Smartphone Inclinometry Is a Valid and Reliable Tool for Measuring Frontal Plane Tibial Alignment in Healthy and Osteoarthritic Knees.

Objective: Frontal plane knee alignment plays an integral role in tibiofemoral knee osteoarthritis development and progression. Accessible methods for obtaining direct or indirect measures of knee alignment may help inform clinical decision making when specialized equipment is unavailable. The present study evaluated the concurrent validity, as well as intersession (within-rater) and interrater (within-session) reliability of smartphone inclinometry for measuring static frontal plane tibial alignment-a known proxy of frontal plane knee alignment.