Biomechanikstudy_MRI_AKT-O_EN.pd - VACOped

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$Aftertreatment of malleolar fractures following ORIF ... - VACOped$

Pressure distribution measurement vacopedes 2004Pressure [N/cm 2 ]Pressure [N/cm 2 ]10.0 seconds10.0 secondsLeft soleRight soleFig. 7, separation of measurement data into step sequences: When the heel makes contact with the floor,the floor contact phase begins (green marking) when the toes lift off from the floor, it ends again (red marking).Average values can subsequently be determined via individual floor contact phases.Maximum pressure analysisA method of data analysis (which can be applied in a similar manner for quitedifferent problems and measurement procedures, e.g. EMG measurements): thepressure curves are examined for the frequency of all pressure values that occur.During the 40-second measurement period, each pressure sensor is recorded40·400=16000 times: All measurement values are entered in a frequency registerwith a resolution of 0.1 N/cm² printing width. The larger the pressure variations, thewider and flatter the distribution (e.g. Fig. 8). The more constant the pressure, thenarrower and the more linear the distribution. The frequency distribution itself is thenexamined at its maximum points (blue and red markings in Fig. 8). To avoid theeffects of individual measurement ‘outliers’, not the absolute pressure maximum ofthe distribution is sought, but rather the value at which a certain percentage (1percent) of all measured values lies above the limit (cf. Fig. 9). Alternatively, thevalue could be chosen as the limit at which the distribution exceeds a certainpercentage of the overall maximum of the distribution.Page 8
Pressure distribution measurement vacopedes 2004Pressure area sensor 27Pressure area sensor 11Pressure [N/cm 2 ]FrequencyPressure [N/cm 2 ]Left soleRight soleSecondsFig. 8, to determine the frequency distribution of the pressure values of a measurement, each of the 16,000 measured pressurevalues (right) is entered in a count register (left). The upper limit is defined in the distribution. The frequency distribution isstandardized so that the surface lies below curve 1.Minimum of pressure distributionSurfaceUpper limitFig. 9, to determine the upper limit of the frequencydistribution for the measured pressure values of a sensor.m = 1The pressure range upper limits determined in this way are compared between theleft foot (test shoe) and the right foot (normal shoe) and between differenttherapeutic solutions for the left foot. These pressure values are reproduced aspressure distributions in Fig. 10 on the left. Fig. 7 on the right shows the plantarpressure distribution pattern of the test person for the measurements walkingbarefoot.Fig. 10, measured pressurevalues represented aspressure distribution pattern.Here: normal shoe on leftand right foot(measurement OPED01).Higher pressure values areshown as lighter shades.Far right: high-resolutionpressure distribution patternunder the sole of the footwhen walking barefoot,pressure maxima pattern(pressure scale on the right)Representation of pressure maximaPage 9
Page 1 and 2: Pressure measurements on the VACOpe
Page 3 and 4: Pressure distribution measurement v
Page 7: Pressure distribution measurement v

Biomechanikstudy_MRI_AKT-O_EN.pd - VACOped

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