The Orthopaedic Supervisory of Sharp Memorial Hospital in San Diego has asked the Infection Prevention and Clinical Epidemiology Department to periodically distribute individual, surgeon specific, surgical site infection (SSI) rates.  Practices proven to minimize the risk of post-operative SSI include:  1) asking patients to shower or bathe with chlorhexidine(Hibiclens) for several days pre-op; 2) the administration of prophylactic antibiotics within 1 hour of incision (2 hours for Vancomycin); 3) using electric clippers (not a razor) to remove hair at the operative site if it will interfere with wound closure; 4)to identify and treat all infections remote to the surgical site before elective operation.

Pre-operative colonization screening for Methicillin-sensitive (MSSA) and Methicillin-resistant (MRSA) Staphylococcus aureus, the application of 2% nasal Mupirocin (Bactroban) in the anterior nares twice a day for 5 days for those colonized and assuring that patients colonized with MRSA receive the appropriate preoperative prophylaxis are further strategies to reduce risk .

The attached figure compares the SSI rates of REOrthopaedics physicians to the SMH aggregate rates and rates generated by the National Healthcare Safety Network (NHSN) at the CDC in Atlanta.  As seen, Dr. Cierny and Dr. DiPasqaule have a 0.00%  post-operative SSI rate following 55 consecutive hip and knee arthroplasties performed 2006-2008. The Risk index is scored from 0-3 points (the higher the risk index, the higher the score), with one point each for: a) wound class of contaminated or dirty; b) ASA score of III, IV or V; c) duration of surgery >2 hours.  NHSN rates reflect the National Healthcare Safety Network Report: a data summary for 2006-2008 (AJIC: Nov 2008; 609-626).  SMH = Sharp Memorial Hospital; San Diego, Calfiornia.  REO = REOrthopaedics, Inc in San Diego, CA; Drs.George Cierny, MD and Doreen DiPasquale, MD.   

 Dr. Cierny’s comments:  Unfortunately, this registry does not differentiate between primary vs revision arthroplasties or clean vs infected arthropasties performed at Sharp Memorial Hospital.   All of the REOrthopaedics’ cases began, initially, as peri-prosthetic total joint infections (54: 2-stage revisions vs 1: primary exchange). 

In a recent article published out of Oxford, England, researchers have found a very high incidence of early and late failures following total joint, hip arthroplasties using a metal-on-metal hip resurfacing prostheses in women under 40 years of age (Glyn-Jones S, Pandit H, Doll H, et al; The Risk Factors for Developing an Inflammatory Pseudotumor following Hip Resurfacing: a survival analysis. British Orthopaedic Association Annual Congress. September 15-18,2009, Manchester).  The study is based on information from their experience with 1,419 patients between the years of 1999 and 2008.    The overall revision rate for revision and psuedotumors was 4% at 8 years.  However, women younger than 40 years had a 25% revision rate for the condition.   

A pseudotumor is an accumulating mass of inflammatory tissue that forms in response to an irritant: “pseuo-“ because it mimics a tumor with its presence /appearance.  It is thought that a high metal ion release can originate from a metal-on-metal interface if there is excessive edge-loading ( women require smaller components and more attention to component positioning due to their increased range of motion).  The tissue reaction within the “pseudotumor” consists numerous histiocytic cells and lymphocytes accompanied by a proliferation of a variable amount of dense fibrous tissue: a chronic granulomatous inflammation.

The tissue reaction can be called a pseudotumor, AVAL (aseptic lymphocyte dominated vasculitis associated lesion) or simply “metalosis”.    When it occurs, it can cause pain, prosthetic loosening /or more severe medical reactions (hemorrhage, loss of function, peri-prosthetic fracture, etc.).   Dr. Cierny’s comment:    It takes a great deal of experience to consistently place these components at the proper angle and to know which smaller patients can successfully receive a hip resurfacing.