Foot landing position during gait influences ground reaction forces.

OBJECTIVE: The purpose of this study was to determine how foot landing position influenced the ground reaction forces of two coordinate systems during gait.DESIGN: Values of ground reaction forces components as expressed in two coordinate systems (room, foot) were used to compare ground reaction forces of different foot landing position.BACKGROUND: Non-neutral foot landing position during gait could influence the mechanics of the whole body motion and/or the foot-ankle complex and produce different ground reaction forces patterns compared to a neutral foot landing position.METHODS: Thirty females were assigned to a foot landing group: toe-out, toe-in or neutral. Each participant walked 10 trials across a force platform while three-dimensional motion was captured.RESULTS: No differences were observed for vertical or anteroposterior ground reaction forces variables between groups for either coordinate system. For medio-lateral forces of both coordinate systems, toe-out participants exhibited greater first lateral and second medial maximum forces and exhibited greater impulses.CONCLUSION: For toe-out participants, greater medio-lateral ground reaction forces of the room coordinate system indicate excessive forces are generated by toe-out participants that do not contribute to moving the participant forward. Furthermore, medio-lateral loading on the foot increases proportionally with the degree of toe-out. RELEVANCE: Establishing norms for clinical populations requires understanding of factors that can influence ground reaction force (GRF). Foot landing position (FLP) only affects the medio-lateral forces. Excessive toe-out landing has been surmised to be related to injury. Greater forces acting medio-laterally to the foot's long axis may have a relevant effect on in/eversion loading of the foot.     

Role of ankle mobility in foot rollover during gait in individuals with diabetic neuropathy

Background

The purpose of this study was to investigate the ankle range of motion during neuropathic gait and its influence on plantar pressure distribution in two phases during stance: at heel–strike and at push-off.

Methods

Thirty-one adults participated in this study (control group, n = 16; diabetic neuropathic group, n = 15). Dynamic ankle range of motion (electrogoniometer) and plantar pressures (PEDAR-X system) were acquired synchronously during walking. Plantar pressures were evaluated at rearfoot, midfoot and forefoot during the two phases of stance. General linear model repeated measures analysis of variance was applied to investigate relationships between groups, areas and stance phases.

Findings

Diabetic neuropathy patients walked using a smaller ankle range of motion in stance phase and smaller ankle flexion at heel–strike (P = 0.0005). Peak pressure and pressure–time integral values were higher in the diabetic group in the midfoot at push-off phase when compared to heel–strike phase. On the other hand, the control group showed similar values of peak pressure in midfoot during both stance phases.

Interpretation

The ankle mobility reduction observed could be associated to altered plantar pressure distribution observed in neuropathic subjects. Results demonstrated that midfoot and forefoot play a different role in subjects with neuropathy by receiving higher loads at push-off phase that are probably due to smaller ankle flexion at stance phase. This may explain the higher loads in anterior areas of the foot observed in diabetic neuropathy subjects and confirm an inadequate foot rollover associated to the smaller ankle range of motion at the heel–strike phase.     

Characterizing multisegment foot kinematics during gait in diabetic foot patients

Background  

The prevalence of diabetes mellitus has reached epidemic proportions, this condition may result in multiple and chronic invalidating long term complications. Among these, the diabetic foot, is determined by the simultaneous presence of both peripheral neuropathy and vasculopathy that alter the biomechanics of the foot with the formation of callosity and ulcerations. To diagnose and treat the diabetic foot is crucial to understand the foot complex kinematics. Most of gait analysis protocols represent the entire foot as a rigid body connected to the shank. Nevertheless the existing multisegment models cannot completely decipher the impairments associated with the diabetic foot.     

The forefoot-to-rearfoot plantar pressure ratio is increased in severe diabetic neuropathy and can predict foot ulceration

OBJECTIVE: We have previously demonstrated that high plantar pressures can predict foot ulceration in diabetic patients. The aim of the present study was to evaluate both the relationship between forefoot and rearfoot plantar pressure in diabetic patients with different degrees of peripheral neuropathy and their role in ulcer development. RESEARCH DESIGN AND METHODS: Diabetic patients of a 30-month prospective study were classified according to the neuropathy disability score: scores of 0, 1-5, 6-16, and 17-28 are defined as absent (n = 20), mild (n = 66), moderate (n = 95), and severe (n = 57) neuropathy, respectively. The F-Scan mat system was used to measure dynamic plantar pressures. The peak pressures under the forefoot and the rearfoot were selectively measured for each foot, and the forefoot-to-rearfoot ratio (F/R ratio) was calculated. RESULTS: Foot ulcers developed in 73 (19%) feet. The peak pressures were increased in the forefoot of the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (6.2 +/- 4.5 and 3.8 +/- 2.7 vs. 3.0 +/- 2.1 and 3.3 +/- 2.1 kg/cm(2) [mean +/- SD], respectively; P < 0.0001). The rearfoot pressures were also higher in the severe and moderate neuropathic groups compared with the mild neuropathic and non-neuropathic groups (3.2 +/- 2.0 and 3.2 +/- 1.9 vs. 2.5 +/- 1.3 and 2.3 +/- 1.0, respectively; P < 0.0001). The F/R ratio was increased only in the severe group compared with the moderate and mild neuropathic and non-neuropathic groups (2.3 +/- 2.4 vs. 1.5 +/- 1.2, 1.3 +/- 0.9, and 1.6 +/- 1.0, respectively; P < 0.0001). In a logistic regression analysis, both forefoot pressure (odds ratio 1.19 [95% CI 1.11-1.28], P < 0.0001) and the F/R ratio (1.37 [1.16-1.61], P < 0.0001) were related to risk of foot ulceration, whereas rearfoot pressure was not. CONCLUSIONS: Both the rearfoot and forefoot pressures are increased in the diabetic neuropathic foot, whereas the F/R ratio is increased only in severe diabetic neuropathy, indicating an imbalance in pressure distribution with increasing degrees of neuropathy. This may lend further evidence toward the concept that equinus develops in the latest stages of peripheral neuropathy and may play an important role in the etiology of diabetic foot ulceration.     

Muscle weakness and foot deformities in diabetes: relationship to neuropathy and foot ulceration in caucasian diabetic men

OBJECTIVE: To examine the relationships among muscle weakness, foot deformities, and peroneal and tibial nerve conduction velocity in diabetic and nondiabetic men. RESEARCH DESIGN AND METHODS: A neuropathic and foot evaluation was undertaken in 10 nondiabetic control subjects (group C) and in 36 consecutive diabetic patients attending Diabetes Centre clinics, including 10 diabetic control subjects (group D), 15 diabetic neuropathic patients (group DN), and 11 diabetic patients with a history of ulceration (group DU). Neuropathy was defined as a peroneal motor nerve conduction <40 m/s. Muscle weakness was assessed in seven intrinsic and seven extrinsic muscles of the foot using a semiquantitative score (max score per muscle = 3). Foot deformities were assessed using a foot deformity score (max score = 3). A higher score indicated increased muscle weakness or more severe foot deformities. Muscle weakness and foot deformities were assessed without prior knowledge of patient and neuropathy status. RESULTS: Peroneal and tibial nerve conduction velocity were associated with weakness in muscles innervated by, respectively, the peroneal and tibial nerve (r = -0.70 and r = -0.51, P < 0.01) and foot deformities (r = -0.60 and r = -0.59, P < 0.001). The DN and DU groups had more weakness in intrinsic and extrinsic muscles compared with the C and D groups. Muscles innervated by the tibial nerve had a greater proportional muscle weakness than those innervated by the peroneal nerve in the DN and DU groups. The DN and DU patients had more foot deformities (median food deformity score [interquartile range]) (3 [2-3] and 2 [2-3]) compared with D and C patients (0 [0-0.75] and 0 [0-0]). CONCLUSIONS: Important relationships have been shown between motor nerve conduction deficit and muscle weakness; however, it is still not clear whether abnormal nerve function, leading to a decrease in muscle strength, could be responsible for the development of foot deformities.     

The effect of custom-made braces for the ankle and hindfoot on ankle and foot kinematics and ground reaction forces

OBJECTIVE: To assess the effects on gait of custom-made polypropylene orthoses: ankle-foot orthosis (AFO), rigid hindfoot orthosis (HFO-R), and articulated hindfoot orthosis (HFO-A). DESIGN: Experimental assessment. SETTING: Institutional practice, motion analysis laboratory. PARTICIPANTS: Twenty asymptomatic normative subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Three-dimensional kinematics, ground reaction force, and time-related factors in 4 conditions: shoe only, and shod with the AFO, HFO-R, and HFO-A. RESULTS: The AFO and HFO-R limited sagittal and coronal plane ankle-hindfoot motion. The HFO-A limited hindfoot coronal motion while allowing normal sagittal motion. At the midfoot, the AFO and HFO-A limited transverse motion, but the HFO-A also limited sagittal and coronal motion. Use of the HFO-R resulted in exaggerated midfoot sagittal and coronal motion. Braces that limited motion to a greater degree were associated with more atypical kinetic variables, indicative of less dynamic gait. The HFO-A resulted in ground reaction forces most similar to unbraced conditions. CONCLUSIONS: Alteration in gait was affected by orthosis design. Orthoses with a rigid component crossing a joint restricted motion at that joint, but potentially compromised typical gait kinetic factors. For immobilizing the hindfoot, the HFO-A may be more comfortable and still provide more stability than the HFO-R or AFO.     

The effect of visual targeting on ground reaction force and temporospatial parameters of gait

BACKGROUND: Visual targeting has been cited as a confounding factor for gait analysis in which measures of ground reaction force and plantar pressure are obtained. OBJECTIVE: To investigate the effect of visual targeting on temporospatial and kinetic aspects of gait when small targets, such as pressure platforms, have to be used. DESIGN: A within subjects repeated measure design was used to measure step parameters and ground reaction forces of 11 healthy volunteers. METHODS: Subjects were required to walk over a 10 m walkway at a self-selected pace. A 30x24 cm(2) target area was superimposed over a hidden Kistler force plate (60x90 cm(2)) mounted at the midpoint of the walkway. Step parameters and ground reaction forces were measured with and without the presence of the target. Ground reaction forces were analysed within the time-domain. RESULTS: Subjects used visual control strategies when approaching targets of similar dimensions to a pressure platform. These strategies were manifested by an increase in the variability of the step length onto the target (P<0.05). However, targeting was observed to have no affect on the magnitude, timing and variability of ground reaction forces when measured within the time-domain and averaged over five trials (P>0.05). CONCLUSIONS: Visual control strategies employed while walking toward a target area have no affect on ground reaction force parameters when measured within the time-domain. RELEVANCE: These findings demonstrate that targeting a 30x24 cm(2) target does not affect ground reaction force parameters, when a gait protocol that fine-tunes the start position is employed. The findings are relevant to gait research in which small force or pressure platforms are used to assess gait kinetics.     

Variability in activity may precede diabetic foot ulceration

OBJECTIVE: To evaluate the role of activity in the development of neuropathic foot ulceration in individuals with diabetes. RESEARCH DESIGN AND METHODS: We evaluated the first 100 consecutive individuals with diabetes (95.0% male, aged 68.5 +/- 10.0 years with concomitant neuropathy, deformity, and/or a history of lower-extremity ulceration/partial foot amputation) enrolled in an ongoing prospective longitudinal activity study. Subjects used a high-capacity continuous computerized activity monitor. Data were collected continuously over a minimum of 25 weeks (or until ulceration) with daily activity units expressed as means +/- SD. RESULTS: Eight subjects ulcerated during the evaluation period of 37.1 +/- 12.3 weeks. The average daily activity was significantly lower in individuals who ulcerated compared with individuals who did not ulcerate (809.0 +/- 612.2 vs. 1,394.5 +/- 868.5, P = 0.03). Furthermore, there was a large difference in variability between groups. The coefficient of variation was significantly greater in the ulceration group compared with the no ulceration group (96.4 +/- 50.3 vs. 44.7 +/- 15.4%, P = 0.0001). In the 2 weeks preceding the ulcerative event, the coefficient of variation increased even further (115.4 +/- 43.0%, P = 0.02), but there was no significant difference in average daily activity during that period (P = 0.5). CONCLUSIONS: The results of this study suggest that individuals with diabetes who develop ulceration may actually have a lower overall activity than their counterparts with no ulceration, but the quality of that activity may be more variable. Perhaps modulating the "peaks and valleys" of activity in this population through some form of feedback might prove to reduce risk for ulceration in this very-high-risk population.     

Versajet hydroscalpel: treatment of diabetic foot ulceration

Treatment of diabetic foot ulceration continues to be a challenge to healthcare professionals. Wound healing can be affected in a number of ways, and it is of paramount importance that wound healing is achieved as quickly as possible to minimize the risk of amputation. One key aspect of management is wound debridement. A number of techniques can be employed, including, in severe cases, surgical debridement. These case histories illustrate where the novel Versajet hydroscalpel (Smith & Nephew) would be a useful tool for debriding a foot ulcer effectively without the patient undergoing orthopaedic surgery. The Versajet debrides quickly and efficiently, and a pink and granulating wound base was achieved in all cases. It should be considered for use in specialist centres where complex diabetic foot ulcers are treated and the expertise is available to use it.     

Management of neuropathy and foot problems in diabetic patients

Diabetic neuropathy (DN) is a complex set of clinical syndromes that affect distinct regions of the nervous system, either singly or combined. DN is the most common form of neuropathy in the developed countries of the world and is responsible for 50% to 75% of nontraumatic amputations. It is also the most life damaging--once autonomic neuropathy sets in, the mortality rate approximates 25% to 50% within 5 to 10 years. Distal symmetric polyneuropathy, the most common form of DN, usually involves both small and large nerve fiber damage. Small nerve fiber neuropathies occur early and are often present without objective signs or electrophysiologic evidence of nerve damage. The greatest risk is foot ulceration and subsequent gangrene. Large nerve fiber neuropathies, which involve the sensory and motor nerves, are generally neuropathies of signs rather than symptoms. Clinical presentation usually includes a "glove and stocking" distribution of sensory loss and the greatest risk is Charcot's neuroarthropathy. Diagnosis of DN relies heavily on a careful patient history and physical examination. Most critical is that both the patient and the patient's shoes should be examined and corrective measures taken. Several studies have shown that good diabetes control can significantly reduce neuropathy. As new drugs and ways to enhance nerve blood flow and block pain pathways at different levels are being explored, the effective treatment of DN and the reduction of its impact on quality of life as well as mortality will become a reality. Patient education and preventive strategies, however, are still the best ways to treat the complications of neuropathy and reduce the amputation rate.     

Relationship of limited joint mobility to abnormal foot pressures and diabetic foot ulceration

OBJECTIVE: To investigate the role of limited joint mobility (LJM) in causing abnormal foot pressures and foot ulceration. RESEARCH DESIGN AND METHODS: The subjects were recruited from a general diabetes clinic where patients were screened for neuropathy, retinopathy, and elevated plantar foot pressure. Sixty-four patients in five groups were matched by age and sex in the following groups: group 1, patients with LJM and neuropathy; group 2, nonneuropathic diabetic patients with LJM; group 3, patients with neuropathy and no LJM; group 4, diabetic control subjects; and group 5, nondiabetic control subjects. Joint mobility was assessed in the foot at subtalar and metatarsophalangeal joints; plantar foot pressures were assessed by optical pedobarography and neuropathic status by a Biothesiometer and electrophysiology. RESULTS: Joint mobility was reduced at both sites in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). Plantar foot pressures were significantly higher in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). No differences in plantar foot pressures were observed between groups 1 and 2. There were strong correlations between plantar foot pressures and joint mobility in the foot (r = -0.7, P less than 0.001). Previous foot ulceration was present in 65% of patients in group 1, none in group 2, and 5% in group 3. CONCLUSIONS: 1) LJM may be a major factor in causing abnormally high plantar foot pressures, 2) abnormal plantar foot pressures alone do not lead to foot ulceration, and 3) LJM contributes to foot ulceration in the susceptible neuropathic foot.     

回顾性调查分析糖尿病足溃疡43例

目的探讨引发糖尿病足部溃疡的危险因素和早期征象。方法对1996年至2006年在我院住院的43例糖尿病足部溃疡患者的临床资料进行回顾性分析。结果糖尿病足部溃疡的发生和严重程度与糖尿病病程、糖尿病水疱病、血糖水平和血浆白蛋白的高低有关。结论糖尿病水疱病是引发糖尿病足部溃疡的重要因素之一。     

Three-point gait crutch walking: variability in ground reaction force during weight bearing

OBJECTIVE: To investigate variability in ground reaction force (GRF) and kinematics on both sides during 3-point partial weight-bearing (PWB) crutch walking. DESIGN: Within-subject comparisons of kinematic and kinetic data collected at different levels of 3-point crutch walking: 10%, 50%, and 90% PWB at comfortable speeds. SETTING: An applied biomechanics lab in a university setting.An applied biomechanics lab in a university setting. PARTICIPANTS: Twelve healthy college students (9 women, 3 men). MAIN OUTCOME MEASURES: Spatial and temporal variables, major peak kinematic data, and peak GRFs from force platforms during the gait cycle. RESULTS: Large variations were found in replicating the target levels of PWB, particularly at 10% and 90% PWB. Subjects had a shorter stance phase and longer swing phase during the crutch walking gait cycle. Velocity significantly decreased (p =.006) because of decreased cadence (p =.002). Slightly greater hip abduction and external rotation on the noninvolved side and slightly less hip adduction and internal rotation on the involved side indicated that the center of gravity shifted slightly from the involved side toward the noninvolved side. There was no increase in vertical GRF, and there was a relatively constant loading pattern on the noninvolved side. CONCLUSIONS: Subjects have difficulty replicating a prescribed weight-bearing restriction. A shift of the center of gravity toward the noninvolved side may reduce the weight distribution on the involved side.     

Frequency domain characteristics of ground reaction forces during walking of young and elderly females

OBJECTIVE: To examine the frequency domain characteristics of the ground reaction forces of young and elderly females during free walking. DESIGN: Independent t-tests were used to examine the frequency content of all three components of the ground reaction force. BACKGROUND: Frequency domain analysis has the potential to assist in identifying changes in gait that may be masked in the time domain. No research has been done to identify changes in gait due to age-related impairments in the frequency domain. METHODS: Ten young and ten elderly females walked at a prescribed speed while ground reaction forces were collected via a force platform. The highest frequency required to reconstruct the 99% of the signal's power in each direction was calculated from the ground reaction forces. RESULTS: The frequency content significantly decreased in the anterior-posterior direction for the young group. No significant differences were found for the other two directions (vertical and mediolateral) between the two groups. The elderly had a significantly higher frequency content compared with the young in the anterior-posterior direction. CONCLUSIONS: Ageing differences were detected using the frequency domain analysis for the anterior-posterior direction. It is possible that these differences were the result of the decrease in walking speed associated with the elderly group. RELEVANCE: Frequency domain analysis of the ground reaction forces is a useful addition to the gait analyst's armamentarium especially when such changes are not obvious in the time domain.     

Pattern of abnormal tangential forces in the diabetic neuropathic foot

OBJECTIVES: The role of tangential stress in neuropathic foot ulceration is yet unknown. The aim of this study was to investigate the tangential forces developed during gait by the whole foot and by selected subareas of it, namely the heel, the metatarsals and the hallux. METHODS: 61 diabetic patients have been evaluated: 27 without neuropathy, 19 with neuropathy and 15 with previous neuropathic ulcer. The patients were compared with 21 healthy volunteers. A piezo-dynamometric platform was used to measure the three components of the ground reaction force under the total foot and the selected subareas. RESULTS: A significant reduction was observed for the forward peak and the backward peak of the anteroposterior ground reaction force component measured under the whole foot. Patients with previous neuropathic ulcer showed a significant increase of the mediolateral stress under the metatarsals. CONCLUSIONS: Tangential stress is altered in diabetic neuropathic patients; the increased mediolateral component suggests that tangential stress could have a role in the high risk of recurrence observed in patients with previous ulceration. RELEVANCE: To assess the effectiveness of a non-invasive methodology for the estimation and the monitoring of significant alterations of the tangential stress with the increase of neuropathy.     

Comparison of F-Scan in-sole and AMTI forceplate system in measuring vertical ground reaction force during gait

To compare an insole foot pressure system (F-Scan) and forceplate (AMTI) system for assessing vertical ground reaction forces (GRF) during walking, 30 adults walked at a self-selected pace with both systems recording GRF data simultaneously. Univariate analysis of variance showed no statistical differences between the two systems (P &gt;. 05) in first peak force (F₁), minimum force (F_m), and second peak force (F₂). F-Scan data, however, showed a significant delay (P &lt;. 05) in times to F₁, F_m, and F₂ (P &lt;. 05). Curve correlation demonstrated higher correlations (r &gt;. 7) for the 21-90% interval of the support phase than both the initial and a brief period before toe-off (r =. 05-.7). These results suggest that, with careful procedure, the F-Scan insole system could be a useful device to measure the vertical GRF during gait. However, caution should be exercised when interpreting the pressure and force data during the initial 21% and final 10% of the support phase of walking.