Yudu - sportEX medicine - 1999-2010

SHOULDER IMPINGEMENT

ASSESSMENT AND DIAGNOSIS OF

By Jo Burgess, MCSP

The shoulder is the most mobile joint of the body and accounts for approximately 11% of all reported orthopaedic injuries within sport. Impingement syndrome is reported to be the most common form of shoulder pathology. The shoulder is notoriously complex and confusing to diagnose, and consequently even more so to treat conservatively. Shoulder impingement syndrome (SIS) diagnosis is complex as the condition is likely to be multi- factorial. This article combines the available research with personal experience to provide a guide for assessment and diagnosis of shoul- der impingement syndrome (SIS).

OVERVIEW As the shoulder joint is the most mobile joint of the body, it is no surprise that with the demands of such sports as swimming, tennis and javelin throwing, it is implicat- ed in a high proportion of reported injuries. Of such injuries to the shoulder complex, impingement syndrome is desc- ribed as the most common form of shoulder pathology (1).

Shoulder impingement syndrome (SIS), also known as subacromial impingement syndrome or painful arc syndrome, occurs when structures within the subacromial space are compressed between the head of

IMPINGEMENT SYNDROME

the humerus and the coracoacromial arch (1). Lying under the coracoacromial arch are a number of soft tissue structures which may be implicated in SIS. From superficial to deep they are: ■ the subacromial bursa ■ rotator cuff tendons (supraspinatus, infraspinatus, teres minor and sub- scapularis)

■ the long head of biceps (2).

SIS commonly occurs in overhead activities such as javelin throwing, tennis serves and freestyle swimming. During elevation of the shoulder the greater and lesser tuberosities of the humerus pass close to the coracoacromial arch. Elevation is achieved through a delicate balance of sta- tic and dynamic muscular control. Instability due to weakness of the shoulder stabilisers, particularly the rotator cuff, has been implicated as a cause of SIS (3). In reality it is likely the condition is multi- factorial.

Possible causes of SIS ■ Bony factors such as osteophytes at the acromioclavicular joint or acromion, or a type III (hook shaped) acromion

■ Shoulder instability for example due to rotator cuff weakness or capsulo-liga- mentous laxity

■ Poor scapulohumeral rhythm/scapula position

■ Posterior capsule tightness ■ Poor posture ■ Soft tissue changes such as calcification of the supraspinatus tendon, chronic

SHOULDER

thickening of subacromial bursa or a partial thickness rotator cuff tear.

While each factor may be a cause of SIS individually, it is more likely there is a combination of one or more factors con- tributing to the overall picture. Taking poor posture as an example - thoracic kyphosis will inevitably lead to cervical hyperexten- sion and head forward position. The shoul- der girdle is likely to be protracted, with scapula protraction, abduction and possi- bly lateral rotation. The result is tightness and shortening of the anterior chest wall muscles and shoulder protractors, with consequent weakness and lengthening of the retractors. The posterior capsule is placed under tension which results in ante- rior translation of the humeral head. The plane of humeral head movement in rela- tion to the glenoid is consequently altered leading to scapulohumeral rhythm dysfunc- tion. With the scapula and humerus moving out of synchrony, the soft tissues are prone to impingement

and consequently the

pain of SIS. Which possible cause occurs first is the million dollar question!

ASSESSMENT Subjective assessment When carrying out the subjective assess- ment, there are five important areas to cover.

Age SIS can occur at any age, but Neer and Welsh’s (1977) (4) classification has long been used to give some indication of the

Figure 1: Lateral view of posterior joint capsule www.sportex.net

Figure 2: Lateral view of cuff attachments

Figure 3: Lateral view of subacromial bursa 11