Mặc dù các thủ tục chỉnh hình tự chọn được coi là "sạch" cũng như những tiến bộ trong kỹ thuật phẫu thuật và chăm sóc chu phẫu, vùng sâu, nhiễm trùng vẫn còn là một nguyên nhân quan trọng gây bệnh tật và thất bại. | 690 W. Dandachli . Cobb acute blood loss is a commonly encountered problem it has not been included in this chapter as it is not specific to orthopaedic surgery. DEEP INFECTION A. Pathology Despite elective orthopaedic procedures being considered clean as well as the advances in surgical technique and perioperative care deep infection remains a significant cause of morbidity and failure. Although the reported rate of deep periprosthetic infection after total hip arthroplasty is around 2 some studies have reported rates as high as .1 2 Various organisms have been implicated in deep periprosthetic sepsis. The most prevalent of these are gram-positive cocci with Staphylococcus aureus accounting for 50 65 of the infections and Staphylococcus epidermidis for 25 30 . Other bacteria fungi and mycobacteria account for 10 15 of deep infections. Schmalzried et al. described four modes by which infections can get These are namely contamination at the time of operation haematogenous spread recurrence of sepsis in a previously infected site and contiguous spread from a local source. Once at the surgical site microorganisms take advantage of the presence of any foreign material . prosthetic implants making them less accessible to the host s immune system. There have been several methods of classifying periprosthetic infections. The original classification was that of Coventry who described three stages by which infection clinically presents stage I acute postoperative infections Stage II delayed infections occurring six months to two years postoperatively and Stage III late haematogenous Recently this system has been expanded to take into consideration current treatment guidelines. The modified classification consists of four categories 1 positive intraoperative culture 2 early postoperative infection 3 acute haematogenous infection and 4 late chronic infection Table 1 . There are several factors that increase the risk of infection .
