Special tests
Impingement tests
The impingement sign is produced by pushing the greatertuberosity upward against the inferior aspect of the acromion first in forward flexion, then in abduction and internal rotation, and finally in abduction and external rotation.1i2 The tests are positive when painful and should be abolished with local anaesthetic under the anterior edge of the acromion.
Adduction test
Acromioclavicular joint pain is aggravated by forced adduction of the shoulder with the arm in 90 degrees of flexion (Figure 2.14). However, this test may also be painful in patients with subacromial impingement. An additional test is resisted active adduction of the shoulder with the arm hanging close to the side (Figure 2.13). Further evidence of acromioclavicular dysfunction can be obtained by repeating the tests after injection of 1-2 ml 1 per cent lignocaine (US: lidocaine) into the acromioclavicular joint.
Figure 2.13 Acromioclavicular joint pain may also be found by adduction in extension.
Figure 2.14 Acromioclavicular joint pain is aggravated by adduction of the shoulder with the arm in 90 degrees of flexion.
Anterior apprehension test
The patient is examined sitting (or if anaesthetized, prior to arthroscopy, supine). The problem shoulder is passively abducted to 90 degrees, and is then passively externally rotated by the examiner into full external rotation. The arm is then pushed into the fully stressed position, while the patient's face is studied for apprehension. The normal shoulder is examined for comparison.
Shift and load test
Under anaesthesia, the shoulder is brought into the 'position of apprehension' and forcefully stressed to provoke subluxation or frank dislocation. Axial load is then applied down the humeral shaft onto the glenoid, and the abducted arm is brought forward into the flexed position, which puts a posterior shear force on the humeral head. If the humeral head had subluxed in the apprehension position then the 'load and shift' test will give a clunk as the shoulder relocates in a similar manner to the Ortolani test in congenital dislocation of the hip (CDH).
Instability tests
These tests are essential in any patient under the age of 40 with shoulder pain, and should be performed not only in the outpatient office but before every shoulder arthroscopy when the patient is anaesthetized and fully relaxed.
Anterior drawer test
To examine the right shoulder, the surgeon stands behind the seated patient, grasps the shoulder girdle with his left hand, the fingers at the front holding the clavicle and coracoid, and the thumb locked over the back of the spine of the scapula. The right hand then grasps the proximal humerus and forcefully translates the humerus forwards and backwards. Excess laxity is judged against the opposite side.
The sulcus sign
The patient (usually a female, as this is a test for multidirectional instability) is seated with her arms hanging down on either side of the chair and asked to relax. The examiner applies downward traction on the arm by holding the wrist and distracting the arm downwards firmly but not roughly. If the shoulder is interiorly unstable, a sulcus will appear between the acromion and the humeral head (Figure 2.15). This sulcus is both visible and palpable. The patient with a positive sulcus sign should be examined for generalized joint laxity.
Figure 2.15 The sulcus sign: inferior traction on the arm in patients with multidirectional instability leads to the appearance of a sulcus between the acromion and the head of the humerus.
Posterior stress test
The patient is examined lying supine (Figure 2.16). The arm is brought to 95 degree elevation in flexion. For examining a right shoulder, the surgeon's left hand is placed behind the glenohumeral joint - that is, under the shoulder blade. The humeral head is then pushed posteriorly by holding the elbow with the surgeon's right hand and applying an axial load down the humerus, trying to push the humeral head backwards out of the joint. If the joint is posteriorly unstable, it will sublux at this stage and this may be detected by the examiner's left hand. However, it may not be picked up at this stage.
Keeping the compressive load applied down the shaft of the humerus, the latter is now brought around into a position of 90 degree abduction. If the shoulder was subluxed it will at this point relocate with a clunk just as in the 'load and shift' test. There is a real risk of producing a frank dislocation with the anterior and posterior stress tests, which does not matter in the anaesthetized patient, but is very embarrassing in the outpatient department, particularly if it can not be relocated!
Figure 2.16a and b Posterior stress test: with the patient lying supine the humerus is pushed out of the back into a subluxed position. Load is then applied to the joint and the humerus brought from 90 degrees of flexion to 90 degrees of abduction, which will reduce the subluxation with a palpable jerk.
Neurological assessment
Finally, the patient should have a rapid neurological assessment made of the rest of the arm, and the pulses and peripheral perfusion should be noted. If abnormal neurology is detected, for instance suprascapular nerve entrapment is suspected, then neurophysiological testing should be advised. Imaging is discussed in Chapter 3.
