Reliability of the dial test using a handheld inclinometer

Purpose: The primary purpose of this study was to investigate the intra-tester and inter-tester reliability of the dial test using a handheld digital inclinometer. Additionally, we examined the responsiveness of the test, and side-to-side differences for meaningful comparison. Materials/methods: Twenty-four healthy subjects (22. 5 ± 2. 8 years) participated in the study. The dial test was performed on both knees at 30° and 90° of knee flexion with the subject supine. While maintaining a neutral position of the ankle, an inclinometer was positioned parallel to the medial border of the foot to quantify external rotation of the tibia. Two examiners performed the dial test in a blinded manner. The minimal detectable change across repeated measures and side-to-side difference was calculated. Results: Intra-tester reliability for examiner 1 (E1) was 0. 83 at 30° knee flexion and 0. 89 at 90° knee flexion. Reliability values for examiner 2 (E2) were 0. 86 at 30° and 0. 87 at 90° knee flexion. Inter-tester reliability was 0. 74 at 30° and 0. 83 at 90°. The minimal detectable change (MDC) for E1 at 30° was ±9. 4° and ±7. 4° at 90°. For E2, the MDC value was ±9. 1° at 30° and ±8. 3° at 90°. Ninety-five percent limits of agreement for side-to-side difference was 16. 1° and 11. 3° ° for E1 at 30° and 90° and for E2 13. 9° at 30° and 14. 1° at 90°. Conclusions: This instrumented dial test using a handheld digital inclinometer to measure external rotation can be performed with acceptable reliability in the clinical setting. A difference of 10° between two measurements on the same knee suggests that a meaningful change has occurred. For right to left comparison, differences greater than 15° suggest clinical significance. Level of evidence: III.