A new anatomically based protocol for gait analysis in children

Test-retest reliability of three dimensional gait analysis: including a novel approach to visualising agreement of gait cycle waveforms with Bland and Altman plots

BACKGROUND/AIM

Estimating the measurement error (reliability) of three dimensional gait analysis (3DGA) is crucial to interpretation of gait data. The purpose of this study was to investigate the intra-rater reliability of 3DGA and apply a novel method of visualising reliability of gait cycle waveforms.

METHODS

A test re-test design was employed. A convenience sample of 30 healthy adults (18F; 12 M: mean age 30 ± 6.8 years) participated. Subjects walked along a 10 m walkway at their preferred gait speed and 3DGA data were collected using a VICON(®) 3DGA system. Testing was performed by the same investigator on two separate days within two weeks. Data from 10 trials were averaged and analysed.

ANALYSIS

The intraclass correlation coefficient (ICC), the standard error of measurement (SEM), minimal detectable change (MDC) and limits of agreement were calculated for kinetic and kinematic data. Bland and Altman plots were applied to gait cycle waveforms.

RESULTS

Spatio-temporal parameters such as cadence, step length, velocity, step time and step width were highly repeatable generating ICC's of 0.90 and above and low SEM/MDC. Range of joint movement across the gait cycle was generally more reliable than either minimum or maximum values and higher ICCs were obtained for movement in the sagittal plane. For kinematic data the standard error of measurement was low (≤ 5) for the majority of parameters. Transverse plane measurements showed poor reliability with lowest ICC's. ICCs for kinetic data ranged from 0.51 to 0.81.

CONCLUSIONS

Reliability of 3DGA has been estimated for our gait laboratory. Bland and Altman plots of gait cycle waveforms provide a useful addition to reliability analysis.

Functional evaluation of patients treated with osteochondral allograft transplantation for post-traumatic ankle arthritis: one year follow-up

Severe post-traumatic ankle arthritis poses a reconstructive challenge in active patients. Whereas traditional surgical treatments, i.e. arthrodesis and arthroplasty, provide good pain relief, arthrodesis is associated to functional and psychological limitations, and arthroplasty is prone to failure in the active patient. More recently the use of bipolar fresh osteochondral allografts transplantation has been proposed as a promising alternative to the traditional treatments. Preliminary short- and long-term clinical outcomes for this procedure have been reported, but no functional evaluations have been performed to date. The clinical and functional outcomes of a series of 10 patients who underwent allograft transplantation at a mean follow-up of 14 months are reported. Clinical evaluation was performed with the AOFAS score, functional assessment by state-of-the-art gait analysis. The clinical score significantly improved from a median of 54 (range 12-65) pre-op to 76.5 (range 61-86) post-op (p=0.002). No significant changes were observed for the spatial-temporal parameters, but motion at the hip and knee joints during early stance, and the range of motion of the ankle joint in the frontal plane (control: 13.8°±2.9°; pre-op: 10.4°±3.1°, post-op: 12.9°±4.2°; p=0.02) showed significant improvements. EMG signals revealed a good recovery in activation of the biceps femoris. This study showed that osteochondral allograft transplantation improves gait patterns. Although re-evaluation at longer follow-ups is required, this technique may represent the right choice for patients who want to delay the need for more invasive joint reconstruction procedures.

Load along the femur shaft during activities of daily living

A comprehensive knowledge of the loads applied during activities of daily living to the femur shaft is necessary to the design of direct attachments of relevant prostheses. A motion analysis system was used together with an established protocol with skin markers to estimate the three components of the forces and moments acting on ten equidistant points along the full femur shaft. Twenty healthy young volunteers were analyzed while performing three repetitions of the following tasks: level walking at three different speeds, straight-line and with sudden changes of direction to the right and to the left, stairs ascending and descending, squat, rising from a chair and sitting down. Average load patterns, after normalisation for body weight and height, were calculated over subjects for each point, about the three anatomical axes, and for each motor task. These patterns were found consistent over subjects, but different among the anatomical axes and tasks. In general, the moments were observed limitedly influenced by the progression speed, and higher for more proximal points. The moments were also higher in abd/adduction (8.1% body weight*height on average), nearly three times larger than those in flex/extension (2.6) during stair descending. The largest value over all moments was 164.8 N m, abd/adduction in level walking at high speed. The present results should be of value also for a most suitable level for amputation in transfemoral amputation, for in-vitro mechanical tests and for finite element models of the femur.

Three-Dimensional Knee Kinematics by Conventional Gait Analysis for Eleven Motor Tasks of Daily Living: Typical Patterns and Repeatability

The availability of detailed knee kinematic data during various activities can facilitate clinical studies of this joint. To describe in detail normal knee joint rotations in all three anatomical planes, 25 healthy subjects (aged 22–49 years) performed eleven motor tasks, including walking, step ascent and descent, each with and without sidestep or crossover turns, chair rise, mild and deep squats, and forward lunge. Kinematic data were obtained with a conventional lower-body gait analysis protocol over three trials per task. To assess the repeatability with standard indices, a representative subset of 10 subjects underwent three repetitions of the entire motion capture session. Extracted parameters with good repeatability included maximum and minimum axial rotation during turning, local extremes of the flexion curves during gait tasks, and stride times. These specific repeatable parameters can be used for task selection or power analysis when planning future clinical studies.

Functional performance of a total ankle replacement: thorough assessment by combining gait and fluoroscopic analyses

BACKGROUND

A thorough assessment of patients after total ankle replacement during activity of daily living can provide complete evidence of restored function in the overall lower limbs and replaced ankle. This study analyzes how far a possible restoration of physiological mobility in the replaced ankle can also improve the function of the whole locomotor apparatus.

METHODS

Twenty patients implanted with an original three-part ankle prosthesis were analyzed 12 months after surgery during stair climbing and descending. Standard gait analysis and motion tracking of the components by three-dimensional fluoroscopic analysis were performed on the same day using an established protocol and technique, respectively.

FINDINGS

Nearly physiological ankle kinematic, kinetic and electromyography patterns were observed in the contralateral side in both motor activities, whereas these patterns were observed only during stair climbing in the operated side. Particularly, the mean ranges of flexion at the replaced ankle were 13° and 17° during stair climbing and descending, respectively. Corresponding 2.1 and 3.1mm antero/posterior meniscal-to-tibial translations were correlated with flexion between the two metal components (p<0.05). In addition, a larger tibiotalar flexion revealed by fluoroscopic analysis resulted in a physiological hip and knee moment.

INTERPRETATION

The local and global functional performances of these patients were satisfactory, especially during stair climbing. These might be associated to the recovery of physiological kinematics at the replaced ankle, as also shown by the consistent antero/posterior motion of the meniscal bearing, according to the original concepts of this ankle replacement design.

Estimation of spatial-temporal gait parameters in level walking based on a single accelerometer: validation on normal subjects by standard gait analysis

This paper investigates the ability of a single wireless inertial sensing device stuck on the lower trunk to provide spatial-temporal parameters during level walking. The 3-axial acceleration signals were filtered and the timing of the main gait events identified. Twenty-two healthy subjects were analyzed with this system for validation, and the estimated parameters were compared with those obtained with state-of-the-art gait analysis, i.e. stereophotogrammetry and dynamometry. For each side, from four to six gait cycles were measured with the device, of which two were validated by gait analysis. The new acquisition system is easy to use and does not interfere with regular walking. No statistically significant differences were found between the acceleration-based measurements and the corresponding ones from gait analysis for most of the spatial-temporal parameters, i.e. stride length, stride duration, cadence and speed, etc.; significant differences were found for the gait cycle phases, i.e. single and double support duration, etc. The system therefore shows promise also for a future routine clinical use.

Biomechanical assessment of balance and posture in subjects with ankylosing spondylitis

Background

Ankylosing spondylitis is a major chronic rheumatic disease that predominantly affects axial joints, determining a rigid spine from the occiput to the sacrum. The dorsal hyperkyphosis may induce the patients to stand in a stooped position with consequent restriction in patients’ daily living activities. The aim of this study was to develop a method for quantitatively and objectively assessing both balance and posture and their mutual relationship in ankylosing spondylitis subjects.

Methods

The data of 12 healthy and 12 ankylosing spondylitis subjects (treated with anti-TNF-α stabilized), with a mean age of 51.42 and 49.42 years; mean BMI of 23.08 and 25.44 kg/m² were collected. Subjects underwent a morphological examination of the spinal mobility by means of a pocket compass needle goniometer, together with an evaluation of both spinal and hip mobility (Bath Ankylosing Spondylitis Metrology Index), and disease activity (Bath Ankylosing Spondylitis Disease Activity Index). Quantitative evaluation of kinematics and balance were performed through a six cameras stereophotogrammetric system and a force plate. Kinematic models together with a test for evaluating balance in different eye level conditions were developed. Head protrusion, trunk flexion-extension, pelvic tilt, hip-knee-ankle flexion-extension were evaluated during Romberg Test, together with centre of pressure parameters.

Results

Each subject was able to accomplish the required task. Subjects’ were comparable for demographic parameters. A significant increment was observed in ankylosing spondylitis subjects for knee joint angle with the target placed at each eye level on both sides (p < 0.042). When considering the pelvic tilt angle a statistically significant reduction was found with the target placed respectively at 10° (p = 0.034) and at 30° (p = 0.019) less than eye level. Furthermore in ankylosing spondylitis subjects both hip (p = 0.048) and ankle (p = 0.029) joints angles differs significantly. When considering the posturographic parameters significant differences were observed for ellipse, center of pressure path and mean velocity (p < 0.04). Goniometric evaluation revealed significant increment of thoracic kyphosis reduction of cervical and lumbar range of motion compared to healthy subjects.

Conclusions

Our findings confirm the need to investigate both balance and posture in ankylosing spondylitis subjects. This methodology could help clinicians to plan rehabilitation treatments.

Muscle activity around the knee and gait performance in unicompartmental knee arthroplasty patients: a comparative study on fixed- and mobile-bearing designs

PURPOSE

Unicompartmental knee arthroplasty (UKA) offers clinical and functional advantages over total knee arthroplasty. The aim of this study was to compare the functional recovery of patients with mobile UKA versus fixed-bearing designs by state-of-the-art gait analysis and, in particular, by assessing muscular activity.

METHODS

Ten patients with the Oxford (mobile bearing) and ten patients with Optetrak (fixed bearing) UKA were evaluated at a minimum follow-up of 1 year post-operatively by gait analysis, which includes the main time-distance parameters, kinematics and kinetics of the replaced knee, and muscular activity of the main relevant muscles. Twenty healthy young subjects were used as controls.

RESULTS

The mean International Knee Society score was 92.7 ± 11.2 for all 20 UKA knees; for the Oxford UKA, it was 94.1 ± 9.5; and for the Optetrak UKA, it was 91.5 ± 12.9, although follow-up was significantly lower for the latter. Time-distance parameters showed a slower gait in both groups compared with that of controls, and the Oxford group had values closer to the controls. Knee joint flexion was similar to that of controls at initial contact and loading response with no differences between groups. In all patients, the joint moments were smaller to that of controls. Residual abnormalities such as the prolonged rectus femoris activity were present in both designs, and the only difference distinguishing the Optetrak group from the others was the combined co-contraction of the hamstrings.

CONCLUSIONS

A good restoration of gait was achieved by most unicompartmental knee patients independently of the UKA design, although some abnormalities persisted in muscle activity around the knee.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

Clinical and functional outcomes of the saddle prosthesis

BACKGROUND

The implantation of a saddle prosthesis after resection of a pelvic tumor has been proposed as a simple method of reconstruction that provides good stability and reduces the surgical time, thus limits the onset of intraoperative complications. There are no studies in the literature of patients evaluated using gait analysis after being implanted with a saddle prosthesis. The present study is a retrospective case review aimed at illustrating long-term clinical and functional findings in tumor patients reconstructed with a saddle prosthesis.

MATERIALS AND METHODS

A series of 15 patients who received pelvic reconstruction with a saddle prosthesis were retrospectively reviewed in terms of clinical, radiographic, and functional evaluations. Two patients were additionally assessed by gait analysis.

RESULTS

Long-term functional follow-up was achieved in only 6 patients, and ranged from 97 to 167 months. Function was found to be rather impaired, as a mean of only 57 % of normal activity was restored. Gait analysis demonstrated that the implant had poor biomechanics, as characterized by very limited hip motion.

CONCLUSIONS

Though the saddle prosthesis was proposed as advance in tumor-related pelvic surgery, the present study indicates that it yields unsatisfactory clinical and functional results due to both clinical complications and the poor biomechanics of the device. The use of a saddle prosthesis in tumor surgery did not provide satisfactory results in long-term follow-up. It is no longer implanted at our institute, and is currently considered a "salvage technique."

Femoral loads during gait in a patient with massive skeletal reconstruction

BACKGROUND

Biological massive skeletal reconstructions in tumours adopt a long rehabilitation protocol aimed at minimising the fracture risk. To improve rehabilitation and surgical procedures it is important to fully understand the biomechanics of the reconstructed limb. The aim of the present study was to develop a subject-specific musculoskeletal model of a patient with a massive biological skeletal reconstruction, to investigate the loads acting on the femur during gait, once the rehabilitation protocol was completed.

METHODS

A personalised musculoskeletal model of the patient's lower limbs was built from a CT exam and registered with the kinematics recorded in a gait analysis session. Predicted activations for major muscles were compared to EMG signals to assess the model's predictive accuracy.

FINDINGS

Gait kinematics showed only minor discrepancies between the two legs and was compatible with normality data. External moments showed slightly higher differences and were almost always lower on the operated leg exhibiting a lower variability. In the beginning of the stance phase, the joint moments were, conversely, higher on the operated side and showed a higher variability. This pattern was reflected and amplified on the femoral forces where the differences became important: on the hip, a maximum difference of 1.6 BW was predicted. The variability of the forces seemed, generally, lower on the operated leg than on the contralateral one.

INTERPRETATION

Small asymmetries in kinematic patterns might be associated, in massive skeletal reconstruction, to significant difference in the skeletal loads (up to 1.6 BW for the hip joint reaction) during gait.

A new protocol for 3D assessment of foot during gait: application on patients with equinovarus foot

BACKGROUND

The aim of this study is to assess the clinical value of a recently introduced original protocol for full three dimensional analysis of ankle rotations in patients with equinovarus foot.

METHODS

A preliminary study merging the Total3Dgait protocol and the conventional Vicon® Plug-in-Gait marker-sets on five patients with foot deformity was performed to compare the output exactly over the same gait cycles. In the second study, 15 patients with equinus varus foot were assessed retrospectively by means of the Total3Dgait protocol before and after surgery. Data on ankle kinematics were compared to those of a control group. The Functional Ambulation Categories scale and other goals such as orthosis/aids removal, decrease in foot pain, healing of calluses and sores were considered as measures of clinical outcome.

FINDINGS

The Total3Dgait protocol provides additional joint motion, in the coronal and transverse planes. Kinematics in the three anatomical planes improved significantly although no changes in time-distance parameters were evident. Improvement in clinical outcome measures was also achieved.

INTERPRETATION

The new protocol provides valuable additional data in measuring full three dimensional kinematics of the foot during gait. Whereas the speed of walking was unchanged after surgery for most of patients, the kinematic changes in the three anatomical planes, as measured by the new protocol, were the only measures able to demonstrate motion changes induced by surgery at the foot and to explain subject-specific gains as improvement in stability during walking, relief of pain, calluses and sores, and removal or modification of foot orthosis and aids.

Biomechanical models in the study of lower limb amputee kinematics: a review

BACKGROUND

Optoelectronic motion capture may provide a platform for the development of objective biomechanical outcome measures applicable to the young, active individual with lower limb loss. In order to create valid and robust tools, the modelling strategy applied must adequately represent both natural and prosthetic segments and joints.

OBJECTIVES

To explore existing usage of optoelectronic motion capture and modelling strategies for the analysis of amputee function.

STUDY DESIGN

Literature review.

METHODS

Systematic search of Medline (OVID) and keyword search of the Journal of Prosthetics and Orthotics.

RESULTS

Over 60% (n = 32) of the 51 studies extracted adopted a conventional three degree-of-freedom modelling approach. Linear segment representation (15%) and six degree-of-freedom techniques (19%) were employed in the remaining papers. Prosthetic modelling strategies were poorly reported. Landmarks were estimated from corresponding positions on the contralateral intact limb, mechanical joint centres and regression equations. No model defined the residuum and socket independently.

CONCLUSIONS

In the absence of a definitive solution, it is essential that the limitations of any model are understood in the development and establishment of reliable outcome measures for this population using motion capture technology. Poor reporting and a lack of consistency make comparison of results between studies and institutions impractical.

CLINICAL RELEVANCE

Standard modelling techniques may not consistently represent the body and prosthesis adequately to produce valid results for the analysis of function of persons with lower limb loss. Variation in modelling techniques limits the utility of findings reported in the literature. Development and application of a uniform, robust modelling strategy would benefit research and clinical practice.

Impaired gait in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic, inflammatory rheumatic disease. The spine becomes rigid from the occiput to the sacrum, leading to a stooped position. This study aims at evaluating AS subjects gait alterations. Twenty-four subjects were evaluated: 12 normal and 12 pathologic in stabilized anti-TNF-alpha treatment (mean age 49.42 (10.47), 25.44 (3.19) and mean body mass index 55.75 (3.19), 23.73 (2.7), respectively). Physical examination and gait analysis were performed. A motion capture system synchronized with two force plates was used. Three-dimensional kinematics and kinetics of trunk, pelvis, hip, knee and ankle were determined during gait. A trend towards reduction was found in gait velocity and stride length. Gait analysis results showed statistically significant alterations in the sagittal plane at each joint for AS patients (P < 0.049). Hip and knee joint extension moments showed a statistically significant reduction (P < 0.044). At the ankle joint, a decreased plantarflexion was assessed (P < 0.048) together with the absence of the heel rocker. Gait analysis, through gait alterations identification, allowed planning-specific rehabilitation intervention aimed to prevent patients' stiffness together with improve balance and avoid muscles' fatigue.

A new classification of diabetic gait pattern based on cluster analysis of biomechanical data

BACKGROUND

The diabetic foot, one of the most serious complications of diabetes mellitus and a major risk factor for plantar ulceration, is determined mainly by peripheral neuropathy. Neuropathic patients exhibit decreased stability while standing as well as during dynamic conditions. A new methodology for diabetic gait pattern classification based on cluster analysis has been proposed that aims to identify groups of subjects with similar patterns of gait and verify if three-dimensional gait data are able to distinguish diabetic gait patterns from one of the control subjects.

METHOD

The gait of 20 nondiabetic individuals and 46 diabetes patients with and without peripheral neuropathy was analyzed [mean age 59.0 (2.9) and 61.1(4.4) years, mean body mass index (BMI) 24.0 (2.8), and 26.3 (2.0)]. K-means cluster analysis was applied to classify the subjects' gait patterns through the analysis of their ground reaction forces, joints and segments (trunk, hip, knee, ankle) angles, and moments.

RESULTS

Cluster analysis classification led to definition of four well-separated clusters: one aggregating just neuropathic subjects, one aggregating both neuropathics and non-neuropathics, one including only diabetes patients, and one including either controls or diabetic and neuropathic subjects.

CONCLUSIONS

Cluster analysis was useful in grouping subjects with similar gait patterns and provided evidence that there were subgroups that might otherwise not be observed if a group ensemble was presented for any specific variable. In particular, we observed the presence of neuropathic subjects with a gait similar to the controls and diabetes patients with a long disease duration with a gait as altered as the neuropathic one.

Repeatability of a new protocol for gait analysis in adult subjects

The reliability of kinematic measurements has a top priority in gait analysis. The aim of the present work was to assess the inter-trial, inter-session and inter-examiner variability of an anatomical-based protocol by an established method. The gait of two young adult volunteers was analyzed by four examiners with different degrees of experience in three sessions 1 week apart. The data of five trials of level walking were collected and the rotations in the three anatomical planes of the pelvis, hip, knee and ankle were calculated. The mean value over the gait cycle of the standard deviation of these rotations was calculated for each of the 24 groups of five trials (inter-trial), the eight groups of five trials multiplied by three sessions (inter-session), and the two groups of five trials multiplied by three sessions multiplied by four examiners (inter-examiner). For each rotation, the inter-examiner variability was larger than the inter-session, and the latter larger than the inter-trial. The present ratio between inter-examiner and inter-trial variability was found to be smaller than that of the conventional protocol for each of the gait variables.

A prospective randomized assessment of earlier functional recovery in THA patients treated by minimally invasive direct anterior approach: a gait analysis study

BACKGROUND

Total hip replacement using a minimally invasive surgical approach is claimed to enable recovering of motor function more quickly. The purpose of this prospective As per the stylesheet, kindly provide section headings for abstract.and randomized study was to test this claim by evaluating early patient functional outcomes by gait analysis.

METHODS

Seventeen patients were operated on using a traditional anterolateral approach (AL), 16 using a minimally invasive direct anterior approach (DA). Gait analysis was performed the day before surgery, and at 6 and 12 weeks after surgery. Time-distance and kinematics analyses were performed by a recently proposed anatomically-based gait analysis protocol. A static double-leg stance and five walking trials at self-selected speeds were recorded on a 9-m walkway.

FINDINGS

At 6 weeks follow-up, but in the DA group only, a statistically significant improvement with respect to preoperative status was observed for the percentage of single support and for the stride time. Between 6- and 12-week follow-up, the DA group showed a significant improvement in cadence, stride time and length, walking speed, hip flexion at foot contact, maximum hip flexion in swing, and hip total range of motion in the sagittal and the coronal planes. Between 6 and 12 weeks, the AL group showed significant improvements in opposite foot contact and step time, and in flexion at foot contact, maximum flexion in swing, and range of flexion at the hip joint.

INTERPRETATION

Minimally invasive DA patients improved in a larger number of gait parameters than patients receiving the traditional AL approach. The majority of improvements occurred between the 6- and 12-week follow-ups.

In vivo kinematics and kinetics of a bi-cruciate substituting total knee arthroplasty: a combined fluoroscopic and gait analysis study

After total knee arthroplasty, changes in articular surface geometry, soft tissue treatment, and component alignment can alter normal lower limb function. The guided motion bi-cruciate substituting prosthesis was designed specifically to restore physiological knee joint motion. We determined whether this design could in vivo normal kinematics and kinetics, not only at the replaced knee, but also throughout both lower limbs. Sixteen patients (4 male, 12 female, mean age of 68.2 years with a range from 58 to 79 years) with primary knee osteoarthritis were implanted with the bi-cruciate substituting prosthesis. At 6-month follow-up, knee joint kinematics was assessed by video-fluoroscopy during stair-climbing, chair-rising/sitting, and step-up/down. Lower limb overall function was also assessed on the same day by standard gait analysis with simultaneous electromyography during level walking. By video-fluoroscopy, mean anteroposterior translations between femoral and tibial components during the three motor tasks were 9.7 +/- 3.0, 10 +/- 2.6, and 6.9 +/- 3.5 mm on the medial compartment, and 14.3 +/- 3.5, 18.5 +/- 3.0, and 13.9 +/- 3.8 mm on the lateral compartment, respectively. Axial rotation ranged from 5.6 degrees to 26.2 degrees. Gait analysis revealed restoration of nearly normal walking patterns in most patients. This rare combination of measurements, i.e., accurate rotation-translation at the replaced knee and complete locomotion patterns at both lower limb joints, suggested that bi-cruciate substituting arthroplasty can restore physiological knee motion and normal overall function.

First in vivo assessment of "Outwalk": a novel protocol for clinical gait analysis based on inertial and magnetic sensors

A protocol named "Outwalk" was recently proposed to measure the thorax-pelvis and lower-limb kinematics during gait in free-living conditions, by means of an inertial and magnetic measurement system (IMMS). The aim of this study was to validate Outwalk on four healthy subjects when it is used in combination with a specific IMMS (Xsens Technologies, NL), against a reference protocol (CAST) and measurement system (optoelectronic system; Vicon, Oxford Metrics Group, UK). For this purpose, we developed an original approach based on three tests, which allowed to separately investigate: (1) the consequences on joint kinematics of the differences between protocols (Outwalk vs. CAST), (2) the accuracy of the hardware (Xsens vs. Vicon), and (3) the summation of protocols' differences and hardware accuracy (Outwalk + Xsens vs. CAST + Vicon). In order to assess joint-angles similarity, the coefficient of multiple correlation (CMC) was used. For test 3, the CMC showed that Outwalk + Xsens and CAST + Vicon kinematics can be interchanged, offset included, for hip, knee and ankle flexion-extension, and hip ab-adduction (CMC > 0.88). The other joint-angles can be interchanged offset excluded (CMC > 0.85). Tests 1 and 2 also showed that differences in offset between joint-angles were predominantly induced by differences in the protocols; differences in correlation by both hardware and protocols; differences in range of motion by the Xsens accuracy. Results thus support the commencement of a clinical trial of Outwalk on transtibial amputees.

Diabetic gait and posture abnormalities: a biomechanical investigation through three dimensional gait analysis

BACKGROUND

Diabetic sensorimotor polyneuropathy is a long-term diabetic complication. It is involved in the pathogenesis of the diabetic foot, which is a major cause of morbidity and mortality. The study aims to investigate the effects of diabetic polyneuropathy on gait and posture.

METHODS

Sixty seven subjects were enrolled: 21 diabetics without polyneuropathy, 26 with polyneuropathy, 20 controls (respectively, mean age 63.8 (SD 5.4), 63.2 (SD 5.6), 59.0 (SD 5.2) years, mean body mass index 26.3 (SD 2.5), 25.6 (SD 3), 24.0 (SD 2.9)). Postural and morphological evaluation and gait analysis were performed. Physical examination, together with a motion capture system synchronized with two force plates and two baropodometric systems were used. We evaluated lower limb mobility, foot deformities, trunk and pelvic posture, knee and heel position, plantar foot arch, three dimensional kinematics and kinetics during gait. The effect of peripheral vascular disease and microangiopathy on trunk and lower limb motion was also evaluated.

FINDINGS

Trunk and lower limb joint mobility (in static and dynamic states) were more reduced in diabetics either with or without polyneuropathy on each plane; however in diabetics with polyneuropathy significantly lower ranges of motion were registered. Furthermore, both groups showed significant reductions in each joint moment and velocity (P0.003) during gait. In presence of both vasculopathy and microangiopathy a further significant reduction (P0.001) was noticed.

INTERPRETATION

Altered gait and posture were found in diabetic patients irrespective of polyneuropathy. This approach may be relevant to predict the risk ulceration before clinically detectable neuropathy.

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.

METHODS

A four segment foot and ankle model for assessing the kinematics of the diabetic foot was developed. Ten normal subjects and 10 diabetics gait patterns were collected and major sources of variability were tested. Repeatability analysis was performed both on a normal and on a diabetic subject. Direct skin marker placement was chosen in correspondence of 13 anatomical landmarks and an optoelectronic system was used to collect the data.

RESULTS

Joint rotation normative bands (mean plus/minus one standard deviation) were generated using the data of the control group. Three representative strides per subject were selected. The repeatability analysis on normal and pathological subjects results have been compared with literature and found comparable. Normal and pathological gait have been compared and showed major statistically significant differences in the forefoot and midfoot dorsi-plantarflexion.

CONCLUSION

Even though various biomechanical models have been developed so far to study the properties and behaviour of the foot, the present study focuses on developing a methodology for the functional assessment of the foot-ankle complex and for the definition of a functional model of the diabetic neuropathic foot. It is, of course, important to evaluate the major sources of variation (true variation in the subject's gait and artefacts from the measurement procedure). The repeatability of the protocol was therefore examined, and results showed the suitability of this method both on normal and pathological subjects. Comparison between normal and pathological kinematics analysis confirmed the validity of a similar approach in order to assess neuropathics biomechanics impairment.

A six degrees-of-freedom marker set for gait analysis: repeatability and comparison with a modified Helen Hayes set

Kinematic gait analysis is limited by simplified marker sets and related models. The majority of sets in clinical use were developed with low resolution imaging systems so required various assumptions about body behaviour. Further major limitations include soft tissue artefact and ambiguity in landmark identification. An alternative is the use of sets based on six degrees-of-freedom (DOF) principles, primarily using marker clusters for tracking. This study evaluates performance of a 6DOF set, based largely on CAST/ISB recommendations, through comparison with a conventional set and assessment of repeatability. Ten healthy subjects were assessed in treadmill walking, with both sets applied simultaneously on two occasions. Data were analysed using repeatability coefficients, correlation of key features, and comparison of joint angle curves and difference curves with confidence bands. Apart from pelvic tilt all segment and joint angles from both sets showed high within and between session repeatability (CMC>0.80). Hip rotations showed clear differences between the two sets with indications in support of the 6DOF set. Knee coronal angles showed evidence of cross-talk in the conventional set, highlighting difficulties with anatomical identification despite control measures such as a foot alignment template. Knee transverse angles showed inconsistent patterns for both sets. At the ankle the conventional set only allowed true measurement in two planes so with high repeatability the 6DOF set is preferable. The 6DOF set showed comparable performance to the conventional set and overcomes a number of theoretical limitations, however further development is needed prior to clinical implementation.

Quantitative comparison of current models for trunk motion in human movement analysis

BACKGROUND

A number of different models for human trunk kinematics during locomotion have been proposed, though mainly addressing specific clinical questions rather than general populations. These differ considerably for the skeletal segments considered, marker-set, anatomical axis and frame definitions, and joint conventions. The scope of the present study is to compare quantitatively these models on the basis of the same motion.

METHODS

Ten subjects were analysed, instrumented with a single comprehensive marker-set of 14 markers identified from the union of the corresponding from eight current models for trunk kinematics. Activities of daily living (walking, chair rising/sitting, step-up/down), elementary trunk movements (flexion, bending and axial rotation), and isolated motion of the shoulders, both synchronous and asynchronous were collected. Resulting rotations in the three anatomical planes, both in the laboratory and in the pelvis reference frames, were calculated.

FINDINGS

In addition to the expected bias between the rotation angle time-histories, very different patterns and range of motion were found between the models. In chair rising/sitting, and in the laboratory global frame, the range of flexion averaged over the subjects was measured by the different models in the full scale from about 28 degrees to 44 degrees. In elementary trunk rotation and in the pelvis anatomical reference frame, three models measured about 10 degrees excursion of the coupled bending motion, other two about 38 degrees and 49 degrees on average.

INTERPRETATION

In trunk kinematics analysis, it is recommended that all models, both in terms of markers involved and of reference frame definitions, are understood carefully before interpreting the results in clinical decision making.

GAIT analysis in patients operated with a novel total ankle prosthesis

A new three-part total ankle prosthesis was designed recently to restore natural joint motion while maintaining full congruity of the articulating surfaces. This was achieved by replicating natural function for the ligaments. Early functional recovery was assessed in the present study in patients who underwent replacement with this prosthesis. This was undertaken using the AOFAS clinical scoring system and gait analysis, performed preoperatively and at 6 and 12 months from surgery. The 10 patients had, at the time of operation, a mean age of 57.4 years (range 45-72), and BMI 25.8 (range 20.4-34.1). A recently proposed protocol for three-dimensional and anatomically based analysis of joint kinematics and kinetics was used. The AOFAS score rose from 44.3 pre-op to 81.5 and 81.0 respectively at 6- and 12-month follow-up, with particular improvement in function. Spatio-temporal parameters improved considerably already at 6 months. More normal patterns and ranges of rotations and moments were observed in the three anatomical planes of the replaced ankle at 6 months and maintained at 12 months. In particular the improvement in dorsi-plantarflexion range in stance was significant, though a limited plantarflexion in swing occurred. EMG revealed a good recovery of physiological activity for the biceps femoris at 12-month follow-up. The new ankle prosthesis contributed to early functional recovery at 6 months, maintained at 1 year.

The reliability of three-dimensional kinematic gait measurements: a systematic review

BACKGROUND/AIM

Three-dimensional kinematic measures of gait are routinely used in clinical gait analysis and provide a key outcome measure for gait research and clinical practice. This systematic review identifies and evaluates current evidence for the inter-session and inter-assessor reliability of three-dimensional kinematic gait analysis (3DGA) data.

METHOD

A targeted search strategy identified reports that fulfilled the search criteria. The quality of full-text reports were tabulated and evaluated for quality using a customised critical appraisal tool.

RESULTS

Fifteen full manuscripts and eight abstracts were included. Studies addressed both within-assessor and between-assessor reliability, with most examining healthy adults. Four full-text reports evaluated reliability in people with gait pathologies. The highest reliability indices occurred in the hip and knee in the sagittal plane, with lowest errors in pelvic rotation and obliquity and hip abduction. Lowest reliability and highest error frequently occurred in the hip and knee transverse plane. Methodological quality varied, with key limitations in sample descriptions and strategies for statistical analysis. Reported reliability indices and error magnitudes varied across gait variables and studies. Most studies providing estimates of data error reported values (S.D. or S.E.) of less than 5 degrees , with the exception of hip and knee rotation.

CONCLUSION

This review provides evidence that clinically acceptable errors are possible in gait analysis. Variability between studies, however, suggests that they are not always achieved.

Effects of an adapted physical activity program in a group of elderly subjects with flexed posture: clinical and instrumental assessment

BACKGROUND

Flexed posture commonly increases with age and is related to musculoskeletal impairment and reduced physical performance. The purpose of this clinical study was to systematically compare the effects of a physical activity program that specifically address the flexed posture that marks a certain percentage of elderly individuals with a non specific exercise program for 3 months.

METHODS

Participants were randomly divided into two groups: one followed an Adapted Physical Activity program for flexed posture and the other one completed a non-specific physical activity protocol for the elderly. A multidimensional clinical assessment was performed at baseline and at 3 months including anthropometric data, clinical profile, measures of musculoskeletal impairment and disability. The instrumental assessment of posture was realized using a stereophotogrammetric system and a specific biomechanical model designed to describe the reciprocal position of the body segments on the sagittal plane in a upright posture.

RESULTS

The Adapted Physical Activity program determined a significant improvement in several key parameters of the multidimensional assessment in comparison to the non-specific protocol: decreased occiput-to-wall distance, greater lower limb range of motion, better flexibility of pectoralis, hamstrings and hip flexor muscles, increased spine extensor muscles strength. Stereophotogrammetric analysis confirmed a reduced protrusion of the head and revealed a reduction in compensative postural adaptations to flexed posture characterized by knee flexion and ankle dorsiflexion in the participants of the specific program.

CONCLUSION

The Adapted Physical Activity program for flexed posture significantly improved postural alignment and musculoskeletal impairment of the elderly. The stereophotogrammetric evaluation of posture was useful to measure the global postural alignment and especially to analyse the possible compensatory strategies at lower limbs in flexed posture.

Quantitative comparison of five current protocols in gait analysis

Data collection and reduction procedures, coherently structured in protocols, are necessary in gait analysis to make kinematic and kinetic measurements clinically comprehensible. The current protocols differ considerably for the marker-set and for the biomechanical model implemented. Nevertheless, conventional gait variables are compared without full awareness of these differences. A comparison was made of five worldwide representative protocols by analysing kinematics and kinetics of the trunk, pelvis and lower limbs exactly over the same gait cycles. A single comprehensive arrangement of markers was defined by merging the corresponding five marker-sets. This resulted in 60 markers to be positioned either on the skin or on wands, and in 16 anatomical landmark calibrations to be performed with an instrumented pointer. Two healthy subjects and one patient who had a special two degrees of freedom knee prosthesis implanted were analysed. Data from up-right posture and at least three gait repetitions were collected. Five corresponding experts participated in the data collection and analysed independently the data according to their own procedures. All five protocols showed good intra-protocol repeatability. Joint flexion/extension showed good correlations and a small bias among protocols. Out-of-sagittal plane rotations revealed worse correlations, and in particular knee abduction/adduction had opposite trends. Joint moments compared well, despite the very different methods implemented. The abduction/adduction at the prosthetic knee, which was fully restrained, revealed an erroneous rotation as large as 30 degrees in one protocol. Higher correlations were observed between the protocols with similar biomechanical models, whereas little influence seems to be ascribed to the marker-set.