Conservative Management of Diabetic Foot Ulcers Complicated by Osteomyelitis
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Foot ulcers in patients with diabetes constitute a growing and costly public health concern. Diabetes is increasing in prevalence, especially in developed nations. In the United States, the prevalence is estimated to be 7.3 percent of adults.1 Foot ulcers in these individuals arise at an incidence of 2.5 percent each year and, unfortunately, may initiate a pathway to amputation and limb loss.2
One adverse consequence of foot ulceration is infection, which becomes limb threatening when there is bone involvement. Repetitive pressures on an ulcer often are rapidly converted to tissue-disruptive inflammation close to an underlying bony prominence; the consequence is that approximately 15 percent of foot ulcers are complicated by osteomyelitis.3 The customary management of osteomyelitis from contiguous foot ulceration is thorough surgical removal of all infected bone and often involves resection of relatively noninfected adjacent soft tissue and bone. Along with concurrent use of appropriate antimicrobials, this aggressive approach may lead to successful eradication of the infection; however, it may also result in the untoward outcome of altered biomechanics, foot instability, and increased residual plantar pressures—placing the patient at greater risk of future ulcerations. Indeed, one of the risk factors for amputation is prior amputation.4
In the past decade, there has been a growing clinical interest in an approach to osteomyelitis in the diabetic foot that is more foot sparing with less aggressive surgical ablation, favoring instead more reliance on conservative surgery and long-term antimicrobials. Besides reducing the number of major amputations as first-line treatment, the advantage to such an approach would be in the maintenance of some biomechanical stability to allow easier accommodation of the foot and prevention of new ulcer events.
In order to evaluate the efficacy of a conservative approach, we retrospectively evaluated a series of patients with diabetes and foot ulcers complicated by osteomyelitis that were managed by an interdisciplinary team. Patients were evaluable only if they had at least 12-months follow up for the assessment of healing and recurrence.
Patients with diabetes and osteomyelitis of the foot who received inpatient care at Staten Island University Hospital from 1994 to 1996 were identified in the hospital discharge database using codes from the International Classification of Diseases, Version 9 (ICD-9 codes). Using medical record numbers, 160 patients with osteomyelitis were identified as having been registered in the outpatient interdisciplinary foot clinic at the Diabetes Treatment Center. Clinic charts for these patients were reviewed, and 58 patients were found to have an adequately documented follow-up observation period of at least 12 months. A long observation period was chosen to address the concern of persistence and/or recurrence in patients with chronic osteomyelitis. These 58 patients comprised the study cohort.
Both inpatient and outpatient records were analyzed for the evaluation and management of the osteomyelitis. The diagnosis of osteomyelitis was made on clinical grounds, defined by grossly infected or exposed bone; an ulcer that probed to bone;5 or a diagnostic radiograph and HMPAO-WBC (Ceretec) or similar nuclear imaging scan. All patients were evaluated surgically. The type and extent of the initial surgical procedure was determined according to clinical judgment of the treatment team, often with a conservative treatment philosophy of minimizing bone resection whenever possible. Patients were all treated with intravenous antibiotics, which were initiated empirically based on expected microbial flora and changed if the patient did not respond clinically or if the bone culture grew clearly resistant pathogens.
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