Answer: Treatment of prosthetic joint infections (PJIs), such as total hip replacements, is challenging. Before we decide on which surgical approach to take, there are two key questions to ask about the patient's history: 1) How long has it been since total hip replacement surgery? and 2) How long have the symptoms of infection been present?
While infections that develop soon after implantation may be successfully treated without device removal, late-onset infections are likely to require device removal for cure.1,2 The Infectious Diseases Society of America (IDSA) notes that early-onset MRSA-associated PJIs that occur <2 months after surgery, or acute hematogenous infections with a stable implant and short duration (≤3 weeks) of symptoms may be treated with surgical debridement and device retention. That approach is accompanied by IV antibiotic therapy, as well as adjunctive oral rifampin therapy for 6 weeks followed by 3-6 months of oral antibiotic therapy. (Note that current IDSA guidelines recommend 2 weeks of parenteral antibiotic therapy.) Oral antibiotic therapy may include a variety of different antibiotics that are active against MRSA, such as trimethoprim sulfamethoxazole (TMP-SMZ), a tetracycline, clindamycin, or a fluoroquinolone.3 Cure rates with this approach are not universal, but have been reported to be over 70%.4,5 Device removal (plus debridement) is recommended, whenever feasible, for patients with unstable implants or >3 weeks of symptoms.
In terms of surgical therapy, randomized clinical trials of approaches are lacking, so expert recommendations are typically based on observational studies. It appears that the ideal treatment is a one-step or two-step exchange (Figure 1). A one-stage (ie, direct exchange) procedure requires removal of the infected joint, debridement of the infected site, and reimplantation of a new prosthesis during a single surgery. The published success rates can be over 85%.2,5 However, for virulent organisms such as MRSA, the cure rates may be lower.5
Most experts recommend a two-step exchange procedure for all PJIs, including those caused by MRSA, as published cure rates are typically about 90%.2,6 The two-stage exchange procedure involves removal of the infected prosthesis, debridement, and placement of an antimicrobial-impregnated spacer. This surgery is followed by 4-6 weeks of intravenous antibiotics active against the infecting organism(s). Reimplantation of a new prosthesis is performed following completion of antibiotic therapy. Some experts recommend that, before the new prosthesis is implanted, follow-up cultures of the infected sites are done for patients with virulent organisms like MRSA, although not all studies have shown this approach is associated with improved cure.7