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 most likely to be successful. Twelve reports provided outcome data on infected hip replacements treated with direct exchange. The average duration of followup was 4.8 years, but the range was broad (0.1-17.1 years). Of the 1,299 infected hip replacements treated with direct exchange, 1,077 (83%) were thought to be free of infection at the last followup. Antibiotic-impregnated bone cement was used in 1,282 of the cases (99%). There was wide variability in the duration of parenteral antibiotic therapy, ranging from just 24 hours 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 after parenteral therapy. Factors associated with a successful direct exchange included: (1) absence of wound complications after the initial total hip replacement; (2) good general health of the patient; (3) methicillin-sensitive Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus species; and (4) an organism that was sensitive to the antibiotic mixed into the bone cement. Factors associated with failure included: (1) polymicrobial infection; (2) gram-negative organisms, especially Pseudomonas species; and (3) certain gram-positive organisms such as methicillin-resistant Staphylococcus epidermidis and Group D Streptococcus. Methicillin-resistant organisms have become more common. Many current revision surgical techniques use cementless implants. Fixation without any cement (no depot antibiotics) may 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.