Diabetic foot osteomyelitis: a progress report on diagnosis and a systematic review of treatment

Review: The varied attractions of the diabetic foot

Various advances have been seen in the management of the diabetic foot. In some areas the rate of diabetes-related major amputations is declining. Duloxetine, pregabalin, venlafaxine and oxycodone are all well proven to help alleviate the pain of diabetic neuropathy. Negative pressure wound therapy has been shown to accelerate the healing of foot ulcers. New antibiotic policies designed to reduce Clostridium difficile and methicillin-resistant Staphylococcus aureus (MRSA) infections focus on narrow spectrum short duration antibiotics, and 80% of osteomyelitis can be successfully treated without surgery. Foot screening identifies patients who will ulcerate, with high-risk patients being up to 83 times more likely to ulcerate than low-risk patients. The ‘holiday foot’ and distal peripheral vascular disease remain as major risk factors for foot ulcer development and non-healing. The diabetic foot provides many interesting and varied challenges for the interested clinician.

Br J Diabetes Vasc Dis 2009;9:155—159

Risk factors for developing osteomyelitis in patients with diabetic foot wounds

AIMS

Osteomyelitis worsens the prognosis in the diabetic foot, but predisposing factors remain largely undefined. In a prospectively followed cohort we assessed risk factors for developing osteomyelitis.

METHODS

We enrolled consecutive persons with diabetes who presented to a managed-care diabetes disease management program. The patients underwent standardized assessments. We monitored for all foot complications, defined infections by criteria consistent with International Working Group guidelines, and defined osteomyelitis as a positive culture from a bone specimen.

RESULTS

1666 persons were enrolled, 50% male, mean age 69 years. Over a mean of 27.2 months of follow-up, 151 patients developed foot infections, 30 (19.9%) of which involved bone. Independent risk factors for osteomyelitis were: wounds that extended to bone or joint (relative risk [RR]=23.1), previous history of a wound prior to enrollment (RR=2.2), and recurrent or multiple wounds during the study period (RR=1.9).

CONCLUSIONS

In this study population, managed in a specialized diabetic foot care center, the results suggest that independent risk factors for developing osteomyelitis are deep, recurrent and multiple wounds. These results may help clinicians target their efforts at diagnosing foot osteomyelitis to the highest risk patients.

Unresolved issues in the management of ulcers of the foot in diabetes

Management of diabetic foot ulcers presents a major clinical challenge. The response to treatment is often poor and the outcome disappointing, while the costs are high for both healthcare providers and the patient. In such circumstances, it is essential that management should be based on firm evidence and follow consensus. In the case of the diabetic foot, however, clinical practice can vary widely. It is for these reasons that the International Working Group on the Diabetic Foot has published guidelines for adoption worldwide. The Group has now also completed a series of non-systematic and systematic reviews on the subjects of soft tissue infection, osteomyelitis, offloading and other interventions designed to promote ulcer healing. The current article collates the results of this work in order to demonstrate the extent and quality of the evidence which is available in these areas. In general, the available scientific evidence is thin, leaving many issues unresolved. Although the complex nature of diabetic foot disease presents particular difficulties in the design of robust clinical trials, and the absence of published evidence to support the use of an intervention does not always mean that the intervention is ineffective, there is a clear need for more research in the area. Evidence from sound clinical studies is urgently needed to guide consensus and to underpin clinical practice. It is only in this way that patients suffering with these frequently neglected complications of diabetes can be offered the best hope for a favourable outcome, at the least cost.

Primarily non-surgical management of osteomyelitis of the foot in diabetes

AIMS/HYPOTHESIS

We examined the use of surgery and assessed the response to non-surgical management of osteomyelitis of the foot in diabetic patients.

METHODS

We reviewed the records of all patients presenting to a single specialist centre with osteomyelitis complicating a diabetic foot ulcer over a 5 year period. Details were extracted on antibiotic choice and treatment duration, hospital admission, incidence of minor and major amputation, and 12 month outcomes.

RESULTS

There were 147 patients, with mean age 64.7 years (66% men). Of these, 26 (18%) were admitted to hospital at the time of presentation and managed with intravenous antibiotics; the remainder were managed with oral antibiotics as outpatients. Surgery was undertaken because of life- or limb-threatening infection, or failure to respond, in 34 (23%) patients (minor amputation 28, major amputation six patients). The remaining 113 were managed non-surgically. Remission was induced in 66 (58.4% of 113), while 35 (31%) had a relapse. Of those experiencing relapse, 27 (77%) achieved apparent arrest of the infection with a further course of antibiotics; six underwent minor and two underwent major amputation. Of all 113 whose infection was initially managed without surgery, apparent remission was achieved with antibiotics alone in 93 (82.3%).

CONCLUSIONS/INTERPRETATION

As these observations were made in an unselected case series, they give more insight into the respective roles of surgical and non-surgical management. The results confirm that although urgent surgery is indicated in some patients, non-surgical management of those without limb-threatening infection is associated with a high rate of apparent remission.