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Reliability and validity of 3D limb scanning for ankle-foot orthosis fitting
Journal article   Peer reviewed

Reliability and validity of 3D limb scanning for ankle-foot orthosis fitting

Olivia A Powers, Jeff R Palmer and Jason M Wilken
Prosthetics and orthotics international, Vol.46(1), pp.84-90
02/01/2022
DOI: 10.1097/PXR.0000000000000066
PMCID: PMC9346570
PMID: 35179523

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Abstract

Recent decreases in the cost of 3D scanners and improved functionality have resulted in increased adoption for ankle-foot orthosis (AFO) fittings, despite limited supporting data. For 3D limb scanning to be a feasible alternative to traditional casting methods, a consistent and accurate representation of limb geometry must be produced at a reasonable cost. To evaluate the repeatability and validity of multiple lower limb measurements obtained using low-cost 3D limb scanning technology. Prospective, randomized, crossover-controlled, cross-sectional, reliability, and validity study. Physical measurements and 3D limb scans were completed for 30 participants. 11 measurements were selected for comparison based on their relevance to AFO fittings. Validity was assessed by comparison of physical and scan-based measures using Pearson's correlation coefficients and root mean square differences. Reliability was assessed using intraclass correlation coefficients and minimal detectable change (MDC) values. Bland-Altman plots were generated for data visualization. All correlation values were above or equal to 0.80. Most intraclass correlation coefficient values were above 0.95. MDC values for physical and scan-based measurements differed by less than 2.0 mm. Scan MDC values were around or below 4 mm for foot and ankle measures and under 6 mm for circumference and length measures. The results of this study demonstrate that low-cost 3D limb scanning can be used to obtain valid and reliable measurements of 3D limb geometry for the purpose of AFO fitting, when collected using the clinically relevant standardized conditions presented here.
Ankle - diagnostic imaging Cross-Sectional Studies Foot Orthoses Humans Imaging, Three-Dimensional Prospective Studies Reproducibility of Results

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