2017 ISAKOS Biennial Congress ePoster #1618

 

THE USE OF SMARTPHONES FOR MEASURING ANGLES IN THE ARTHRITIC KNEE

Dinesh Mohan-Choudary, MS(Orth), Chennai INDIA
Pramod Kumar, MS (Orth), Bangalore INDIA

Apollo hospital, Chennai, TN, INDIA

FDA Status Cleared

Summary

Knee angle measurement using the smartphones was comparable with the manual methods in our study.

Abstract

INTRODUCTION:Measurement of varus/valgus angles in arthritic knees has been widely accepted to analyze the extent of deformities and can be used as an indicator of the degree of correction obtained following a corrective surgery. Measurement has traditionally been manual using a pencil and protractor/goniometer on radiographs. Smartphones have changed the way we live in every field of life. Use of apps in smartphones with accelerometers aids to measure the angle quickly. This study analyzes the accuracy and efficiency of the Inclinometer app in smartphones to measure varus/valgus knee angles.
METHODS:We analyzed varus/valgus angles in arthritic knees who underwent total knee replacement surgery at our center over the past 2 years. Inclinometer app was used in the smartphone by the primary observer over the computer screen to measure the angle and then manual method was used. Time taken to measure using both the techniques was noted by other observers. Another two observers then independently measured the angle using their smartphones to assess the interobserver variability. Data was tabulated and analyzed by a biostatistician.
RESULTS:Knee angles of 25 patients with mean age of 61.5 years were analyzed for varus/valgus angles separately. The mean angle of all measured x-rays was 7.8 degrees in the manual set and 7.9 degrees in the smartphone set. The mean time consumed was 13.5 seconds for the smartphone set, significantly shorter than that of the manual set which was 36.2 seconds (statistically significant – p<0.05). 95% confidence intervals for inter-observer variability using smartphones were ±1.5degrees.

Discussion

AND CONCLUSION:Knee angle measurement using the smartphones was comparable the manual methods in our study. With significant time difference between the methods indicating the simplicity of the use of apps in our daily use and the minimal interobserver variability, smartphones indeed can replace the manual methods and can be a reliable tool in the hands of arthroplasty surgeons.