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Validation and reliability testing of a new, fully integrated gait analysis insole


Abstract


Background: A new tool (OpenGo, Moticon GmbH) was introduced to continuously measure kinetic and temporospatial gait parameters independently through an insole over up to 4 weeks. The goal of this study was to investigate the validity and reliability of this new insole system in a group of healthy individuals.


Methods: Gait data were collected from 12 healthy individuals on a treadmill at two different speeds. In total, six trials of three minutes each were performed by every participant. Validation was performed with the FDM-S System (Zebris). Complete sensor data were used for a within test reliability analysis of over 10000 steps. Intraclass correlation was calculated for different gait parameters and analysis of variance performed.


Results: Intraclass correlation for the validation was >0.796 for temporospatial and kinetic gait parameters. No statistical difference was seen between the insole and force plate measurements (difference between means: 36.3 ± 27.19 N; p = 0.19 and 0.027 ± 0.028 s; p = 0.36). Intraclass correlation for the reliability was >0.994 for all parameters measured.


Conclusion: The system is feasible for clinical trials that require step by step as well as grouped analysis of gait over a long period of time. Comparable validity and reliability to a stationary analysis tool has been shown.


Keywords: Gait analysis, Integrated insole system, Validation, Reliability


Benedikt Johannes Braun, Nils Thomas Veith, Rebecca Hell, Stefan Döbele, Michael Roland, Mika Rollmann, Jörg Holstein and Tim Pohlemann


Department of Trauma, Hand and Reconstructive Surgery, Saarland University Hospital, Germany


A novel tool for continuous fracture aftercare – Clinical feasibility and first results of a new telemetric gait analysis insole


Abstract


Weight bearing after lower extremity fractures still remains a highly controversial issue. Even in ankle fractures, the most common lower extremity injury no standard aftercare protocol has been established. Average non weight bearing times range from 0 to 7 weeks, with standardised, radiological healing controls at fixed time intervals. Recent literature calls for patient-adapted aftercare protocols based on individual fracture and load scenarios. We show the clinical feasibility and first results of a new, insole embedded gait analysis tool for continuous monitoring of gait, load and activity.

Ten patients were monitored with a new, independent gait analysis insole for up to 3 months postoperatively. Strict 20 kg partial weight bearing was ordered for 6 weeks. Overall activity, load spectrum, ground reaction forces, clinical scoring and general health data were recorded and correlated. Statistical analysis with power analysis, t-test and Spearman correlation was performed.

Only one patient completely adhered to the set weight bearing limit. Average time in minutes over the limit was 374 min. Based on the parameters load, activity, gait time over 20 kg weight bearing and maximum ground reaction force high and low performers were defined after 3 weeks. Significant difference in time to painless full weight bearing between high and low performers was shown. Correlation analysis revealed a significant correlation between weight bearing and clinical scoring as well as pain (American Orthopaedic Foot and Ankle Society (AOFAS) Score rs = 0.74; Olerud–Molander Score rs = 0.93; VAS pain rs = -0.95).

Early, continuous gait analysis is able to define aftercare performers with significant differences in time to full painless weight bearing where clinical or radiographic controls could not. Patient compliance to standardised weight bearing limits and protocols is low. Highly individual rehabilitation patterns were seen in all patients. Aftercare protocols should be adjusted to real-time patient conditions, rather than fixed intervals and limits. With a real-time measuring device high performers could be identified and influenced towards optimal healing conditions early, while low performers are recognised and missing healing influences could be corrected according to patient condition.


Benedikt J. Braun, Eva Bushuven, Rebecca Hell, Nils T. Veith, Jan Buschbaum,Joerg H. Holstein, Tim Pohlemann


Department of Trauma, Hand and Reconstructive Surgery & Department of Diagnostic and Interventional Radiology, Saarland University Hospital, Germany


Optimization of a foot model for the evaluation of the injury risk during cutting movements in football


Abstract


Cutting movements in football (soccer) induce high loads on the anterior cruciate ligament in the knee. The injury risk is affected by the shoe-surface interaction. For the evaluation of different influencing factors of this interaction the TrakTester, a custom-made device, was used. To obtain significant results from testing ACL loading a realistic plantar pressure distribution in the shoe is required. Using the TrakTester several cutting movements were carried out using two different foot models with the resultant plantar pressure analysed with three different systems: The original foot model with Parotec insoles (24 integrated sensors; Paromed GmbH, Markt Neubeuern, Germany), the modified version of this foot model with Pedar-X insoles (99 sensors; novel GmbH, Munich, Germany) and the inflexible model was surveyed with the OpenGo science system (13 sensors, Moticon, Munich, Germany). For the inflexible model distinct angles between the lower leg and the surface were adjusted and the obtained plantar pressure distributions were analyzed. As the first version showed high pressures in the arch region, it was modified to reduce the load in this area. A second inflexible model induced the pressure in the heel and forefoot region. For various angles similar plantar pressure distributions were obtained. Highest pressures were applied on the medial side of the heel and forefoot with minor load in the arch region. This corresponds to literature data investigating cutting movements with subjects. Tests with the inflexible foot model achieved similar and realistic patterns of the plantar pressure distribution for different angles. This is an important precondition to obtain reproducible data for ACL loading during cutting movements.


Stefan Lehner, Christine Dießl, Dennis Chang, Veit Senner


Technische Universität München, Institute of Ergonomics, Department Sport Equipment and Material, Boltzmannstraße 15, 85747, Garching, Germany


Received 20 March 2013; revised 20 May 2013; accepted 27 May 2013


Available online at www.sciencedirect.com


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