Published 5/1/2014

Second Look—Clinical News and Views

Synovial fluid biomarkers and PJI
Study findings published in Clinical Orthopaedics and Related Research (CORR) online suggest that synovial fluid biomarkers may help diagnose periprosthetic joint infection (PJI). The prospective, diagnostic study included 95 patients who were being evaluated for a revision hip or knee arthroplasty. Researchers found five biomarkers in the synovial fluid—human alpha-defensin 1-3, neutrophil elastase 2, bactericidal/permeability-increasing protein, neutrophil gelatinase-associated lipocalin, and lactoferrin—that correctly predicted the Musculoskeletal Infection Society classification of all patients in the study, with 100 percent sensitivity and specificity for diagnosis of PJI.

Statins and VTE in TKA, THA patients
When statins are combined with conventional prophylactic therapy for venous thromboembolism (VTE), they significantly reduce the risk of VTE after total knee arthroplasty (TKA) and total hip arthroplasty (THA), according to data presented at the AAOS 2014 Annual Meeting. Of 417 randomly selected patients who underwent TKA or THA during a 7-year period at a single institution, the control group (n = 221) was not on statin therapy, while the statin group (n = 196) had already been taking statins before surgery and continued taking hypercholesterolemia medications at the same dosage after surgery. At minimum 11-month follow-up, 32 VTE events occurred in the control cohort compared to just 15 in the statin group.

Value of disk herniation surgery
Study data published in CORR (April) suggest that increased worker earnings after disk herniation surgery may offset increased medical costs associated with that surgery. Based on data from the National Health Interview Survey, patients who undergo disk herniation surgery earn an average of $1,925 more per year than those who don’t and miss 3 fewer days of work per year than those who are treated nonsurgically.

Aseptic SSI protocol for THA patients
Data presented at the AAOS 2014 Annual Meeting suggest that use of a comprehensive aseptic protocol may reduce the likelihood of surgical site infection (SSI) for high-risk patients undergoing THA. The prospective cohort study of 774 patients undergoing primary or revision hip arthroplasty at a single center found that the overall SSI rate among protocol patients was 0.39 percent—significantly lower than the institution’s historic rate and than that of six previously published reports. The same aseptic protocol consisted of preoperative mupirocin nasal ointment and surgical-site chlorhexidine wipes, modified instrument care, perioperative prophylactic vancomycin and cefazolin, and surgical site skin preparation with chlorhexidine, alcohol, and iodophor.

Blood biomarkers for concussion
Study data from Sweden published online in JAMA Neurology indicate that blood biomarkers may indicate concussion in athletes. The multicenter, prospective cohort study of 228 hockey players found that concussed players had increased levels of the axonal injury biomarker total tau and the astroglial injury biomarker S-100 calcium-binding protein B, compared against baseline, preseason values. The highest biomarker concentrations of total tau and S-100 calcium-binding protein B were measured immediately after a concussion and decreased during rehabilitation.

Team approach for complex spinal reconstructions
Study findings published in Spine Deformity (March) indicate that adopting team-based methods in the operating room (OR) and for managing coagulopathy may significantly reduce perioperative complication rates for patients who undergo complex spinal reconstructions for adult spinal deformity. The retrospective, consecutive case review covered 40 consecutive control patients and 124 consecutive patients treated with a dual–attending surgeon approach, a live multidisciplinary preoperative screening conference, and the intraoperative protocol. The control group had a 52 percent complication rate, compared to a 16 percent complication rate in the intervention group; rates for return to the OR during the perioperative 90-day period, wound infection requiring débridement, deep vein thrombosis/pulmonary embolism, and urinary tract infection requiring antibiotics were also lower in the intervention group.

Stem cell use in Achilles tendon repair
Rat study data published in Foot and Ankle International (March) suggest that embedding stem cells directly into a suture may enhance healing after Achilles tendon repair. The randomized study involved 108 rat tendons repaired with suture only, suture plus injection of mesenchymal stem cells (MSCs), or suture loaded with MSCs. Both MSC groups were associated with increased ultimate failure strength compared to controls. In the MSC injection cohort, ultimate failure strength decreased significantly at 28 days compared to 14 days. Histology score in the suture-loaded group was significantly improved compared to the other groups.

Metal ion levels with MOM hip implants
A study in The Journal of Bone & Joint Surgery (JBJS, March 19) compares metal ion levels for patients who underwent THA using 28 mm and 36 mm metal-on-metal (MOM) hip devices and 28 mm metal-on-polyethylene (MOP) hip devices. The blinded, randomized trial of 105 patients assigned to one of the three treatment groups found that—with the exception of chromium in erythrocytes—cobalt and chromium ion levels in all blood sample types were significantly lower in patients who received MOP devices than in either of the two MOM groups at 5-year follow-up. Cobalt in serum and erythrocytes showed significant increases from 2 years to 5 years in the 36 mm MOM group, but similar increases were not seen in the 28 mm MOM group.

Opioid use after trauma surgery
According to findings published in JBJS (March 19), patients who continue to use opioid pain medication after surgery for musculoskeletal trauma are more likely to have psychological distress, less effective coping strategies, and greater symptoms and disability, compared to patients who do not take opioids. Based on outcome data for 145 surgical trauma patients, patients who scored higher on catastrophic thinking, anxiety, posttraumatic stress disorder, and depression questionnaires were significantly more likely to report taking opioid pain medications 1 to 2 months after surgery, regardless of injury severity, fracture site, or treating surgeon.

Revision TKA in younger patients
Study findings published in JBJS (April 2) suggest that, compared to older patients, patients younger than age 50 have a significantly higher risk of undergoing revision TKA within the first year after surgery due to PJI or aseptic mechanical failures. Based on data from the California Patient Discharge Database, investigators identified all patients who underwent primary unilateral TKA between 2005 and 2009 and used multivariate analysis to perform risk adjustment for important clinical and demographic variables. At one year after primary TKA, 983 (0.82 percent) of 120,538 patients had undergone revision due to PJI, while 1,385 patients (1.15 percent) had undergone revision surgery due to aseptic mechanical failure. Patients younger than age 50 were 1.8 times more likely to have PJI than patients 65 years or older. Younger patients also had a 4.7 times greater risk of aseptic mechanical failure.

Trauma center closures
A study in The Journal of Trauma and Acute Care Surgery (April) finds a strong association between closure of trauma centers in California and increased mortality for patients with injuries. The retrospective review of data on all adult patient visits for injuries at Level I and II nonfederal trauma centers in California from 1999 through 2009 found that the odds of inpatient mortality increased by 21 percent among trauma patients who experienced an increased drive time to their nearest trauma center as a result of a trauma center closure.

Opioid analgesics in EDs
Findings from a study in Academic Emergency Medicine (March) suggest that growth in the prescribing of opioid analgesics in U.S. emergency departments (EDs) has outpaced a rise in pain-related complaints over the last 10 years. Based on data from the National Hospital Ambulatory Medical Care Survey between 2001 and 2010, the percentage of overall ED visits where any opioid analgesic was prescribed increased from 20.8 percent to 31.0 percent. The percentage of visits for painful conditions during the period increased from 47.1 percent in 2001 to 51.1 percent in 2010. Overall, use of schedule III through V agents increased from 12.6 percent in 2001 to 15.6 percent in 2010, an absolute increase of 3.0 percent and a relative increase of 23.8 percent.

The prescribing of hydrocodone, hydromorphone, morphine, and oxycodone all increased significantly during that period, while codeine and meperidine use declined. Prescribing of nonopioid analgesics did not change significantly, increasing from 26.2 percent in 2001 to 27.3 percent in 2010.

ACL reconstruction and risk of OA
Data presented at the Specialty Day meeting of the American Orthopaedic Society for Sports Medicine suggest that adolescents who undergo anterior cruciate ligament (ACL) reconstruction may be at long-term increased risk of osteoarthritis (OA) in their injured knees. The research team evaluated 29 patients aged 12 years to 16 years who underwent reconstruction for symptomatic unilateral ACL rupture using bone-patellar bone-tendon or hamstring tendon autograft. At a mean follow-up of 14 years, 7 months, reconstructed knees displayed significantly more osteoarthritic changes compared to the non-involved contralateral knee.

Implant labeling may reduce errors, costs
Data presented at the AAOS Annual Meeting suggest that a computer-based labeling and compatibility system may decrease costs and waste associated with TKA. The 1-year prospective study involved six orthopaedic surgeons who performed 461 TKAs while using an e.Label system, in which a standardized electronic label is created by scanning a barcode on each arthroplasty implant. Findings were compared against a retrospective analysis of a 1-year period before implementation of the e.Label system. Before the labeling system was implemented, 83 implants (5.7 percent) were wasted; after it was implemented just 4 implants (0.9 percent) were wasted. During the study period, the e.Label system also helped avoid implantation of one wrong-sided implant.

Septic shock protocols
Data from a study published in The New England Journal of Medicine (March 18) suggest that protocol-based resuscitation of patients with septic shock diagnosed in the ED may not improve outcomes. The randomized, multicenter trial involved 439 patients assigned to protocol-based early goal-directed therapy, 446 patients asigned to protocol-based standard therapy, and 456 patients assigned to usual care. No significant differences were found between cohorts in 90-day mortality, 1-year mortality, or need for organ support.

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)