AAOS Now

Published 4/1/2012

Second Look—Clinical News and Views

New tool to reduce wrong-site surgeries
The Joint Commission has released a new tool designed to help healthcare organizations identify, measure, and reduce risks in key processes that can contribute to a wrong-site surgery. The Targeted Solutions Tool™ can help identify and eliminate risks in all phases of the surgery process. The tool is available to all Joint Commission-accredited hospitals.

Biomarker linked to knee OA
A study in the Journal of Biological Chemistry (Feb. 10) finds that the biomarker deamidated cartilage oligomeric matrix protein (D-COMP) is specific to joint site. Mass spectroscopy was used to analyze cartilage in 450 participants in the Johnston County (N.C.) Osteoarthritis (OA) Project. The presence of D-COMP was associated with radiographic hip OA severity, but not with knee OA severity; in contrast, total COMP was associated with radiographic knee OA severity, but not hip OA severity.

Mortality after pelvic fracture
According to a German study published online in Clinical Orthopaedics and Related Research, predictors of mortality after pelvic fracture include male sex, severe multiple trauma, and major hemorrhage. The authors prospectively collected data on 5,340 patients listed in the German Pelvic Trauma Registry between April 30, 2004 and July 29, 2011. At a median 2 days after trauma, 238 patients (4 percent) had died. The main cause of death was massive bleeding (34 percent), predominantly from the pelvic region. Nonsurvivors were characterized by a higher incidence of complex pelvic injuries, less isolated pelvic ring fractures, lower initial blood hemoglobin concentration and systolic arterial blood pressure, and higher injury severity scores.

UK: Monitor patients with MoM hip implants closely
The United Kingdom’s Medicines and Healthcare Products Regulatory Agency (MHRA) has updated its advice to surgeons regarding the monitoring of patients with metal-on-metal (MoM) hip replacements. A new MHRA Medical Device Alert calls for annual monitoring for the life of the implant, as a precautionary measure. Previous recommendations were for 5 years of monitoring.

In related news, two feature articles published in the British Medical Journal look at the issue of MoM hip implants. The authors of the first article point out that a systematic review of 29 studies of hip resurfacing found that none of the studies met a preferred benchmark of a less than 10 percent revision rate at 10-year follow-up. The author of a second article states that ions released by MoM implants have been associated with increased likelihood of cancer, although she admits that no studies have directly linked MoM implants with cancer.

Concussion effects last longer in adolescents
According to a study in Brain Injury (March), neurophysiological deficits are present for at least 6 months following a concussion, and adolescents are more sensitive than children or adults to the consequences of concussions. A cross-sectional study of 96 athletes (aged 9–12 years, n = 32; 13–16 years, n = 34; adults, n = 30), half of whom had a sport-related concussion, found that concussed athletes had significantly lower amplitude on the P3b component of a standardized neuropsychological assessment tool than noninjured teammates. In addition, adolescent athletes showed persistent deficits in working memory.

Compressive muscle loading after SCI
According to Osteoporosis International, electrically induced compressive muscle loading could reduce bone loss after spinal cord injury (SCI). The pilot study of 41 individuals included 27 patients with SCI and 14 participants without SCI who provided normative data. After 3 years of training, SCI patients who participated in a program providing 150 percent body weight [BW] compressive load applied to one leg while the opposite leg received 40 percent BW had more bone mineral density (BMD) in the treated femur than in the contralateral femur, and significantly more BMD than in the femurs of patients in either of the other arms of the study.

PRP preparation, methodology lack consistency
Two studies in the Journal of Bone and Joint Surgery—American (Feb. 15) call into question the methods used to determine the efficacy of platelet-rich plasma (PRP) for orthopaedic purposes. In the first, the authors examined three different PRP separation methods and found that the content and concentrations of platelets, white blood cells, and growth factors for each method of separation varied significantly. The second study, a meta-analysis of23 randomized trials and 10 prospective cohort studies, found a lack of consistency in outcome measures across all studies.

Instrument sterility
An article by the nonprofit Center for Public Integrity raises concerns about retained tissue on surgical instruments. Several cases of patient harm—including that of a patient who underwent rotator cuff surgery—have been linked to the use of unsterile instruments. Experts suggest that a rise in the popularity of minimally invasive surgery has led to the development of complex medical instruments that are more difficult to sterilize than their simpler counterparts.

Patch testing for orthopaedic patients?
A study in Archives of Dermatology (Feb. 20) suggests that patients with a clinical history of metal hypersensitivity should be patch tested for allergic contact dermatitis before receiving orthopaedic implants. The medical chart review of 72 patients with potential metal hypersensitivity at a single center found 31 patients who were patch tested prior to implantation. Of these, 21 had positive results reflecting allergy to one or more metals used in the implant. In all cases, the positive results influenced the decision-making process of the referring surgeon. The metals most often associated with a positive patch test were nickel, cobalt, palladium, and chromium.

Trunk control may be key component in ACL injury
A case-control study in the American Journal of Sports Medicine (PreView March 1) looks at trunk control as a factor in anterior cruciate ligament (ACL) injury. Movie captures of 20 athletes performing a one-legged landing maneuver that resulted in a torn ACL were compared to those of a matched group of athletes performing a similar maneuver that did not result in ACL disruption. Participants who sustained an ACL injury landed with their center of mass far posterior to their base of support at initial ground contact than controls (average 38 cm more posterior).

Serotonin may be linked to cancer-related bone loss
According to a study in American Journal of Physiology—Endocrinology and Metabolism (Feb. 21), serotonin production may be linked to secretion of parathyroid hormone related protein (PTHrP), which acts as a driver of osteoclastic bone demineralization. Through a series of experiments involving mice, cow cells, and human breast cancer cells, the authors demonstrated a link between serotonin production and the expression of PTHrP. Lactating mice genetically modified to prevent them from making serotonin efficiently had significantly less PTHrP in their mammary glands compared to normal mice. In addition, mouse and cow mammary cells treated with serotonin increased their expression of the gene responsible for PTHrP production. Treating three human breast cancer cell lines with serotonin increased expression of the PTHrP gene by 20-fold, and the gene Runx2, which has been shown to be involved in metastatic breast cancer and bone loss.

These items originally appeared in AAOS Headline News Now, a thrice-weekly enewsletter that keeps AAOS members up to date on clinical, socioeconomic, and political issues, with links to more detailed information. Subscribe at www.aaos.org/news/news.asp (member login required).