Joint Mobility Measurements: Reliability of a Standardized Method

Abstract

Assessment of hypermobility and hypomobility is frequently performed visually with all its limitations. In this study, a standardized joint mobility measurement method is suggested, and its reliability is tested. The maximal range of motion of passive digit five hyperextension, passive thumb apposition to the wrist, active elbow and knee hyperextension, active ankle dorsal flexion and trunk flexion was measured in 30 healthy subjects. All measurements were performed bilaterally, except for trunk flexion. Three experienced observers performed the measurements according to a rigidly standardized protocol, using appropriate goniometers and rulers. During one measurement session each observer measured each subject. Two consecutive measurement sessions were organized. Analysis of variance, with subject and time as explaining variables, was performed on the data obtained. The inter-observer variability ranged from 1.42° (left knee hyperextension) to 4.05 mm (right thumb apposition) in the first measurement session and from 1.35° (left knee hyperextension) to 4.58° (right digit five hyperextension) in the second measurement session. The intra-observer variability ranged for observer A from 0.75° (left knee hyperextension) to 3.67 mm (left thumb apposition), and from 0.93° (left knee hyperextension) to 3.88° (left digit five hyperextension) for observer B. Observer C ranged from 0.710 (left knee hyperextension) to 4.01 mm (right thumb apposition). Based on the results of this study, the authors conclude that joint mobility can be measured reliably and accurately with the presented simple tools. The joint mobility measurement method reveals the mobility for each separate joint and provides a basis for comparison between individuals and between groups of individuals, both in the case of single and generalized joint mobility assessment.