Shoulder impingement (FS-22)

Shoulder impingement syndrome: how does opinion regarding aetiology influence treatment?

Karen Ginn (Australia), Ann Cools (Belgium), Jeremy Lewis (United Kingdom), Jean-Sébastien Roy (Canada)

Focused symposium

Monday 4 May 2015, 15:45-17:15, Hall 404

Shoulder impingement syndrome: how does opinion regarding aetiology influence treatment?

Ginn K. 1, Cools A. 2, Lewis J. 3, Roy J.-S. 4,5

1University of Sydney, Biomedical Science, Lidcombe, Australia, 2Ghent University, Rehabilitations Sciences and Physiotherapy, Gent, Belgium, 3University of Hertfordshire, Department of Allied Health Professions and Midwifery, School of Health and Social Work, Hatfield, United Kingdom, 4Laval University, Department of Rehabilitation, Quebec City, Canada, 5Centre for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Canada

Learning objectives

  1. To explain and provide evidence for alternative hypotheses regarding the aetiology of shoulder impingement syndrome.
  2. To describe and evaluate the efficacy of alternative treatment approaches for shoulder impingement syndrome.
  3. To evaluate whether differences in opinion regarding the aetiology of shoulder impingement syndrome have a significant impact on how physiotherapists treat this common musculoskeletal problem.

Description

Subacromial impingement syndrome (SIS) is considered to be the most common of the musculoskeletal conditions affecting the shoulder. However, health professionals hold differing opinions as to the aetiology of SIS. Four hypotheses as to the cause of SIS follow:

1) Acromial irritation leads to external abrasion of the bursa and rotator cuff (RC). Surgery to decompress the subacromial space is a common treatment to address this supposed cause of SIS. There is a body of evidence that suggests there is a lack of concordance regarding (i) the area of tendon pathology and acromial irritation, (ii) the shape of the acromion and symptoms, (iii) the proposal that irritation leads to the development of tendinitis and bursitis, and (iv) imaging changes and symptoms and the development of the condition. Exercise has been shown to be as effective as surgery in treating SIS with reduced economic burden. In addition, there is no certainty that the benefit derived from the surgery is due to the removal of the acromion, and the benefit may simply be relative rest.

2) Because of the requirement at the shoulder for large ranges of movement in order to maximise hand function, the glenohumeral joint has very limited passive support from skeletal, capsulolabral or ligamentous structures. As a result the glenohumeral joint relies on dynamic support, particularly the RC muscles, to achieve functional stability. The two main mechanisms by which RC muscles provide dynamic joint support are: to co-contract to provide a balanced, medial force to the humeral head to centre it in the glenoid fossa; and to counterbalance humeral head translation generated by muscles moving the humerus. Deficits in RC muscle strength and/or timing of recruitment in association with deltoid activity will result in superior translation (“impingement”) of the humeral head into the subacromial space and are a likely cause of SIS. Evidence from randomised, controlled clinical trials indicates that exercises designed to improve RC muscle function are effective in the treatment of SIS.

3) There is scientific evidence showing an association between chronic, impingement related shoulder pain and abnormal scapular kinematics and muscle recruitment patterns. Faulty position and movements of the scapula, aberrant muscle strength, balance, and timing properties may result in onset or aggravation of chronic shoulder pain. On the other hand, recent studies suggest that pain mechanisms possibly can influence scapular muscle recruitment, and thus induce changes in scapular motion and stability. Although the cause-consequence relationship between both entities is under debate, a wide variety of treatment options is available for correction of scapular function. These scapular rehabilitation programs seem to increase muscle strength in the scapular and glenohumeral muscles, and reduce symptoms.

4) Changes in the central nervous system have been documented in individuals with SIS, namely decreased corticospinal excitability of the infraspinatus. Being positively associated with duration of pain, infraspinatus corticospinal excitability seems to decrease over time. Central changes could be attributable to several causes. For example, pain has been shown to exert an inhibitory effect over the primary motor cortex. Moreover individuals with SIS typically move their affected limbs differently from normal, which likely leads to altered shoulder afferent input, which might in turn lower corticospinal excitability. Current interventions for SIS mainly target deficits at the joint level. However, specific interventions, such as movement training used in neurorehabilitation, should be performed to reverse these central changes. In fact, the use of movement training has been shown to improve the functional level of individuals with SIS. Reversal of central changes could be an important step towards recovering normal shoulder function.

Implications / Conclusions

But do different opinions regarding the "existence" and/or aetiology of SIS have a significant impact on physiotherapy treatment for SIS? Four physiotherapists with expertise in the treatment of shoulder dysfunction will present a treatment program for SIS and provide available evidence of the efficacy of this approach. This will be followed by a panel discussion with the audience on how and/or if the treatment approach for SIS is influenced by beliefs about the cause of this common musculoskeletal condition. Following this discussion all/any common elements of the treatment programs presented will be summarised.

Keywords

Shoulder; Impingement; Treatment

Funding acknowledgements

Nil

Relevance to WCPT and expected audience

This symposium addresses a very common musculoskeletal problem, will be directed at practicing clinicians & will be of relevance to experienced physiotherapists as well as new graduates. As such it will be potentially interesting to a many WCPT members & attendees at the WCPT Congress. This Focused Symposium has the potential to begin the process of gaining an international concensus for the treatment of SIS to inform current best practice guidelines & future clinical research.

Target audience

Musculoskeletal & orthopaedic specialist physiotherapists & general physiotherapists treating musculoskeletal conditions.