The patient with subacromial impingement syndrome usually presents with a gradually progressive history of pain aggravated with use of the arm above shoulder level. As the symptoms persist and progress, the pain, initially present only with activity, may become present at rest and especially at night, awakening the patient from a sound sleep. The patient with a full-thickness rotator cuff tear may or may not notice weakness in the arm. With small cuff tears, strength may be maintained surprisingly well, although the patient may notice diminished endurance and fatigability of the arm when it is used in the overhead position. Patients
with cuff tears often note that the pain affects such activities as opening doors, reaching behind the back to do bra straps, reaching high shelves, or participating in sports such as tennis, racquetball, and swimming. On physical examination, inspection often reveals few abnormalities. A patient with a rotator cuff tear may have a rupture of the long head of the biceps or muscle atrophy in the supraspinatus fossa, although atrophy generally accompanies larger tears of long duration. There may be fullness in the subdeltoid area as joint fluid fills the subacromial space. Occasionally a patient with a full-thickness tear will present with an AC joint “ganglion.” This is, in fact, glenohumeral joint fluid that has leaked out into the subacromial space and through the eroded inferior capsule of the AC joint. This fluid sac gradually enlarges superiorly to present as a ganglion on top of the AC joint. It is important to recognize that the underlying pathology is not localized to the AC joint but reflects the more difficult problem of a full-thickness tear that is usually large. Palpation of the affected shoulder not uncommonly reveals AC tenderness especially if AC arthrosis is present. There is usually a palpable subdeltoid soft crepitation, which may represent a subacromial bursal fluid, a thickened bursa, or a torn tendon moving under the coracoacromial arch. A patient with subacromial impingement syndrome without rotator cuff tearing may have normal passive range of motion; however, it is not uncommon for a mild frozen shoulder to accompany this syndrome. In the latter case, there is usually some restriction of motion passively in forward elevation, external rotation, and internal rotation. In the presence of a fullthickness rotator cuff tear, passive range of motion is often remarkably normal, as joint fluid leaks out and lubricates the subacromial space.

On physical examination, a number of impingement signs are usually positive and are very helpful in documenting the diagnosis of subacromial impingement. These include a positive painful arc as the arm is lowered to the side from the fully overhead position, the classic impingement sign, pain with abduction in the plane of the scapula, and pain with internal rotation up behind the back. There may or may not be pain with resisted external rotation and resisted abduction. Active range of motion may be normal or may be reduced. A discrepancy between active and passive motion is highly suggestive of full-thickness disruption of the rotator cuff. A classic and most convincing clinical sign of a full-thickness cuff tear is weakness with external rotation. This is tested with the arm at the side and the elbow flexed to 90 degrees. Both arms may be tested simultaneously. It is common, even in the presence of an isolated supraspinatus tear, to have demonstrable weakness of external rotation. The patient often can distinguish between lack of strength and the need to “let go” secondary to pain. In the larger tears of the rotator cuff, the patient often has so much external rotation weakness that he or she can neither initiate active motion of the arm nor maintain the arm in a position of external rotation in which it has been passively placed. In addition, a “lift-off” test has been described: The arm is brought behind the back, and an attempt is made to lift the hand off the small of the back. Inability to do this is highly suggestive of a subscapularis tear.

An alternative lift-off test for subscapularis insufficiency is the abdominal compression or “belly press” test, in which the hand is placed on the abdomen, the elbow is placed away from the side of the body and paramount to the hand, and the hand is pressed on the abdomen. Subscapularis insufficiency will result in the failure to maintain the elbow in the frontal plane, as the elbow folds into the side because of lack of internal rotation strength.

One of the most helpful radiographs in the diagnosis of subacromial impingement syndrome is an anteroposterior (AP) view of the shoulder in external rotation, which often reveals cystic changes, sclerosis, or bone reaction in the area of the greater tuberosity of the humerus. In addition, a subacromial traction spur may be identified and associated AC joint pathology may be present, as reflected by cystic changes, joint narrowing, or osteophyte formation. In the larger tears, this view often shows changes in the acromiohumeral interval, and in the most massive tears of long-standing duration, arthritic changes may be identified. Another AP view, with a 30-degree caudal tilt, will often more specifically show the anterior acromial spur; this view is used to outline the amount of acromion that projects anterior to the anterior edge of the AC joint, thought to be that amount of acromion pathologically projecting inferiorly. A lateral radiographic view of the scapula and acromion, with a 20-degree caudal tilt, has been termed the “outlet” view. This is intended to identify any bone projecting downward into the supraspinatus outlet, that space through which the supraspinatus passes. This view often identifies inferior protrusion of the acromion and the undersurface of the clavicle, and it may outline the shape of the acromion or an unfused acromial epiphysis. A supine axillary view is perhaps best to identify glenohumeral joint narrowing and the presence of an unfused acromial epiphysis. In a patient who has undergone previous surgery, this view also can reveal the amount of acromion that remains (Fig. 25-2).

If a rotator cuff tear is suspected, any one of a number of imaging studies may be utilized. The most common are arthrography, ultrasonography, and MRI. Arthrography is easily interpretable and can clearly define the presence or absence of a rotator cuff tear. Its disadvantages include that it is invasive, its helpfulness is usually limited to the identification of full-thickness tears only, and it rarely gives information about the quality of the tendon or the precise location of the tendons that are torn. Ultrasonography has been used to identify fullthickness tears, but it may have difficulty revealing small tears. In addition, small tears, partial tears, and even degenerative and scarred tissue may look similar. The reproducibility and high degree of accuracy that have been reported at some centers in this country and in Europe have not been uniformly reproduced in community hospitals and centers with less experience.

Although an MRI scan clearly gives the highest quality image of the shoulder and precise information about the extent and location of the tendon tear (Fig. 25-3) and may give information about associated biceps instability and associated muscle atrophy or fatty infiltration, its disadvantages include the fact that the patient may become claustrophobic and movement may interfere with MRI quality. In addition, the cost of an MRI scan is substantially greater than either of the other two imaging methods. However, for the most information and the clearest prognosis about surgical treatment and anticipated results, I prefer an MRI scan of the shoulder to identify the cuff pathology. For identification of tear extent, quality of remaining tissue, degree of muscle damage, and extent of associated pathology, there is no test that compares with a well-done and interpreted MRI, with or without contrast.

If a full-thickness rotator cuff tear has been documented, I tell the patient the following:

The operation is done under either interscalene regional anesthesia or general anesthesia. Interscalene regional anesthesia can also be used in combination with endotracheal anesthesia for postoperative pain management.

In a mini-open rotator cuff repair, standard arthroscopic positioning, portals, and techniques are used for the complete glenohumeral joint inspection, as well as débridement of loose and torn tendon edges, greater tuberosity preparation, and arthroscopic subacromial decompression. After completion of the arthroscopic decompression, if minimal exposure is required, the standard lateral portal may be extended, subcutaneous flaps developed, and the deltoid split without detachment. With the rotation of the humerus, the torn supraspinatus can be brought into view and the standard repair accomplished with bone tunnels or suture anchors as a single or double row. My preference, however, even if a mini-open repair is going to be done using a deltoid split, is to use a standard anterior oblique incision similar to that described for the open technique. This places the incision in Langer lines and is more cosmetic than the extension of one of the arthroscopic portals (12).

Once anesthetized, the patient is placed in a beach-chair position. The head is secured to the operating table and tilted slightly away from the affected shoulder, which helps provide space for retractors. A rolled-up towel is placed along the medial border of the scapula to stabilize it. The patient is positioned so that a line along the superior cortex of the acromion is perpendicular to the floor. In this way, during the acromioplasty, the osteotome or oscillating saw will be directed perpendicular to the floor, thus ensuring that the undersurface of the acromion will indeed be flat. The arm is draped free (Fig. 25-4). The hand is
covered with an elastic bandage or stockinette, up to the elbow. Prominent anatomic landmarks, such as the coracoid process, AC joint, posterolateral corner of the acromion, and lateral edge of the acromion, are identified.

The skin incision extends from just lateral to the coracoid process over the anterolateral corner of the acromion, ending just lateral to the acromion at a point halfway between the anterior and posterolateral corners of the acromion (Fig. 25-5). The length of the skin incision is typically 6 cm. The skin and subcutaneous tissue are infiltrated with a 1 to 500,000 concentration of epinephrine, which will minimize skin and subcutaneous bleeding (Fig. 25-6). Injecting the epinephrine solution in the area of the coracoacromial ligament and the AC joint also helps control troublesome bleeding in these areas. The subcutaneous tissue is divided down to the fascia investing the deltoid muscle (Fig. 25-7). It is helpful to avoid cutting into the fascia of the deltoid muscle, as this fascial envelope helps hold sutures for secure deltoid reattachment and minimizes fragmentation of the deltoid muscle during retraction. Flaps are developed in such a way that the entire superior AC joint may be palpated superiorly. They are undermined as far as the posterolateral corner of the acromion, and the anterior flap is undermined to a distance of at least 5 cm, which is the distance the deltoid muscle will be split. The deltoid muscle is split along the lines of its fibers in one of two areas. One split, in the raphe between the
anterior and middle deltoid, gives excellent exposure of the posterior cuff and is the direction of the split if the tear involves supraspinatus and infraspinatus tendons. If the tendon tear involves the subscapularis, particularly if the tear is large and retracted, I will often split the tendon instead at the level of the AC joint in line with its fibers. The split begins at a point on the anterior surface of the AC joint and extends distally a distance of approximately 5 cm (Fig. 25-8). Limiting the distance of the deltoid split to 5 cm avoids injuring the terminal branches of the axillary nerve. A no. 1 Tevdek suture marks the distal-most split in the deltoid so that during deltoid retraction the split will not be propagated. The deltoid muscle is bluntly dissected in line with its fibers through this 5-cm distance, until the whitish yellow bursa layer is identified. Bleeding is often present in the most proximal portion of the wound and is usually easily handled with electrocauterization. Adhesions under the deltoid often prevent insertion of retractors. It is usually helpful to use a blunt instrument or an index finger to break up adhesions under the medial and lateral deltoid flaps, so that retractors can be placed beneath the deltoid muscle. Deep fasciae of the deltoid often invest and adhere to the superior surface of the coracoacromial ligament. Using a sponge and a blunt retractor to sweep this off the coracoacromial ligament will isolate and identify this ligament for clear division or excision (Fig. 25-9). The acromial branch of the thoracoacromial artery crosses the top portion of the coracoacromial ligament. Identification and cauterization of this troublesome bleeder before division of the ligament is helpful. The ligament is identified, isolated, and completely excised. Care must be taken to make sure that both anterior and posterior bands of the coracoacromial ligament are removed. This is done by clamping the coracoacromial ligament and using electrocautery or scissors along the lateral edge of the coracoid process to divide this ligament all the way to the base of the coracoid process (Fig. 25-10). Removal of the coracoacromial ligament can then be completed by retracting the deltoid out of the way and removing the ligament from the undersurface of the acromion.