Percent Weightbearing in Foot and Ankle X-rays

Category: Other; Ankle; Hindfoot; Midfoot/Forefoot Introduction/Purpose: Weightbearing x-rays remain standard of care in diagnosing and evaluating foot and ankle injuries and are crucial for clinicians to evaluate foot alignment and ligamentous injuries. Failure for patients to place adequate body weight on x-ray may produce a radiograph that inaccurately demonstrates foot alignment and injury. The objective of the study was to evaluate the percentage of body weight a patient puts on his/her foot during weight bearing x-ray. Methods: Study participants (n= 278) included patients requiring a clinically indicated x-ray. They were asked to place body weight on foot/ankle during x-ray. The radiograph categories included: lateral foot, AP ankle, oblique ankle and lateral ankle. The scale was concealed from patients and wrapped in a pad and placed on platform as to avoid any bias. The scale measured the weight each patient placed on their foot during each radiograph. The scale was connected to Bluetooth and data was recorded on computer during imaging. The percent of body weight placed on x-ray was calculated using weight during radiograph and weight measured in clinic. Results: Acute injury was defined as pain/injury of duration less than or equal to 3 months with chronic being pain greater than 3 months. Percent bodyweight data in both acute and chronic groups is as follows. Lateral foot acute: mean= 47.39%, max=84.94%, median=46.90%, min= 6.25%; lateral foot chronic: mean=54.80%, max =99.87%, median=54.44%, min=11.56%. AP ankle acute: mean= 56.74%, max=99.51%, median=56.36%, min=6.63%; AP ankle chronic: mean=58.90%, max=97.90%, median=58.42%, min=11.58%. Oblique ankle acute: mean=57.68%, max=98.32%, median=57.40%, min =6.27%; oblique ankle chronic: mean=58.91%, max=96.15%, median=58.46%, min=17.17%. Lateral ankle acute: mean= 50.42%, max=97.92%, median=50.41%, min=11.52%; lateral ankle chronic: mean= 50.03%, max=82.12%, median=50.32%, min=14.10%. Please see attached graphs. Conclusion: Preliminary data suggests patients are not placing full body weight during weightbearing x-ray (lateral foot, AP ankle, oblique ankle, lateral ankle). In lateral foot x-rays, patients with acute injuries place less weight during x-ray as compared with patients of chronic conditions (p=0.02). In the categories of AP ankle, oblique ankle and lateral ankle x-rays, the difference in means between acute/chronic was not statistically significant. We plan to further analyze the data to determine how injury type and time since injury changes the percent body weight placed on foot during x-ray as this may affect how patients are diagnosed via radiographs.FIG