Measurement properties of walking outcome measures for neurogenic claudication: a systematic review and meta analysis

Walking test outcomes in adults with genetic neuromuscular diseases: a systematic literature review of their measurement properties

INTRODUCTION

Neuromuscular diseases (NMDs) include a large group of heterogeneous diseases. NMDs frequently involve gait disorders, which affect quality of life. Several walking tests and tools have been described in the literature, but there is no consensus regarding the use of walking tests and tools in NMDs or of their measurement properties for walking outcomes. The aim of this review is to present an overview of walking tests, including their measurement properties when used in adults with inherited or genetic NMDs. The aim is to help clinicians and researchers choose the most appropriate test for their objective.

EVIDENCE ACQUISITION

A systematic review was conducted after consulting MEDLINE (via PubMed), EMBASE, Science direct, Google Scholar and Cochrane Central Register of Controlled Trials databases for published studies in which walking outcome measurement properties were assessed. The validity, reliability, measurement error and responsiveness properties were evaluated in terms of statistical methods and methodological design qualities using the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) guidelines.

EVIDENCE SYNTHESIS

We included 46 studies in NMDs. These studies included 15 different walking tests and a wide variety of walking outcomes, assessed with six types of walking tools. Overall, the 6MWT was the most studied test in terms of measurement properties. The methodological design and statistical methods of most studies evaluating construct validity, reliability and measurement error were "very good." The majority of outcome measurements were valid and reliable. However, studies on responsiveness as minimal important difference or minimal important change were lacking or were found to have inadequate methodological and statistical methods according to the COSMIN guidelines.

CONCLUSIONS

Most walking outcomes were found to be valid and reliable in NMDs. However, in view of the growing number of clinical trials, further studies are needed to clarify additional measurement properties.

Measurement properties of utility-based health-related quality-of-life measures in cardiac rehabilitation: a systematic review protocol

OBJECTIVE

This review will identify and appraise existing evidence on the measurement properties of utility-based health-related quality-of-life (HRQoL) measures used in cardiac rehabilitation programs. The review will map the measure domains against the International Classification of Functioning, Disability and Health and the International Consortium of Health Outcome Measures domains for cardiovascular disease.

INTRODUCTION

Improving HRQoL is an international key indicator for delivering high-quality and person-centered secondary prevention programs. Many instruments and measures assess HRQoL in individuals undergoing cardiac rehabilitation. Utility-based measures are suitable for calculating quality-adjusted life years, a required outcome metric in cost-utility analysis. Cost-utility analysis requires the use of utility-based HRQoL measures. However, there is no consensus on which utility-based measure is best for populations undergoing cardiac rehabilitation.

INCLUSION CRITERIA

Eligible studies will include patients aged ≥18 years with cardiovascular disease who are undergoing cardiac rehabilitation. Empirical studies that assess quality of life or HRQoL using a utility-based, health-related, patient-reported outcome measure or a measure accompanied by health state utilities will be eligible. Studies must report at least 1 of the following measurement properties: reliability, validity, responsiveness.

METHODS

This review will follow the JBI methodology for systematic reviews of measurement properties. The following databases will be searched from inception to the present: MEDLINE, Emcare, Embase, Scopus, CINAHL, Web of Science Core Collection, Informit, PsyclNFO, REHABDATA, and the Cochrane Library. Studies will be critically appraised using the The COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) risk of bias checklist. The review will be reported in line with the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines.

REVIEW REGISTRATION

PROSPERO CRD42022349395.

Validity of outcome measures used in randomized clinical trials and observational studies in degenerative lumbar spinal stenosis

It is unclear whether outcome measures used in degenerative lumbar spinal stenosis (DLSS) have been validated for this condition. Cross-sectional analysis of studies for DLSS included in systematic reviews (SA) and meta-analyses (MA) indexed in the Cochrane Library. We extracted all outcome measures for pain and disability. We assessed whether the studies provided external references for the validity of the outcome measures and the quality of the validation studies. Out of 20 SA/MA, 95 primary studies used 242 outcome measures for pain and/or disability. Most commonly used were the VAS (n = 69), the Oswestry Disability Index (n = 53) and the Zurich Claudication Questionnaire (n = 22). Although validation references were provided in 45 (47.3%) primary studies, only 14 validation studies for 9 measures (disability n = 7, pain and disability combined n = 2) were specifically validated in a DLSS population. The quality of the validation studies was mainly poor. The Zurich Claudication Questionnaire was the only disease specific tool with adequate validation for assessing treatment response in DLSS. To compare results from clinical studies, outcome measures need to be validated in a disease specific population. The quality of validation studies need to be improved and the validity in studies adequately cited.

Objective Evaluation of Neurogenic Intermittent Claudication for Patients With Lumbar Spinal Stenosis Based on Plantar Pressure Analysis

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

To quantify the severity of neurogenic intermittent claudication (NIC) for patients with lumbar spinal stenosis (LSS) based on the center of pressure trajectory.

SUMMARY OF BACKGROUND DATA

NIC is one of the typical symptoms of LSS. So far, the severity level of NIC is mainly evaluated by the subjective description of patients, which might be biased by patients' background differences and thus lead to an ineffective diagnosis or inappropriate treatment for LSS. Therefore, it remains necessary to develop a reliable clinical technique for quantitative evaluation of NIC to achieve more effective therapy for LSS.

MATERIALS AND METHODS

In the present study, the Footscan pressure system was used to detect the center of pressure trajectory. The real-time walking distance (rtWD) and the corresponding displacement of the medial-lateral center of pressure (ML-COP) were calculated based on the trajectory. The differences of ML-COP between LSS and control groups were analyzed using a one-way repeated measures analysis of variance. Regression and Pearson correlation analysis were used to investigate the correlation between rtWD and ML-COP, as well as the relation between the Oxford Claudication Score (OCS) and clinical evaluation indicators.

RESULTS

The present study included 31 LSS patients and 31 healthy controls. There were no significant differences in demographic data between the two groups ( P >0.05). The results indicated that ML-COP would increase with the number of laps in the LSS group while not in the control group. Also, a linear relationship was identified between the ML-COP and rtWD for LSS patients ( R2 >0.80, P <0.05). Since the incremental rate of ML-COP for LSS patients was reflected by the regression coefficients of the linear regression analysis, thus the regression coefficients were defined as the claudication correlation coefficients (CCCs). In addition, it was indicated by the statistical analysis that there was a strong positive correlation between OCS and CCC ( r =0.96; P <0.001) and a medium negative correlation with final walking distance ( r =-0.67; P <0.001). It was also noticed that there was no significant correlation between the average ML-COP and OCS ( r =-0.03; P =0.864).

CONCLUSIONS

The ML-COP of LSS patients would increase with the patients' walking distance. This incremental rate, characterized by the CCC, would be used as an effective indicator to quantify the severity level of the NIC for potentially more accurate and reliable diagnosis, evaluation, and treatment of LSS.

LEVEL OF EVIDENCE

3.

Outcome Domain and Measurement Instrument Reporting in Randomized Controlled Trials of Interventions for Lumbar Spinal Stenosis: A Systematic Review

OBJECTIVE

To describe outcome measurement instruments and outcome domains in randomized controlled trials of any interventions for lumbar spinal stenosis (LSS).

DESIGN

Systematic review.

LITERATURE SEARCH

The Cochrane Central Register of Controlled Trials (CENTRAL) and PubMed were searched from inception to May 2020.

STUDY SELECTION CRITERIA

Trials were eligible if patients were diagnosed with LSS, with or without neurogenic claudication. Trials were eligible if they used at least 1 outcome measurement instrument.

DATA SYNTHESIS

Measurement instruments used in trials were extracted and then classified into outcome domains. We described the frequency of measurement instruments and outcome domains.

RESULTS

After study screening, 29 trials were included. In total, 54 different individual outcome measurement instruments were used. The Visual Analogue Scale (59%; n = 17) and the Oswestry Disability Index (52%; n = 15) were the most frequently used outcome measurement instruments in trials; function (90%; n = 26) and pain (62%; n = 18) were the most common outcome domains.

CONCLUSION

In total, 54 different measurement instruments were used in trials of interventions for LSS. This diverse range of observations contributes to outcome instrument heterogeneity between trials and impedes the analysis of data due to lack of comparability. The most common outcome domains assessed were pain and function, which will help inform a core outcome measure set for symptomatic LSS. J Orthop Sports Phys Ther 2022;52(7):446-456. Epub: 18 May 2022. doi:10.2519/jospt.2022.10879.

Gait assessment tools for degenerative cervical myelopathy: a systematic review

BACKGROUND

Degenerative cervical myelopathy (DCM) is a common progressive neurological disorder which may affect one's activities of daily living or even result in paraplegia/tetraplegia if left untreated. Currently, there is lack of consensus of the gait assessment tools for DCM. This systematic review aims to (I) provide an appraisal of the psychometric properties of the available gait assessment tools for DCM, (II) to assess their methodological quality according to The Consensus-based Standards for the selection of health Measurement COSMIN risk of bias checklist and (III) to assess each measurement property result against externally validated criteria.

METHODS

Six electronic full-text databases [PubMed (via NLM^® database], Medline (via OvidSP), CINAHL (via Ebsco), EMBASE (via Ovid), PsycINFO (via CSA) and Web of Science (via Thomson Reuters)] were systematically searched from inception to June 2020. The methodological quality of each study was analysed using the COSMIN risk of bias checklist. The measurement property result and methodological quality of each study were evaluated.

RESULTS

Twenty studies were included from 3,339 citations retrieved. Twelve assessment tools for assessing gait in DCM were identified. According to COSMIN criteria, only five studies (25%) included in this review were found to have "very good" methodological quality. For construct validity, five tools had "sufficient" quality. For reliability, two assessment tools [the Total modified Japanese Orthopaedic Association Score (Italian Translation) (mJOA-ITTotal) and the modified Japanese Orthopaedic Association (Italian Translation) Motor dysfunction of the Lower Extremity (mJOA-ITMDLE)] were rated as "sufficient" for interobserver reliability while six assessment tools (the 10 second step test (10 sec ST), 30 minute walk test (30MWT), foot tapping test, mJOA-ITTotal, mJOA-ITMDLE and the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire) were rated as "sufficient" for test-retest reliability. The JOA (6 scores) received a "sufficient" rating for internal consistency. No assessment was available for responsiveness, as only the effect size was available.

DISCUSSION

Based upon current evidence, the mJOA in combination with an objective functional test (i.e., 30MWT) is recommended for clinicians assessing gait in DCM, although this may change with an increase in the number of studies completed. Given the importance of assessment tools possessing adequate measurement properties, a focus on studies in this area is warranted.

The Reliability of the Microsoft Kinect and Ambulatory Sensor-Based Motion Tracking Devices to Measure Shoulder Range-of-Motion: A Systematic Review and Meta-Analysis

Advancements in motion sensing technology can potentially allow clinicians to make more accurate range-of-motion (ROM) measurements and informed decisions regarding patient management. The aim of this study was to systematically review and appraise the literature on the reliability of the Kinect, inertial sensors, smartphone applications and digital inclinometers/goniometers to measure shoulder ROM. Eleven databases were screened (MEDLINE, EMBASE, EMCARE, CINAHL, SPORTSDiscus, Compendex, IEEE Xplore, Web of Science, Proquest Science and Technology, Scopus, and PubMed). The methodological quality of the studies was assessed using the consensus-based standards for the selection of health Measurement Instruments (COSMIN) checklist. Reliability assessment used intra-class correlation coefficients (ICCs) and the criteria from Swinkels et al. (2005). Thirty-two studies were included. A total of 24 studies scored "adequate" and 2 scored "very good" for the reliability standards. Only one study scored "very good" and just over half of the studies (18/32) scored "adequate" for the measurement error standards. Good intra-rater reliability (ICC > 0.85) and inter-rater reliability (ICC > 0.80) was demonstrated with the Kinect, smartphone applications and digital inclinometers. Overall, the Kinect and ambulatory sensor-based human motion tracking devices demonstrate moderate-good levels of intra- and inter-rater reliability to measure shoulder ROM. Future reliability studies should focus on improving study design with larger sample sizes and recommended time intervals between repeated measurements.

Prediction of walking ability following posterior decompression for lumbar spinal stenosis

PURPOSE

Following surgery for lumbar spinal stenosis (LSS) up to 40% of people report persistent walking disability. This study aimed to identify pre-operative factors that are predictive of walking ability post-surgery for LSS.

METHODS

An observational cohort study was conducted using data from the British Spine Registry (2017-2018) of adults (≥ 50 years) with LSS, who underwent ≤ 2 level posterior lumbar decompression. Patients receiving fixation or who had previous lumbar surgery were excluded. Walking ability was assessed by a single item on the Oswestry Disability Index and dichotomised into poor/good outcome. Multivariable regression models were performed.

RESULTS

14,485 patients were identified. Pre-operatively 30% patients reported poor walking ability, this decreased to 8% at 12 months follow-up. Predictors associated with poor walking ability at 12 months were: increasing age (≥ 75 years OR 1.54, 95% CI 1.07, 2.18), BMI ≥ 35 kg/m² (OR 1.52, 95% CI 1.00, 2.30), severity of leg pain (OR 1.10, CI 95% 1.01, 1.21), disability (OR 1.01, 95% CI 1.01, 1.02) and quality of life (OR 0.72, 95% CI 0.56, 0.89). Pre-operative maximum walking distance (OR 1.10, 95% CI 1.05, 1.25) and higher education (OR 0.90, 95% CI 0.80, 0.96) were associated with reduced risk of poor walking ability at 12 months; p < 0.05. Depression, fear of movement and symptom duration were not associated with risk of poor outcome.

CONCLUSION

Older age, obesity, greater pre-operative pain and disability and lower quality of life are associated with risk of poor walking ability post-operatively. Greater pre-operative walking and higher education are associated with reduced risk of poor walking ability post-operatively. Patients should be counselled on their risk of poor outcome and considered for rehabilitation so that walking and surgical outcomes may be optimised.

Responsiveness of Outcome Measures in Nonsurgical Patients with Lumbar Spinal Stenosis: A Secondary Analysis From a Randomized Controlled Trial

STUDY DESIGN

Secondary analysis from a randomized controlled trial on nonsurgical interventions for patients with lumbar spinal stenosis (LSS).

OBJECTIVE

The aim of this study was to assess the responsiveness of the Self-Paced Walking Test (SPWT), Swiss Spinal Stenosis Questionnaire (SSS), and Oswestry Disability Index (ODI) and determine their minimal clinically important differences (MCID) in nonsurgical LSS patients.

SUMMARY OF BACKGROUND DATA

Limited information is available about the responsiveness of these tests in nonsurgical LSS population.

METHODS

A total of 180 participants completed the SPWT, SSS, and ODI at baseline, 2, and 6 months. Responsiveness was assessed by distribution-based method, including effect size and standardized response mean, and anchor-based method, using the patient global index of change (PGIC) as the external anchor to distinguish responders and non-responders. Areas under the curve (AUC) were calculated along with MCIDs for "minimal" and "moderate improvement" subgroups.

RESULTS

The following values represent 2- and 6-month analyses of each outcome measure, respectively. Standard effect sizes: 0.48 and 0.50 for SPWT, -0.42 and -0.36 for SSS, and -0.29 and -0.25 for ODI. Spearman correlation coefficients between PGIC and outcomes were: 0.44 and 0.39 for SPWT, -0.53 and -0.55 for SSS, and -0.46 and -0.54 for ODI. MCIDs for the "minimal improvement" subgroup were: 375.9 and 319.3 ms for SPWT, -5.3 and -5.8 points for SSS, and -9.3 and -10.8 points for ODI. AUCs was 0.68 to 0.76. MCIDs for the "moderate improvement" subgroup were: 344.2 and 538.2 m for SPWT, -5.5 and -7.5 points for SSS, and -9.1 and -13.6 points for ODI. AUCs ranged from 0.68 to 0.76.

CONCLUSION

The SPWT, SSS, and ODI are responsive outcome measures to assess nonsurgical patients with LSS. This finding, along with the reported MCIDs, can help clinicians to monitor changes in their patients' walking and physical function over time and make clinical decisions. They also provide researchers with reference for future studies in LSS.Level of Evidence: 2.

Predicting recovery after lumbar spinal stenosis surgery: A protocol for a historical cohort study using data from the Canadian Spine Outcomes Research Network (CSORN)

Background: Symptomatic lumbar spinal stenosis (SLSS) is a condition in which narrowing of the spinal canal results in entrapment and compression of neurovascular structures. Decompressive surgery, with or without spinal fusion, is recommended for those with severe symptoms for whom conservative management has failed. However, significant persistent pain, functional limitations, and narcotic use can affect up to one third of patients postsurgery. Aims: The aim of this study will be to identify predictors of outcomes 1-year post SLSS surgery with a focus on modifiable predictors. Methods: The Canadian Spine Outcomes Research Network (CSORN) is a large database of prospectively collected data on pre- and postsurgical outcomes among surgical patients. We include participants with a primary diagnosis of SLSS undergoing their first spine surgery. Outcomes are measured at 12 months after surgery and include back and leg pain, disability (Oswestry Disability Index, ODI), walking capacity (ODI item 4), health-related quality of life, and an overall recovery composite outcome (clinically important changes in pain, disability, and quality of life). Predictors include demographics (education level, work status, marital status, age, sex, body mass index), physical activity level, smoking status, previous conservative treatments, medication intake, depression, patient expectations, and other comorbidities. A multivariate partial least squares model is used to identify predictors of outcomes. Conclusion: Study results will inform targeted SLSS interventions, either for the selection of best candidates for surgery or the identification of targets for presurgical rehabilitation programs.

The Reliability and Validity of Wearable Inertial Sensors Coupled with the Microsoft Kinect to Measure Shoulder Range-of-Motion

Background: Objective assessment of shoulder joint active range of motion (AROM) is critical to monitor patient progress after conservative or surgical intervention. Advancements in miniature devices have led researchers to validate inertial sensors to capture human movement. This study investigated the construct validity as well as intra- and inter-rater reliability of active shoulder mobility measurements using a coupled system of inertial sensors and the Microsoft Kinect (HumanTrak). Methods: 50 healthy participants with no history of shoulder pathology were tested bilaterally for fixed and free ROM: (1) shoulder flexion, and (2) abduction using HumanTrak and goniometry. The repeat testing of the standardised protocol was completed after seven days by two physiotherapists. Results: All HumanTrak shoulder movements demonstrated adequate reliability (intra-class correlation (ICC) ≥ 0.70). HumanTrak demonstrated higher intra-rater reliability (ICCs: 0.93 and 0.85) than goniometry (ICCs: 0.75 and 0.53) for measuring free shoulder flexion and abduction AROM, respectively. Similarly, HumanTrak demonstrated higher intra-rater reliability (ICCs: 0.81 and 0.94) than goniometry (ICCs: 0.70 and 0.93) for fixed flexion and abduction AROM, respectively. Construct validity between HumanTrak and goniometry was adequate except for free abduction. The differences between raters were predominately acceptable and below ±10°. Conclusions: These results indicated that the HumanTrak system is an objective, valid and reliable way to assess and track shoulder ROM.

Normative data of a smartphone app-based 6-minute walking test, test-retest reliability, and content validity with patient-reported outcome measures

OBJECTIVE

The 6-minute walking test (6WT) is used to determine restrictions in a subject's 6-minute walking distance (6WD) due to lumbar degenerative disc disease. To facilitate simple and convenient patient self-measurement, a free and reliable smartphone app using Global Positioning System coordinates was previously designed. The authors aimed to determine normative values for app-based 6WD measurements.

METHODS

The maximum 6WD was determined three times using app-based measurement in a sample of 330 volunteers without previous spine surgery or current spine-related disability, recruited at 8 centers in 5 countries (mean subject age 44.2 years, range 16-91 years; 48.5% male; mean BMI 24.6 kg/m2, range 16.3-40.2 kg/m2; 67.9% working; 14.2% smokers). Subjects provided basic demographic information, including comorbidities and patient-reported outcome measures (PROMs): visual analog scale (VAS) for both low-back and lower-extremity pain, Core Outcome Measures Index (COMI), Zurich Claudication Questionnaire (ZCQ), and subjective walking distance and duration. The authors determined the test-retest reliability across three measurements (intraclass correlation coefficient [ICC], standard error of measurement [SEM], and mean 6WD [95% CI]) stratified for age and sex, and content validity (linear regression coefficients) between 6WD and PROMs.

RESULTS

The ICC for repeated app-based 6WD measurements was 0.89 (95% CI 0.87-0.91, p < 0.001) and the SEM was 34 meters. The overall mean 6WD was 585.9 meters (95% CI 574.7-597.0 meters), with significant differences across age categories (p < 0.001). The 6WD was on average about 32 meters less in females (570.5 vs 602.2 meters, p = 0.005). There were linear correlations between average 6WD and VAS back pain, VAS leg pain, COMI Back and COMI subscores of pain intensity and disability, ZCQ symptom severity, ZCQ physical function, and ZCQ pain and neuroischemic symptoms subscores, as well as with subjective walking distance and duration, indicating that subjects with higher pain, higher disability, and lower subjective walking capacity had significantly lower 6WD (all p < 0.001).

CONCLUSIONS

This study provides normative data for app-based 6WD measurements in a multicenter sample from 8 institutions and 5 countries. These values can now be used as reference to compare 6WT results and quantify objective functional impairment in patients with degenerative diseases of the spine using z-scores. The authors found a good to excellent test-retest reliability of the 6WT app, a low area of uncertainty, and high content validity of the average 6WD with commonly used PROMs.

Objective activity tracking in spine surgery: a prospective feasibility study with a low-cost consumer grade wearable accelerometer

Patient-reported outcome measures (PROMs) are commonly used to estimate disability of patients with spinal degenerative disease. Emerging technological advances present an opportunity to provide objective measurements of activity. In a prospective, observational study we utilized a low-cost consumer grade wearable accelerometer (LCA) to determine patient activity (steps per day) preoperatively (baseline) and up to one year (Y1) after cervical and lumbar spine surgery. We studied 30 patients (46.7% male; mean age 57 years; 70% Caucasian) with a baseline activity level of 5624 steps per day. The activity level decreased by 71% in the 1^st postoperative week (p < 0.001) and remained 37% lower in the 2^nd (p < 0.001) and 23% lower in the 4^th week (p = 0.015). At no time point until Y1 did patients increase their activity level, compared to baseline. Activity was greater in patients with cervical, as compared to patients with lumbar spine disease. Age, sex, ethnic group, anesthesia risk score and fusion were variables associated with activity. There was no correlation between activity and PROMs, but a strong correlation with depression. Determining activity using LCAs provides real-time and longitudinal information about patient mobility and return of function. Recovery took place over the first eight postoperative weeks, with subtle improvement afterwards.

Factors Associated with Successful Response to Balloon Decompressive Adhesiolysis Neuroplasty in Patients with Chronic Lumbar Foraminal Stenosis

Epidural neuroplasty, often called percutaneous epidural adhesiolysis, is often performed in refractory patients with chronic lumbar radiculopathy or neurogenic claudication. Recent studies have showed that decompressive adhesiolysis with an inflatable balloon catheter (balloon neuroplasty) is efficient in patients who experience refractory pain from epidural steroid injection or even epidural neuroplasty with a balloon-less catheter. However, exact indications or predictive factors for epidural balloon neuroplasty have not been fully evaluated. Therefore, to assess associated factors that could affect a favorable outcome, we analyzed a prospectively collected multicenter cohort of patients with chronic refractory lumbar foraminal stenosis after balloon neuroplasty. At the 6-month point in follow-up, 92 (44.4%) patients among 207 subjects were classified as successful responders according to a robust combination of outcome measures. Multivariate logistic regression analysis also showed that mild grade lumbar foraminal stenosis may be an independent factor associated with a successful response 6 months after balloon neuroplasty (odds ratio = 2.829; 95% confidence interval = 1.351–5.923; p = 0.006). However, we found that there were 29.4% and 24.6% successful responders with moderate and severe foraminal stenosis, respectively. Attempting balloon neuroplasty in refractory lumbar foraminal stenosis, especially mild grade, may be worthwhile.

Real Time Estimation of the Pose of a Lower Limb Prosthesis from a Single Shank Mounted IMU

The command of a microprocessor-controlled lower limb prosthesis classically relies on the gait mode recognition. Real time computation of the pose of the prosthesis (i.e., attitude and trajectory) is useful for the correct identification of these modes. In this paper, we present and evaluate an algorithm for the computation of the pose of a lower limb prosthesis, under the constraints of real time applications and limited computing resources. This algorithm uses a nonlinear complementary filter with a variable gain to estimate the attitude of the shank. The trajectory is then computed from the double integration of the accelerometer data corrected from the kinematics of a model of inverted pendulum rolling on a curved arc foot. The results of the proposed algorithm are evaluated against the optoelectronic measurements of walking trials of three people with transfemoral amputation. The root mean square error (RMSE) of the estimated attitude is around 3°, close to the Kalman-based algorithm results reported in similar conditions. The real time correction of the integration of the inertial measurement unit (IMU) acceleration decreases the trajectory error by a factor of 2.5 compared to its direct integration which will result in an improvement of the gait mode recognition.