High blood sugar, obesity increase risk for surgical site infection

Two recent studies in the July issues of the Journal of Bone and Joint Surgery (JBJS) looked at surgical site infections and hyperglycemia, the technical term for high blood glucose, or high blood sugar. According to the first study "Relationship of Hyperglycemia and Surgical-Site Infection in Orthopaedic Surgery," high blood sugar is a concern during the post-traumatic and post-operative period and it may help to preoperatively identify a population of patients with musculoskeletal injuries who are at significant risk for infectious complications.

Nearly, one-third of patients who are admitted to the hospital without a history of diabetes have hyperglycemia, which is associated with a longer hospital stay, higher rates of admission to the intensive care unit (ICU), and increased mortality.

Study authors reviewed data on patients 18 years or older who had isolated orthopaedic injuries requiring acute operative intervention. Patients diagnosed with diabetes or who were in the ICU were not included in the study.

Of 790 patients, there were 268 open fractures (if the bone breaks in such a way that bone fragments stick out through the skin, or a wound penetrates down to the broken bone), and 21 surgical-site infections (SSIs) at 30-day follow-up. Age, race, comorbidities, injury severity, and blood transfusion were not associated with SSI at 30 days.

Specific study details: SSIs developed in 13 of 294 patients (4.4 percent) who had more than one glucose value greater than or equal to 200 mg/dL and 8 of 496 patients (1.6 percent) without more than one glucose value greater than or equal to 200 mg/dL. The authors concluded that hyperglycemia was an independent risk factor for thirty-day SSI in orthopaedic trauma patients without a history of diabetes.

This study suggests that recognition of the relationship between hyperglycemia and infectious complications may substantially influence post-operative care of orthopaedic patients. Large, prospective, randomized studies are necessary to further delineate this relationship.

A second study featured in the July 18 issue of JBJS, found that diabetes and morbid obesity increased the risk of infection following hip and knee replacement. Authors of "Obesity, Diabetes, and Preoperative Hyperglycemia as Predictors of Periprosthetic Joint Infection" analyzed 7,181 hip and knee replacements and found that 52 post-operative joint infections occurred within the first year, and that the infection rate increased from a .37 percent in patients with a normal body index to 4.66 percent in the morbidly obese group. Normal BMI was defined as a body mass index (BMI) of less than 25, while morbid obesity was defined as more than 40. (BMI is a calculation that is determined using height and weight).

Diabetes more than doubled the risk of a post-operative joint infection independent of obesity. The infection rate was the highest in morbidly obese, diabetic patients.

For patients without a diagnosis of diabetes at the time of surgery, there was a trend toward a higher infection rate in association with a pre-operative glucose level of more than 124 mg/dL.

The authors suggest that identifying and/or treating hyperglycemic patients preoperatively, especially if they are obese, would help patients achieve a better outcome by avoiding complications caused by infection. In addition, identifying patients with undiagnosed diabetes would be important for their overall long-term prognosis. Authors further conclude that the benefits of joint replacement should be carefully weighed against the incidence of postoperative infection, especially among the morbidly obese patients.

Full JBJS July 18 Table of Contents

• A Multicenter Randomized Control Trial Comparing Single Row Fixation in Arthroscopic Cuff Repair
• Suture Number Determines Strength of Rotator Cuff Repair
• Spica Casting for Pediatric Femur Fractures: A Prospective, Randomized Controlled Study of Single-leg versus Double-leg Spica Casts
• Reliability of predictors for Screw Cutout in Peritrochanteric Hip Fractures
• The prognosis for Improvement in Comfort and Function after the Ream and Run Arthroplasty for Glenohumeral Arthritis
• Evaluation of Muscle Size and Fatty Infiltration with MRI 9-11 years Following Hamstring Harvest for ACL reconstruction
• Adverse Outcomes in Hip Arthroplasty: Long Term Trends
• The Safety of Controlled Hyoptension for Shoulder Arthroscopy in the Beach Chair Position
• Simple Guidelines for Efficient Referral of Soft Tissue Sarcomas: a population-based evaluation of adherence to guidelines and referral patterns
• Selective Plantar Fascia Release for Non-healing Diabetic Plantar Ulcerations
• A Clove-Hitch Suture Method for Small Caliber Tendon Ends
• Arthroscopic Bankart Repair and Capsular Shift for Recurrent Anterior Shoulder Instability: Functional Outcomes and Identification of Risk Factors for Recurrence
• The Benefits of Implant Removal from the Foot and Ankle

The Journal of Bone & Joint Surgery has been the most valued source of information for orthopaedic surgeons and researchers for over 100 years and is the gold standard in peer-reviewed scientific information in the field. JBJS is published twice a month online and in print. Abstracts are available online at (http://www.jbjs.org). Contact Michelle Hache for general information on JBJS at mhache@jbjs.org

For more AAOS News, visit the News Bureau

Follow AAOS on Twitter and Facebook

More information about the AAOS

More than one in four Americans have bone or joint health problems, making them the greatest cause of lost work days in the U.S. When orthopaedic surgeons restore mobility and reduce pain, they help people get back to work and to independent, productive lives. Orthopaedic surgeons provide the best value in American medicine in both human and economic terms and access to high-quality orthopaedic care keeps this "Nation in Motion." To learn more, to read hundreds of patient stories or to submit your own story, visit anationinmotion.org