Chapter 6: Abnormal findings

This chapter deals with the variety of abnormali­ties which can be seen arthroscopically, using the routine laid down in Chapter 5.

Long head of biceps

Fortunately, since the long head of biceps is the primary reference point of shoulder arthro­scopy, abnormalities are seen in only some 10 per cent of cases. In patients with impinge­ment, there may be fraying or tendinitis (Figure 6.1), often associated with changes in the rotator cuff. Some patients who have partial or full thickness rotator cuff tears may have debris hanging down into the joint obliterating the view of the long head of biceps (Figure 6.2). In some patients, the tendon may be missing following rupture. In approximately 3 per cent of patients, the long head of biceps will have a synovial mesentery, either complete (Figure 6.3), or represented by a strand (Figure 6.4), which should be considered as a variant of the norm.

Figure 6.1 Fraying of the biceps tendon can be seen at the impingement point, c = cuff, b = biceps, h = humeral head.

Figure 6.2 Sometimes the biceps tendon cannot be seen if tags from a rotator cuff tear hang down and hide it.

Figure 6.3 The biceps tendon may be enfolded by a mesentery. This is not an abnormal finding but a variation of normal.

Figure 6.4 The mesentery to biceps tendon may be represented by a single strand which could be taken for an adhesion.

 

Rotator cuff

A spectrum of abnormal changes can be found in the rotator cuff. The first evidence of impinge­ment may be reddening of the cuff, and an increase in small-size vessels in the synovium (Figure 6.5). The next stage in the sequence is a 'hairy' degeneration of the cuff in the impinge­ment area (close to the biceps tunnel) (Figure 6.6). The next stage is seen as a deep surface tear (Figure 6.7).

Figure 6.5 Vasculitis of the rotator cuff.

Figure 6.6 Fraying of the rotator cuff at the impingement point, c = cuff, b = biceps, h = humeral head.

Figure 6.7 Partial thickness rotator cuff tear covered with thickened synovium.

Figure 6.8 Full thickness rotator cuff tear.

Finally, the partial thickness tear will give way to a full thickness tear (Figure 6.8), which matures to give rounded-off edges (Figure 6.9) through which can be seen bursal proliferation and the undersurface of the acromion (Figure 6.10).

Figure 6.9 A full thickness rotator cuff tear has rounded mature edges and the proliferative bursal tissue hangs down through it.

Figure 6.10 A collage of arthroscopic photographs to show the rotator cuff tear seen in Figure 6.9 in relation to the rest of the joint.

Massive rotator cuff tears may be confusing initially. Instead of the rotator cuff the undersur­face of the acromion is seen, and when probed it can be appreciated just how massive a cavity is present (Figures 6.11 and 6.12)

Figures 6.11 and 6.12 In a massive rotator cuff tear, the edges may not be seen. There is just a large and very irregular cavity, the size of which can be judged by the extent to which the hook probe travels.

Glenoid labrum, inferior glenohumeral ligament complex

In traumatic dislocation, the labrum avulses from the glenoid rim (see pages 143-158), known as the Bankart lesion. This may give a variety of appearances. The normal labrum looks very similar to the meniscus of the knee (Figure 6.13). The usual pattern of the Bankart lesion is separation of the labrum from the rim (Figure 6.14), with a space visible both above and below the labrum. Another appearance is where the avulsed labrum prolapses over the front of the glenoid (Figure 6.15). Finally, if there has been a high number of episodes of disloca­tion then the labrum and the associated glenohumeral ligaments will be torn, shredded and eventually disappear (Figure 6.16). The anterior rim of the glenoid will become crevassed by repeated episodes of dislocation (Figures 6.17 and 6.18).

Figure 6.13 The normal labrum looks similar in appearance to the normal knee meniscus.

Figure 6.14 The usual Bankart appearance of separation between the glenoid and the labrum.

Figure 6.15 The labrum may prolapse in front of the glenoid rim in the 'over-the-top' type of Bankart lesion.

Figure 6.16 After several episodes of dislocation, the labrum becomes disrupted. Along with the middle glenohumeral ligament, it may eventually disappear altogether, g = glenoid, s = subscapularis tendon.

Figures 6.17 and 6.18 The front edge of the glenoid may become crevassed.

Labral tears

If the labrum is torn or avulsed in the inferior two-thirds of its extent, this usually signifies a Bankart lesion. However, there is some discus­sion about tears in the upper third (Figures 6.19 and 6.20), and tears without separation.

Detrisac1 has described a normal separation of the labrum in the upper third, occurring in some 80 per cent of the cadavers he examined. Others have described a superior tear, or avulsion of the superior labrum and the origin of the long head of biceps, which may be common in throwing sports. This is thought to be caused by the pull of biceps in the decelera­tion phase of elbow extension.

Figures 6.19 and 6.20 Tears of the glenoid labrum.

Posterior labrum

The posterior labrum may be torn, just as the anterior labrum. However, this does not signify a posterior dislocation as anterior dislocation may cause a tear of the posterior labrum (see Chapter 9).

Glenohumeral ligaments

The normal appearance of the glenohumeral ligaments on pages 85-93 has been discussed (see also Figure 6.21). The middle glenohume­ral ligament is variable, from a thin translucent sheet to a strong thick ligament. It may be absent following repeated dislocation (see Chapter 9 and Figure 6.22). The inferior gleno­humeral ligament should be considered as a prolongation of the anterior labrum (Figure 6.23).

Figure 6.21 The normal middle glenohumeral ligament passing obliquely over the intra-articular upper edge of the subscapularis tendon.

Figure 6.22 Absent middle glenohumeral ligament.

Figure 6.23 The inferior glenohumeral ligament as a prolongation of the labrum.

Inferior glenohumeral recess

In the normal shoulder the inferior glenohume­ral recess is a large cavity (see Figure 5.27). The recess may be constricted in patients with a stiff painful shoulder (frozen shoulder). The inferior glenohumeral recess is a favourite hiding place for loose bodies, which vary in size from a needle point (Figure 6.24) to large bodies (Figures 6.25 and 6.26). The usual source of loose bodies is the Hill-Sachs impac­tion fracture of dislocation.

Figure 6.24 A small loose body the size of a needle.

Figures 6.25 and 6.26 Larger loose bodies.

Figure 6.27 Hill-Sachs defect can be a small dimple.

Hill-Sachs lesions

Once more, a spectrum of lesions can be seen on the back of the humeral head depending on the energy of the initial dislocation episode, and the frequency of dislocation. Hill-Sachs lesions can vary from a small cartilaginous dimple (Figure 6.27), to a full-blown osteochondral defect (Figures 6.28, 6.29, 6.30 and 6.31). It should be re-emphasized that the normal humeral head has a bare area of bone between the posterior synovial reflection and the cartila­ginous surface (Figures 6.32 and 6.33), which must not be confused with a Hill-Sachs lesion.

 

Figures 6.28, 6.29, 6.30 and 6.31 A large Hill-Sachs defect.

Figures 6.32 and 6.33 The bare area of the humeral head should not be mistaken for a Hill-Sachs defect. Note the difference from 6.28 to 6.31 in that there is no articular cartilage to the right (reflection side) of the bare area.

Arthritis

Osteoarthritis is rare in the shoulder joint. The appearance of the cartilage of both the glenoid and the humerus parallels the pattern of the disease in other joints (Figures 6.35, 6.36 and 6.37).

Figures 6.35, 6.36 and 6.37 Arthritic joint surfaces in the shoulder.

Rheumatoid arthritis commonly affects the shoulder joint. In the early stages, there is an aggressive synovitis. Pannus can be seen eroding the cartilage in the humeral head (Figure 6.38).

Figure 6.38 Vascular pannus eroding the articular surface of the humeral head.

Fractures & Joint replacement

It is rare to arthroscope a patient with a glenoid fracture. The case with a displaced glenoid fracture shown in Figures 6.39 and 6.40 was arthroscoped prior to open reduction and internal fixation to assess whether the maximum incongruity was at the front or back, in order to plan the approach as the three-dimensional computer tomography (3D CT) reconstruction program had temporarily gone down. Bleeding from fractures is more difficult to control in the shoulder than the knee, making the photogra­phy of poor quality (Figure 6.41), but the major incongruity could be seen anteriorly, and an anterior approach was used for reconstruction.

Figures 6.39 and 6.40 Three-dimensional subtraction CT scan of a fracture of the glenoid.

Figure 6.41 The fracture could be visualized arthroscopically, although the field was distorted due to bleeding.

Figures 6.42 and 6.43 Neer shoulder replacement visualized arthroscopically.

Joint replacement

Again it is extremely rare to arthroscope a patient following a shoulder replacement. One patient had residual pain following his second shoulder replacement, the eighth operation on this shoulder. He had a small radiolucent line around the glenoid component, but shoulder arthroscopy (Figures 6.42 and 6.43) with prob­ing confirmed that the glenoid component was not loose from the scapula.

Shoulder sepsis

Another rare indication for shoulder arthro­scopy is sepsis. The cannula can be used to wash out the shoulder joint copiously. The synovial appearance depends on the length of history but can be quite florid. Following wash­out of the joint, drains can be placed both from the anterior portal and up the arthroscope cannula prior to withdrawal, allowing a con­tinuous irrigation system to be used postopera­tively.