3D limb scanning systems have recently been implemented for the clinical fitting of prosthetic and orthotic devices due to substantial decreases in costs. However, little data is available regarding the repeatability and validity of systems currently in use. In this study the investigators seek to evaluate the repeatability and validity of multiple lower limb measurements obtained using low-cost 3D limb scanning technology.
Two groups of subjects will be recruited for this study. The first group (Group 1) will consist of healthy able-bodied individuals with no history of lower extremity trauma. The second group (Group 2) will consist of individuals with unilateral, below knee functional deficits that require an AFO (ankle foot orthosis) for daily activities (e.g. fracture, muscle and/or nerve injury, ankle arthritis, or peripheral neurologic disease). The investigators will obtain a brief medical history to identify major medical conditions or prior injuries that could influence limb geometry, and lead to reliance on an AFO for Group 2 participants. A 3D representation of each participant's lower limb geometry will be obtained using a Structure Core scanner (Occipital, Inc.) which uses an infrared structured light projector to construct a 3D image of an object. The scanner is connected to an iPad; to operate the user rotates the iPad camera around the desired object. In seconds, the entire geometry is digitally reconstructed. Measurements will be evaluated using digital imaging analysis software (Standard Cyborg, Inc.). The investigators will evaluate concurrent validity by directly comparing software-based measurements from limb scans, with direct measurements on the same individual collected using digital calipers. The investigators will determine repeatability of each technique by conducting three identical limb scans and actual physical measurements at two time points on the same day in each individual, and then comparing the results between time points. The interior of the AFO worn by participants in Group 2 will also be scanned to obtain its geometry for comparison with measurements obtained from each individual's limb. Validity and repeatability will be assessed using measurements at multiple locations on the lower leg. Limb measurements will include 1) width of the metatarsal heads, 2) width of the calcaneus, 3) foot length, 4) foot height, 5) arch height, 6) medial-lateral width between ankle malleoli, 7) minimum circumference above the ankle malleoli, 8) maximum calf circumference , 9) medial-lateral width of the knee condyles 10) anterior-posterior width at mid patellar tendon, 11) distance from bottom of foot to tibial tubercle. Concurrent validity will be determined using the intra-class correlation coefficient and absolute error (root mean square error) for comparisons between measurements from limb scanning and the calipers. Reliability will be determined using the intra-class correlation coefficient and the minimal detectable change value for comparisons over time.
Study Type
OBSERVATIONAL
Enrollment
30
A 3D representation of each participant's lower limb geometry will be obtained using a Structure Core scanner (Occipital, Inc.) which uses an infrared structured light projector to construct a 3D image of an object. The scanner is connected to an iPad; to operate the user rotates the iPad camera around the desired object. In seconds, the entire geometry is digitally reconstructed.
Caliper: An OriginCal IP54 digital caliper (Anytime Inc, Granada Hills, CA) was used to take three consecutive physical measurements in millimeters at each identified measurement location. For measurements outside of the caliper's scope a tape measure was used in place of the caliper. Physical measuring devices were reset to zero between each measure.
University of Iowa
Iowa City, Iowa, United States
Width of the Metatarsal Heads (Minimal Detectable Change [MDC])
The width of the metatarsal heads was measured as the distance from the medial aspect of the first metatarsal head to the lateral aspect of the fifth metatarsal head. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intrarater-intersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Width of the Metatarsal Heads (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the width of the metatarsal heads. The width of the metatarsal heads is the distance from the medial aspect of the first metatarsal head to the lateral aspect of the fifth metatarsal head. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Width of the Metatarsal Heads (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the width of the metatarsal heads. The width of the metatarsal heads is the distance from the medial aspect of the first metatarsal head to the lateral aspect of the fifth metatarsal head. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
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Time frame: Less than 2 days
Width of the Calcaneus (Minimal Detectable Change [MDC])
The width of the calcaneus was measured as the distance from the medial aspect of calcaneus parallel to lateral aspect of calcaneus. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Width of the Calcaneus (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the width of the calcaneus. The width of the calcaneus is the distance from the medial aspect of calcaneus parallel to lateral aspect of calcaneus. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Width of the Calcaneus (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the width of the calcaneus. The width of the calcaneus is the distance from the medial aspect of calcaneus parallel to lateral aspect of calcaneus. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Foot Length (Minimal Detectable Change [MDC])
Foot length was measured as the distance from the most posterior aspect of calcaneus to the most anterior toe (1st or 2nd). Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Foot Length (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the foot length. The foot length is the distance from the the most posterior aspect of calcaneus to the most anterior toe (1st or 2nd). Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Foot Length (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the foot length. The foot length is the distance from the most posterior aspect of calcaneus to the most anterior toe (1st or 2nd). RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Foot Height (Minimal Detectable Change [MDC])
Foot height was measured as the distance from the most superior point on the foot distal to the tibialis anterior insertion. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Foot Height (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the foot height. The foot height is the distance from the most superior point on the foot distal to the tibialis anterior insertion. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Foot Height (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the foot height. The foot height is the distance from the most superior point on the foot distal to the tibialis anterior insertion. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Arch Height (Minimal Detectable Change [MDC])
Arch height was measured as the dorsum height at 50% foot length. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Arch Height (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the arch height. The arch height is at 50% foot length. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Arch Height (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the arch height. The arch height is at 50% foot length. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Medial-lateral Ankle Malleoli Width (Minimal Detectable Change [MDC])
Medial-lateral ankle malleoli width was measured as the distance from the lateral malleolus to the medial malleolus. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Medial-lateral Ankle Malleoli Width (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the width of the medial-lateral ankle malleoli. The width of the medial-lateral ankle malleoli is the distance from the lateral malleolus to the medial malleolus. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Medial-lateral Ankle Malleoli Width (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the width of the medial-lateral ankle malleoli. The width of the medial-lateral ankle malleoli is the distance from the lateral malleolus to the medial malleolus. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Minimum Ankle Circumference (Minimal Detectable Change [MDC])
Minimum ankle circumference was measured as the minimum ankle circumference above the ankle malleoli. Must be less than 10 cm proximal to the ankle malleoli. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Minimum Ankle Circumference (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the minimum ankle circumference. The minimum ankle circumference is the circumference above the ankle malleoli. Must be less than 10 cm proximal to the ankle malleoli. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Minimum Ankle Circumference (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the minimum ankle circumference. The minimum ankle circumference is the circumference above the ankle malleoli. Must be less than 10 cm proximal to the ankle malleoli. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Maximum Calf Circumference (Minimal Detectable Change [MDC])
Maximum calf circumference was measured as the maximum calf circumference greater that 5 cm distal to the knee condyles. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Maximum Calf Circumference (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the maximum calf circumference. The maximum calf circumference is the distance greater than 5 cm distal to the knee condyles. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Maximum Calf Circumference (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the maximum calf circumference. The maximum calf circumference is the distance greater than 5 cm distal to the knee condyles. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Width of the Knee Condyles (Minimal Detectable Change [MDC])
Width of the knee condyles was measured as the distance from the medial condyle to the lateral condyle. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Width of the Knee Condyles (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for the width of the knee condyles. The width of the knee condyles is the distance from the medial condyle to the lateral condyle. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Width of the Knee Condyles (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the width of the knee condyles. The width of the knee condyles is the distance from the medial condyle to the lateral condyle. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Anterior-posterior Width at Patella (Minimal Detectable Change [MDC])
Anterior-posterior width at patella was measured as the distance from mid patellar tendon to a parallel point most posterior on the back of the knee. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Anterior-posterior Width at Patella (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated for anterior-posterior width at patella. The anterior-posterior width at patella is the distance from mid patellar tendon to a parallel point most posterior on the back of the knee. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Anterior-posterior Width at Patella (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for anterior-posterior width at patella. The anterior-posterior width at patella is the distance from mid patellar tendon to a parallel point most posterior on the back of the knee. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Tibial Tubercle Height (Minimal Detectable Change [MDC])
Tibial tubercle height was measured as the distance from the floor to tibial tubercle. Reliability of these measures was assessed using minimal detectable change (MDC) values. MDC values are in the same units as the original measure, and smaller values are better. Minimal Detectable Change (MDC) values are presented for: caliper intraraterintersession, scan intrarater-intersession, scan interrater-intrasession, and scan interrater-intersession. MDCs were calculated for all participants as a whole using the equation SEM x 1.96 x SQRT where SEM was calculated using the equation SD x SQRT (1-ICC), where SD is the pooled variance. ICC values were calculated using SPSS v.25 using model (2,k). \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Tibial Tubercle Height (Pearson's Correlation Coefficient)
Pearson's correlation coefficient was calculated tibial tubercle height. The tibial tubercle height is the distance from the floor to tibial tubercle. Pearson product-moment correlations were calculated for all participants as a whole to compare between caliper and scan measurements using the function PEARSON (array1, array2) and categorized based on the scale of negligible (0-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and very high (0.90-1.0) correlation. \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Tibial Tubercle Height (Mean Root Mean Square [RMS] Difference)
The mean Root Mean Square (RMS) difference was calculated for the tibial tubercle height. The tibial tubercle height is the distance from the floor to tibial tubercle. RMS was calculated by squaring the mean for all participants, adding up the squares (which are all positive) and dividing by the number of samples to find the average square or mean square, then taking the square root of that. And the root mean square difference was calculated by comparing caliper and scan measurements \[Powers OA, et al. (2022), Prosthet Orthot Int. 46(1)\] Data is only presented for group 1 as study activities related to group 2 were terminated due to the COVID pandemic.
Time frame: Less than 2 days
Bland-Altman Plots
Bland-Altman plot (difference plot) is a method of data plotting used in analyzing the agreement between scan and caliper measures for each identified measurements.
Time frame: Less than 2 days
Intrarater-intersession ICC Values
Intrarater-intersession ICC values were calculated to determine the test-retest reliability of scanning and digital measurements, whereas inter-rater-intrasession and inter-rater-intersession ICC values were calculated to determine the reliability of digital measurements. Intrarater-intersession ICC values were calculated to determine the reliability of physical measures between sessions. ICC values generally range from 0-1 with higher values indicating better reliability
Time frame: Less than 2 days