Evaluation of Acromioclavicular joint

							       The diagnosis of acromioclavicular separation is based upon the typical deformity

described earlier, the prominent clavicle and the depression below it. If the arm is raised

passively upward obliterating the cavity and approximating the outer end of the clavicle to the

shoulder, the deformity appears to have been corrected, but as soon as the supporting hand is

withdrawn, the arm sinks back into its abnormally low position and the depression reappears.34

Evaluation of Acromioclavicular joint:

       Evaluation of acromioclavicular joint was made on the basis of pain, deformity and

shoulder motion. The evaluation of pain was made by each patient, who was asked to describe its

frequency and was offered a choice of the terms slight, moderate and severe to describe the

intensity of his pain. Most of the patients who had pain described it as an ache about the shoulder

associated with such factors as inclement weather, sleeping on the affected side or heavy lifting.

An attempt was made to evaluate the possible sources of pain.

       Shoulder motion was assessed by comparing abduction (elevation to the side) with that of

the opposite normal shoulder. A differential of less than 20 degrees was considered slight

restriction and a differential of 20 to 40 degrees was considered moderate. Deformity was

assessed on the basis of residual step-off between the clavicle and acromion separation of more

than 50 percent of the depth of the clavicle was considered marked, 25 to 50 percent, moderate

and less than 25 percent, slight.31

History

       It is well documented that the fibrocartilageous disk of the acromioclavicular joint

deteriorates with age. This natural aging process begins in the second decade of life. Despite the

abundant evidence that degenerative changes at the acromioclavicular joint are common with

aging, little is understood about the likelihood that such changes will eventually result in clinical
symptoms. A detailed history is critical to making an accurate diagnosis of acromioclavicular

joint pathology. Pain is universally the chief complaint. The patient should be questioned to

determine the onset, location, and character of pain. In addition, a history of prior trauma or

surgery should be excluded. Finally, previous treatment, and the response to that treatment,

should be known.

       Pain associated with isolated acromioclavicular joint arthrosis or synovitis is typically

anterosuperior in location, in direct proximity to the joint itself. Not infrequently, the pain may

radiate anterior, posterior, proximal, or distal, and may mimic pain experienced with other

shoulder conditions, such as rotator cuff tears, subacromial or subcoracoid impingement,

bicipital tendonitis, or labral or other intra-articular pathology. Most commonly, pain is

described as a dull ache, but may be sharp or burning. Symptoms are usually activity related but

may be present either at rest or during the night, and patients may experience symptoms when

sleeping on the affected shoulder.

        The patient should be asked about typical activities that produce symptoms. Using the

affected arm across the body (in shoulder adduction) or behind the back (such as reaching a

wallet or tucking in a shirt) may be particularly bothersome. As well, reaching with the arm

elevated or overhead can produce pain, not unlike that associated with impingement pathology.

The patient may also describe crepitation that localizes to the acromioclavicular joint with

certain maneuvers. However, such mechanical sensations can be difficult to localize and should

be correlated during the physical examination.38

Clinical Examination:

       The examination of a patient with a suspected acromioclavicular joint injury should be

performed with the patient in the standing position. The weight of the arm in a dependant
position may accentuate a deformity that may not otherwise be apparent in the sitting or the

supine positions. In type I injuries, pain is often present with palpation over the

acromioclavicular joint, with no detectable instability. Type II injuries engender pain over the

acromioclavicular joint and at times may result in increased motion in the transverse plane with

attempts at anterior or posterior displacement of the clavicle. In type III injuries the weight of the

arm produces an impression of superior displacement of the clavicle. Pain is elicited over the

acromioclavicular joint and coracoclavicular ligaments and the incongruence of the

acromioclavicular joint may be easily palpated.17

Physical Examination:

       The examination begins with a thorough inspection of the entire shoulder girdle. Male

patients should have the shirt removed, while female patients should be appropriately gowned to

leave the shoulder girdle exposed. The resting posture of the shoulder is assessed, including the

sternoclavicular (SC) joint, clavicle, acromioclavicular joint, scapula, and surrounding

musculature. Prior incisions should be documented, particularly in the region of the

acromioclavicular joint. Occasionally, the acromioclavicular joint may demonstrate swelling,

hypertrophic change, or resting deformity consistent with prior acromioclavicular joint

ligamentous injury.

       Anatomic landmarks should be palpated for tenderness. This includes the sternoclavicular

joint, acromioclavicular joint, acromion, proximal humerus, and periscapular region. Palpation

tenderness at the acromioclavicular joint is the hallmark of the condition. However, this should

be compared to the unaffected side. As well, the patient may not have direct tenderness at the

joint on examination, but should be asked whether the joint is the typical location of pain.
        Next, shoulder range of motion is assessed. Movement in forward elevation, abduction,

external rotation (both adducted and abducted) and internal rotation are documented. In patients

with isolated acromioclavicular joint pathology, there typically is no primary limitation to

shoulder movement. As well, scapular control and scapulohumeral rhythm are evaluated to rule

out underlying neurologic injuries or dysfunction. Additionally, strength and function of the

rotator cuff, deltoid, trapezius and distal extremity are assessed.35, 38

Finally, specific tests to elicit isolated acromioclavicular joint symptoms are performed.

    1. Acromioclavicular Shear Test.

    2. Acromioclavicular cross-over; crossbody or horizontal adduction test.

    3. Ellman’s Compression Rotation Test.

    4. Coracoclavicular Ligament Test.

    1. Acromioclavicular Shear Test: With the patient in the sitting position, the examiner cups

        his or her hands over the deltoid muscle, with one hand on the clavicle and one hand on

        the spine of the scapula. The examiner then squeezes the heels of the hand together (fig.

        7.1). Abnormal movement at the acromioclavicular joint indicates a positive test as well

        as acromioclavicular joint pathology.




                            Fig. 7.1 Acromioclavicular Shear Test.
  2. Acromioclavicular cross-over; crossbody or horizontal adduction test: the patient stands

     and reaches the hand across to the opposite shoulder. The examiner may also passively

     perform the test. With the patient in a sitting position the examiner passively forward

     flexes the arm to 900 and then horizontally adducts the arm as far as possible (fig. 7.2). If

     the patient feels localized pain over the acromioclavicular joint, the test is positive.

     Localized pain in the sternoclavicular joint indicates the joint is at fault.




Fig. 7.2 Acromioclavicular crossover, crossbody, or horizontal adduction test.

  3. Ellman’s Compression Rotation Test: The patient lies on the unaffected side. The arm is

     in 900 elevation and 10-150 adduction, with the arm in maximal internal rotation with the

     thumb pointed down. Likewise this maneuver loads the acromioclavicular joint and often

     reproduces pain. It must be determined the pain is located mainly at the

     acromioclavicular joint, as this test is also used to demonstrate superior labral pathology

     (fig. 7.3).
                Fig. 7.3 Ellman’s Compression-rotation Test.

4. Coracoclavicular Ligament Test: The integrity of the conoid portion of the

   coracoclavicular ligament may be tested by placing the patient in a side lying position on

   the unaffected side with the hand resting against the lower back. The examiner stabilizes

   the clavicle while pulling the inferior angle of the scapula away from the chest wall

   (fig.7.4). The trapezoid portion of the ligament may be tested from the same position. The

   examiner stabilizes the clavicle and pulls the medial border of the scapula away from the

   chest wall (fig.7.5). Pain in either case in the area of the ligament (anteriorly under the

   clavicle between the outer one-third and inner two-thirds) constitutes a positive test.
Fig. 7.4 Coracoclavicular Ligament Test- Conoid portion.




Fig. 7.5 Coracoclavicular Ligament Test- Trapezoid portion.
Radiographic Evaluation

       Most commonly a routine anteroposterior (AP) radiograph of the shoulder is taken to

assess injuries to the shoulder girdle. While abnormalities of the acromioclavicular joint may be

detected, this radiograph is exposed for the glenohumeral joint, and often the acromioclavicular

joint is overexposed or not well visualized. The ideal radiographic views are an AP view

centered over the acromioclavicular joint, directed 15 degrees cephalad and a lateral view of the

acromioclavicular joint. These views require approximately one-third the radiation exposure of a

radiograph of the shoulder joint.

       The Zanca view of the acromioclavicular joint was developed to address the

superimposition of the acromioclavicular join on the scapular spine. The patient is positioned

standing, with both acromioclavicular joints projected onto a single large cassette, and a true

anteroposterior view (450 angulation from the thoracic plane) with a 100 to 150 cephalic tilt is

performed (fig.7.6). The cephalic tilt maximizes visualization of the joint and helps to identify

small fractures that may be present. The axillary lateral view of the shoulder is important to

identify any posterior displacement of the clavicle and it may also reveal small fractures not

visible on the anteroposterior X-ray. The axillary lateral view is taken with the arm abducted 700

to 900 and the radiographic beam directed cranially.

       Stress views of the shoulder are often recommended to detect the presence of injuries that

may have been sustained yet do not produce readily discernable deformities on clinical or

radiographic evaluations. 10 to 15 pounds of weight are suspended from the wrists of the patient,

not held in the hands. Anteroposterior views of both acromioclavicular joints are taken

simultaneously. The distance between the coracoids process and the clavicle is measured,

comparing the injured and uninjured sides. Normal coracoids to clavicle distance is
approximately 1.3 cm, and an increase of 40% to 50% of the distance compared to the uninjured

shoulder is diagnostic of a type III acromioclavicular joint disruption.17, 26




Fig. 7.6 The Zanca view of the acromioclavicular joint. A standing, true

anterioposterior view of both acromioclavicular joints is performed with or

without weights suspended on the forearms. A 10° to 15° cephalic tilt

maximizes visualization of the joint and helps to identify small fractures that

may be present.
MRI Imaging Findings.

       Our clinical images were obtained with 1.5-T MR scanners, using a standard shoulder

coil. Oblique dual-echo coronal, oblique T2-weighted fat-saturated sagittal and axial

intermediate weighted MR images were always obtained; some patients underwent additional

gadolinium-enhanced T1-weighted clavicular ligament is best seen on T1-weighted images

because of their inherently high signal to noise ratio, structures in T2-weighted fat-saturated

images tend to be indistinct, although continuous ligamentous fibers are identified with some

effort (fig.7.7). With injury, edematous fluid around the coracoclavicular ligament makes the

fibers more evident on T2-weighted fat-saturated or intermediate-weighted MR images.

Conversely, T1-weighted images are difficult to interpret because of the edematous fluid and

blood products. Although not essential for diagnosis, IV gadolinium can delineate the extent and

path of the soft tissue damage exquisitely (fig.7.8).39




                                                                          Fig.7.7
Normal MRI of acromioclavicular joint.




                                                                                  Fig. 7.8

                     Sprained acromioclavicular joint (type IV).



Evaluation of Acromioclavicular joint:5

 Examination Segment. Clinical Findings.

History                  Onset: Usually acute.

                          Location of pain: Localized to the acromioclavicular joint area. Pain

                          may radiate down the deltoid muscle or along the clavicle.

                          Mechanism: Force applied longitudinally to the clavicle, such as

                          falling on an outstretched arm.

                          Falling on the point of the shoulder.

Inspection.               Displacement of the clavicle may be present. Step deformities indicate
                      damage to the coracoclavicular ligament.

Palpation.            Anterior displacement of the clavicle demonstrates the piano key sign.

Functional tests.     AROM: There is pain with elevation of the humerus and during

                      protraction and retraction of the scapula.

                      PROM: Pain is produced during elevation of the humerus owing to

                      movement at the acromioclavicular joint.

                      PROM: Decreased strength may be noted for all movements,

                      especially with those muscles having an attachment on the acromion

                      or clavicle.

Ligamentous tests.    Joint play movements reveal hypermobility of the acromioclavicular

                      joint.

Neurological tests.   Not applicable.

Special tests.        Traction test.

Comments.             Athletes with fractures of the distal clavicle may present with the

                      clinical signs and symptoms of an acromioclavicular joint sprain.