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of the clavicle to the shoulder, the deformity appears to have been corrected, but as soon as the supporting hand is withdrawn, the arm sinks back into its abnormally low position and the depression reappears.
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of the clavicle to the shoulder, the deformity appears to have been corrected, but as soon as the supporting hand is withdrawn, the arm sinks back into its abnormally low position and the depression reappears.34 Evaluation of Acromioclavicular joint: Evaluation of acromioclavicular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.