Limited role of direct exchange arthroplasty in the treatment of infected total hip replacements

A literature review was performed to determine when direct exchange was mos t likely to be successful, Twelve reports provided outcome data on infected hip replacements treated with direct exchange. The average duration of fol lowup was 4.8 years, but the range was broad (0.1-17.1 years). Of the 1299 infected hip replacements treated with direct exchange, 1077 (83%) were tho ught to be free of infection at the last followup, Antibiotic-impregnated b one cement was used in 1282 of the cases (99%), There was wide variability in the duration of parenteral antibiotic therapy, ranging from just 24 hour s to as many as 8 weeks. In some cases, no oral antibiotics ever were given , whereas in others, oral antibiotics were given for as many as 8 months af ter parenteral therapy. Factors associated with a successful direct exchang e included: (1) absence of wound complications after the initial total hip replacement; (2) good general health of the patient; (3) methicillin-sensit ive Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus sp ecies; and (4) an organism that was sensitive to the antibiotic mixed into the bone cement. Factors associated with failure included: (1) polymicrobia l infection; (2) gram-negative organisms, especially Pseudomonas species; a nd (3) certain gram-positive organisms such as methicillin-resistant Staphy lococcus epidermidis and Group D Streptococcus, Methicillin-resistant organ isms have become more common. Many current revision surgical techniques use cementless implants, Fixation without any cement (no depot antibiotics) ma y be a contraindication to direct exchange. Additionally, there essentially are no data on the use of bone graft in association with direct exchange. For these reasons, the indications for direct exchange are limited.