The Intrarater and Interrater Reliability and Validity of Universal Goniometer, Digital Inclinometer, and Smartphone Application Measuring Range of Motion in Patients with Total Knee Arthroplasty.

OBJECTIVES

The aim of this study was to investigate the intrarater and interrater reliability and validity of range of motion measurements obtained with a universal goniometer, digital inclinometer, and smartphone application in patients with total knee arthroplasty.

METHODS

Range of motion of the knee joint was measured by two examiners with a universal goniometer, digital inclinometer, and a smartphone application. Data were obtained from 51 knees of 27 patients at postoperative 6 months. Two measurements made by the first examiner were compared to assess interrater reliability, and measurements from both examiners were compared to assess intrarater reliability. Statistical analysis was performed using intraclass correlation coefficient (ICC) and Spearman's rho values.

RESULTS

With all three methods, active and passive knee flexion range of motion measurements showed high intrarater and interrater reliability (ICC = 0.749-0.949). Concurrent validity analysis also demonstrated statistically significant, moderate to strong correlation among the three methods ( = 0.775-0.941).

CONCLUSION

The universal goniometer, digital inclinometer, and smartphone application were all found to be reliable and valid assessment tools in clinical practice for patients with total knee arthroplasty.