To investigate whether smartphone photo screening can be used as a more simple, efficient and widely available method for rapid screening of flatfoot.

A screening was conducted on October 15, 2024, in a middle school in Guangzhou, and informations such as gender and age of students were collected. Inclusion criteria: age from 12 to 14 years, the students could standing on one foot for at least five seconds without other supporting. Exclusion criteria: abnormality of foot or ankle, student was incompetent to cooperate, incomplete data, etc. Orthopedic surgeons used smartphones to photograph the inside position of feet while standing on one foot and were screened by the pictures. Plantar pressure screening was performed using pressure plate measurements (ZKBF-D1E, JOINCA), measuring foot width and length, plantar contact areas of forefoot, midfoot and heel, pressures on ground of forefoot, midfoot and heel, loads of forefoot, midfoot and heel, and arch types. The screening outcomes of smartphone-based photo and plantar-pressure were compared using the McNemar test, and differences in their data characteristics were evaluated with independent-samples t test.

A total of 596 students (332 males and 264 females) were photo-screened, and 85 students (49 males and 36 females, 170 feet) completed both screenings. The positive detection rate for plantar pressure (62.9%) was higher than that for smartphone photography (41.8%) (χ²=22.34, P<0.001), and the characteristics with statistically significant differences between the two screening methods were in line.

The features of reduced heel load and increased midfoot load in photo-screened positive feet are consistent with the results of plantar pressure screening, but smartphone photography cannot be directly used for rapid screening of adolescent flatfoot yet.