**5.3 Imaging**

34 Modern Arthroscopy

The examiner should obtain a thorough history, which should offer information regarding symptoms, type and direction of instability, age and time elapsed from the initial dislocation, number of instability episodes, need for medical assistance for reduction versus

The provocative position for dislocation is indicative of the direction of instability. Patients with anterior traumatic instability generally describe the event occurring with the arm in the abducted, extended and externally rotated position. Patients who do not recall a specific dislocation event may have pathologic instability due to generalized ligamentous laxity. Pain may also be associated with instability. For example, overhead-throwing athletes with anterior instability may complain of pain due to repetitive stress on the anteroinferior

Patients who present with a long history of recurrent instability episodes, high-energy trauma leading to dislocation, a progressive ease of symptoms or demonstrate instability in the midrange of motion should be meticulously evaluated for glenohumeral bone deficiencies. The ability to voluntarily dislocate the shoulder should be thoroughly examined because it may be attributed to psychological factors and, secondly, is generally associated with increased rates of recurrence after surgery. Similarly, patients with multiple dislocation events or whose shoulders slip out with limited force (during sleep or when reaching overhead) may have a significant glenohumeral bone defect or other pathology, such as multidirectional laxity or glenoid hypoplasia. Therefore, they would necessitate a different surgical plan. Finally, the degree of disability and loss of functionality should be

Both shoulders are exposed for visual inspection and comparative examination. Testing for range of motion and overall muscle strength, and neurovascular examination are performed. The opposite shoulder and other joints are examined to assess the degree of ligamentous laxity normally present in any individual. Clinical tests for glenohumeral laxity and provocative or

Examination for glenohumeral laxity includes the anterior and posterior drawer, and the anterior and posterior load and shift tests, which quantitate the amount of anterior and posterior humeral head translation respectively. The Gagey hyperabduction test is used to measure the laxity of the inferior glenohumeral ligament complex. The sulcus sign also evaluates glenohumeral laxity at the inferior direction when an inferior stress is applied with the arm in adduction and both neutral and 30o external rotation. It is important for the surgeon to discern between pathologic shoulder instability and normal laxity. Instability is generally described as symptomatic laxity, which requires the patients subjectively experiencing the shoulder subluxating or recalling a frank dislocation event. On the contrary, laxity is the normal translation between the components of the glenohumeral joint

Testing for instability includes the apprehension-relocation, and the anterior release and surprise tests. The apprehension test is positive when the patient experiences pain and has a subjective feeling of the arm dislocating when the shoulder is progressively moved to abduction and external rotation. It is especially important to determine the ease with which the shoulder begins to dislocate and engage on the glenoid. If this occurs even with limited

instability tests are the hallmarks in the physical examination of an unstable shoulder.

**5. Evaluation and decision-making** 

self-reduction, activity level and prior treatment.

thoroughly evaluated as part of decision making.

to achieve full normal range of motion (Bigliani et al, 1996).

**5.1 Patient history** 

capsulolabral complex.

**5.2 Physical examination** 

Routine radiographic imaging of the shoulder should include a true anteroposterior, axillary and scapular-Y views. Hill-Sachs lesions can be best appreciated on the anteroposterior view in internal rotation and the notch view (Hall et al, 1959). Avulsion fractures and glenoid bone deficiencies can be visualized with the Velpeau or West point axillary views (Rokous et al, 1972).

Advanced imaging has offered an improved ability to evaluate soft tissue lesions as well as glenohumeral deficiencies following shoulder dislocation. MRI has become the gold standard in evaluating glenohumeral instability demonstrating a high accuracy for detecting labral tears using noncontrast, enhanced imaging techniques (Ng et al, 2009). MR arthrography, however, has been found to present the highest sensitivity in detecting labral pathology compared with plain MRI and CT arthrography (Chandnani et al, 1993). It also achieved the best visualization of the inferior glenohumeral ligament and labrum. Both MRI and MR arthrography can also be helpful in evaluating bone loss. However, recently volume-rendering three-dimensional CT scans have offered a highly accurate method of measuring glenoid deficiencies and Hill-Sachs lesions. The humeral head can be digitally subtracted to allow for preoperative measurement of the inferior glenoid surface and the percentage of bone missing (Fig 5). Glenoid bone defects occur along a line parallel to its long axis. The inferior two thirds of the glenoid have been described as a well-conserved circle and the amount of bone missing is assessed in respect to surface area loss of the circle. Glenoid bone loss of between 6 to 8 mm of the anteroposterior diameter corresponds to 20- 25% of the surface of the inferior glenoid. In a similar fashion, the extent and morphology of a Hill-Sachs lesion can be evaluated to assess the degree of engagement.

Fig. 5. Volume-rendering 3D reconstructed image of a cadaveric shoulder before (left image) and after (right image) artificially creating a glenoid bone defect. The surface area of the inferior glenoid is being measured.

Arthroscopic Treatment of Recurrent Anterior Glenohumeral Instability 37

0%-30% respectively), improvements in patient selection and operative technique have steadily decreased recurrence rates to match that of open procedures (Geiger et al, 1997; Roberts et al, 1999; Fabbriciani et al, 2004). In a systematic meta-analysis, which included 62 studies and 3044 arthroscopic operations, no difference was found in failure rates between open and arthroscopic treatment of anterior shoulder instability with suture anchors or bio-absorbable tacks. On the contrary, there was a higher rate of failure compared with open techniques when staples or transglenoid sutures were used

However, data from prospective randomized trials are still limited. Fabbriciani et al found no difference between open and arthroscopic repair of isolated Bankart lesions in a group of 60 patients at 2-year follow-up (Fabbriciani et al, 2004). Similarly, Bottoni et al found no differences in functional scores and recurrence rates between open and arthroscopic techniques for isolated anterior instability repair. However, a trend was established towards improved external rotation and forward flexion as well as significantly reduced operative time in the group of arthroscopic repair. The authors concluded that the latter was equivalent to the open surgical technique for anterior shoulder instability repair (Bottoni et

**8. Suture anchor surgical technique for anterior shoulder instability repair** 

both positions is abnormal and indicative of rotator interval pathology.

A meticulous examination under anaesthesia should be performed in all cases before arthroscopy. A sensitivity of 100% and specificity of 93% have been found for this examination as confirmed by the actual arthroscopic findings (Cofield et al, 1993). The examination should be performed either in the supine or beach chair positions. Passive range of motion is recorded first with the arm at the side and 90o of abduction. With the arm abducted at 90o, posterior and anterior forces are applied to provoke translation of the humeral head in relation to the glenoid. A sulcus sign is tested in adduction and external rotation, and also at 45o abduction that tightens the inferior capsule. Persistent sulcus sign in

The patient can be positioned in either the lateral decubitus or beach chair positions, which is mainly based on surgeon preference. The beach chair position affords several advantages including the ease to address concomitant rotator cuff pathology and the ability to convert to open surgery if necessary. However, it is often easier to address the pathology at the anteroinferior capsulolabral complex with the patient in the lateral decubitus position, because it provides a wider distension of the glenohumeral joint (Fig 6). The arm is usually placed at 45o abduction and traction is applied both in the axial and lateral directions. One of the disadvantages of this patient setup is the difficulty to achieve rotational control during the repair. For example, subscapularis repair and rotator interval closure are best performed

in 30o to 45o of external rotation, which cannot be easily done at the lateral position.

Basic equipment for shoulder arthroscopy includes a tower containing a video monitor, control box, light source, shaver power and electrocautery source, and irrigation pump. A

arthroscopically (Hobby et al, 2007).

**8.1 Examination under anaesthesia** 

**8.2 Patient positioning** 

**8.3 Instrumentation** 

al, 2006).
