A mechanical equinometer to measure the range of motion of the ankle joint: interobserver and intraobserver reliability.
BACKGROUND
Clinical measurement of passive dorsiflexion of the ankle joint is essential for the diagnosis of various pathologic conditions of the foot and ankle but is of unreliable precision with high interobserver variability in nonweightbearing tests. This work was designed to develop and test a precise, standardized, and reliable technique for measurement of passive and active ankle range of motion.


METHODS
The proposed measurement tool is composed of two mobile parallelograms, one attached to the tibia, the second one to the plantar surface of the foot. The parallelograms are connected with a hinge with an angular scale to measure the angle between the foot and tibia.


RESULTS
Interobserver correlation between clinical measurements for maximal passive foot dorsiflexion were 0.03 with knee extension and 0.38 with knee flexion, while for measurements with the proposed tool they reached 0.89 and 0.97, respectively, with a mean measurement error of 0.9 degrees. Intraobserver correlations reached values of r = 0.98 and 0.99.


CONCLUSIONS
The proposed tool allows measurement of the ankle range of motion with very high precision and reproducibility far superior to clinical measurements.


CONCLUSIONS
Precise measurement of ankle range of motion is clinically challenging. With the use of the proposed tool, measurement precision and reliability are decisively improved.
Meyer
Dominik C
DC
Orthopedics, Uniklinik Bagrist, Forchstr. 340, Zürich, 8008, Switzerland. dominikmeyer@bluewin.ch
Werner
Clement M L
CM
Wyss
Tobias
T
Vienne
Patrick
P
D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D004867:Equipment Design; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology; D008297:Male; D009983:Orthopedic Equipment; D010808:Physical Examination / Q000295:instrumentation*; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results