Clinical Evaluation of Unstable Shoulders
The diagnosis is largely based on the history. The main points that the physician will ask you are:
- What symptoms do you have and how long have you had them?
- What forces were involved in the original injury (if there was one)? What was the direction and the magnitude of the forces involved, and where did they have contact with your body? For example, were you hit at high speed front-on by a car, did your shoulder impact with the steering wheel, or did you fall onto your outstretched arm while walking, running, skating, or cycling?
- How long was your shoulder out of place before it was put back into place?
- Did you shoulder go back into place by itself or was it put back into place by someone?
- Did you have numbness or tingling in your arm after you were injured?
- Did the injury occur at work?
- What body positions or activities cause or exacerbate pain and other symptoms?
- Is this a recurrence of symptoms or of a previous injury? If so, were the forces involved similar or was less force required to produce similar symptoms?
- Has your shoulder problem affected your daily living skills, sporting performance, training, etc.?
- How many other times have you had shoulder injury?
Clinical Tests for Shoulder Instability
A physical examination aids the physician in determining the precise cause of the symptoms. It is important to realise that if a shoulder is sore or uncomfortable when moved then the physician may not be able to fully examine it, making the diagnosis more difficult.
There are two basic types of tests for shoulder instability. (1) Laxity examinations aim to determine how loose the ligaments are that stabilise the shoulder. These tests are usually painless. (2) Provocative examinations provoke symptoms in the shoulder by stressing it in ways which let the physician know that the shoulder being tested is damaged.
Load and Shift Test: this test is used to determine how loose the shoulder ligaments are. There are several variations of this test in use. One of the most common tests involves having the patient lie flat on the back so that the centre of the shoulder blade is on the edge of the bed (Fig. 5a).
The physician holds the arm out at 90° from the side to see how much movement there is in the shoulder joint in the anterior direction (towards the front of the body) and the posterior direction (towards the back). The distance the arm can be moved in this position can be scored for a rough indication of the shoulder's stability or instability (Fig. 5b)
This test is used to determine how loose your shoulder ligaments are in the inferior (downward) direction.
The patient stands or sits with the arms hanging by the side. The examiner then pulls down on the patient's arm and looks to see if a dimple-like sulcus appears in the shoulder (Fig. 5c). The sulcus is due to the humerus sliding down over the surface of the joint -- leaving a gap at the top which resembles a dimple in the skin of the shoulder. About 25% of people with multidirectional instability show a sulcus of 2 centimetres or more when their arm is pulled down.
As most people dislocate their shoulder in the anterior direction (i.e. their shoulder pops out towards the front), the tests described here are for anterior instability.
This test puts the shoulder in a position where the patient may become apprehensive that it is about to dislocate. The examiner will want to know this and will look for signs that the patient is apprehensive.
Lying on the back, the patient's arm is extended 90° from the side and rotated clockwise ("externally rotated"). This is similar to the position your arm would be in if you were getting ready to throw a ball or wave to someone. From this position, the examiner will continue to externally rotate the patient's arm. This is the position that puts the most strain on the ligaments which stop normally stop the shoulder from dislocating anteriorly. If those ligaments are weak or damaged, the shoulder may feel like it is going to pop out of joint -- which is what the physician wants to know (Fig. 5d).
This test is performed immediately after the apprehension test. While the arm is still in the position where it felt like it was going to pop out of the socket, the examiner will push the humeral head backwards. This is in the opposite direction to where it was being pushed when the examiner was doing the apprehension test. If the humeral head has started to slide forward, this test will push it back into place and should lessen any feeling of apprehension that the arm is about to pop out of joint. Some physicians think that people whose shoulder has become unstable due to repeated strain on the ligaments (e.g. athletes who do a lot of throwing/overhead activity) won't feel as though their shoulder is about to dislocate. Instead, they will get pain in their shoulder while their already stretched ligaments are stretched once more.
Warning: Do not attempt any of these procedures unless you are fully trained as serious damage may result. Always seek expert medical advice and aid.