University of Oulu

On the pathogenesis of shoulder impingement syndrome

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Author: Hyvönen, Pekka1,2
Organizations: 1University of Oulu, Faculty of Medicine, Division of Orthopaedic and Trauma Surgery
2University of Oulu, Faculty of Medicine, Department of Surgery
Format: ebook
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
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Language: English
Published: 2003
Publish Date: 2003-05-02
Thesis type: Doctoral Dissertation
Defence Note: Academic Dissertation to be presented with the assent of the Faculty of Medicine, University of Oulu, for public discussion in the Auditorium 1 of the University Hospital of Oulu, on May 2nd, 2003, at 12 noon.
Reviewer: Docent Jan-Magnus Björkenheim
Emeritus Professor Hiroaki Fukuda


The pathomechanism of the shoulder impingement syndrome has been under debat. Two main theories of the pathogenesis of the disease exists; mechanical (extrinsic) and degenerative (intrinsic) theory.

The purpose of this work was to evaluate the pathogenesis of impingement syndrome with five studies that consentrate to aspects related to ethiopathology as outcome and recovery after surgery, radiological diagnosis, immunohisto- and histopathology of subacromial bursa, and subacromial mechanical pressures.

The good results of 14 shoulders of 96 operated with an open acromioplasty turned painful after an average of 5 (2 - 10) years postoperatively and had developed 6 full-thickness and 4 partial rotator cuff tears. Initially good result is not permanent in all cases, suggesting that a degenerative process is involved in the pathogenesis of impingement syndrome.

Shoulder muscle strengths of 48 patients, who had undergone an open acromioplasty, restored to near normal within one year after open acromioplasty, suggesting that mechanical compression plays a role in the pathogenesis of impingement syndrome.

Variation in the shape of the acromion, evaluated in 111 patients and their matched controls by a routine supraspinatus outlet view, is associated with impingement syndrome, but this association is weak. Validity of this radiograph in the diagnosis of impingement syndrome is therefore a minor adjunct to the other diagnostic methods.

The role of subacromial bursa in impingement syndrome was studied in 62 patients (33 tendinitis, 11 partial and 18 full-thickness RC tear) suffering from a unilateral impingement syndrome and 24 controls. Tenascin-C proved to be a more general indicator of bursal reaction compared to the conventional histological markers, being especially pronounced at the more advanced stages of impingement.

The local subacromial contact pressures measured in 14 patients and 8 controls with a piezoelectric probe were elevated in the impingement syndrome, supporting the mechanical theory.

On the basis of this study, both mechanical and degenerative factors are involved in the pathogenesis of impingement syndrome.

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Series: Acta Universitatis Ouluensis. D, Medica
ISSN-E: 1796-2234
ISBN: 951-42-7025-8
ISBN Print: 951-42-7024-X
Issue: 725
Copyright information: © University of Oulu, 2003. This publication is copyrighted. You may download, display and print it for your own personal use. Commercial use is prohibited.