SALVAGE OF DIABETIC FOOT OSTEOMYELITIS BY LOCAL NECROSECTOMY AND IMPLANTATION OF VANCOMYCIN / TOBRAMYCIN IMPREGNATED BONE GRAFTS
H. Winkler
Osteitis Center, Privatklinik Döbling
Heiligenstädterstr. 57-63
1190 Vienna
AUSTRIA
Introduction: Osteomyelitis represents the major complication in the neuropathic foot., mostly caused by diabetes. Systemic antibiotic therapy alone usually is not sufficient for eradication of bacteria because of inferior penetration into devascularized bone. Due to toxic side effects, dosage of antibiotics and duration of application are limited. A high percentage of cases result in major amputation. Local application of antibiotics can provide high drug levels at the site of infection avoiding systemic effects. Vancomycin is effective against most gram-positive pathogens and is the agent of choice for infections with MRSA. Tobramycin is effective against a manyfold of pathogens, covering the majority of the relevant spectrum in orthopaedic surgery. Bone processed in an adaequate way represents an excellent carrier for vancomycin and tobramycin. Using an antibiotic bone composite (ABC), eradication of pathogens and grafting of bony defects may be accomplished in a one stage procedure. The purpose of this study was to investigate the efficacy of vancomycin / tobramycin-loaded bone grafts in the treatment of chronic osteomyelitis in the neuropathic foot.
Patients and Methods: 42 patients with 44 neuropathic foot lesions were included into a prospective study. Entry criteria comprised neuropathy (usually diabetic) and infection of bone proven by bacterial culture and by clinical and radiological findings. Necrotic bone and infected tissue were radically debrided and the sites lavaged using pulsed irrigation. Resulting defects were filled with vancomycin/tobramycin-loaded bone grafts. Infections of the forefoot were treated by resection of the infected metatarsal joint and filling of the medullary cavity of the remaining diaphysis. The bone grafts were prepared according to our standard procedure for the production of antibiotic impregnated bone allografts. Clinical examinations, radiologic follow-up, and assessment of laboratory data were performed at given intervals for one year.
Results: One year after surgery clinical examinations and laboratory showed no sign of persistent infection in 39 of the feet. In 3 patients the procedure needed to be repeated due to ongoing infection, leading to sanitation in two more cases. Only one case still shows fistulation. Some patients called again for lesions on other locations, which were treated the same way. No patient required amputation so far.
Conclusions: The use of bone grafts as a carrier for vancomycin and tobramycin avoids systemic side-effects while providing high and prolonged drug levels at the site of infection. Surgical sanitation of infected feet can be achieved in a one-step procedure by meticulous debridement of necrotic / infected tissue and filling the resulting osseous defects with antibiotic loaded bone-graft composites. Procedures mostly can be performed under regional anaesthesia, hospital stays are short (1 to 7 days), time to healing of ulcers is less than four weeks. Vancomycin/tobramycin loaded bone grafts represent a new effective tool in the foot surgeon´s armamentarium avoiding amputation in the majority of cases.
Presented at 24th Annual Meeting of the European Bone and Joint Infection Society, Ljubljana 2005
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