Improved knowledge of normal shoulder girdle proprioception should benefit the treatment and rehabilitation of shoulder disorders. Whereas many of the available methods for assessing joint position sense (JPS) are costly and complex, Balke et al. have described a simple test. The primary objective of this study was to use this test to identify factors that influence shoulder-girdle JPS evaluation in healthy individuals. The secondary objective was to determine reference values based on the values obtained and on the factors associated with their variability.
Age and dominant limb influence the results of shoulder girdle JPS evaluation, creating a need for reference values that take these factors in account.
Patients and methods
A single-centre prospective study of healthy volunteers was performed between September 2012 and January 2013. In each volunteer, shoulder repositioning accuracy was assessed bilaterally as described by Balke et al. A line was drawn on the floor parallel to and 1 metre away from a wall. A target on the wall showed marks corresponding to three angles of arm elevation: 55°, 90°, and 125°. The volunteer was asked to raise the arm to the three positions, in abduction and in flexion, while memorising the joint positions, then to replicate the same positions with the eyes closed. The absolute differences between the replicated positions and the reference positions, designated angle deviations, were measured in degrees. Age, sex, and dominant upper limb were recorded.
The 88 shoulders of 44 healthy volunteers were studied. No significant difference was found between males and females (p>0.05). The only significant difference between sides was better replication by the dominant arm of flexion at 55° (p=0.03). By univariate analysis, age was the only factor significantly associated with repositioning errors (p=0.003); neither dominant limb nor sex were significant (p=0.29 and p=0.59, respectively). In flexion, the angle deviation increased significantly with movement amplitude. The measurements were used to create a chart of expected angle deviations in healthy individuals according to age and to plane and amplitude of movement.
The test described by Balke et al. is simple and feasible in everyday practice. Age, dominance, and plane of movement should be considered when evaluating abnormal shoulders. Further studies in larger numbers of individuals are needed to better define normal angle deviations related to these factors.
Level of evidence
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Keywords : Shoulder, Proprioception, Proprioception test, Joint position sense, Instability