Case 4
A 48-year-old man sustained an open olecranon fracture in another country. The fracture was initially treated with 1 dose of intravenously administered antibiotics and 5 days of orally administered antibiotics. The patient returned to the United States and was treated with intravenously administered antibiotics for cellulitis of the elbow for 11 days before referral to our institution, where he underwent ORIF with placement of an antibiotic-coated plate and tension-band wiring. Soft-tissue and bone cultures had no growth. He received intravenously administered antibiotics for 6 weeks. At 5 months postoperatively, the plate was removed because of pain. The patient has remained free of clinical signs of infection for more than 1 year and has achieved bony union (Figures 8A-8C).
Discussion
Acute infections of fractures have recently been treated with success by Berkes and colleagues,1 who reported a 71% union rate achieved with operative débridement, antibiotic suppression, and retention of fixation until fracture union occurs. The study by Berkes and colleagues1 had a small patient population, and larger cohorts are needed to show more reliable results; however, this treatment maintains structural support for the fracture during healing but requires multiple trips to the operating room for débridements as well as the use of systemic intravenous antibiotic therapy.
A technique that was developed by the primary author (Janet D. Conway, MD) and has not been described in the literature allows for use of antibiotic cement–coated plates to treat early postoperative infections and osteomyelitic nonunions. This approach permits fracture stabilization and local delivery of high concentrations of broad-spectrum antibiotics and can reduce the number of débridement procedures required in the operating room. We present a technique that includes the use of antibiotic cement–coated plates to treat early postoperative infections associated with fractures and nonunions in order to provide eradication of infection and bony stabilization.
Our approach parallels the current theory that treating infection at a site of union is preferable to treating infection at a site of nonunion.1 Fixation devices should remain in place until osseous union is achieved. With the addition of antibiotics to the plate, removal might not be necessary unless a device is loose, nonfunctional, or, ultimately, causing pain. Other options, such as external fixation, can be burdensome to patients and can be associated with other risks. One of our 4 patients required fixation removal because of pain at the elbow; however, even noncoated olecranon plates typically are removed because of pain after fracture healing. Antibiotic cement adds bulk to the construct and can become very prominent in areas of little soft-tissue coverage (Figure 9).
Studies, assessing variables that correlate with higher likelihood of failure for primary repairs, have shown that open fracture, use of an intramedullary nail, and smoking are the highest risk factors for infected nonunion.1−4 Among our 4 patients, 3 were smokers and 1 originally had an open fracture. Smokers have been found to have a 37% higher nonunion rate and are 2 times more likely to develop wound infection and osteomyelitis.1,5 More than 60% of the time, infections are caused by S aureus or coagulase-negative staphylococci.1,5,6 In our study population, 3 of the 4 patients had coagulase-negative staphylococci grow in the cultures. Implants infected with S aureus or Candida require surgical removal. Those with less virulent coagulase-negative staphylococci might not necessitate removal; however, our population had had antibiotic therapy and continued draining sinus.5 Rightmire and colleagues7 reported that those who develop infection earlier than 16 weeks postoperatively have a 68% success rate and that smoking is a major risk factor for infection. Development of Pseudomonas in the wound has been shown to have a positive correlation with amputation.1,2 Infection with Pseudomonas, smoking, and involvement of the femur, tibia, ankle, or foot tended to result in failure.1,2 Being clinically free of signs of infection after 3 months offers a 50% cure rate, with 78% at 6 months and 95% after 1 year.2
When determining an antibiotic to use with the polymethylmethacrylate (PMMA) cement, many factors must be considered, including spectrum, heat stability, and elution characteristics.8 A synergistic effect has been seen with combinations of antibiotics (eg, vancomycin and tobramycin used together). Vancomycin concentrations increased by 103% and tobramycin by 68% when used together compared with their elution rates when used alone, showing passive opportunism.9 This will, in essence, increase concentrations of antibiotics at the site locally, which will increase the bacteriocidal potential but also create a larger antimicrobial spectrum.9
The authors used Cobalt Bone Cement (Biomet Orthopedics, Inc, Warsaw, Indiana) which been shown to have higher elution properties than Simplex P Bone Cement (Stryker, Kalamazoo, Michigan).3,10 The majority of elution occurs in the first 3 to 5 days but can continue for weeks after implantation. We place the cement on the plate allowing for its retention, hoping to eliminate a second surgery for removal.8 We recommend 3.6 g of tobramycin, and 1 g of vancomycin per 40-g bag of PMMA.3 This dose has been shown to be safe in respect to renal toxicity, plus the entire dose is not administered in a single setting because only a small portion of the cement is used when coating the plate. We close all wounds primarily, and do not regularly use drains or vacuum-assisted closures to help prevent a decrease in the local concentration of the antibiotics.11