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6

VOLUME 14 NUMBER 1 • JULY 2017

REVIEW

SA JOURNAL OF DIABETES & VASCULAR DISEASE

Although there are indications that therapeutic footwear may

be effective in secondary prevention of DFUs,

8

according to some

literature, there are no experimental studies that report on the role

of therapeutic footwear in primary ulcer prevention compared to

normal footwear. This conclusion only came about because one

randomised control trial found no effect of therapeutic footwear

in the secondary prevention of ulcers.

8,20

However other literature

suggests that various designs of therapeutic footwear such as rocker

bottom outsole and half-shoes can effectively off-load at-risk foot

regions, thus preventing ulcer formation or recurrence.

8

Key message:

Therapeutic footwear and custom-made

orthoses are generally used by podiatrists to prevent the

secondary occurrence of DFU.

and MP caused a substantial and additive reduction in pressure (29

to 47%) under the metatarsal heads of the feet by increasing the

contact area of weight-bearing forces when compared to wearing

shoes alone. In addition, it was reported that the MP reduced the

pressure at the metatarsal heads of feet by off-loading the soft

tissue and bone structures proximal to the metatarsal heads.

21

These findings are similar to a study done by Tong and Ng who

investigated the amount of pressure reduction that occurred in feet

when using different types of padding and four insole materials that

are commonly used in podiatry. In this study it was found that all four

commonly used materials, Slow Recovery Poron (SRP), Poron, Poron

+ Plastazote firm (PPF) and Poron + Plastazote soft (PPS), were able

to reduce pressure across the whole foot, with PPF achieving the

most significant result of 28% pressure reduction. The subjects in

this study were also tested with a semi-compressed felt metatarsal

pad (Fig. 3) with an aperture on the first metatarsophalangeal joint

of both feet. The peak pressure in this area showed a significant

reduction of 37% compared to a 29% decrease when PPF was

used alone.

22

Overall, both studies noted that the human foot generally has

increased pressure at the periphery of the aperture site, which,

if not corrected, can cause harmful skin breakdown, and in the

insensate feet of diabetic patients, this can sometimes lead to

severe ulceration. In addition, the pressure responses varied in

the two studies, suggesting that pressure reduction in terms of

using footwear and orthotic devices is highly dependent upon the

condition of the patient’s feet and the patients’ health status, as

well as differences in metatarsal pad material used, including its

size and shape.

Fig. 2.

Custom-made orthoses.

Fig. 3.

Semi-compressed felt metatarsal pads.

Total-contact casting

Over the years, total-contact casting (TCC) has been known to be

more effective in the treatment of non-infected diabetic plantar

neuropathic ulcers, compared to other removable off-loading

devices. Studies by Sambrook

et al.

noted that TCC has been shown

to reduce plantar pressure by 84 to 94%, and increase healing rates

and treatment time of plantar ulcers.

23

However, TCC is a difficult and time-consuming treatment for

podiatrists to apply and generally there is low patient tolerance, with

a number of side effects associated with its application. Therefore

most clinicians prefer to not use this technique and rather prescribe

various other off-loading techniques that are far easier to apply,

such as felt padding, removable cast walkers (RCW), therapeutic

footwear and orthotic devices.

24

Studies performed by Fife

et al.

using real-world data from a

large wound-care registry found that only 6% of DFU patients

received TCC.

25

Some years later in their reflective analysis, Fife

et

al.

found that in over 25 000 patients with diabetes, only 3.7% of

eligible ulcers received TCC.

26

Currently there are no data on the

use of TCC for the management of DFUs in South Africa.

Alternative approaches of non-removable off-loading devices

that are far more effective have been developed in recent years.

These are a substitute for the classic Plaster-of-Paris total-contact

casting. Armstrong and colleagues performed a study to evaluate

the effectiveness of a RCW (Fig. 4) and an ‘instant’ total-contact

cast (iTCC) (Fig. 5) in the healing of neuropathic DFUs.

27

Patients

with foot ulcers that were cast using iTCC reported more significant

ulcer healing rates of 82.6% over a 12-week period than the 51.9%

healing of patients who received RCW.

Fig. 4.

Removable cast walker.