Patients with an infected nonunion have a superimposed infection to their fracture. Often these infections are polymicrobial with multidrug-resistant bacteria. In our experience, imipenem has been the most commonly used antibiotic to treat these infections due to the prevalence of gram-negative organisms cultured from these wounds, particularly Acinetobacter, Enterococcus, and Klebsiella. Similar findings have been reported in the literature from war-injured soldiers in Iraq [6]. In addition, we have had a very low threshold to resect the affected bone and treat the infection locally, with the use of antibiotic-impregnated calcium sulfate pellets . These two steps have significantly decreased the duration of systemic antibiotics and increased the rate of infection eradication and bone healing [7]. This was an important advancement for our patient population due to their limited financial resources and inability to continue prolonged intravenous antibiotic administration. This has also decreased the duration of hospitalization as well as the side effects associated with prolonged antibiotic use.

These patients can be divided into two categories:

In the first category , resection of the infected dead bone edges may result in sterilization of the field. Often, we applied the one step or global approach. This includes radical debridement and cleansing of the soft tissue, resecting dead bone until paprika sign is noted. The gap is then filled with calcium sulfate pellets (Stimulan, Biocomposites^R) impregnated with 1 g of vancomycin powder and 240 mg of gentamycin liquid for each 10 cc (which replaced the mixing liquid provided by the manufacturer) [7]. Then the external fixator is applied, a remote osteotomy is performed, and the wound is closed primarily or with local flaps, if need be. These patients typically receive a very short course of systemic antibiotics (3–14 days) (Fig. 11.3).

In the second category, we prefer the two-stage approach. The first stage includes resection of necrotic bone and soft tissue , filling the defect with a cement spacer impregnated with high doses of vancomycin and gentamycin (2 G Vancomycin and 240 mg Gentamycin for each 40 mg methylmetacrylate), and applying the external fixator. The second stage takes place after 3–6 weeks of systemic antibiotic administration . It consists of removing the cement spacer and application of the calcium sulfate pellets impregnated with vancomycin and gentamycin, as above. The remote osteotomy for bone regeneration can be done at either stage. The duration of systemic antibiotics depends on the host, bacteria, and condition of the wound (Fig. 11.4).

Another appealing approach is the membrane-induced technique described by Masquelet [8]. The main indication for this technique is a patient with a proximal femur fracture that was initially fixed with an intramedullary rod, or after wound healing. In this scenario an external fixator may be difficult to apply and the pins may have to be intracapsular. In this two-stage technique, we debride the fracture site in the first stage without exchanging the nail. Cultures are taken and intravenous antibiotics are started. Typically, a cement mantle is applied as described previously. After 6 weeks, the cement is removed and bone grafting is performed using a combination of autogenous bone graft and calcium sulfate pellets (Fig. 11.5).

Alternatively, a vascularized or non-vascularized free fibula graft may be used in a single-stage procedure to fill the bone defect and create a structural graft. This procedure has the benefit of having a relatively straightforward dissection, high union rate, and excellent functional outcomes [9–12]. Additionally, in an adult there is up to 26 cm of length available for harvesting, provided the fibular head and distal one-quarter of the fibula are retained for knee and ankle stability, respectively. In children, a syndesmotic screw is placed through the distal fibular stump to prevent a valgus ankle deformity. The ipsilateral fibula may be transposed or the contralateral fibula can be harvested. When harvesting a vascularized graft, the peroneal or anterior tibial vessels may be used, with or without a cutaneous flap [12]. The anterior tibial vessel is preferred for epiphyseal transfers due to better blood supply [13]. The fibula graft should be imbedded into the canal of each end of the long bone with a large segmental defect, whether the tibia or femur . Fixation may be achieved with cannulated screws, small diameter elastic stable intramedullary nails, external fixators, or bridge plating [9, 12, 14] (Fig. 11.6).