Archive | June 2015

Three Steps Cut Surgical Site Staph Infections after Joint Replacement

Surgical site infections (SSIs) can cancel out the benefits of surgery, and they’re the number-one cause of hospital readmissions following surgery. The most prevalent pathogenic culprit is Staphylococcus aureus.

A study of patients undergoing cardiac or hip or knee arthroplasty surgery at 20 hospitals in nine states found that the following protocol reduced the rate of complex (deep incisional or organ-space) S. aureus SSIs by about 40% overall—and by about 50% among patients undergoing hip or knee arthroplasty (an absolute difference of 17 infections per 10,000 joint replacements):

  • Preoperative screening of nasal samples
  • Intranasal mupirocin and chlorhexidine baths for up to five days prior to surgery for patients testing positive for methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA)
  • Perioperative prophylaxis with vancomycin plus cefazolin or cefuroxime for MRSA carriers and perioperative cefazolin or cefuroxime for all others

Rates of complex SSIs decreased most substantially among patients who were fully adherent to the protocol, although only 39% of the subjects experienced implementation of all the steps. Adherence rates were especially low among those who presented in urgent and emergency settings.

In an editorial accompanying the study, Preeti Malani, MD wrote that “although the absolute difference [in infections] seems modest, each complex SSI prevented is clinically meaningful.”

Joint Replacement Associated with Postop Weight Loss in Obese Patients

The relationships between body weight and joint replacement are debated often in the orthopaedic community. Some surgeons are so concerned about perioperative complications related to obesity that they recommend delaying arthroplasty in obese patients until weight loss is achieved.

But what are the likelihood and implications of weight changes after joint replacement? For those answers, in the June 3, 2015 edition of JBJS, Ast et al. tracked differences in body mass index (BMI) among nearly 7,000 patients for two years after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Establishing a 5% BMI change as “clinically meaningful,” the researchers found that:

  • Most patients (73% of those undergoing THA and 69% of those undergoing TKA) experienced no weight change.
  • Female patients, patients with a higher preoperative BMI, and those undergoing TKA were most likely to lose weight after surgery.
  • Weight loss was associated with improved clinical outcomes after THA, but not after TKA. However, weight gain in general was associated with inferior clinical outcomes.
  • Those with better preoperative functional status were less likely to gain weight after THA or TKA.

Countering conventional wisdom that weight loss after total joint arthroplasty is unlikely, Ast. Et al. emphasize that “obese patients who undergo total joint arthroplasty are more likely than non-obese patients to lose weight after surgery.”