These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Cranial humerus translation, deltoid activation, adductor co-activation and rotator cuff disease - different patterns in rotator cuff tears, subacromial impingement and controls.
    Author: de Witte PB, Henseler JF, van Zwet EW, Nagels J, Nelissen RG, de Groot JH.
    Journal: Clin Biomech (Bristol, Avon); 2014 Jan; 29(1):26-32. PubMed ID: 24238958.
    Abstract:
    BACKGROUND: Arm adductor co-activation during abduction has been reported as a potential compensation mechanism for a narrow subacromial space in patients with rotator cuff dysfunction. We assessed differences in acromiohumeral distance at rest and the amount of humerus translation during active abduction and adduction in patients with rotator cuff tears (n=20) and impingement (n=30) and controls (n=10), controlled for deltoid, pectoralis major, latissimus dorsi and teres major activation (electromyography). METHODS: During the acquirement of shoulder radiographs, subjects performed standardized isometric arm abduction and adduction tasks. EMG's were normalized between -1 and 1 using the "Activation Ratio", where low values express (pathologic) co-activation, e.g. adductor activation during abduction. FINDINGS: In patients with cuff tears mean rest acromiohumeral distance was 7.6mm (SD=1.6): 3.5mm narrower compared to patients with impingement (95%-CI: 2.4-4.5) and 1.3mm narrower compared to controls (95%-CI: -0.1-2.7). Both during abduction and adduction tasks, cranial translation was observed with equal magnitudes for patients and controls, with average values of 2.3 and 1.7mm, respectively. Where patients with cuff tears had lower adductor Activation Ratios (i.e. more adductor co-activation during abduction), no association between abductor/adductor muscle activation and acromiohumeral distance was found. INTERPRETATION: The subacromial space is narrower in patients with rotator cuff tears compared to patients with impingement and controls. We found additional subacromial narrowing during isometric abduction and, to a lesser amount, during adduction in all subjects and more adductor co-activation in patients with cuff tears. We found no association between subacromial space and activation of the deltoid and main adductors.
    [Abstract] [Full Text] [Related] [New Search]