The diabetic foot: aetiopathogenesis and management

Diabetic Foot Complications: Diagnosis and Management

Foot complications in patients with diabetes mellitus are a challenge to the health care industry. A great deal of expenditure is due to the management of diabetic foot complications. This places a great burden on the health care industry. It also places a great burden on those diabetic patients with foot complications and their families. Therefore, their effective management in an efficient manner is crucial to our patients. To deal with these problems, a dedicated, knowledgeable, and experienced multidisciplinary team is key. Intervention at the earliest possible time yields the best outcome. Prevention is the focus for those with no ulcerations. For those with ulcerations, prompt recognition and treatment is key. The importance of classifying ulcerations according to size, depth, presence or absence of infection, and vascular status can not be overstated. Proper offloading is vital for those with neuropathic lesions. Recognition of patients with a component of ischemia and vascular intervention to increase perfusion will aid in wound healing. Of course deep infection requires immediate drainage. All efforts of those in the multidisciplinary team are directed at the restoration and maintenance of an ulcer-free foot which is important in enabling our patients to maintain their ambulatory status.

Is scintigraphy a guideline method in determining amputation levels in diabetic foot?

BACKGROUND

In this study, we aimed to evaluate the potential use of a 3-phase bone scintigraphy method to determine the level of amputation on treatment cost, morbidity and mortality, reamputation rates, and the duration of hospitalization in diabetic foot.

METHODS

Thirty patients who were admitted to our clinic between September 2008 and July 2009, with diabetic foot were included. All patients were evaluated according to age, gender, diabetes duration, 3-phase bone scintigraphy, Doppler ultrasound, amputation/reamputation levels, and hospitalization periods. Patients underwent 3-phase bone scintigraphy using technetium-99m methylene diphosphonate, and the most distal site of the region displaying perfusion during the perfusion and early blood flow phase was marked as the amputation level. Amputation level was determined by 3-phase bone scintigraphy, Doppler ultrasound, and inspection of the infection-free clear region during surgery.

RESULTS

The amputation levels of the patients were as follows: finger in six (20%), ray amputation in five (16.6%), transmetatarsal in one (3.3%), Lisfranc in two (6.6%), Chopart in seven (23.3%), Syme in one (3.3%), below-the-knee in six (20%), above the knee in one (3.3%), knee disarticulation in one (3.3%), and two patients underwent amputation at other centers. After primary amputation, reamputation was performed on seven patients, and one patient was treated with debridement for wound site problems. No mortality was encountered during study.

CONCLUSIONS

We conclude that 3-phase bone scintigraphy prior to surgery could be a useful method to determine the amputation level in a diabetic foot. We conclude that further, comparative, more comprehensive, long-term, and controlled studies are required.

Effectiveness of insoles used for the prevention of ulceration in the neuropathic diabetic foot: a systematic review

CONTEXT

Ulceration can be a debilitating and costly complication of the neuropathic diabetic foot. Insoles inserted into footwear are routinely used in clinical practice to help to prevent ulceration. AIM AND SCOPE OF THE REVIEW: This review evaluated the effectiveness of insoles used for the prevention of ulcer in the neuropathic diabetic foot.

METHODS

Databases were searched from inception to 2008, supplemented by hand searching of references and grey literature. Data extraction and methodological quality assessment were independently conducted by two reviewers following the recommendations of the Centre for Reviews and Dissemination.

RESULTS

A total of five trials met the inclusion criteria: two randomised control trials (RCTs), two case control studies, and one follow-up study. The methodological quality of the majority of studies was poor. Omitted details regarding the generalisability of results made study comparison and inference to practice difficult. There is a small amount of limited evidence indicating that insoles are effective in reducing incidence of ulceration and reducing plantar peak pressures in the diabetic neuropathic foot. No study included economic analysis or patient-based outcome measures.

CONCLUSIONS

Insoles appear of use for the prevention of neuropathic diabetic foot ulceration, although evidence is limited. Clinical recommendation regarding type and specification of insole is not possible at this time. There is an essential need for a large well-designed RCT comparing different types of commonly used insole for the prevention of ulceration in the diabetic neuropathic foot. Outcome measures should include patient perceptions of the effectiveness and cost-effectiveness analysis.

Diabetic effects on microchambers and macrochambers tissue properties in human heel pads

BACKGROUND

The study attempted to highlight the differences of mechanical properties in microchambers and macrochambers between patients with type 2 diabetes mellitus and age-matched healthy volunteers.

METHODS

A total of 29 heels in 18 diabetic patients and 28 heels in 16 age-matched healthy participants were examined by a loading device consisting of a 10-MHz compact linear-array ultrasound transducer, a Plexiglas cylinder, and a load cell. Subjects in both groups were on average about 55 years old with a body mass index of approximately 25 kg/m(2). A stepping motor was used to progressively load the transducer on the tested heels at a velocity of 6mm/s from zero to the maximum stress of 78 kPa. Unloaded thickness, strain, and elastic modulus in microchambers, macrochambers and heel pads were measured.

FINDINGS

Microchambers strain in diabetic patients was significantly greater than that in healthy subjects (0.291 (SD 0.14) vs. 0.104 (SD 0.057); P<0.001). Macrochambers strain in diabetic patients was significantly less than that in healthy subjects (0.355 (SD 0.098) vs. 0.450 (SD 0.092); P=0.001). Microchambers stiffness in diabetic patients was significantly less than that in healthy persons (393 (SD 371)kPa vs. 1140 (SD 931)kPa; P<0.001). Macrochambers stiffness in diabetic patients was significantly greater than that in healthy persons (239 (SD 77)kPa vs. 181 (SD 42)kPa; P=0.001).

INTERPRETATION

Heel pad tissue properties are altered heterogeneously in people with diabetes. Increased macrochambers but decreased microchambers stiffness may cause diminished cushioning capacities in diabetic heels.

Mortality and hospitalization in patients after amputation: a comparison between patients with and without diabetes

OBJECTIVE

We sought to compare the risk of mortality and hospitalization between patients with and without diabetes following incident lower-extremity amputation (LEA).

RESEARCH DESIGN AND METHODS

We performed a retrospective data-linkage review of all incident amputations between 1 January 1992 and 31 December 1995. Patients were categorized according to their diabetes status. Follow-up for mortality was until 1 January 2005 and until 31 March 1996 for hospitalization.

RESULTS

Of 390 major-incident LEAs performed during the study period, 119 (30.5%) were in patients with diabetes and 271 (69.5%) were in nondiabetic subjects. The median time to death was 27.2 months in patients with diabetes compared with 46.7 months for patients without (P = 0.01). Diabetic subjects had a 55% greater risk of death than those without diabetes. The risk of developing congestive cardiac failure with diabetes was 2.26 (95% CI 1.12-4.57) and of further amputation was 1.95 (1.14-3.33) times that of a patient without diabetes after incident LEA.

CONCLUSIONS

After LEA, patients with diabetes have an increased risk of death compared with nondiabetic patients. Efforts should be made to minimize these risks with aggressive treatment of cardiovascular risk factors and management of cardiac failure.

Magnetic resonance elastography of the plantar fat pads: Preliminary study in diabetic patients and asymptomatic volunteers

OBJECTIVE

To test the feasibility of applying the magnetic resonance elastography (MRE) technique to map the elastic modulus of the plantar fat pads in diabetic and nondiabetic subjects.

METHODS

A prototype MRE imaging apparatus was used to produce quantitative maps of the heel fat pad in a pilot study of 12 volunteers and 4 patients with diabetes with neuropathy. Anatomic images corresponding to MRE maps allowed precise selection of regions of interest in the fat.

RESULTS

Magnetic resonance elastograms of the heel fat pads were successfully created; mean measurements in the volunteers and the diabetic patients were 4.85 and 5.26 kPa, respectively.

CONCLUSION

It is feasible to perform MRE on the plantar fat pads and to produce elasticity maps. The trend toward stiffer fat pads, as demonstrated in patients with diabetes, suggests that the fat pads were qualitatively different. Magnetic resonance elastography offers great potential to investigate the mechanical properties of soft tissues in vivo noninvasively.

Hospital separations indicate increasing need for prevention of diabetic foot complications in central Australia

The aim of this study was to guide service provision for prevention of diabetic foot complications through the analysis of hospital separation data for those with diabetes in central Australia. We reviewed the hospital separation data for central Australia from 1992 to 1997 for adults known to be diabetic and those with diabetic foot complications. Foot complications were identified from International Classification of Diseases-9th Revision (ICD-9) codes. Additionally, we assessed the proportion of cases with diabetic foot, identified by ICD-9 coding and confirmed by record review, that were identified by Australian National-Diagnostic Related Group-Version 3 (AN-DRG-3) coding. Separations with diabetes doubled from 352 in 1992 to 796 in 1997. This represents an increase from 1232 to 2521 separations per 100,000 people over 15 years of age. Separations with foot complications increased threefold from 28 in 1992 to 90 in 1997, a rate increase from 98 to 285 per 100,000 people over 15 years of age. The proportion of diabetes separations that had foot complications remained around 10% during the 6 year period. Aboriginal people made up 89% of the individuals with foot complications and 91% of separations for diabetic foot. Foot complications were predominantly of the more acute type (90%), amenable to early intervention. The AN-DRG-3 code for diabetic foot identified only 59% (37/63 in 1997) of the separations identified by the ICD-9 codes, and admitted primarily for foot complications in Alice Springs Hospital. The known burden of hospital care for diabetes and diabetic foot complications has increased markedly in recent years. A combination of changes in prevalence, primary care utilisation, detection, hospital access or re-admission rates may underlie the observed increases. As it is very unlikely that diabetes or diabetic foot complications are being over diagnosed, or that the hospitals are over utilised, this analysis shows there is an increasingly apparent need for improved prevention of diabetic foot complications. Therefore primary health care systems should ensure that they implement evidence-based care for preventing foot complications among people with diabetes.

Altered heel-pad mechanical properties in patients with Type 2 diabetes mellitus

AIMS

To compare the heel-pad mechanical properties in patients with Type 2 diabetes mellitus with forefoot ulceration, without forefoot ulceration and age-matched healthy subjects.

METHODS

Heel-pad mechanical properties in 40 heels of 20 healthy subjects (group I) age-matched with the other groups, 42 heels of 21 diabetic patients without forefoot ulceration (group II), and 14 heels of 12 diabetic patients with active forefoot ulceration (group III) were assessed using a self-constructed loading-unloading device and a 10-MHz linear-array ultrasound transducer.

RESULTS

There were no differences in the unloaded heel-pad thickness, compressibility index and elastic modulus between the three groups. When compared with group I subjects (mean +/- SD, 27.9 +/- 6.1%), a significant increase (P < 0.001) was found in both group II (36.1 +/- 8.7%) and group III patients (43.2 +/- 6.6%) for the energy dissipation ratio. This ratio was also significantly different (P = 0.003) between groups II and III.

CONCLUSIONS

The higher impact energy dissipated in the heel-pad may put patients with Type 2 diabetes at higher risk for developing foot ulceration.

Recombinant human platelet-derived growth factor-BB (becaplermin) for healing chronic lower extremity diabetic ulcers: an open-label clinical evaluation of efficacy

Topically applied recombinant human platelet-derived growth factor-BB (becaplermin) is a new pharmacologically active therapy for chronic, neuropathic, lower extremity diabetic ulcers. In previous studies, becaplermin gel was administered once daily but dressings were changed twice daily. In the present study of 134 patients with diabetes mellitus and full thickness lower extremity ulcers, dressings were changed only once per day, simplifying the treatment regimen. Efficacy criteria included the percentage of patients achieving complete healing within the 20-week treatment period, the time to achieve complete healing, the rate of ulcer recurrence during the 6-month period following healing, and treatment compliance. Complete healing of ulcers was achieved in 57. 5% of patients, with a mean time to closure of 63 days and a recurrence rate of 21% at 6 months. Of the potential factors affecting ulcer healing, only drug compliance (p < 0.001), dressing compliance (p < 0.01), the presence of infection (p < 0.01), baseline ulcer area (p < 0.05), and baseline total wound evaluation score (p < 0.05) were significantly associated with healing. Results of this study further confirm the efficacy and safety of becaplermin gel for the treatment of lower extremity diabetic ulcers.

A new standard for the nursing assessment of leg ulcers

In the UK, the majority of patients with leg ulcers are treated by nurses in the community. Nurses are central to the diagnosis and management of these patients. Formal clinical assessments are not always conducted; where they are, there is not always compliance or access to Doppler ultrasound scanners, or training in the necessary skills and techniques. Assessment should be routine and systematic; an understanding of why each observation is required will aid compliance. This article includes a review of the current requirements for assessment and sets out a minimum standard. This has been devised with the practicalities of community nursing and of nurse accountability in mind.

The value of combined radionuclide and magnetic resonance imaging in the diagnosis and conservative management of minimal or localized osteomyelitis of the foot in diabetic patients

Early diagnosis of osteomyelitis is helpful for a successful conservative treatment. The value of bone scanning combined with granulocytes labeled with hexamethylpropylene amine oxime (HMPAO) granulocyte-Tc99m (GN) radionuclide imaging (combined [RI]) with magnetic resonance imaging (MRI) for the diagnosis of osteomyelitis was assessed in 24 diabetic patients with foot ulcers. Evidence of osteomyelitis was based on the presence of at least one of the following criteria: (1) clinical bone involvement, (2) radiological bone involvement, (3) both positive combined RI and MRI, and (4) evidence of clinical bone involvement during the follow-up period. Thirteen patients had osteomyelitis. Seven patients had clinical bone involvement (sensitivity, 54%), five had radiological bone involvement (sensitivity, 38%), and 10 had positive combined RI for osteomyelitis (sensitivity, 77%). MRI demonstrated a higher sensitivity (100%). The specificity for combined RI and MRI was 82%. These results lead to a new diagnostic strategy for the early detection of minimal or localized osteomyelitis to avoid amputations. MRI is most appropriate following a negative x-ray in determining whether to treat osteomyelitis, since a negative MRI result rules out osteomyelitis. Antibiotic therapy should be used in the case of a positive MRI result, but Charcot joint disease can lead to false-positive MRI results. In this case, combined RI should be performed.

Diabetic foot ulcers: A framework for prevention and care

Complications secondary to diabetes, such as diabetic foot ulcers, continue to be a major worldwide health problem. At the same time, health care systems are changing rapidly, causing concern about the quality of patient care. While the ultimate effect of current changes on health care professionals and patient outcomes remain uncertain, measures commonly used to reduce costs, e.g., disease and multi- disciplinary management strategies, have been shown to help prevent the occurrence of diabetic ulcers. In addition, utilizing a multi- disciplinary approach, the principles of off-loading and optimal wound care, the vast majority of diabetic foot ulcers can be expected to heal within 12 weeks of treatment. Education of primary care providers and patients is paramount.

Resection of the metatarsal head for diabetic foot ulcers

BACKGROUND

Diabetic foot ulceration is a worldwide health problem. Approximately 15% of the 10 million diabetic patients in the United States will develop a foot ulceration at some time in their lives. The presence of a foot ulcer in this population is extremely debilitating and dramatically increases the risk of lower extremity amputation, accounting for approximately 67,000 lost limbs each year. Additionally, the costs associated with treating foot ulcers in diabetic patients is a major expense in the overall care of this patient group.

METHODS

An 11-year retrospective study was conducted to evaluate 101 consecutive patients with diabetic ulcers of the forefoot who were treated using resection of the metatarsal head as the primary means of obtaining wound closure.

RESULTS

The results indicate that 88% of the ulcers were healed by using this technique, and relatively more rapidly than would be expected when compared with historical norms.

CONCLUSIONS

Resection of the metatarsal head is a safe and relatively inexpensive procedure that facilitates closure of the lesion, helps to control infection, and prevents countless and costly amputations.

Diabetic foot ulcers: current concepts

Foot ulcerations and their sequelae remain a major source of morbidity for patients with diabetes mellitus. Often leading to infection, osteomyelitis, or gangrene, these lesions have consistently been ascertained as significant risk factors for subsequent lower extremity amputation. Hence education, appropriate foot care, and early intervention have assumed important roles in programs focused on amputation prevention. Multidisciplinary cooperation has been demonstrated as the most successful approach to the management and prevention of foot lesions in patients with diabetes. This article reviews the epidemiology, current understanding of the underlying pathophysiology, and treatment rationale for diabetic foot ulcerations. Such knowledge is essential in the overall management of these complicated patients and, when incorporated into daily practice, can significantly reduce the incidence and morbidity of foot disease in diabetes.

Longitudinal in-shoe foot pressure relief achieved by specially designed footwear in high risk diabetic patients

Specially designed Thor-Lo footwear has been shown to reduce the in-shoe foot pressures in diabetic patients at risk of foot ulceration when compared to their own footwear. Fifty at high risk patients 32 (64%) males, 17 (34%) type 1 diabetes) have been provided with this foot wear and have been followed up for 6 months. Mean age was 57.6 (range, 34-78) years, duration of diabetes 22.4 (range, 4-50) years, Neuropathy Symptom Score 3.36 +/- 2.96 (mean +/- S.D.), Neuropathy Disability Score 16.8 +/- 6.83, VPT 43.4 +/- 11.8 Volts while 43 (86%) could not feel a 5.07 or smaller Semmes-Weinstein monofilament. Forty-two (84%) patients were re-examined at an interim visit 3 months after baseline, while 37 (74%) completed the study. In-shoe peak forces and pressures were measured using the F-Scan system. No difference was found among the peak force among baseline (95.5 +/- 26 kg), interim (96.5 +/- 33) and final visit (97.7 +/- 25.2, P + NS). There was no difference in peak pressures at the baseline (3.98 +/- 1.42 kg.cm-2), second visit (4.13 +/- 2.30) and the final visit (4.25 +/- 1.51). Nine (18%) patients developed foot problems and one died during the study. We conclude that no changes in foot pressures were found over a period of 6 months of continuous usage of the specially designed footwear in a group of diabetic patients at risk of foot ulceration. Further prospective studies are required to evaluate the impact of specially designed footwear in reducing the rate of foot ulceration.

Why bother educating the multi-disciplinary team and the patient--the example of prevention of lower extremity amputation in diabetes

Amongst all the long-term complications of diabetes it is believed that foot ulceration and amputation are the most preventable: small studies have suggested that more than 50% of amputations should be avoidable by screening and appropriate education. There is ample evidence that simple non-invasive screening tests are not being carried out in many diabetic clinics--one study confirmed that poor patient care was responsible for 50% of heel ulcers in a hospital setting. There is a similar lack of awareness of potential problems in many 'at risk' diabetic patients. Thus, simple screening of diabetic patients should be routine clinical practice: those identified as being at 'high risk' of foot, problems should receive appropriate education in protective foot care. The rewards are potentially great, and include the realization of the St. Vincent target, a 50% reduction in amputation.

Differences in joint mobility and foot pressures between black and white diabetic patients

Limited joint mobility is common in diabetes and is related to high foot pressures and foot ulceration. We have examined the differences in joint mobility and foot pressures in four groups matched for age, sex, and duration of diabetes: 31 white diabetic, 33 white non-diabetic, 24 black diabetic, and 22 non-diabetic black subjects. Joint mobility was assessed using a goniometer at the fifth metacarpal, first metatarsal, and subtalar joints. In-shoe and without shoes foot pressures were measured using an F-Scan system. Neuropathy was evaluated using clinical symptoms (Neuropathy Symptom Score), signs (Neuropathy Disability Score), and Vibration Perception Threshold. There was no difference between white and black diabetic patients in Neuropathy Symptom Score, Neuropathy Disability Score, and Vibration Perception Threshold. Subtalar joint mobility was significantly reduced in white diabetic patients (22 +/- 7 degrees) compared to white controls (26 +/- 4 degrees, black diabetic patients (25 +/- 5 degrees), and black controls (29 +/- 7 degrees), and increased in black controls compared to white controls and black diabetic patients (level of statistical significance p < 0.05). Without shoes foot pressures were higher in white diabetic patients (8.31 +/- 400 kg cm-2) compared to white controls (6.81 +/- 2.31 kg cma2), black diabetic patients (6.2 +/- 2.53 kg cm-2) and black controls (5.00 +/- 1.24 kg cm-2) and lower in black controls compared to white and black diabetic patients (p < 0.05 in all cases). We conclude that racial differences exist in joint mobility and foot pressures between black and white subjects.(ABSTRACT TRUNCATED AT 250 WORDS)