Flatfoot is a common structural abnormality of the foot, which is mainly manifested by the collapse or disappearance of the arch of the foot, resulting in an increase in the contact area between the inner side of the sole and the ground. Its causes are complex, involving genetic factors, tendon dysfunction, ligament laxity and biomechanical imbalance. Clinically, accurate measurement and evaluation of flatfoot is crucial for formulating treatment plans (such as orthopedic insoles, rehabilitation training or surgical intervention). Among many measurement methods, the 3D foot scanner has become an important tool for modern flatfoot assessment due to its high precision, non-contact measurement and all-round data collection.
Basic principle of 3D foot scanner
3D foot scanner is a measurement device based on optical, laser or structured light projection technology, which can obtain complete 3D data of the foot and build a high-precision foot model. Its core working principles include the following aspects:
Data acquisition
The device obtains the surface morphology information of the foot by laser scanning, white light scanning or structured light projection. For example, the laser scanning system uses a laser beam to project on the surface of the foot and captures the reflected light through a camera to calculate the spatial coordinates of each point. The structured light projection system uses a specific grating pattern to illuminate the foot and calculates the three-dimensional shape of the foot based on the degree of grating deformation.
Data processing
The collected point cloud data undergoes coordinate conversion, filtering and noise reduction, and surface reconstruction to generate a high-precision three-dimensional foot model. Some advanced systems can automatically identify the arch contour and calculate key parameters such as longitudinal arch height and plantar contact area in combination with artificial intelligence (AI) algorithms.
Analysis and evaluation
By analyzing the foot model through software, a variety of key indicators can be obtained, including Arch Index, Medial Longitudinal Arch Height Ratio, and plantar size. These parameters can be used to diagnose the severity of flat feet and guide the formulation of subsequent correction plans.
Application of foot 3D scanners in flat foot measurement
Compared with traditional foot measurement methods (such as footprint method, X-ray, CT scan), foot 3D scanners have many advantages in measuring and evaluating flat feet.
Accurately measure arch height
The traditional footprint method relies on flat footprints and is difficult to accurately reflect the true height of the arch. The 3D foot scanner can directly measure the 3D shape of the arch and calculate key indicators such as arch height and longitudinal arch angle, so as to more accurately evaluate the degree of flat feet.
Combination of dynamic and static measurements
Advanced 3D foot scanners can not only be used for static measurements, but also can be combined with gait analysis systems to measure dynamic arch changes. For example, some devices can continuously collect data in different standing postures or walking, and analyze the deformation of the arch under load to more comprehensively evaluate the impact of flat feet.
Non-invasive, efficient and convenient
Although traditional imaging methods (such as X-rays and CT scans) can provide bone structure information, they have radiation exposure problems and require professional operation. The 3D foot scanner does not need to contact the skin, and the scanning process only takes a few seconds to complete, which is suitable for large-scale screening and daily clinical applications.
Customized correction solutions
The 3D foot scanner can be combined with computer-aided design (CAD) and 3D printing technology to provide patients with personalized corrective insoles or orthopedic shoes. By scanning the patient’s foot data, the arch shape can be accurately matched, and a targeted correction plan can be designed to improve the comfort and correction effect of the orthotic device.
Key parameters and judgment criteria for flat foot measurement
In flat foot measurement, the foot 3D scanner can provide multiple key parameters to assist clinical judgment:
MLA Height: Measure the height of the medial longitudinal arch of the foot. The lower the value, the more severe the arch collapse.
MLA Index: Calculate the ratio of the longitudinal arch height to the foot length to determine whether the arch is abnormal.
Arch Index (AI): Calculate the relative proportion of the arch height by the sole contact area. The higher the AI value, the more severe the flat foot.
Heel Inclination Angle: Reflects the degree of inversion or eversion of the heel, and is one of the important parameters for evaluating flat feet.
Generally speaking, if the arch index (AI) is greater than a certain threshold (such as 0.26) or the longitudinal arch height ratio is lower than the normal range, it can be judged as flat foot. Some devices also combine machine learning algorithms to automatically classify scan data to improve the objectivity of diagnosis.
