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AAOS Now

Published 2/1/2015

SECOND LOOK – CLINICAL NEWS AND VIEWS

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)

Diagnosing compartment syndrome
Data from a study in The American Journal of Sports Medicine (online) support the use of anterior compartment intramuscular compartment pressure (IMCP) as a diagnostic indicator of chronic exertional compartment syndrome (CECS). cohort study of 40 men aged 21 to 40 years (20 with CECS symptoms of the anterior compartment and 20 asymptomatic controls) found that, compared to controls, symptomatic participants had higher IMCP immediately upon standing at rest, as well as during and after a weight-bearing treadmill exercise. The greatest difference corresponded to the period of maximal tolerable pain. Sensitivity and specificity of ICMP were consistently higher than existing criteria with improved diagnostic value.

Risk factors for cardiac complication after TJA
A study in The Journal of Bone & Joint Surgery (Dec. 17, 2014) focused on risk factors for cardiac complications within 30 days after primary total joint arthroplasty (TJA). Based on data on 46,322 patients from the American College of Surgeons National Surgical Quality Improvement Program data set, the overall cardiac complication rate per total knee and total hip arthroplasty patients was 0.33 percent (n = 153) at 30-days postoperative. Across both cohorts, risk factors for cardiac complication included age of 80 years or older, hypertension requiring medication, and history of cardiac disease. Among patients who had a cardiac complication, 79 percent experienced it within 7 days of surgery.

Liposomal bupivacaine for pain after knee arthroplasty
Data presented at the 2014 annual meeting of the American Association of Hip and Knee Surgeons suggest that an injection of iposomal bupivacaine into the tissue surrounding the knee during surgery may reduce recovery time and increase patient satisfaction in the hours following knee arthroplasty. Based on an evaluation of 216 knee arthroplasty patients, half of whom received continuous femoral nerve block and half liposomal bupivacaine injection, researchers found that patients in the bupivacaine group had better pain relief for up to 2 days after surgery, and better knee function than those in the nerve block cohort.

(Search poster #57.)

Risk factors for complications after ORIF of wrist fractures
A study in the Journal of Hand Surgery (December 2014) looks at risk factors for postoperative complication and mortality following open reduction internal fixation (ORIF) of distal radius fracture (DRF). The retrospective review of 1,673 cases of closed DRF managed with internal fixation found that, at 30-day follow-up, the overall incidence of any early complication was 3 percent. Major morbidity was 2.1 percent, including 4 patient deaths, and minor morbidity was 1 percent. The most common major morbidity was a return to the operating room; the most common minor morbidity was urinary tract infection. ASA class III or IV, dependent functional status, hypertension, and myocardial infarction/congestive heart failure were not significant risk factors for any early complication. Overall, the inpatient group had a 10.0 percent complication rate; the outpatient group had a 1.3 percent complication rate.

Nonsurgical treatment of pediatric type I open fractures
Findings from a study in the Journal of Children’s Orthopaedics (online) suggest that forearm or tibia type I open fractures in pediatric patients may often be treated nonsurgically with little risk of infection. The retrospective chart review of 40 patients younger than 18 years who were treated nonsurgically with irrigation and debridement, followed by closed reduction and casting, found no reported or documented infections, but one case of a retained foreign body and one case of delayed union. All patients eventually had complete bony union, with minimal residual angulation in both upper and lower extremities at last follow-up.

Regenerating the meniscus
According to a sheep study published in Science Translational Medicine (Dec. 10, 2014), a 3-D printed scaffold may have efficacy for the regeneration of meniscal tissue. The authors used MRIs of the undamaged knee to generate a scaffold made of polycaprolactone—a biodegradable polymer. The scaffold was then infused with connective growth factor (CTGF) and transforming growth factor β3 (TGFβ3). The sequential delivery of the two proteins induced endogenous stem progenitor cells to differentiate and synthesize zone-specific type I and type II collagens, regenerating the meniscus with zone-specific matrix phenotypes reminiscent of the native meniscus.

IM pinning for displaced fifth metacarpal neck fractures
Data in Clinical Orthopaedics and Related Research (December 2014) suggest that antegrade intramedullary (IM) pinning may offer very short-term clinical advantages over percutaneous retrograde IM pinning for treatment of displaced fifth metacarpal neck fractures. The randomized, prospective study of 46 patients who had displaced fifth metacarpal neck fractures with an apex dorsal angulation greater than 30° found that patients treated with antegrade IM pinning displayed improved outcomes for all clinical parameters at 3-month follow-up, compared to patients treated with percutaneous retrograde IM pinning. At 6 months, no significant differences in outcomes between cohorts were found.

Deaths from superbugs
A report from the U.K.-based Review on Antimicrobial Resistance estimates that by 2050, 10 million deaths could potentially be attributable at least in part to antimicrobial resistance (AMR), including 317,000 deaths in North America. The projections were based on scenarios developed by two independent teams. Countries with high malaria, human immunodeficiency virus, or tuberculosis rates are likely to be at increased risk. The economic impact of AMR is projected to result in a worldwide gross domestic product loss of $100.2 trillion by 2050.

Risk of neuropathic pain in OA knee patients
A study in Arthritis Research & Therapy (online) suggests that meniscal lesions may be among the strongest risk factors for neuropathic pain (NP) in patients with knee osteoarthritis (OA). The cross-sectional, observational, pilot study of 50 knee OA patients with moderate to severe pain in the target knee found that 25 had PainDETECT scores ≤12 (unlikely NP), 9 had PainDETECT scores between 13 and 18 (uncertain NP), and 16 had PainDETECT scores ≥19 (likely NP). Although no difference in cartilage volume was found between groups, the presence of meniscal extrusion in both medial and lateral compartments and meniscal tears in the lateral compartment were significantly associated with increasing PainDETECT score. The presence of bone marrow lesions in the lateral plateau and the extent of the synovial membrane thickness in the lateral recess were also associated with increasing PainDETECT scores.