Published 2/1/2012

Second Look- Clinical News and Views

Risk factors for ION after spinal fusion

A study published in Anesthesiology (January 2012) identifies risk factors for ischemic optic neuropathy (ION), a common cause of perioperative visual loss as a complication of spinal fusion surgery. The multicenter case-controlled study of 80 adult patients with ION and 315 adult controls without ION after spinal fusion surgery found that male sex, obesity, Wilson frame use, longer anesthetic duration, greater estimated blood loss, and decreased percent colloid administration were significantly and independently associated with ION after spinal fusion surgery.

Reducing post-thrombotic syndrome in DVT patients
A Norwegian randomized controlled study published online in The Lancet (Jan. 7, 2012) suggests that catheter-directed thrombolysis (CDT) using alteplase can reduce the development of post-thrombotic syndrome in patients treated for acute deep vein thrombosis (DVT). Of 189 patients, 90 were randomly assigned to receive CDT and 99 served as controls. At 24-month follow-up, post-thrombotic syndrome had developed in 37 patients in the experimental group and in 55 patients in the control group, corresponding to an absolute risk reduction of 14.4 percent. Iliofemoral patency after 6 months was reported in 58 CDT patients versus 45 control group patients; 20 bleeding complications were related to CDT, including three major and five clinically relevant bleeds. The authors suggest that additional CDT should be considered in patients with a high proximal DVT and low risk of bleeding.

Hyaluronic acid versus placebo for ankle OA
According to a study in the Journal of Bone & Joint Surgery—American (JBJS-A) (Jan. 4, 2012), a single injection of low-molecular-weight, non–cross-linked hyaluronic acid has no advantages over placebo for treating osteoarthritis (OA) of the ankle. The randomized, double-blind, placebo-controlled study involved 56 patients with ankle OA, who received either a single intra-articular injection of 2.5 mL of low-molecular-weight, non–cross-linked hyaluronic acid or a single intra-articular injection of 2.5 mL of normal saline solution. Mean American Orthopaedic Foot & Ankle Society (AOFAS) scores in the hyaluronic acid group improved from baseline by 4.9 points at 6- and 12-week follow-up, while mean AOFAS scores in the placebo group initially worsened by 0.4 points at 6 weeks, then improved by 5.4 points at 12 weeks.

Cooling sore muscles and athletic performance
A review of 35 trials with a mean sample size of 19 published in Sports Medicine (January 2012) suggests that athletes who return to play immediately after cooling an injury are likely to be at a performance disadvantage. Of the 25 studies that reported strength, 75 percent reported a decrease in strength immediately following cooling. Six studies found that cooling adversely affected speed, power, and agility-based running tasks, although two studies found that the effect was negated after a short rewarming period. Evidence of the effect of cooling on isolated muscular endurance was conflicting. Most of the studies looked at cooling durations longer than 20 minutes.

Liberal transfusion strategy after hip fracture surgery has no benefits
A study published online in the New England Journal of Medicine (Dec. 29, 2011) finds that a liberal blood transfusion strategy may not improve short-term outcomes for patients who undergo surgery for hip fracture. The authors randomly assigned 2,016 patients 50 years or older who had either a history of or risk factors for cardiovascular disease, and whose hemoglobin level was less than 10 g/dL after hip-fracture surgery to either a liberal transfusion strategy (hemoglobin threshold of 10 g/dL) or a restrictive transfusion strategy (symptoms of anemia or at physician discretion for a hemoglobin level of less than 8 g/dL). At 60-day follow-up, no significant differences were found in primary outcome rates (death or an inability to walk across a room without human assistance), rates of in-hospital acute coronary syndrome or death, or mortality rates. Rates of other complications were similar in the two groups.

Graphite, not protein, is primary lubricant in MoM implants
A study in Science (Dec. 23, 2011) investigates the reasons for lower wear in metal-on-metal (MoM) hip implants compared to metal-on-polyethylene (MoP) devices, and finds evidence for graphitic material in the tribologic layer in retrieved MoM hip replacements. The researchers say that this finding may enable the production of bearings that are less susceptible to corrosion and wear. It also raises the issue of the physiologic effects of graphitic wear debris.

No clear preference for C. difficile agent
According to data in the Annals of Internal Medicine (Dec. 20, 2011), no antimicrobial agent stands out as clearly superior for the initial cure of Clostridium difficile infection. The retrospective review of 11 trials (low- to moderate-strength of evidence) covering 1,463 patients and comparing agents such as metronidazole, vancomycin, fidaxomicin, and placebo found no one antimicrobial agent was significantly superior for initial cure of C. difficile infection. Recurrence was less frequent with fidaxomicin than with vancomycin.

Improving postfracture care
According to a study in the Canadian Medical Association Journal (Dec. 19, 2011), a mailed notification program targeting primary care physicians can improve patients’ postfracture care. The randomized, controlled trial of 4,264 men and women age 50 years or older who had recently reported major fractures and who had not undergone recent bone mineral density (BMD) testing or treatment for osteoporosis found that 30.3 percent of women and 19.0 percent of men in the physician notification group underwent BMD testing or started pharmacologic treatment for osteoporosis within the following 12 months, while 15.8 percent of women and 7.6 percent of men in the usual treatment group received similar treatment. No significant benefit was noted for adding patient notification.

Low iron levels increase blood clot risk
According to a British study in the journal Thorax (Dec. 14, 2011), low iron levels may increase a patient’s risk of blood clots. Elevated plasma levels of coagulation factor VIII have previously been established as a strong risk factor for pulmonary emboli and deep venous thromboses. The study found an inverse association between factor VIII and serum iron that persisted after adjustment for age, inflammation, and von Willebrand factor. Low serum iron levels were also associated with venous thromboemboli (VTE)—an association that appeared to depend on factor VIII, because once adjusted for factor VIII, the association between VTE and iron was no longer evident.

Using locked angular-stable IM nails for humeral fractures
According to a study in the JBJSA (Dec. 7, 2011), patients managed with locked angular-stable intramedullary (IM) nailing of two-part surgical neck proximal humeral fractures via an articular entry point had reliable fracture-healing, favorable clinical outcomes, and little residual shoulder pain. The multicenter retrospective observational study of 38 patients with Neer two-part surgical neck proximal humeral fractures who were managed with locked angular-stable IM nail fixation found that all fractures had healed at mean 20-month follow-up. The mean follow-up Constant score was 71 points, with a mean age-adjusted Constant score of 97 percent. The mean Constant pain score was 13 (15 = no pain). The mean forward flexion was 132 degrees. All fractures but one healed with a neck-shaft angle of greater than or equal to 125 degrees.

Training program for THA patients
According to a Norwegian study published online in Arthritis Care & Research (Dec. 14, 2011), patients who take part in a training regimen after total hip arthroplasty (THA) for OA show improved physical function over control patients. Researchers randomized 68 patients to either a training group (12 70-minute physical therapy sessions) or a control group. Compared to baseline measures taken 3 months postoperatively, 66 percent of patients in the training group and 15 percent of patients in the control group had improved their walking distance to 50 meters or more at 5 months after surgery. At 12 months after surgery, patients in the training group showed greater improvement in walking distance and stair climbing abilities than controls.

Early revision surgery more likely as surgeons learn to use new implants
According to a study published online in Clinical Orthopaedics and Related Research (Dec. 9, 2011), patients who receive a new artificial knee joint design are more likely to need early revision surgery than patients who receive an implant with which surgeons are more familiar. A study of mandatory registry data for total knee arthroplasty (TKA) procedures performed between 1998 and 2004 for 69 centers in Finland found that the first 15 patients implanted with a new endoprosthesis design were at 48 percent greater risk for early revision than patients who received a conventional design. The increased risk did not extend past the first 15 surgeries with the new model.

Steroid use increases risk of ON
According to data presented at the annual meeting of the American College of Rheumatology, even a short period of glucocorticoid (GC) use can increase patients’ risk of osteonecrosis (ON). The case-controlled study of 172 ON cases (164 men) and 1,581 matched controls (1,553 men) treated during fiscal years 1999 through 2006 found 43 ON cases (25.0 percent) and 82 controls (5.2 percent) who had at least one GC prescription. Compared to no GC use, the risk of ON was elevated in all strata regardless of how recent the use. The risk of ON was also elevated for all categories of cumulative use, even for patients who had discontinued the drug a year or more previously. Nearly all (92 percent) ON cases developed in the hip.

Recruiters favor younger docs
Healthcare Finance News
reports that survey data released by the Medicus Firm, a physician recruiting company, suggest that recruiters may be more interested in hiring younger physicians than seasoned veterans. According to survey data, physicians at least 16 years out of training applied to approximately 7.95 opportunities and received an average of 2.12 offers while those within 15 years of their training applied to approximately 8.25 positions and received an average of 7.88 offers during the same period.

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)