Development of modern total hip and knee arthroplasty represented a milestone in orthopedic surgery. Modern prostheses consist of metal (typically cobalt–chromium or titanium), and plastic (an ultrahigh-molecular-weight polyethylene material). These components may be attached to the native bone with surgical cement and/or polymethylmethacrylate. New prosthetic materials with porous coating that allows bone formation around the prosthesis have been developed in recent years. Many joint prostheses are used in orthopedic practice and, whereas hip and knee joint replacement is performed thousands of times per year throughout the world, shoulder, elbow, wrist, ankle, metacarpophalangeal or interphalangeal joint replacement is much more recent and experimental. In 2004, hip and knee replacement procedures accounted for 95% of the 1.07 million arthroplasty procedures performed in the USA. It is estimated that 3.5 million primary total knee and 572,000 primary total hip arthroplasties will be performed annually in the USA by 2030.
Although prosthetic joint implantations improve patients' quality of life, these procedures are associated with complications, including aseptic failure (i.e., aseptic loosening) and prosthetic joint infection (PJI). More than 25% of all prostheses will eventually demonstrate evidence of loosening, often necessitating a revision arthroplasty. Infection, although uncommon, is the most serious complication following joint prosthesis implantation. In patients with primary joint replacement, the infection rate in the first 2 years is usually <1% in hip and shoulder prostheses, <2% in knee prostheses, and <9% in elbow prostheses. The reported infection rates are probably underestimated, since many cases of presumed aseptic failure may be due to unrecognized infection. In addition, infection rates after surgical revision are usually considerably higher (up to 40%) than after primary replacement.
The most significant risk factors for total hip arthroplasty are postoperative surgical site infection (odds ratio [OR]: 35.9), a National Nosocomial Infection Surveillance score >2 (OR: 3.9), concurrent malignancy (OR: 3.1) and prior total hip arthroplasty (OR: 2). Although this is valid for hip arthroplasties, we speculate that they may also hold true for other arthroplasties. Other factors predisposing to PJI are older age, poor nutritional status, underlying joint disease (i.e., rheumatoid arthritis, psoriasis), obesity, diabetes mellitus, malignancy, remote infection, prior native joint infection, presence of bacteremia (especially due to Staphylococcus aureus), advanced HIV infection, a revision surgery, or preoperative use of low-molecular-weight heparin. The mortality rate attributed to PJI may range between 0.4% in 65-year-old patients to 7% in 80-year-old patients. The estimated cost associated with a single episode of PJI may be as high as US$50,000.
Expert Rev Anti Infect Ther. 2011;9(9):787-802. © 2011 Expert Reviews Ltd.