Footwear and offloading interventions to prevent and heal foot ulcers and reduce plantar pressure in patients with diabetes: a systematic review.

BACKGROUND: Footwear and offloading techniques are commonly used in clinical practice for preventing and healing of foot ulcers in persons with diabetes. The goal of this systematic review is to assess the medical scientific literature on this topic to better inform clinical practice about effective treatment. METHODS: We searched the medical scientific literature indexed in PubMed, EMBASE, CINAHL, and the Cochrane database for original research studies published since 1 May 2006 related to four groups of interventions: (1) casting; (2) footwear; (3) surgical offloading; and (4) other offloading interventions. Primary outcomes were ulcer prevention, ulcer healing, and pressure reduction. We reviewed both controlled and non-controlled studies. Controlled studies were assessed for methodological quality, and extracted key data was presented in evidence and risk of bias tables. Uncontrolled studies were assessed and summarized on a narrative basis. Outcomes are presented and discussed in conjunction with data from our previous systematic review covering the literature from before 1 May 2006. RESULTS: We included two systematic reviews and meta-analyses, 32 randomized controlled trials, 15 other controlled studies, and another 127 non-controlled studies. Several randomized controlled trials with low risk of bias show the efficacy of therapeutic footwear that demonstrates to relief plantar pressure and is worn by the patient, in the prevention of plantar foot ulcer recurrence. Two meta-analyses show non-removable offloading to be more effective than removable offloading for healing plantar neuropathic forefoot ulcers. Due to the limited number of controlled studies, clear evidence on the efficacy of surgical offloading and felted foam is not yet available. Interestingly, surgical offloading seems more effective in preventing than in healing ulcers. A number of controlled and uncontrolled studies show that plantar pressure can be reduced by several conservative and surgical approaches. CONCLUSIONS: Sufficient evidence of good quality supports the use of non-removable offloading to heal plantar neuropathic forefoot ulcers and therapeutic footwear with demonstrated pressure relief that is worn by the patient to prevent plantar foot ulcer recurrence. The evidence base to support the use of other offloading interventions is still limited and of variable quality. The evidence for the use of interventions to prevent a first foot ulcer or heal ischemic, infected, non-plantar, or proximal foot ulcers is practically non-existent. High-quality controlled studies are needed in these areas.

Real-life step and activity measurement: reliability and validity.

OBJECTIVES: Investigation of the reliability and validity of activity monitoring using a range of methods, namely manual counting, self report and two commercially available activity monitors. STUDY DESIGN: Reliability, accuracy and validity study. METHODS: Multiple convenience samples of healthy subjects were recruited to the study. Reliability of manual step count was determined using an intraclass correlation coefficient (ICC) (n = 10). Relationships between data from the Step Watch monitor (SAM) and (a) manual step counts (n = 18); (b) a second (different) activity monitor (ActivPAL); and (c) self reported activity levels (n = 22) were assessed using correlations. A Pearson's correlation and paired t-test was used to assess relations between routinely used monitors. RESULTS: Intra-rater reliability for manual step counts was excellent (ICC 0.99), but inter-rater reliability was poor (ICC 0.26). Indoor accuracy of the SAM was 96.06% and outdoor accuracy was 99.58%. Moderate correlations (rho = 0.423 to 0.595, p < 0.05) were identified between the SAM monitor activity levels and self report diaries. The SAM and the ActivPAL were found to be internally reliable within themselves (ICC 0.96 and 0.95 respectively), significantly correlated (r = 0.93, p < 0.001) but also significantly different (t = 2.179, p < 0.05) when used simultaneously over the same circuit. CONCLUSIONS: Activity monitors provide information that is related to actual activity and provide accurate and reliable data when tested on functional walking circuits. Activity monitors should not be used interchangeably due to the potential for systematic differences between the measurements obtained when applied simultaneously over the same repeated circuit.

Landing stability in anterior cruciate ligament deficient versus healthy individuals: a motor control approach.

OBJECTIVES: To compare the temporal effectiveness of landing strategies in anterior cruciate ligament deficient (ACLD) versus non-injured participants, when they landed on one leg after running or after a single leg hop. DESIGN: Case control study. SETTING: Laboratory setting. PARTICIPANTS: Participants were 30 ACLD patients and 30 control subjects. MAIN OUTCOME MEASURES: Time to stabilise (TTS) was measured using centre of pressure (COP), horizontal (Fy) and vertical (Fz) force velocity on a Kistler forceplate. Kinematic data were collected using a Vicon 512 system with 8 IR cameras. Between group differences were analysed using a two-way ANOVA with post hoc t-tests. RESULTS: Significant group differences were found in running speed, hop distance, failed attempts, deceleration, and TTS using COP velocity in both activities. CONCLUSIONS: When required to stop and balance on their injured leg, ACLD participants selected slower running speeds and less hop distance to succeed from than did controls, and they used different strategies to stabilise upon landing. They also showed a significantly poorer ability to maintain stable stance following deceleration. ACLD individuals who were able to adapt with some success did so by increasing the time available to them and limiting function to within the boundaries they can control effectively.

Investigation of standing balance in patients with diabetic neuropathy at different stages of foot complications.

BACKGROUND: Diabetic peripheral neuropathy is known to cause postural instability. This study investigated standing balance in patients with diabetic neuropathy with secondary foot complications: foot ulceration, partial foot amputation and trans-tibial amputation, which are expected to pose further challenge to balance control. METHODS: In this cross-sectional study, 23 patients with diabetic neuropathy alone (controls) were compared with 23 patients with diabetic foot ulceration, 16 patients with partial foot amputation and 22 patients with trans-tibial amputation. Posturography was used to determine the centre of pressure excursion during quiet standing. Differences between the 4 groups were tested using ANOVA and post-hoc comparisons. FINDINGS: The 4 groups varied in neuropathy score (P=0.001) and demonstrated significant decline in balance from neuropathy alone to foot ulceration, to partial foot amputation and trans-tibial amputation based on total excursion of centre of pressure (P<0.001) and centre of pressure excursion in antero-posterior direction (P<0.001). The excursion of centre of pressure in medio-lateral direction varied between 4 groups (P<0.05) however, there was no significant trend. The distance between ankles increased significantly from neuropathy to trans-tibial amputee group (P=0.001). Post-hoc comparison with controls revealed that each of three study groups demonstrated decreased balance (diabetic neuropathy vs. foot ulceration, P=0.001, diabetic neuropathy vs. partial foot amputation, P=0.002 and diabetic neuropathy vs. trans-tibial amputation, P=0.009). INTERPRETATION: Balance deterioration among patient groups from diabetic neuropathy alone to trans-tibial amputation appears to result from bio-mechanical impairment caused by progression of foot complications in addition to postural instability caused by diabetic neuropathy.

The effectiveness of footwear and offloading interventions to prevent and heal foot ulcers and reduce plantar pressure in diabetes: a systematic review.

BACKGROUND: Footwear and offloading techniques are commonly used in clinical practice for the prevention and treatment of foot ulcers in diabetes, but the evidence base to support this use is not well known. The goal of this review was to systematically assess the literature and to determine the available evidence on the use of footwear and offloading interventions for ulcer prevention, ulcer treatment, and plantar pressure reduction in the diabetic foot. METHODS: A search was made for reports on the effectiveness of footwear and offloading interventions in preventing or healing foot ulcers or reducing plantar foot pressure in diabetic patients published prior to May 2006. Both controlled and uncontrolled studies were included. Assessment of the methodological quality of studies and data extraction was independently performed by two reviewers. Interventions were assigned into four subcategories: casting, footwear, surgical offloading and other offloading techniques. RESULTS: Of 1651 articles identified in the baseline search, 21 controlled studies were selected for grading following full text review. Another 108 uncontrolled and cross-sectional studies were examined. The evidence to support the use of footwear and surgical interventions for the prevention of ulceration is meagre. Evidence was found to support the use of total contact casts and other non-removable modalities for treatment of neuropathic plantar ulcers. More studies are needed to support the use of surgical offloading techniques for ulcer healing. Plantar pressure reduction can be achieved by several modalities including casts, walkers, and therapeutic footwear, but the diversity in methods and materials used limits the comparison of study results. CONCLUSIONS: This systematic review provides support for the use of non-removable devices for healing plantar foot ulcers. Furthermore, more high-quality studies are urgently needed to confirm the promising effects found in both controlled and uncontrolled studies of footwear and offloading interventions designed to prevent ulcers, heal ulcers, or reduce plantar pressure.

Walking performance in people with diabetic neuropathy: benefits and threats.

AIMS/HYPOTHESIS: Walking is recommended as an adjunct therapy to diet and medication in diabetic patients, with the aim of improving physical fitness, glycaemic control and body weight reduction. Therefore we evaluated walking activity on the basis of capacity, performance and potential risk of plantar injury in the diabetic population before it can be prescribed safely. SUBJECTS, MATERIALS AND METHODS: Twenty-three subjects with diabetic neuropathy (DMPN) were compared with 23 patients with current diabetic foot ulcers, 16 patients with partial foot amputations and 22 patients with trans-tibial amputations. The capacity for walking was measured using a total heart beat index (THBI). Gait velocity and average daily strides were measured to assess the performance of walking, and its impact on weight-bearing was studied using maximum peak pressure. RESULTS: THBI increased (p<0.01) and gait velocity and daily stride count fell (p<0.001 for both) with progression of foot complications. The maximum peak pressures over the affected foot of patients with diabetic foot ulcers (p<0.05) and partial foot amputations (p<0.01) were higher than in the group with DMPN. On the contralateral side, the diabetic foot ulcer group showed higher maximum peak pressure over the total foot (p<0.05), and patients with partial foot amputations (p<0.01) and trans-tibial amputations (p<0.05) showed higher maximum peak pressure over the heel. CONCLUSIONS/INTERPRETATION: Walking capacity and performance decrease with progression of foot complications. Although walking is recommended to improve fitness, it cannot be prescribed in isolation, considering the increased risk of plantar injury. For essential walking we therefore recommend the use of protective footwear. Walking exercise should be supplemented by partial or non-weight-bearing exercises to improve physical fitness in diabetic populations.

Community walking activity in neurological disorders with leg weakness.

BACKGROUND: The aims of this study were to determine walking mobility in the community in individuals with lower limb weakness and to establish the extent to which some clinic based measures predict such activity. METHODS: Five groups (n = 12-18) of independently ambulant patients with lower limb weakness due to neurological conditions and a matched healthy control group were recruited. Measures of isometric knee extension/flexion muscle strength, time to stand up (sit-to-stand, STS), gait speed, and daily step counts (recorded over 7 days) were obtained. The Rivermead Mobility Index (RMI) provided a measure of functional ability. Between group differences and associations were explored. Backward stepwise regression analysis was used to identify variables influencing daily step count in individuals with neurological impairment. RESULTS: Patients were significantly weaker (mean (SD) quadriceps strength 69+/-34% v 102+/-37% predicted), slower to stand up (2.9+/-1.3 v 2.0+/-0.6 s), and had slower self selected gait speed (0.74+/-0.3 v 1.2+/-0.2 m/s) than controls. Mean daily step count was also lower (3090+/-1902 v 6374+/-1819) than in controls. In neurology patients step count was correlated with RMI score (r(s) = 0.49, p<0.01) and STS (r = -0.19, p<0.05). However, self selected gait speed was the only significant predictor in the regression analysis (p<0.01) of daily mean step count. CONCLUSIONS: Measures of muscle strength, timed STS, and RMI do not appear to closely reflect community walking activity in these patient groups. Self selected gait speed was partially predictive. Measurement of community walking activity may add a new dimension to evaluating the impact of interventions in neurological disorders.

Risk of plantar ulceration in diabetic patients with single-leg amputation.

BACKGROUND: There is a disconcerting rate of bilateral limb loss in patients with diabetes. Therefore, this study aimed to explore plantar loading of the surviving foot following unilateral trans-tibial amputation within a wider context of daily walking activity to investigate the precise risk to the surviving limb. METHODS: Twenty-one subjects with diabetic neuropathy and trans-tibial amputation were matched for weight; height; age and gender with 21 control subjects with diabetic neuropathy without history of plantar ulceration. Gait parameters, in-shoe plantar pressure distribution and daily walking (using the step activity monitor) were recorded. Student's t-tests were used to compare groups (alpha-level: 0.05). FINDINGS: The trans-tibial amputations group walked almost 30% slower compared to controls (P < 0.01), with reduced cadence (P < 0.01), and shorter strides (P < 0.01). Despite walking slower, the surviving foot showed higher mean peak plantar pressures in the trans-tibial amputations group over the heel (P < 0.001) however there was no significant difference over the I-II and lateral III-IV-V metatarso-phalangeal regions. Pressure time integral was higher over the heel (P < 0.00), I-II (P < 0.01) and III-IV-V metatarso-phalangeal (P < 0.05) in the trans-tibial amputations group. The amputee group walked less steps per day (P < 0.01). INTERPRETATION: Adaptations in gait and level of walking activity affect plantar pressure distribution and ultimately the risk of ulceration to the surviving foot. Therefore rehabilitation measures should consider implications for plantar loading and the potential risk of ulceration to the surviving foot.

Vibration perception threshold testing in patients with diabetic neuropathy: ceiling effects and reliability.

AIMS: To test the reliability of a new vibrometer (Maxivibrometer) which was constructed so that vibration perception threshold (VPT) could be determined without the disadvantage of the off-scale measurements frequently experienced with the Biothesiometer. METHODS: The two devices were compared and tested on a group of diabetic neuropathic subjects and a group of healthy, matched control subjects. VPT was tested on the plantar surface of the feet. RESULTS: The Maxivibrometer gave an actual measurement in all cases even if subjects were severely neuropathic. The replication-to-replication and day-to-day intraclass correlation coefficients for the Maxivibrometer VPT were, except in one case, above 0.94, indicating excellent reliability. The Biothesiometer VPT could also be measured with excellent reliability but only within a limited range of mild to moderate neuropathy, so it appears to be an appropriate screening tool. The replication-to-replication intraclass correlation coefficient was 0.93. CONCLUSIONS: Because VPT could be measured over a wide range with the Maxivibrometer, it was demonstrated that loss of sensation in diabetic neuropathy can progress far beyond the maximum VPT value of the Biothesiometer. The wide measurement range and the excellent reliability make the Maxivibrometer a valuable research tool to quantify loss of sensation, particularly in the presence of severe neuropathy and to record changes over time. Diabet. Med. 18, 469-475 (2001)

Foot and ankle sensory neuropathy, proprioception, and postural stability.

Foot and ankle sensory neuropathy may result from a variety of pathologic conditions, especially diabetes mellitus. Decreased sensation, particularly on the plantar surface of the feet, leads to obvious risks of cutaneous injury. Less obvious are the risks of fall-related injury associated with changes in other sensory systems of the foot and ankle, such as the receptors involved in joint movement and position perception. The results of a number of studies demonstrate that the neuropathic process affects these receptors in individuals with diabetes mellitus. Associated with the decreased sensory function of the foot and ankle is decreased performance on tests of static and dynamic postural stability. Subjective feelings of instability and an increased incidence of fall-related injuries have also been reported. The reduced postural stability in persons with diabetic neuropathy cannot be attributed exclusively to loss of plantar cutaneous sensation; it appears to be the result of a general loss of peripheral sensory receptor function in the lower legs, including that of the muscle spindles. During the evaluation of an individual with foot and ankle sensory neuropathy, the possibility of balance deficits should be given proper attention. Assessment of balance deficits could be particularly important when planning the course of rehabilitation for individuals with foot and ankle neuropathy who use modified footwear or have an amputation of a section of the foot or lower extremity.

The role of muscle spindles in ankle movement perception in human subjects with diabetic neuropathy.

The objective of this study was to develop a quantitative method to assess muscle spindle function. Three groups of subjects were studied: ten young and healthy subjects, 15 older subjects with diabetic neuropathy, and 15 age-matched controls. All subjects performed an ankle-movement matching task with and without muscle vibration. Input from the plantar cutaneous mechanoreceptors was minimized by using a foot-clamping device. The younger subjects tracked the movement very well, but vibration had a significant effect on their performance (P < 0.001). Similar results were seen in the older control subjects, but they were less successful in tracking movement and slightly less affected by vibration. The neuropathic subjects had the most difficulty tracking, and vibration had only a small but still significant effect on their performance. The interaction between the group and the vibration effect was highly significant (P < 0.001), indicating that the performance of the control subjects changed to a greater degree in the presence of vibration than the performance of the subjects with diabetic neuropathy. Muscle spindles are the primary receptors that are involved in the change in tracking performance when vibration is added during an ankle-movement matching task, and we therefore conclude that the procedure described provides a quantitative evaluation of muscle spindle function. The results demonstrate that diabetic neuropathy degrades muscle sensory function, which may contribute to the impaired balance and unsteadiness of gait that has been observed in diabetic neuropathy.