Rotator Cuff Injury Case File

Rotator Cuff Injury Case File

Eugene C. Toy, MD, Andrew J. Rosenbaum, MD, Timothy T. Roberts, MD, Joshua S. Dines, MD

CASE 21

An otherwise healthy, right-hand-dominant, 25-year-old man is seen in the emergency department after slipping on the front steps of his house 2 days ago. He states that he landed on an outstretched right upper extremity and immediately began experiencing shoulder pain. He has been unable to move his shoulder since the fall and has had his arm in a sling that a friend gave him. On physical exam, you note no ecchymosis, abrasions, or any other deformity. However, shoulder range of motion, especially internal rotation, is significantly limited. Anteroposterior, axillary, and scapular-Y radiographs of his right shoulder reveal no abnormalities. The patient is most concerned about his ability to return to his competitive tennis league by next week, as he is playing for the club championship.

► What is the most likely diagnosis?

► What are the imaging studies of choice for evaluating this patient’s problem?

► What is the most appropriate treatment for this patient?

ANSWER TO CASE 21:

Rotator Cuff Injury                              

Summary: An otherwise healthy and active 25-year-old man slips and lands on his right shoulder. He is unable to raise his arm and has limited active range of motion. Neurovascular examination is normal. Radiographs are negative for a fracture and dislocation.

• Most likely diagnosis: Acute tear of the rotator cuff.
• Imaging studies of choice: Plain radiographs must always be obtained first in the setting of acute trauma to the shoulder, as has been done here. When rotator cuff tear (RCT) is suspected, magnetic resonance imaging (MRI) should also be performed. It is extremely accurate (93%-100%) in detecting full-thickness tears and can evaluate tear size, tendon retraction, muscle atrophy, and related intraarticular pathology. However, it cannot be used in patients with pacemakers, aneurysm clips, metal in the eye, or other metal implants within the body.
• Treatment: The appropriate treatment for an acute, full-thickness RCT in an otherwise healthy and physically active young patient is primary repair.

ANALYSIS

Objectives

1. Understand rotator cuff anatomy.
2. Properly diagnose a rotator cuff tear.
3. Be familiar with treatment options for rotator cuff tears.

Considerations

This 45-year-old man sustained an injury to his right shoulder after slipping on his front steps. He presents with pain and weakness of the right shoulder in the setting of normal radiographs. This constellation of findings is concerning for an acute RCT.

    A complete history and physical exam of the neck and involved extremity must be done. Although active range of motion is typically decreased because of pain and/or weakness, passive range of motion is expected to be normal. Shoulder strength in elevation, abduction, external rotation, and internal rotation should be assessed, and specific provocative maneuvers can be performed to evaluate the individual muscles of the rotator cuff ( Table 21–1 , Figure 21–1 ).

    An MRI, which is the gold standard for diagnosis of RCTs, should be obtained (Figure 21–2). However, if a contraindication to MRI exists, an arthrogram or ultrasound can be done. MRI in this patient will confirm an RCT. Given the patient’s described mechanism of a hyperabduction/external rotation injury during a fall, he has likely torn his subscapularis tendon.

    Although nonoperative management is appropriate for some people, this patient will benefit from a rotator cuff repair, as he is young and active.

Figure 21–1. The empty can test, which evaluates supraspinatus pathology. (Reproduced, with permission, from Tintinalli J, et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York, NY: McGraw-Hill; 2010:Fig. 277-5.)

Figure 21–2. Rotator cuff tear. MRI coronal image of the shoulder reveals a tear in the supraspinatus

tendon (arrow) with edema (arrowhead). (Reproduced, with permission, from Tintinalli J, et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York, NY: McGraw-Hill; 2010:Fig. 277-7.)

APPROACH TO:

Rotator Cuff Tears                                 

DEFINITIONS

ROTATOR CUFF: A confluence of 4 muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) that arise from the scapula and insert on the humeral head. The main functions of the rotator cuff are to stabilize the glenohumeral joint and to rotate the humerus outward.

ROTATOR CUFF TEAR: A common cause of shoulder pain that can involve an individual tendon or a combination of tendons. The supraspinatus is the most commonly torn rotator cuff tendon.

ROTATOR CUFF ARTHROPATHY: A condition of the shoulder in which glenohumeral arthritis develops secondary to a chronic, irreparable rotator cuff tear. It is typically seen in older individuals with loss of shoulder motion and strength.

SUBACROMIAL IMPINGEMENT: Term used to describe the process and continuum by which rotator cuff tendons become irritated and inflamed as they pass through the subacromial space. This is secondary to impingement of the humeral head and rotator cuff beneath the coracoacromial (CA) arch of the shoulder. With the arm in neutral position, the greater tuberosity (where the supraspinatus inserts) lies anterior to the CA arch. With forward flexion and internal rotation, the subacromial bursa and supraspinatus tendon become entrapped between the anterior acromion/coracoid and greater tuberosity.

Figure 21–3. Posterior view of the shoulder illustrating rotator cuff muscles. (Reproduced, with permission, from Tintinalli J, et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York, NY: McGraw-Hill; 2010:Fig. 277-1.)

CLINICAL APPROACH

Shoulder Anatomy and Biomechanics

The shoulder complex is comprised of the glenohumeral (GH), sternoclavicular (SC), acromioclavicular (AC), and scapulothoracic (ST) joints ( Figures 21–3 and 21–4 ). There is a 2:1 ratio of shoulder motion between the GH and ST joints (ie, 180 degrees of abduction consists of 120 degrees of GH motion and 60 degrees of ST motion). Both static stabilizers (ie, bony structures, labrum, joint capsule, ligaments) and dynamic stabilizers (ie, rotator cuff, periscapular muscles) help in maintaining congruity and providing GH joint stability. Static stabilizers can function in the setting of intrinsic muscle damage and neuromuscular injury, whereas the dynamic stabilizers cannot. Table 21–2 outlines the muscles vital to shoulder function.

Figure 21–4. Anterior view of the shoulder illustrating the supraspinatus muscle and the long head

of the biceps. (Reproduced, with permission, from Tintinalli J, et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York, NY: McGraw-Hill; 2010:Fig. 277-2.)

    The rotator cuff helps to maintain a stable fulcrum for shoulder motion via its role as a dynamic stabilizer of the glenohumeral joint. The cuff balances the force couples in the coronal and transverse planes. In the coronal plane, the inferior rotator cuff (infraspinatus, teres minor, subscapularis) balances the support moment created by the deltoid. In the transverse plane, the anterior cuff (subscapularis) functions to balance the moment created by the posterior cuff (infraspinatus and teres minor).

Etiology

The incidence of RCTs ranges from 5% to 40% and increases with age. Of note, 55% of asymptomatic patients ≥ 60 years of age will have rotator cuff pathology evident on MRI. RCTs should be thought of as part of a continuum of disease involving the shoulder. The continuum includes subacromial impingement, subcoracoid impingement, calcific tendonitis, rotator cuff tears, and rotator cuff arthropathy.

    Tears can be acute, iatrogenic, or secondary to chronic degenerative changes. Acute avulsion injuries include subscapularis tears in younger patients after a fall and supraspinatus, infraspinatus, and/or teres minor tears in those older than 40 years after a shoulder dislocation. Overhead throwing athletes are susceptible to cuff tears secondary to the high tensile forces that the rotator cuff is subjected to during the deceleration phase of throwing. Iatrogenic injuries are commonly seen after repair failure of the subscapularis tendon after an open anterior shoulder surgery. Chronic degenerative tears are seen in older patients and typically involve the supraspinatus, infraspinatus, and/or teres minor.

Presentation and Diagnosis

Patients with RCT present either after an acute trauma and inability to move the arm and shoulder (ie, shoulder dislocation or fall) or with the insidious onset of symptoms such as night pain and difficulty performing overhead activites. Physical examination of the shoulder should begin with inspection of the skin for scars, atrophy, swelling, droop, and scapular winging. Palpation of the bony prominences and muscles of the shoulder girdle should be done next. The patient should then be placed supine, at which time active and passive range of motion of both shoulders is assessed. Planes of motion to be evaluated include forward elevation (150-180 degrees is considered normal), abduction, internal rotation to vertebral height (T4-8 is considered normal), internal rotation at 90 degrees of abduction, external rotation at side, and external rotation at 90 degrees of abduction. A neurovascular exam of the entire upper extremity should also be done, as should the specific tests that isolate the individual muscles of the rotator cuff ( Table 21–1 ).

    Imaging studies are ordered based on the findings from the history and physical exam, with plain radiographs the first ones obtained. Findings on plain x-ray associated with rotator cuff pathology include calcific tendonitis, proximal migration of the humerus (seen with chronic RCT), or a hooked acromion. MRI, when obtained, evaluates muscle quality and the tear size, tear shape, and degree of tendon retraction. Other findings on MRI consistent with RCT include muscle atrophy, medial biceps tendon subluxation (indicative of a subscapularis tear), and cysts in the humeral head (seen in the majority of patients with a chronic RCT).

Classification

Classification of cuff tears can be done based on anatomical location, tear size, amount of cuff atrophy, tear shape, thickness, and chronicity. Partial-thickness tears often appear as fraying of an intact tendon, whereas full-thickness tears are through-and-through. These can be small pin-point defects, large buttonhole tears (the tendon still remains attached to the humeral head and thus retains function), or tears in which the tendon is completely detached from the humeral head. When classified by chronicity, they can be described as acute (due to a sudden, powerful movement or trauma), subacute, or chronic (develops over a longer period of time, seen in individuals who frequently participate in overhead activities).

TREATMENT

Rotator cuff tears can be managed via both operative and nonoperative means. The patient’s age, activity level, overall health, cuff status (ie, size and age of tear, amount of retraction, muscle quality), and presence of GH arthritis must be considered when determining the best treatment for a given patient. In general, young, active patients presenting with an acute tear and a primary complaint of weakness are best treated with early surgical repair, whereas older patients complaining of pain in the setting of chronic, degenerative tears are most responsive to nonoperative treatment.

    Nonoperative treatment includes nonsteroidal anti-inflammatory drugs, (NSAIDs), activity modifications, subacromial corticosteroid injections, and physical therapy. Corticosteroid injections into the subacromial space are done with failure of other conservative modalities for greater than 4 to 6 weeks. The goal of these injections is to decrease pain. They may be repeated after several months if initially effective. However, the patient should receive no more than 3 injections per year. Physical therapy focuses on aggressive rotator cuff and periscapular muscle strengthening.

    Operative repair of an RCT can be done through either open or arthroscopic approaches, which have been shown to have equivalent results. With both techniques, the goal is to restore the native tendon(s) insertional footprint area on the tuberosities. It is thought that a larger, more anatomic footprint improves healing and the mechanical strength of the repair. Biologic healing of the cuff is estimated to take approximately 8 to 12 weeks; this is the rate-limiting step for recovery. Anatomic footprint restoration is often achieved with double-row suture techniques. Of note, animal models have failed to show increased repair strength with the addition of a trough in the greater tuberosity.

    Complications after rotator cuff repair include recurrence, deltoid detachment (with open procedures), acromiclavicular joint pain, axillary nerve injury, and suprascapular nerve injury. Worker’s compensation patients report worse outcomes with higher postoperative disability and lower satisfaction.

    There are several procedures that may be performed at the time of rotator cuff repair or as independent operations before repair. Subacromial decompression is done if impingement is thought to have contributed to tendon irritation and tearing. AC joint resection is performed via distal clavicle excision in patients whose AC joint is tender to palpation and painful. A long head of the biceps tenotomy (detachment of the tendon origin from the labrum or glenoid) or tenodesis (releasing of the tendon origin and suturing it to the proximal humerus) is done in patients with a symptomatic biceps tendon.

    Irreparable and massive rotator cuff tears require special consideration. In patients with this but an otherwise normal GH joint, tendon transfer can be performed with the goal of restoring overhead function. For irreparable or chronic subscapularis tears, pectoralis major transfer is performed. For large tears of the supraspinatus and infraspinatus, a latissimus dorsi transfer is performed. In this procedure, the latissimus is attached to the cuff muscles, subscapularis, and greater tuberosity. The given extremity is then immobilized in a brace for 6 weeks in 45 degrees of abduction and 30 degrees of external rotation. Of note, the best candidate for a latissimus dorsi transfer is a young laborer.

COMPREHENSION QUESTIONS

21.1 A 45-year-old man has a fall from his motorcycle and is complaining of shoulder pain. Radiographs are negative for fracture and dislocation. On exam, you note a positive lift-off test. What is the most likely diagnosis?

A. Teres minor tear

B. Supraspinatus tear

C. Infraspinatus tear

D. Subscapularis tear

21.2 An 80-year-old man sustained an anterior shoulder dislocation 2 weeks ago. He was reduced in the emergency department acutely and has been treated in a sling by his primary care physician. Radiographs after reduction appear normal. He now presents with severe pain and weakness of his shoulder. What is the most likely diagnosis?

A. Continued anterior subluxation of the humerus

B. Rotator cuff tear

C. Cervical spine radiculopathy

D. Proximal humerus fracture

21.3 A 65-year-old woman presents to the clinic complaining of worsening pain in her left shoulder that is most severe at night. She is an avid swimmer and states that she has been unable to swim for the last 3 weeks because of the pain. She denies any recent trauma and has brought plain radiographs of her shoulder in 3 views (ordered by her internist) with her, which are negative. You suspect a torn rotator cuff and order an MRI. However, the patient tells you that she cannot have one, due to her pacemaker. Which of the following imaging modalities is the most appropriate for this patient?

A. Ultrasound

B. PET scan

C. Arthrogram

D. Additional plain radiographs

ANSWERS

21.1 D. A positive lift-off test is consistent with a subscapularis injury. In this maneuver, the patient’s arm is internally rotated, the elbow flexed to 90 degrees, and hand held posteriorly at the waist. If the patient experiences pain or weakness as he tries to move his arm away from his body against resistance, the test is positive.

21.2 B. Forty percent of patients older than 60 years with a shoulder dislocation will have a concomitant RCT. However, it is also important to recognize that even in the absence of trauma, RCT is very common in older individuals. Sixty-five percent of patients older than 70 years have a full-thickness RCT.

21.3 C. Arthrograms are used when MRI is contraindicated. They improve sensitivity and specificity in the diagnosis of an RCT. It is a fluoroscopic examination of the shoulder joint after the introduction of contrast media into the joint. Extravasation of the dye from the joint would support the clinical diagnosis of an RCT. Although ultrasound is also an alternative imaging modality in the setting of a contraindication to an MRI, an arthrogram is a better choice. There is no role for PET scans in the diagnosis of RCT. Additional plain radiographs will likely be of no benefit unless the originals are of poor quality.

    CLINICAL PEARLS    

► The rotator cuff is an important dynamic stabilizer of the shoulder and provides humeral head depression, rotation, shoulder abduction, and GH joint compression. ► The supraspinatus is the most commonly torn tendon. ► MRI is extremely accurate in detecting full-thickness tears of the rotator cuff and can evaluate tear size, tendon retraction, muscle atrophy, and related intraarticular pathology. ► Young, active patients presenting with an acute tear and a primary complaint of weakness are best treated with early surgical repair of a rotator cuff tear. ► Open and arthroscopic techniques are used to repair the rotator cuff.

REFERENCES

Bassett RW, Cofield RH. Acute tears of the rotator cuff: the timing of surgical repair. Clin Orthop. 1983;175:18-24. 

McMahon P. Current Diagnosis and Treatment in Sports Medicine . New York: McGraw-Hill; 2007:120-155. 

Rockwood CA, Matsen FA. The Shoulder . Philadelphia: WB Saunders; 1998:755-795. 

Sperling JW, Cofield RH. Rotator cuff repair in patients fifty years of age and younger. J Bone Joint Surg Am . 2004;86:2212-2215. 

Vaccaro AR. Orthopaedic Knowledge Update 8 . Washington, DC: American Academy of Orthopaedic Surgeons; 2005:257-350. 

Wilk KE, Reinold MM, Andrews JR. The Athlete’s Shoulder . New York: McGraw-Hill; 2008:25-60.

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