Is a smartphone application as accurate as a traditional goniometer for assessing finger joint angles in Dupuytren's disease?

OBJECTIVES

Smartphone applications are available using the smartphone accelerometer to measure angles. This study compared finger joint angle measurements using a traditional goniometer (TG) versus a smartphone application (SPA) in a group of patients with Dupuytren's disease, to determine if they were equally accurate. This was a clinical measurement case series. A group of patients with Dupuytren's disease were invited to participate.

MATERIAL AND METHODS

The Apple iPhone 7 "Measure" application was used. Participants were asked to place their hand as flat as possible on the table in a clinic room. Each joint of the ring and little fingers was measured using the TG and the SPA. Power calculation by paired t-test determined a sample size of 25.

RESULTS

28 hands were measured. The Pearson correlation coefficients for the various finger joints were: metacarpophalangeal joint (MCPJ), 0.989; proximal interphalangeal joint (PIPJ), 0.997; and distal interphalangeal joint (DIPJ), 0.977. The root mean square errors (RMSE) for the various joints were: MCPJ, 3.190; PIPJ, 2.019; and DIPJ, 1.897. Bland-Altman analysis showed the two methods to be in agreement.

CONCLUSION

The SPA was consistent, reliable and in agreement with a TG for assessing ring and little finger joint angles. The SPA could be used by healthcare professionals instead of a TG.