Lindy Begg

Randomized trial of custom orthoses and footwear on foot pain and plantar pressure in diabetic peripheral arterial disease

Aim  Custom‐made foot orthoses reduce plantar pressure, ulceration and amputation in patients with diabetes mellitus. There is limited evidence of their effect on foot pain. In a randomized, single‐blind, sham‐controlled trial, the efficacy of custom orthoses on foot pain and plantar pressure in diabetic patients with peripheral arterial disease was investigated.

Characteristics of diabetic foot ulcers in Western Sydney, Australia

BackgroundAustralia is ranked ninth of 39 countries in the Western Pacific region most affected by diabetes. Patients with diabetes are at high risk of developing foot ulcerations that can develop into non-healing wounds. Recent studies suggest that the lifetime risk of developing a diabetic foot ulcer is as high as 25%. Few studies have reported the prevalence of, risk factors and socioeconomic status associated with, diabetic foot ulcers in Australia. The aim of this study was to evaluate the characteristics of diabetic foot ulcers in a tertiary referral outpatient hospital setting in Western Sydney, Australia.MethodsFrom January-December 2011, a total of 195 outpatients with diabetes were retrospectively extracted for analysis from the Westmead Hospitals Foot Wound Clinic Registry. Data on demographics, socioeconomic status, co-morbidities, foot ulcer characteristics and treatment were recorded on a standardised form.ResultsDemographics and physical characteristics were: 66.2% male, median age 67 years (IQR: 56-76), median body mass index (BMI) of 28 kg/m2 (IQR: 25.2-34.1), 75.4% had peripheral neuropathy and the median postcode score for socioeconomic status was 996 (IQR: 897-1022). Diabetic foot ulcer characteristics were: median cross sectional area of 1.5 cm2 (IQR: 0.5-7.0), median volume of 0.4 cm3 (IQR: 0.11-3.0), 45.1% on the plantar aspect of the foot, 16.6% UT Wound Grade of 0C to 3C (with ischaemia) and 11.8% with a Grade 0D to 3D (with infection and ischaemia) and 25.6% with osteomyelitis. Five patients required an amputation: 1 major and 4 minor amputations.ConclusionsIn accordance with other international studies, foot ulcers are more likely to present on the plantar surface of the foot and largely affect overweight older males with a long standing history diabetes in our outpatient hospital in Western Sydney.

Optimizing the offloading properties of the total contact cast for plantar foot ulceration

Diabet. Med. 28, 179–185 (2011)

Interrater and intrarater reliability of photoplethysmography for measuring toe blood pressure and toe-brachial index in people with diabetes mellitus

BackgroundA reliable tool to measure arterial flow to the feet in people with diabetes is required given that they are particularly prone to peripheral arterial disease. Traditionally, the ankle brachial index (ABI) has been used to measure arterial circulation, but its application is limited due to calcification of larger arteries. More recently, toe pressure and the toe brachial index (TBI) has been suggested as superior to ABI measurements because they assess smaller digital arteries less prone to arterial calcification. However, reliability studies for the clinical use of photoplethysmography (PPG) in people with diabetes are lacking.MethodsSixty people with diabetes mellitus (35 males and 25 females, mean age 59.6 yrs) consented to take part in the study. The majority (92%) had type 2 diabetes and 8% had type 1 diabetes. Forty-three percent were diagnosed as having peripheral neuropathy when tested using a biothesiometer and 15% were current smokers (10 – 40/day). A podiatrist and a diabetes educator measured toe and brachial blood pressure independently and in a random order using PPG. These measurements were repeated again seven days later, and subsequently analysed with intraclass correlation coefficients (ICC), 95% confidence intervals (CI) and standard error of measurement (SEM).ResultsThe intrarater reliability of measuring toe pressures was excellent (ICC3,1 =0.78-0.79, SEM 8 mmHg) and interrater reliability was also excellent (ICC2,2 = 0.93, SEM 4 mmHg). The intrarater reliability for measuring brachial pressures was generally poor (ICC3,1 = 0.40 – 0.42, SEM 19 mmHg) and interrater reliability was fair-good (ICC2,2. 0.65, SEM 14 mmHg). The TBI intrarater reliability was fair-good (ICC3,1 = 0.51-0.72, SEM 0.08), whilst the interrater reliability of TBI was excellent (ICC2,2 = 0.85, SEM 0.07).ConclusionsBased on these results, interrater and intrarater reliability of PPG is excellent for measuring toe blood pressure, good for TBI and only fair for brachial pressures in people with diabetes mellitus.

Comparison of orthotic materials on foot pain, comfort, and plantar pressure in the neuroischemic diabetic foot: a case report.

Foot pain and lower-limb neuroischemia in diabetes mellitus is common and can be debilitating and difficult to treat. We report a comparison of orthotic materials to manage foot pain in a 59-year-old man with type 1 diabetes mellitus, peripheral neuropathy, peripheral arterial disease, and a history of foot ulceration. We investigated a range of in-shoe foot orthoses for comfort and plantar pressure reduction in a cross-sectional study. The most comfortable and most effective pressure-reducing orthoses were subsequently evaluated for pain relief in a single system alternating-treatment design. After 9 weeks, foot pain was completely resolved with customized multidensity foot orthoses. The outcome of this case study suggests that customized multidensity foot orthoses may be a useful intervention to reduce foot pain and maintain function in the neuroischemic diabetic foot.

A novel approach to mapping load transfer from the plantar surface of the foot to the walls of the total contact cast: a proof of concept study

BackgroundTotal contact casting is regarded as the gold standard treatment for plantar foot ulcers. Load transfer from the plantar surface of the foot to the walls of the total contact cast has previously been assessed indirectly. The aim of this proof of concept study was to determine the feasibility of a new method to directly measure the load between the cast wall and the lower leg interface using capacitance sensors.MethodsPlantar load was measured with pedar® sensor insoles and cast wall load with pliance® sensor strips as participants (n=2) walked along a 9 m walkway at 0.4±0.04 m/sec. The relative force (%) on the cast wall was calculated by dividing the mean cast wall force (N) per step by the mean plantar force (N) per step in the shoe-cast condition.ResultsThe combined average measured load per step upon the walls of the TCC equated to 23-34% of the average plantar load on the opposite foot. The highest areas of load on the lower leg were located at the posterior margin of the lateral malleolus and at the anterior ankle/extensor retinaculum.ConclusionsThese direct measurements of cast wall load are similar to previous indirect assessment of load transfer (30-36%) to the cast walls. This new methodology may provide a more comprehensive understanding of the mechanism of load transfer from the plantar surface of the foot to the cast walls of the total contact cast.

SGLT2 inhibitors and amputation risk: Real-world data from a diabetes foot wound clinic

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are effective agents in the management of type 2 diabetes mellitus (T2DM), with significant improvements in glycaemic control and favourable cardiovascular and renal profiles [1,2]. In 2017, however, the CANVAS and CANVAS-R trials reported a two-fold increase in the occurrence of lower limb amputations (LLAs) in participants receiving canagliflozin [2]. These were predominantly toe or metatarsal amputations and they occurred in individuals without established peripheral vascular disease prior to study commencement. These findings prompted the United States Food and Drug Administration (FDA) to issue a caution on the use of canagliflozin in individuals at risk of amputation [3]. Other SGLT2i have not been associated with an increased risk of LLA. In the EMPA-REG OUTCOME study, rates of LLAs were not significantly higher in those randomised to empagliflozin [4]. Similarly, a pooled analysis of 30 phase II and III trials did not find a significant association between dapagliflozin and LLAs [5]. However, real-world data are lacking, in particular regarding the use of SGLT2i amongst people at high baseline risk of amputation. Whether SGLT2i increase the risk of poor wound healing in subjects with established diabetic ulcers and severe peripheral vascular disease remains an open question. On this basis, the European Medicines Agency has adopted a cautious approach, advising against the use of any SGLT2i in patients at risk of amputation until further data are available [6]. We conducted a retrospective case-controlled study of people with T2DM attending a foot-wound clinic in a tertiary hospital in Sydney, Australia over a 30-month period (April 2015-September 2017). Incidences of LLAs, including minor and major amputations, were compared in participants with active diabetic foot wounds who were receiving SGLT2i or not. Twenty-seven people with open foot wounds who were receiving SGLT2i therapy were identified. Among them, 16 were on dapagliflozin (59%), 9 were on empagliflozin (33%), 1 person took dapagliflozin which was changed to empagliflozin, and another person took canagliflozin which was changed to dapagliflozin. They were matched by age, duration of diabetes, HbA1c, and smoking status, in a 1 to 3 ratio, with control subjects with diabetic foot wounds who were not receiving SGLT2i for the study duration. Renal function was not statistically different between the groups and on average, control subjects did not have a degree of renal dysfunction that would contraindicate SGLT2i use. In the SGLT2i group, only LLAs that occurred more than one month following the commencement of therapy were included. The mean duration of SGLT2i use was 12.9 ± 5.3months, and the control group was observed for a similar duration. Baseline characteristics and amputation rates in each group are listed in Table 1. Ten out of the 27 (37.0%) people in the SGLT2i group had at least 1 episode of LLA, compared to 37 of the 81 (45.7%) people in the control group. The odds ratio of having an LLA in association with SGLT2i use was not significant (OR 0.70 [95% CI 0.29, 1.71]; p= 0.43). Similarly, there were a total number of 11 LLAs in the SGLT2i group (0.41 per patient) while there were 49 LLAs in the control group (0.60 per patient) and the difference between the groups in the number of LLAs was not statistically significant (difference −0.19 [95% CI −0.52, 0.13]; p= 0.23). Therefore, the number of people having LLA and the number of LLAs in each of the groups were not significantly higher in the SGLT2i group. To date, safety data exonerating empagliflozin and dapagliflozin did not specifically stratify subjects on the basis of their baseline amputation risk or on the presence of established foot wounds. By studying such a high-risk population, our study seeks to clarify whether SGLT2i

Using standard treatment and offloading principles to heal a wound of a patient who ambulates upon “all fours”

Background A 71 year old, weighing 80 kg was referred to the Foot Wound Clinic despite not having feet. The patient had suffered a traumatic Above Knee Amputation of the right limb and an Above Knee Amputation of the left limb from the same incident in 1969. The patient ambulates on “all fours” or upon the femurs alone and continues to work full-time as a landscaper. The patient presented for review of a wound over the right stump with the expectation that he would undergo surgical debridement and a skin graft. The patient had adequate arterial flow therefore with standard wound care and offloading, healing should ensure. The patient has been referred to Rehabilitation Services for review and in the interim consented to being treated with a Total Contact Cast (TCC).