because casts cannot be removed by patients, there is a strong element of forced compliance with this therapy.
Patients have no choice but to keep pressure off their ulcer during every step they take during the day.
It has been theorised that the total contact nature of the cast disperses forces to the lower tibia; however, there is little evidence to support this notion.
TCCs probably reduce shear forces on the sole of the foot because they limit joint motion of the foot and ankle, force an apropulsive gait pattern and reduce stride length and cadence.
TCCs have been shown to reduce pressure at the site of ulceration by 84, 92%.21,22 This is far superior to most other commercially available products.
TCCs have a significant impact on patients’ level of activity.
Because a TCC is confining and heavy, patients simply walk less.
For instance, in a randomised clinical trial that compared TCCs, removable cast walkers (RCW) and healing sandals, patient treated with TCCs had a higher proportion of wounds that healed (90%) compared to either the RCW (65%) or the healing sandal (58%) group.9 In addition, patients in TCCs took 58% fewer steps than subjects treated with healing sandals and 22% fewer steps than subjects treated with RCWs.9,23
BARRIERS TO USING TOTAL CONTACT CASTS The TCC was a concept that was developed and popularised by Dr Paul Brand as a tool to heal neuropathic foot wounds in people with leprosy (Hansen’s disease) in India.
It was ideal for this rural setting because it was inexpensive and the materials were readily available even in an impoverished area with few medical resources.
Dr Brand subsequently taught this technique at workshops on the insensate limb at the Gillis W.
Long Hansen’s Disease Centre in Carville, Louisiana.
It is ironic that despite a large body of clinical and laboratory evidence in post- industrialised countries with advanced therapies and abundant resources, TCCs are not widely used.
There are several practical barriers that limit their adoption by the general medical com- munity.
TCCs are difficult to apply.
TCCs require a physician, therapist or cast technician who is skilled at using this technique.
In an insensate patient, tight or incorrectly applied casts can cause iatrogenic wounds.
Total contact casting can require a significant amount of human resources, materials and space in a busy clinic.
In addition, TCCs must be removed and then fully reapplied every 7 to 14 days.
In settings with a low volume of foot wounds, dedicating the resources and training to safely and effectively apply TCCs may not be practical.
However, even when TCCs are applied correctly, patients often complain that the cast is hot and heavy.
It is difficult to bathe and sleep with a TCC, especially in the elderly, obese patients.
Many patients will refuse this type of therapy without a dedicated clinician to explain the risks and benefits of this form of TCCs.
REMOVABLE CAST WALKERS
There are a number of removable cast walkers (RCWs) that have been designed to help protect and heal foot wounds in people with diabetes.
RCWs offer several advantages compared to TCCs.
RCWs are relatively inexpensive, and the protective inner sole can be easily replaced if it shows signs of wear.
The DH pressure relief walker (Royce Medical, Camarillo, CA, USA) has been shown to be almost identical to TCCs in pressure reduction at the site of ulcerations on the sole of the foot (Figure 25.2).21,22 It does not require special training to correctly and
JWBK089-25 JWBK089-Boulton April 24, 2006 19:51 Char Count= 0
298 CONVENTIONAL OFFLOADING AND ACTIVITY MONITORING
Figure 25.2 Removable cast walker. Active offloading walker, Royce Medical, Camarillo, CA, USA
safely apply these devices.
In addition, they can be easily removed to assess and debride the wound, to bathe or to sleep.
And they can be used in patients with infection or severe PVD.
Standard RCWs have been demonstrated to reduce peak pressures as effectively as TCCs,21,22 but in both descriptive studies and randomised clinical trials, TCC have higher rates of healing.9,12,24 A logical explanation for RCWs’ less effective clinical performance is non-compliance to treatment: these devices are being removed by the patients who use them.23 Armstrong and colleagues measured the number of steps taken with and without a remov- able cast boot in 20 patients with neuropathic foot ulcerations.
Activity was measured from a waist-worn computerised accelerometer and correlated to activity recorded on an accelerome- ter mounted on the RCW, which was not readily accessible to the patient.
Surprisingly, patients removed the RCW for 72% of their daily activity on average.
Although a total of 30% of the patients in the study recorded more daily activity while wearing the device, this subgroup wore the RCW only for 60% of their total daily activity.23 It would be ideal to be able to take the clinical efficacy of the TCC and combine it with the relative ease of application of the RCW.25,26 In an effort to achieve this, Armstrong and Katz
JWBK089-25 JWBK089-Boulton April 24, 2006 19:51 Char Count= 0
HEALING SANDALS AND HALF SHOES 299
modified the RCWs by merely wrapping them with a layer of cohesive tape or plaster bandage.
This technique has been termed the ‘instant’ total contact cast (ITCC).24−26 In two randomised clinical trials, this technique has demonstrated clinical efficacy and safety.
Armstrong et al.26 compared a commercially available cast boot (Royce Medical, Camarillo, CA, USA) and the same RCW but making it ‘irremovable’.
A significantly higher proportion of patients healed at 12 weeks in the ITCC group when compared with the RCW (86.4% vs 58.3%).
Of the patients that healed, persons treated with the ITCC healed significantly faster (41.6 ± 18.7 days vs 58.0 ± 15 days).
Katz and colleagues24 then compared the ITCC concept to a traditional TCC and found no difference in clinical outcomes or complications.
The mean healing time was 5.4 weeks in the TCC group and 5.1 weeks in the ITCC group.
We conclude that the ITCC is equally efficacious in healing diabetic foot ulcers, when compared to the TCC.
However, it was quicker, easier and more cost-effective than the TCC.
The concept of an ITCC allows physicians, nurses and technicians to significantly improve the effectiveness of offloading with no additional training or expertise.
The cost of many RCWs is similar to the cost of materials required to apply a TCC.
Initial studies demonstrate the same proportion and rate of wound healing compared to TCCs.
This is a very straightforward approach that can be adopted by most physicians that care for the diabetic foot.
CHARCOT RESTRAINT ORTHOTIC WALKER
The Charcot restraint orthotic walker (CROW) is a custom-made lower extremity clamshell foot and ankle orthosis that is designed to protect the neuropathic foot and aids in con- trolling lower extremity oedema.
The CROW is a rigid polypropylene shell with a rocker bottom sole (Figure 25.3).
The primary drawback to this type of device is that it is cus- tom made and often takes several weeks to manufacture.
It is very expensive, and if the structure or size of the lower extremity changes because of oedema or muscle atrophy, the custom device will no longer fit properly, and it cannot be used.
Unfortunately, there is very little evidence in the medical literature that supports the effectiveness of this offloading technique.27
HEALING SANDALS AND HALF SHOES There are growing numbers of healing sandals, half shoes and wedged shoes designed to reduce pressure on the forefoot.
Half shoes such as the OrthoWedge or Darco products were originally designed to protect the forefoot after elective surgery (Figure 25.4).
Half shoes are not very well accepted by patients.
They are difficult to walk in.
They often cause pain of the contralateral extremity, and patients with postural instability cannot safely use the device.
As a result, compliance with these modalities is generally poor, and this is reflected in the clinical outcomes reported in the medical literature.9,22,28,29 Healing sandals can be custom made and moulded to the contour of the foot (Figure 25.5).
Surgical shoes can be quickly modified by adding a pressure-reducing insole.
In addition, there are a number of commercially available products designed specifically for the diabetic foot.
These are easy to use and ideal for patients with impaired balance.
They are tolerated well, but offer a significant compromise in pressure reduction and healing potential.
There are a number of reports that give us insight into the effectiveness of various heal- ing sandals to treat foot ulcers in persons with diabetes.
Veves and colleagues18 used a
JWBK089-25 JWBK089-Boulton April 24, 2006 19:51 Char Count= 0
300 CONVENTIONAL OFFLOADING AND ACTIVITY MONITORING
Figure 25.3 (a,b) Charcot restraint orthotic walker (CROW)
JWBK089-25 JWBK089-Boulton April 24, 2006 19:51 Char Count= 0
FELTED FOAM PADDED DRESSINGS 301
Figure 25.4 Darco half shoe
custom-healing sandal as the standard offloading modality in the pivotal, randomised clinical trail of Graftskin.
Only 38% of subjects healed in the control arms, with an average healing time of 90 days.
Likewise, Armstrong and colleagues9 evaluated a half shoe (Darco, Huntington, WV, USA) compared to a removable cast boot and TCC, in a 12-week randomised clinical trial.
Subjects treated with the half shoe had the lowest proportion of healed wounds (58%) and slowest rates of healing, with an average healing time of 61 days, compared to 33.5 days in the TCC group and 50.4 days in the RCW group.
Likewise, Ha Van and colleagues28 reported that more patients with neuropathic ulcers healed faster when immobilised with a fibreglass cast (81%) compared to healing sandals (70%).
Cast therapy was also protective against deep infection.
In addition, very poor com- pliance was observed with the healing sandal.
Only 10% of patients were compliant with the healing sandal compared to 98% of patients treated with fibreglass casts.