Total contact casting versus traditional dressing in diabetic foot ulcers

Abstract

This study compared the treatment of total contact casting (TCC) with traditional dressing treatment (TD) in the management of neuropathic diabetic plantar ulcers. Thirty-one patients with plantar ulcers without any gross infection, osteomyelitis or gangrene were randomly assigned to the TCC group (n = 15) or TD group (n = 16). In the experimental group, TCC was applied on the initial visit and subjects were instructed to limit ambulation to one-third of their usual activity. Subjects in the control group (TD) were prescribed dressing changes and were advised against bearing weight on the involved extremity. Ulcers were considered healed if they showed complete skin closure with no drainage. Ulcers were considered not healed if they showed no decrease in size by 6 weeks or if infection developed requiring hospitalization. In the TCC group, 12 of 15 ulcers healed in 48 ± 7 days; in the TD group, 10 of 16 ulcers healed in 58 ± 9 days. Comparatively higher rate of ulcer healing with fewer infections was seen in the TCC group. We conclude TCC is a more effective method than dressing for treating diabetic plantar ulcers reducing the risks of amputation.

Introduction

Neuropathic ulcers are the prime precipitant of diabetes-related amputations of the lower extremity. ¹ Traditionally, diabetic foot ulcers are treated with regular dressings with frequent debridements with minimal weight bearing on the affected foot. The key element of any treatment programme designed to heal these wounds is effective reduction in pressure (offloading). ^2,3

Several offloading devices are available, such as walkers, half shoes, orthoses, felted foam and the total contact casting (TCC). Total contact casts are anatomically confirming below knee cast with minimal padding. TCC acts by providing protection from further trauma and deformity, reducing oedema, immobilization to help bone and soft tissue healing, offloading or redistribution of pressure and by providing protected weight bearing.

This study is aimed to compare the treatment of TCC with traditional dressing treatment (TD) in the management of diabetic plantar ulcers with respect to outcomes and complications. ⁴

Materials and methods

All the patients with diabetic foot ulcers up to grade 2 of Wagner’s classification system (ulcers extending into soft tissues without abscess or osteomyelitis), attending the outpatient department of VIMSAR, Burla, were included in this study. Patients with ulcers higher than grade 2 of Wagner’s classification, with active infection, non-ambulatory patients, patients with wounds in locations on the hind foot or area other than the plantar aspect of the foot, moderate-to-severe limb ischemia, that is, absence of both pedal pulses on the affected foot and/or ankle brachial index of <0.9, were excluded from the study. If patients had more than one plantar wound, the largest wound was used as the index ulcer for inclusion in this study.

A detailed history was taken from each patient regarding the duration and type of diabetes, duration of ulcer, any prior treatment taken for ulcer and any other co-morbid condition like ischemic heart diseases, renal or ophthalmological problem. General and systemic examinations were performed. Detailed examination of involved foot was done to determine the ulcer location, size, shape, depth, any discharge, tenderness or rise in temperature. Ulcers were graded according to Wagner’s system. ⁵

Any foot deformity caused by neuropathy or Charcot joint such as clawing, cavus or valgus foot was noted. Vascular evaluation was done by checking pedal pulses (dorsalis pedis and posterior tibial), capillaries filling time to the digits, ankle brachial index, oximetry and Doppler ultrasound studies. Anteroposterior and oblique X-ray views of the foot were taken to exclude the presence of osteomyelitis or Charcot joint. The patients were randomly assigned to the TCC group or to the TD group.

Before applying total contact cast, hypertrophic marginal callus, necrotic tissue, infected and foreign material around the ulcer were debrided. Wound was then irrigated with saline and properly dressed with a povidone iodine soaked gauze pad. Once the ulcer became clean, total contact cast was applied. Interdigital padding was given first. Stockinette was applied from the knee to the toes taking care that it neither wrinkled nor bunched. Cotton padding was applied over the stockinette. Extra padding was applied over the malleoli and over the shin. Plaster of Paris cast was applied over cast padding, starting from one inch distal to fibular head and extending up to the tip of the toes. The cast was moulded to the exact contour of the leg and foot to provide maximum contact (Figure 1). Patients were advised to limit ambulation to one-third of usual activities. They were followed up weekly and TCC was renewed till the ulcer healed. On each visit, ulcer size was measured and complications like skin breakdown, new ulcer or joint problem were noted. Cast treatment was terminated when there was no reduction in size or depth of the wound during 4 consecutive weeks, when an infection developed or when the patient had some discomfort with the cast. These cases were defined as cast failure.

Figure 1.

Method of total contact cast application.

In the second group (TD), callus, necrotic tissue and foreign material were debrided and traditional dressing with povidone iodine solution was applied. Patients were advised to avoid weight bearing. Dressing was done every 2 days after proper cleaning and debridement of the wound. Patients who missed three or more dressings consecutively were excluded from the study.

Main outcome measures included the percentage of the ulcers healed and time to heal. Data were collected and analyzed on SPSS software. Student’s t-test was used to compare mean duration of diabetes, presence of other complications of diabetes, mean size and duration of ulcer.

Results

Thirty-three patients were enrolled in this randomized controlled trial. Two patients were lost to follow-up, so finally there were 31 patients in the study. Two patients had recurrent ulcers. Twenty-four (77.4%) patients were males and 7 (22.6%) were females. The mean age was 60 ±7.52 years. Of the 31 ulcers, 15 ulcers were treated with total contact cast and 16 ulcers were with traditional dressing. Ulcers treated with TCC healed in a mean duration of 48 ± 7 days (6–7 casts; Figure 2) while those treated with TD took an average of 58 ± 9 days to heal (p = 0.011). Three (20%) ulcers in the TCC group and 6 (37.5%) in the TD group did not heal.

Figure 2.

Pre and post total contact casting.

Of the 9 non-healing ulcers, 4 patients, that is, 3 in TD group (18.7%) and 1 in TCC group (6.7%) developed osteomyelitis. Two cases of osteomyelitis in TD group required amputation while the other two were treated with curettage, debridement and dressing.

Discussion

Pressure reduction is a critical component of therapy in the management of diabetic foot ulcers. The total contact cast has proved to be the standard treatment because of its ability to reduce pressure on the ulcer area along with providing mobility, thereby facilitating patients’ adherence to the method. ⁶ Several orthotics aid offloading, most of these are removable and strict compliance is not achieved thus reducing their effectiveness. TCC has the advantage that it cannot be easily removed by the patient and limits the activity of patients, which helps in rapid healing of ulcers. When correctly applied, it has proved not only to interrupt the chain of pathogenesis that produces the ulceration but also to induce modifications in the histology of the ulcer.

Patients with obvious foot deformity yield better results because ulcers were due to mechanical derangement caused by diabetic neuropathy, which was corrected with TCC. Poor patient’s compliance has been a problem with TCC which require repeated counselling and reassurance. Using TCC, majority of the ulcers in this study healed in a relative short time (mean 48 days). Various studies by Baker et al., Armstrong et al. and so on report healing rates between 73% and 100% from 1 month to several weeks (Figure 3). ^7,8,9

Figure 3.

Healing rates of TCC in various studies.

Traditional dressing though cheaper and commonly done doesn’t address the pathogenesis of the ulcer. It also has no effect on the deformities which cause the ulcers leading to unfavourable results.

Although TCC makes for a highly attractive offloading modality, it has its disadvantages like occurrence of new ulcers, hampering of daily wound care, impaired mobility and relatively high cost. Joint rigidity and muscular atrophy occur in prolonged casting.

The limitations of the study were the small number of patients. There are studies regarding the efficacy of total contact cast or comparing total contact cast with other methods of offloading. There are very few comparative studies regarding traditional dressing and TCC.

Conclusion

TCC is an effective treatment modality for neuropathic, non-ischemic, early grade diabetic foot ulcers. TCC achieves forefoot unloading by transfer of load from the leg directly to the cast wall and greater proportionate load sharing by the heel. ¹⁰ It requires careful application, close follow-up and patient compliance with scheduled appointments to minimize complications. TCC minimizes the risks of amputation and provides a better and earlier outcome than traditional dressing. The high efficacy of the total contact cast with the low risk of major complications will continue to make it a gold standard for the treatment of neuropathic foot ulcers.