Variation in measurements of range of motion: a study in reflex sympathetic dystrophy patients.
OBJECTIVE
To quantify the amount of variation attributed to different sources of variation in measurement results of upper extremity range of motion, and to estimate the smallest detectable difference (SDD) between measurements in reflex sympathetic dystrophy (RSD) patients.


METHODS
Two observers each measured in two sessions the range of motion of several upper extremity joints of RSD patients participating in an outcome study.


METHODS
Department of Rehabilitation of a university hospital.


METHODS
Twenty-nine upper extremity RSD patients.


METHODS
The range of motion of forward flexion and external rotation of the shoulder, extension, flexion and supination of the elbow, palmar, dorsiflexion and ulnar, radial deviation of the wrist of affected and nonaffected sides, using a two-armed goniometer and an inclinometer. The measurement results were analysed using an analysis of variance according to the generalizability theory.


RESULTS
The results indicate that observer and patient-observer were important sources of variation. The random error was the most important source of variation. Averaged over all ranges of motion the observer contributed 3.9% to the total variation, patient-observer interactions contributed 5.2% and the random error 20.3%. The SDD was smallest for elbow flexion, 7.1 degrees and 9.6 degrees and was largest for external rotation of the shoulder, 24.8 degrees and 28.7 degrees. The SDD was smaller for the nonaffected side as compared to the affected side for the majority of ranges of motion except elbow extension, wrist dorsiflexion, and radial and ulnar deviation.


CONCLUSIONS
Clinically, our results indicate that range-of-motion measurements in RSD patients are subject to considerable variation and indicate that results of medical examinations in order to assess disability on the basis of range-of-motion measurements are subject to the same variation.
Department of Rehabilitation, University Hospital Groningen, The Netherlands.
J H
JH
Geertzen
P U
PU
Dijkstra
R E
RE
Stewart
J W
JW
Groothoff
H J
HJ
Ten Duis
W H
WH
Eisma
D001132:Arm / Q000503:physiopathology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D016059:Range of Motion, Articular / Q000502:physiology*; D012019:Reflex Sympathetic Dystrophy / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results