Transitional off-loading: an evidence-based approach to pressure redistribution in the diabetic foot

Prediction of callus and ulcer development in patients with diabetic peripheral neuropathy by isosceles triangle-forming tuning fork

Objectives:

Tuning fork vibration sensation testing is widely used as a diagnostic test to detect diabetic neuropathy. However, evidence-based literature indicates that reliability between examiners is low. Attaching isosceles triangle diagrams on tuning forks lowers the discrepancy between examiners. This study aimed to analyze the relationship between vibration sensation measurement using an improved tuning fork and the presence of callus and wound development in patients with diabetic peripheral neuropathy.

Methods:

Participants included 56 general older adults and 52 patients with diabetic peripheral neuropathy. The methods included confirmation of the presence or absence of callus, range of motion of the ankle and the first metatarsophalangeal joint, vibratory sensitivity of the medial malleolus and the dorsal aspect of the first distal phalanx using an improved tuning fork, and touch-pressure sensitivity of the plantar aspect of the hallux. Patients with diabetic peripheral neuropathy were followed up for 3 years to check for the presence or absence of wounds.

Results:

When compared with the general older adults, the patients with diabetic peripheral neuropathy had significantly lower touch-pressure sensitivity (p < 0.01), vibratory sensitivity at the distal phalanx (p < 0.01) and medial malleolus (p < 0.01), ankle dorsiflexion range of motion (p < 0.01), and metatarsophalangeal joint extension range of motion (p < 0.01). The area under the receiver operating characteristic curve with callus formation was 0.93 for the medial malleolus and 0.96 for the distal phalanx, indicating that the accuracy of the distal phalanx was higher (p < 0.01) than the medial malleolus. According to the Cox proportional hazard analysis, the vibratory sensitivity of the distal phalanx was a significant risk factor for ulcer development (p < 0.05).

Conclusion:

These findings suggest that the vibration sensation test, which we improved via the technique described in this study, is useful for predicting the occurrence of callus and ulcer.

Conservative Offloading

The etiology of ulcerations in diabetes mellitus is associated with the presence of peripheral sensory neuropathy and repetitive trauma due to normal walking activities to areas on the foot that are subject to moderate or high pressures and shear. The combination of loss of protective sensation, deformity, and repetitive trauma is the perfect storm for ulcer development. Once an ulcer is developed, the most important part of the healing process is offloading the ulcer site. Offloading is the mainstay of healing neuropathic ulcers.

Factors Associated With Callus in Patients with Diabetes, Focused on Plantar Shear Stress During Gait

BACKGROUND

The aim of this study is to identify whether plantar shear stress in neuropathic patients with diabetes with callus is increased compared with those without callus.

METHOD

The differences in foot deformity, limited joint mobility, repetitive stress of walking, and ill-fitting shoes between patients with callus and those without callus were also determined. Subjects were recruited from the Diabetic Foot Outpatient Clinic. A newly developed in-shoe measurement system, which has flexible and thin insoles, enabled measurement of both plantar pressure and shear stress simultaneously when subjects walked as usual on a 10 m walkway.

RESULTS

It was found that plantar shear stress adjusted for weight during the push-off phase was increased by 1.32 times in patients with callus compared with those without callus (mean ± SD: 0.0500 ± 0.0160 vs 0.0380 ± 0.0144, P = .031). Moreover, hallux valgus deformity, reduction in dorsiflexion of the ankle joint and increase in plantar flexion were showed in feet with callus. Increased plantar shear stress may be caused by gait change that patients having callus push off with the metatarsal head instead of the toe as a result of foot deformity and limited joint mobility.

CONCLUSIONS

It was found that plantar shear stress adjusted for weight during the push-off phase was increased in patients with callus compared with those without callus by using the newly developed measurement system. These results suggest that reduction of plantar shear stress during the push-off phase can prevent callus formation in neuropathic patients with diabetes.

A comparative study between total contact cast and pressure-relieving ankle foot orthosis in diabetic neuropathic foot ulcers

Off-loading of the ulcer area is extremely important for the healing of plantar ulcers. Off-loading with total contact cast (TCC) may be superior to other off-loading strategies studied so far, but practical limitations can dissuade clinicians from using this modality. This study was conducted to evaluate the efficacy of TCC compared with that of a pressure-relieving ankle foot orthosis (PRAFO) in healing of diabetic neuropathic foot ulcers and their effect on gait parameters. Thirty adult diabetic patients attending the foot clinic with neuropathic plantar ulcers irrespective of sex, age, duration and type of diabetes were randomly assigned to 1 of 2 off-loading modalities (TCC and PRAFO). Main outcome measures were ulcer healing after 4 weeks of randomization and effect of each of the modalities on various gait parameters. The percentage reduction of the ulcer surface area at 4 weeks from baseline was 75.75 ± 9.25 with TCC and 34.72 ± 13.07 with PRAFO, which was significantly different (P < .001). The results of this study however, showed that most of the gait parameters were better with PRAFO than with TCC. This study comprehensively evaluated the well known advantages and disadvantages of a removable (PRAFO) and a nonremovable device (TCC) in the treatment of diabetic neuropathic foot ulcer. Further studies are needed involving larger subjects and using 3D gait analysis to collect more accurate data on gait parameters and wound healing with different off-loading devices.

Orthotic management of the neuropathic foot: an interdisciplinary care perspective

BACKGROUND

Clinical management of the patient with neuropathic foot is becoming commonplace in orthotic clinics worldwide. The presentations that can result from neuropathic foot are diverse, requiring clinicians to understand the pathomechanics of ulceration, infection, and Charcot joint arthropathy to provide effective interventions.

OBJECTIVES

The purpose of this clinical perspective is to provide a review of the literature regarding clinical concepts associated with orthotic management of neuropathic foot.

STUDY DESIGN

Literature review and clinical case study.

METHODS

Relevant literature were reviewed and summarized, and a clinical case study synthesizing reviewed concepts was presented.

RESULTS

Given the multifactorial nature of the neuropathic foot, treatments must be multifaceted and patient-specific to effectively address the underlying disease processes. While systemic issues such as peripheral arterial disease are treated by physicians, local issues such as foot deformity are managed by orthotists. Orthotic interventions commonly include custom footwear to reduce the risk of ulceration through creation of a protective environment or targeted plantar offloading. Patient and caregiver education to encourage management compliance is equally as important to ensure successful treatment.

CONCLUSION

Patients with neuropathic foot benefit from an interdisciplinary care approach which engages physicians, wound care practitioners, and orthotists to treat and manage systemic and local problems. Addressing this pathology through interdisciplinary care may positively affect the patient's health status while lowering associated healthcare costs through improved treatment efficacy.

CLINICAL RELEVANCE

The commonality of neuropathic foot and associated complications including ulceration, infection, and Charcot joint arthropathy requires that the patient care team have a fundamental understanding of these pathologies and common treatment modalities. We review orthotic treatment modalities to assist clinicians with the management of patients with neuropathic foot.