Use of Tobramycin-Impregnated Calcium Sulphate Pellets in Addition to Oral Antibiotics: An alternative treatment to minor amputation in a case of diabetic foot osteomyelitis

To supplement surgical debridement, pellets of calcium sulfate (CS) were used as vehicles for local antibiotic delivery in treating osteomyelitis (1). We are aware of one case series in which diabetic pedal osteomyelitis was resolved with postoperatively implanted polymethylmethacrylate antibiotic beads and intravenous antibiotics (2). We now present a case of radiologically successful, nonsurgical management of diabetic foot osteomyelitis with tobramycin-impregnated CS pellets, in addition to oral antibiotic treatment, following our previous report on the pellets’ anecdotal success in treating diabetic infected wounds (3).

A 41-year-old male with type 1 diabetes referred to the diabetic foot clinic had radiological findings of septic arthritis and diffuse osteomyelitis (anatomic stage IV) of the right fourth metatarsal head and adjacent phalanx overlying a chronic neuropathic ulcer. He refused to undergo a ray excision of the infected bones despite the suggestion of our surgical colleagues. Local therapy with prefabricated tobramycin-impregnated CS pellets, which were inserted twice into a deep cavity beneath the small foot ulcer, was then added to supplement oral Ciprofloxacin and Clindamycin and later to Amoxicillin/clavulanic acid treatment due to drug-related diarrhea. Further radiographs of the right forefoot after 4 and 6 weeks of the above treatment revealed radiological improvement of osteomyelitis and signs of bone reconstruction in the affected bones (online appendix Fig. 1 [available at http://care.diabetesjournals.org]).

In a randomized study (4), high local antibiotic bioavailability from implantable beads in infected joint arthroplasties was found to be as effective as conventional parenteral antibiotic treatment. The nonadherent state of CS pellets versus bone substitutes, like polymethylmethacrylate, could be advantageous for antibiotic delivery in chronic osteomyelitis with antibiotic resistance (5). The potential role of local administration of antibiotics from CS pellets in healing and bone repair is reported in a case series of patients with osteomyelitis (6).

In the infected nonischemic diabetic foot, the possible synergistic effect of tobramycin-impregnated CS pellets as an additional treatment to systemic antibiotics should be further investigated in clinical trials.