3D scanner can identify early foot deformity in RA patients

By Lauretta Ihonor

Researchers report that a digital 3D foot scanner can detect foot deformities in patients with rheumatoid arthritis (RA), even before clinical signs are present.

Early detection of foot deformities by means of a 3D scanner may help to prevent the secondary mechanical strains that can be induced by RA foot deformities, explain Dirk Elewaut (Ghent University Hospital, Belgium) and colleagues.

They add that "early treatment with customized insoles or shoe wear" may prevent the development of foot deformities if implemented at an early stage in "at-risk" individuals.

The researchers therefore surmise that the preventive role of the 3D scanner requires further research.

As reported in Arthritis Care and Research, 3D scans were performed on the feet of 106 RA patients (diagnosis made using American College of Rheumatology criteria) and 135 RA-free controls.

The participants had a mean age of 50 years, no obvious foot deformities, and no history of foot surgery.

In all, 41% of RA patients had more than one structural foot abnormality detected on 3D scanning. Most RA patients (62%) had signs of foot erosions.

Specifically, erosions were located throughout the whole foot in 25% of these patients, in the forefoot only among 54%, the hindfoot only in 1%, in the forefoot and the midfoot in 4%, in the forefoot and hindfoot in 15%, and in the midfoot and hindfoot in 1%.

Elewaut and team report that the 3D scanner's findings were independent of age, body weight, disease duration, and gender.

Furthermore, no correlation was found between the presence or location of foot erosions and patient-reported foot pain and disability.

This, say the researchers, indicates that the scanner can detect subclinical foot changes.

Measurements taken by the 3D scanner also revealed structural differences between the RA patients and controls. For example, mean ball girth circumference and height were significantly larger among RA patients compared with controls.

The 3D foot scanner "provides a global, multiplanar picture of the foot in a functional, loaded condition," say Elewaut and co-researchers.

They therefore conclude that it may be a useful investigative tool when used in the setting of a RA outpatient clinic.

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