The clinical presentation of patients with a subscapularis tear can be quite variable, depending largely upon the etiology and chronicity of the injury. In the case of an acute traumatic subscapularis tear, the patient will often report a traumatic external rotation and/or hyperextension force with the arm in an adducted position, with nearly half of these being sports related [2, 6]. Nearly all of these patients will report anterior shoulder pain with activities of daily living both above and below the level of the shoulder and weakness in the affected shoulder. Seventy percent will have anterior shoulder night pain, and 50 % will report inability to work secondary to their pain [2].

In the majority of patients, a subscapularis tear will present in the setting of a massive rotator cuff tear with concurrent involvement of the supraspinatus and possibly infraspinatus tendons as well. These are often chronic and degenerative in nature and will often present with a constellation of symptoms indistinguishable from that of a standard rotator cuff tear.

Another subset of patients with subscapularis tears will have experienced recurrent anterior shoulder dislocations; thus, it is important to ascertain this history during the clinical interview as well. It is important to maintain a high level of suspicion for subscapularis tendon involvement in each of these subsets of patients as it has been shown that there is often a significant delay in diagnosis resulting in interval degeneration, atrophy, fatty infiltration, and tendon retraction, all of which have direct implications on the reparability of the tear and overall outcome [8–11].

As with any orthopedic physical examination, evaluation of the shoulder in a patient with suspected subscapularis disease should proceed in a logical, organized, and efficient manner directed at elucidating the underlying pathology. It should always include a comparison to the contralateral side. It should proceed through inspection, palpation, assessment of both passive and active range of motion, and assessment of joint stability, followed by strength and provocative testing.

As stated previously, patients with subscapularis tears will frequently have anterior shoulder pain that worsens with activity both above and below the level of the shoulder; however, this is neither sensitive nor specific for subscapularis pathology. Patients with a subscapularis tear associated with recurrent glenohumeral instability will be expected to have physical examination findings consistent with instability such as a positive apprehension and Jobe relocation test and possibly a positive sulcus sign. Additionally, when examining a patient with shoulder complaints, the examining physician must also consider the possibility of cervical spine disease manifesting as shoulder pain and/or weakness. The patient should be examined in a gown with both shoulders exposed. Inspection may reveal atrophy of the anterior shoulder with asymmetry to the contralateral side. Prior surgical incisions should be noted (Fig. 8.2). Scapular mechanics with elevation and abduction should be noted with attention to any dyskinesis, winging, or compensatory scapular motion patterns. Palpation of the lesser tuberosity or bicipital groove may elicit pain in the setting of subscapularis injury with or without biceps involvement.

The majority of physical examination tests directed at evaluating a possible subscapularis tear come in the form of range of motion and strength testing. Frequently patients with a complete subscapularis tear will exhibit increased passive external rotation compared to the contralateral shoulder [6]. Loss of the integrity of the subscapularis as a restraint to excessive external rotation is responsible for this finding, and this may be subtle or nonexistent in partial tears or in patients with concurrent degenerative conditions.

A number of specific examination tests have been described to assess subscapularis integrity. The most common of these tests are the lift-off test, internal rotation lag sign, the belly-press test, the belly-off sign, and the bear-hug test [6, 22, 42–46]. The lift-off test described by Gerber and Krushell [6] evaluates the subscapularis by placing the dorsum of the hand on the side of the affected shoulder onto the patient’s lumbar spine and asking the patient to actively lift the hand off the back in a posterior direction by further internally rotating the arm. A positive test indicates the patient’s inability to do so and suggests weakness of the subscapularis as the primary internal rotator of the humerus (Fig. 8.3). The internal rotation lag sign described by Hertel et al. [44] begins with the patient in a similar position. The examining physician then stabilizes the elbow and the dorsum of the hand while further internally rotating the arm by lifting the hand off of the patient’s back. The patient is then asked to maintain this position as the examiner releases the hand. The test is considered positive if the patient is unable to maintain this position (Fig. 8.4). Multiple variations of the belly-press test have been described [42, 47, 48]. In general, this test is performed by having the patient place both hands flat on the abdomen with the elbow close to the body in 90 degrees of flexion. The patient is then asked to press in against the abdomen while bringing the elbow forward while maintaining a straightened posture of the wrist (Fig. 8.5). Depending on the variation used, the test can be considered positive if there is (1) asymmetry in the amount of anterior movement of the elbow (less forward movement indicating subscapularis weakness), (2) less posteriorly directed force into the abdomen (as measured by a tensiometer), (3) clinical evidence of elbow and or shoulder extension while performing the maneuver (as compensation for subscapularis weakness), or (4) differences in the wrist flexion angle at the terminus of the maneuver (as measured by a goniometer, with the pathologic side showing greater wrist flexion). This final variation has been described as the Napoleon sign, named as such based upon the position in which Napoleon Bonaparte held his hand in multiple portraits [49, 50]. The belly-off sign, described by Scheibel et al. [46], begins with the patient in a similar position to that of the belly-press test. The examiner then supports the elbow with one hand and brings it into a position of maximum internal rotation by bringing the elbow forward while stabilizing the palm of the patient’s hand against the abdomen. The examiner then asks the patient to actively maintain that position while releasing the patient’s hand. An inability to maintain the palm against the abdomen, or wrist flexion as a compensatory mechanism, constitutes a positive test. The bear-hug test, described by Barth et al. [22], is performed by placing the palm of the affected shoulder on the contralateral shoulder with the elbow pointed anteriorly and the humerus in 90 degrees of forward flexion. The examiner applies an external rotation force to the arm by attempting to lift the hand off the shoulder while asking the patient to actively resist this force. An inability to resist this force implies subscapularis weakness and thus constitutes a positive test (Fig. 8.6).

Numerous studies have evaluated the diagnostic value of these clinical tests. In an electromyographic study, Pennock et al. [45] evaluated the effect of arm and shoulder position on isolating the subscapularis from the remainder of the cuff musculature as well as differential activation of the upper and lower subscapularis while performing the bear-hug, belly-press, and lift-off tests. They concluded that the level of subscapularis activation was similar for all three tests regardless of arm position, with each being significantly greater than that of the other rotator cuff muscles. Furthermore, they found that shoulder and arm positioning did not produce significantly different results between the upper and lower divisions of the subscapularis within and between each of the three tests. Bartsch et al. [51] examined 50 consecutive patients who were scheduled to undergo shoulder arthroscopy, subjecting them to the lift-off test, internal rotation lag sign, belly-press test, and belly-off test. The clinical exams were then compared to the arthroscopic findings. They concluded that the most sensitive tests were the belly-press test and belly-off tests (88 % and 87 %, respectively), the most specific test was the belly-off test (91 %), and the most accurate test being the belly-off test (90 %). Fifteen percent of subscapularis tears were not detected by any of the aforementioned tests, although it is worth noting that the majority of the tears in this study were partial thickness in nature. Rigsby et al. [52] performed a systematic review of the available literature from which pooled indices regarding the diagnostic value of the lift-off test, internal rotation lag sign, Napoleon sign, bear-hug test, belly-off test, and belly-press test were developed specifically as they relate to full-thickness subscapularis tears. They concluded that the Napoleon sign (sensitivity 98 %, specificity 97 %), internal rotation lag sign (sensitivity 98 %, specificity 94 %), and lift-off test (sensitivity 94 %, specificity 99 %) were all clinically useful tests for ruling in and ruling out full-thickness subscapularis tears. There is no literature examining the diagnostic value of these physical examination findings as they relate to irreparable subscapularis tears.

As with most orthopedic evaluations, imaging studies often start with plain radiographs. Three views, including an AP in the scapular plane, an axillary lateral, and a scapular-Y, should be obtained and are generally normal in patients with subscapularis tears. Chronic tears, especially those associated with anterior glenohumeral instability, may demonstrate anterior subluxation on the axillary lateral radiographs, but this is neither sensitive nor specific for a subscapularis tear. In patients with massive rotator cuff tears, which sometimes include the subscapularis, one may see a high-riding humeral head relative to the glenoid and narrowing of the acromiohumeral space. In patients with chronic massive rotator cuff tears, there may be degenerative changes noted on plain radiographs such as joint space narrowing, subchondral sclerosis, rimming inferior osteophytes, and potentially signs of rotator cuff tear arthropathy such as superior glenoid wear and acetabularization of the undersurface of the acromion.

Ultrasound has increased in popularity as an imaging modality for visualizing the rotator cuff and diagnosing related pathology. It is relatively inexpensive, noninvasive, and allows for easy comparison to the contralateral shoulder. Teefey et al. evaluated the accuracy of ultrasound compared to arthroscopy in detecting rotator cuff lesions and reported 100 % sensitivity and 85 % specificity in detecting all rotator cuff tears, and accurately diagnosed 6 of 7 subscapularis tears [53]. These results approach those reported by MRI; however, the ability to accurately quantify the size and depth of partial-thickness tears as well as the ability to distinguish between partial- and full-thickness tears is often called into question; thus the role in ultrasound as a routine imaging modality for diagnosing rotator cuff pathology remains undefined.

MRI is the imaging modality of choice for diagnosing and characterizing rotator cuff tears, including those of the subscapularis. CT arthrogram can be utilized in those unable to undergo MRI. MRI arthrography has been shown to be superior to standard MRI for the diagnosis of rotator cuff tears [54] as has fat-saturated imaging versus standard sequences [55]. Abnormally high signal in the subscapularis tendon on T2-weighted imaging, disorganized tendon morphology, frank disruption of the subscapularis tendon, contrast leakage onto the lesser tuberosity during arthrography, subscapularis muscle belly atrophy and/or fatty infiltration, and medial subluxation of the biceps tendon from the bicipital groove are all well-accepted MRI findings that should alert the physician as to a possible subscapularis tear (Fig. 8.7a–c). In a study on traumatic tears of the subscapularis, Deutsch et al. reported medial subluxation of the biceps tendon on MRI in 46 % of full-thickness tears [2]. A recent study, Jung et al. [56], described a new MRI arthrography finding, coined the “bridging sign,” that was highly correlated with full-thickness tears of the subscapularis that also involved at least the anterior half of the supraspinatus. This sign is described as a band-like structure on axial cuts of low to intermediate signal intensity on all sequences that connects the superior margin of the subscapularis to the inferior margin of the supraspinatus through the subcoracoid and subacromial space. It is thought to be the MRI correlate to the arthroscopic “comma sign” as described by Burkhart et al. [49]. For full-thickness subscapularis tears that also involved the anterior half of the subscapularis, the bridging sign was found to have 81 % sensitivity, 100 % specificity, and 86.2 % accuracy [56].

Unlike physical examination and plain radiography, MRI lends critical information regarding the status of the torn tendon and whether it is a repairable injury or likely to require a salvage procedure. While the true and definitive determination of the reparability of a subscapularis tear occurs with intraoperative assessment, advanced imaging studies such as MRI often shed considerable light on the subject preoperatively, allowing the surgeon to begin planning accordingly. No consensus exists regarding what constitutes an irreparable subscapularis tear on MRI; however, some general concepts are routinely applied. Muscle belly atrophy, fatty infiltration, tear size, and degree of tendon retraction have all been shown to be associated with worse clinical outcomes and increased re-tear rates after primary repair of the rotator cuff [8–11]. This has led some surgeons to utilize these findings to various degrees as potential indicators of irreparability. Warner et al. [7] described a grading system to evaluate the amount of subscapularis muscle atrophy on MRI. Their system utilizes T1-weighted sagittal oblique MRI sequences medial to the coracoid process. A line is drawn from the tip of the coracoid process to the inferior tip of the scapular body to define the fossa, and subscapularis muscle belly atrophy is graded as follows: (1) no atrophy – muscle belly fills the fossa and the outer contour is convex in nature; (2) minimal atrophy – muscle belly outer contour is flat with respect to the fossa; (3) moderate atrophy – muscle belly outer contour is concave and does not completely fill the fossa; and (4) severe atrophy – muscle belly is barely evident in the fossa.

Goutallier et al. [8] first described a staging system utilizing axial CT scan to characterize the degree of rotator cuff fatty infiltration. This was divided into five stages: stage 0 – indicating normal muscle; stage 1 – muscle has some fatty streaks; stage 2 – fatty infiltration is important, but more muscle than fat; stage 3 – as much fat as muscle; and stage 4 – more fat than muscle is present. This staging system was later adapted for MRI by Fuchs et al. who evaluated fatty infiltration in the same manner using the most lateral parasagittal MRI cut in which the scapular spine is attached to the scapular body [57]. The evaluation of subscapularis tendon retraction is relatively straightforward and best evaluated on axial imaging. Most of the literature regarding irreparable subscapularis tears utilizes MRI characteristics as inclusion criteria. Generally speaking, subscapularis tears with Goutallier stage 3 or 4, fatty infiltration, and ± subscapularis tendon retraction to the level of glenoid rim are considered irreparable [8–11, 58]. As stated previously, the definitive and final determination of subscapularis reparability is determined intraoperatively.

Pectoralis major transfer for an irreparable anterosuperior rotator cuff tear was first described by Wirth and Rockwood in 1997 [18]. Wirth and Rockwood’s original indications for pectoralis major transfer were patients with recurrent anterior instability in the setting of an irreparable subscapularis tear [18]. Pectoralis major transfer has since been reported by multiple authors as a treatment of irreparable anterosuperior rotator cuff tears [13, 17, 18]. Several modifications of the original technique have subsequently been described, with no study to show the superiority of one method over the others. The indications always include an irreparable subscapularis tear and generally have either anterior instability [13, 18] or significant functional limitations and pain as features precipitating surgical intervention [17, 59]. Pectoralis major transfers have been performed in patients with isolated subscapularis ruptures and those with a concomitant supraspinatus tear; several studies have shown that transfers in the setting of both subscapularis and supraspinatus tears have inferior outcomes when compared to isolated irreparable subscapularis ruptures [15]. This has led some authors to consider irreparable subscapularis tears in the setting of an irreparable supraspinatus tear to be a relative contraindication to pectoralis major transfer [15]. Other contraindications include advanced patient age (>65), glenohumeral joint arthrosis, fixed anterior joint subluxation, an inability to comply with postoperative measures and rehabilitation, and obviously pectoralis major dysfunction or insufficiency.

The initial management of a massive rotator cuff tear should be a nonsurgical, multifaceted approach. Formal physical therapy, aimed at deltoid and periscapular strengthening, is a key component [60]. Nonsteroidal anti-inflammatories should be used in patients without a contraindication. Corticosteroid injections into the subacromial space or glenohumeral joint can be an adjunct, especially in conjunction with physical therapy.

If nonoperative management has failed, it is first important to differentiate between a “massive” and an “irreparable” rotator cuff repair as these terms are often mistakenly used interchangeably. Not all massive tears are irreparable and several classification systems have been described to help surgeons determine which of these larger tears will be ultimately reparable. Cofield et al. originally classified rotator cuff tears based solely on size, with massive tears being greater than 5 cm in diameter [61]. Gerber later identified massive tears as those involving two or more tendons [62]. The pragmatic definition of an irreparable rotator cuff tear is one where the quality and/or mobility of the tendon does not allow for direct repair to bone. This further differentiation to an irreparable tear is more difficult and generally related to three factors: retraction, atrophy, and fatty infiltration. Goutallier et al. attempted to quantify fatty infiltration by classifying the rotator cuff muscle based on CT findings [8]. The authors also noted a direct correlation between the amount of fatty infiltration and muscular atrophy. Multiple studies have validated the use of the Goutallier classification in MRI studies [57]. The exact cutoff for the amount of fatty infiltration before a rotator cuff tear is irreparable is unknown, but many authors believe Goutallier stage 3 or 4 (50 % or greater fatty infiltration) suggests an irreparable tear [58]. Acromiohumeral distance, measured on plain radiographs of the shoulder, can also be a tool in determining if a RCT is repairable. It has been noted that an acromiohumeral distance of less than 7 mm is suggestive of an irreparable tear [63].

Several other surgical treatment options are available for patients with massive rotator cuff tears including debridement or partial rotator cuff repair. Debridement alone will only offer improvement in pain and no strength or functional improvement, and the durability of this pain relief is thought to be limited [64]. Burkhart et al. found that partial rotator cuff repair can provide improvements in both pain and function [65]. The obvious prerequisite for this option is having some of the rotator cuff muscle and tendon amenable for partial repair; in the setting of a ruptured subscapularis with significant atrophy and fatty infiltration, this is not always possible. In patients who present with chronic anterior-superior instability, reconstruction of the coracoacromial arch has been described, but results have been unsatisfactory in the majority of patients [66]. Another option, in lower demand and more elderly patients, is reverse total shoulder arthroplasty. Early and intermediate outcomes appear promising, but long-term results are not known at this time [67]. For many patients with subscapularis insufficiency, this is not a great option due to age and functional demands.