a clinical diagnosis of lateral elbow tendinopathy. They identified a positive correlation between the presence of a lateral collateral ligament tear (p < 0.0001), the size of the largest intrasubstance tear (p < 0.0001), and a poor outcome. A negative correlation was found between the amount of hypoechogenicity (p = 0.0009) and a poor outcome. No correlation was found with age, sex, side, duration of symptoms, thickness of tendon, or amount of neovascularity.

VTE risk factors and race
A study in the American Journal of Hematology (July) finds significant differences between white and black patients regarding demographic and baseline characteristics as risk factors for venous thromboembolism (VTE). The researchers prospectively collected data from 2,397 consecutive consenting adults (2,002 white, 395 black) diagnosed with VTE at seven centers from August 2003 to March 2009. A significantly higher proportion of black patients had pulmonary embolism (PE) compared to white patients, along with a significantly higher mean body mass index. However, compared to white patients, a significantly lower proportion of black patients had recent surgery, trauma or infection, family history of VTE, and documented thrombophilia. Black patients were significantly more likely to have hypertension, diabetes mellitus, chronic renal disease and dialysis, HIV, and sickle cell disease.

Reducing postoperative infection rates
According to data from a retrospective cohort study in the Journal of the American Medical Association (JAMA) (June 23/30), adherence reported on individual Surgical Care Improvement Project (SCIP) measures is not associated with a significantly lower probability of postoperative infection, but adherence to composite measures is. The authors reviewed cases from 398 hospitals of 405,720 patients (69 percent white and 11 percent black; 46 percent Medicare patients; and 68 percent elective surgeries) who were discharged between July 1, 2006 and March 31, 2008.

Hospital performance on three original infection-prevention measures (S-INF-Core) and all six infection-prevention measures (S-INF) was aggregated into two separate all-or-none composite scores. Based on 3,996 documented postoperative infections in the patient cohort, the authors found that the S-INF composite process-of-care measure predicted a decrease in postoperative infection rates from 14.2 to 6.8 per 1,000 discharges; however, the S-INF-Core composite process-of-care measure predicted a decrease in postoperative infection rates from 11.5 to 5.3 per 1,000 discharges, which was not a statistically significantly lower probability of infection. None of the individual SCIP measures was significantly associated with a lower probability of infection.

HAM as scaffolding for cartilage repair
Data from a study published in Cell and Tissue Banking (May) suggest that human amniotic membrane (HAM) may be used as a scaffold for cartilage regeneration. The authors isolated chondrocytes from human articular cartilage, cultured them on the chorionic basement membrane side of HAMs, and used the HAMs with chondrocytes in 44 in vitro human osteoarthritis cartilage repair trials. Chondrocytes cultured on the HAM grew on the chorionic basement membrane layer, but not on the epithelial side and expressed type II collagen but not type I, indicating that they had not de-differentiated into fibroblasts. Additionally, in vitro repair experiments on osteoarthritic cartilage showed formation of new tissue expressing type II collagen.

Return to sports after hip resurfacing
A study in AJSM (June) finds that sports activity after total hip resurfacing is possible, but that in general, a patient’s level of sports activity is likely to decrease. The authors asked 138 consecutive patients (152 hips) to complete a standardized questionnaire 2 years after hip resurfacing. Preoperatively, 98 percent of those questioned participated in sports activities, and at 2-year follow-up, 98 percent of patients participated in at least 1 sports activity. The number of sports activities per patient decreased from 3.6 preoperatively to 3.2 postoperatively. Additionally, intermediate- and high-impact sports showed a significant decrease while low-impact sports showed a significant increase. Overall, 82 percent of patients felt no restriction while performing sports.

Predicting potential for cartilage defect development
Baseline bone area may be linked with the likelihood of cartilage defect development at the medial and lateral tibial sites, according to research in Arthritis & Rheumatism (July). A prospective study of 341 participants with a mean age of 63 years found that baseline bone area positively predicted cartilage defect development at the medial and lateral tibial sites and that cartilage volume loss at the medial tibial site was also positively predicted by baseline bone area. Baseline subchondral bone mineral density positively predicted cartilage defect development at the medial tibial site only and was not associated with loss of cartilage.

Higher sepsis rates among black patients
According to a study in JAMA (June 23/30), severe sepsis is more likely to develop in black patients than in white patients due to higher infection rates and a higher risk of acute organ dysfunction. An analysis of infection-related hospitalizations from the 2005 hospital discharge data of seven states and infection-related emergency department visits from the 2003–2007 National Hospital Ambulatory Care Survey (total: 2,261,857 discharges) found that 381,787 (16.8 percent) severe sepsis cases. Black patients had a 67 percent higher age- and sex-standardized severe sepsis rate than did white patients and an 80 percent higher standardized mortality. Black patients were found to have both a higher infection rate and a higher risk of acute organ dysfunction development.

Researchers find a genetic cause of clubfoot
A study in American Journal of Human Genetics (July 9) identifies a potential common genetic cause for clubfoot. A chromosomal microarray screening of 66 patients with an inherited form of clubfoot showed abnormalities in a region of chromosome 17 in four patients. Three of the patients had small recurrent DNA duplications, and one had a small recurrent DNA deletion on chromosome 17. When the same tests were run on 10 family members of the three patients with the duplications, researchers found that all of the family members who had clubfoot and the duplication were male, and one female family member with the duplication had hip dysplasia but not clubfoot. Orthopaedic surgeons may consider using the same screening test on children who have inherited clubfoot and may be at risk of hip abnormalities.

Patients stop taking osteoporosis medication
A report released by SDI Health LLC (a provider of data analysis for the healthcare industry) finds that many patients who are prescribed drugs for osteoporosis stop taking their medication within the first year. At 6 months, 49 percent of new alendronate patients had discontinued taking the drug, and 61 percent had discontinued therapy at 12 months. In addition, 54 percent of patients taking risedronate sodium had discontinued therapy by 6 months, and 64 percent had stopped at 12 months. Only 47 percent of patients prescribed the once-a-month version of risedronate sodium had discontinued therapy by 6 months, but 63 percent had discontinued at 12 months. Finally, 57 percent of patients prescribed ibandronate sodium had stopped after 6 months, with 70 percent stopping at 12 months.