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Impaired Control of Scapular Rotation during a Clinical Dissociation Test in People with a History of Shoulder Pain

28th March 2012



Abstract from 3rd International Conference on Movement Dysfuction, Edinburgh, UK

30 October - November 1 2009

Impaired Control of Scapular Rotation during a Clinical Dissociation Test in People with a History of Shoulder Pain

S Mottram (1), M Warner (1),  P Chappell (2), D Morrissey (3),  M Stokes (1)
(1) Schools of Health Sciences, (2) Electronics and Computer Science, University of Southampton, UK
(3) Centre for Sports and Exercise Medicine, Queen Mary, University of London, UK

Introduction
Reduced upward rotation of the scapula has been found in people with shoulder dysfunction during functional tasks and arm elevation. [1, 2]  The purpose of this study was to evaluate the use of a clinical test to detect such altered kinematics in people with a history of shoulder pain. The test is based on the concept of ‘dissociation’ defined here as inability to control movement of the scapula whilst moving the arm.  

Methods
Nineteen healthy people were studied; 13 (9 female) controls with no history of shoulder pain (mean age 30.6 years, SD9.1) and 6 (5 males) with a history of shoulder pain (mean age 44.3 years, SD14.7). The test involved passive placement of the scapula in mid-range position and the subject aimed to maintain this position during shoulder flexion to 90o, and when lowering the arm to their side.  A six-camera Vicon 460 (Oxford, UK) motion capture system recorded the scapular position relative to the thorax during the test.
   

Results
At 90o flexion, significantly greater upward rotation (p=0.03) had occurred in the control group (-13.2° ± 4.6) compared with the pain history group (-7.8° ± 5.3).  A greater difference (8.2°, p=0.004) was found between the groups at the end of the test:
-0.3 ° ± 4.4 controls; and 7.9° ± 6.4 in the history of pain group, indicating downward rotation of the scapula.  

Discussion
During flexion, the impaired upward scapular rotation confirms the findings of previous studies. The novel finding of increased downward rotation position compared to controls at the end of the test, suggests that the history of pain subjects were unable to control downward rotation movement of the scapula.  This finding is consistent with the uncontrolled movement theory [3].  Research is required to validate this test by comparing blinded clinical observations with motion analysis results.
 
References
1.    Lin JJ, Hanten WP, Olson SL et al. 2005 J Electromyogr Kinesiol 15(6):576-86
2.    Ludewig PM, Cook TM  2000 Phys Ther 80(3):276-91
3.    Comerford M J, Mottram S L 2001 Manual Therapy 6:15-26

Acknowledgments
We thank the Private Physiotherapy Educational Foundation and Vicon Oxford for funding, Faizura Fadzil for technical assistance and the participants.

Manual  Therapy  2009;14:pS20

Keywords: Research,