Arthroscopic Treatment of Rotator Cuff Tears
Surena Namdari
Jay D. Keener
Ken Yamaguchi
Aaron M. Chamberlain
DEFINITION
Rotator cuff disease encompasses a spectrum of disorders ranging from tendinitis to partial and full-thickness tendon tears.
It is the most common shoulder disorder treated by an orthopaedic surgeon, with over 17 million U.S. individuals at risk for the disabilities caused by the disease.
The prevalence of full-thickness tearing of the rotator cuff ranges from 7% to 40% across multiple studies.30,40
Age-related degenerative change is a primary factor in the development of rotator cuff tears.44
Asymptomatic full-thickness tears have been found in 10% of patients between 50 and 59 years old, 20% of patients between 60 and 69 years old, and 40.7% of patients 70 years old or older.21
The risks and benefits of both nonoperative and operative treatment must be considered for each individual patient.
A number of factors are critical in deciding how to treat full-thickness tears, including a history of trauma, patient age, tear size, tear retraction, degenerative muscle and tendon changes, and functional disability.
Traditionally, open rotator cuff repair was the standard of care for symptomatic full-thickness rotator cuff tears.
Several disadvantages are inherent to traditional open rotator cuff repairs. These include the need for deltoid detachment, difficult visualization of associated glenohumeral joint pathology, larger incisions, more extensive surgical dissection, and a higher complication rate.
The surgical treatment of full-thickness rotator cuff tears has evolved with the advent of arthroscopic techniques.
Rotator cuff repair techniques have progressed from mini-open repairs to repairs performed completely arthroscopically.
As techniques of arthroscopic rotator cuff repair have advanced, larger tears are also commonly repaired completely arthroscopically.
Single-row suture anchor repairs have been reported with good overall clinical results, but healing rates decrease as tear size increases.6,10
In some studies, biomechanical properties of the double-row repair are improved compared to single-row repairs and include decreased strain over the footprint area, increased stiffness, and increased ultimate failure load.20,22,26,28 In other studies, modified single-row techniques have demonstrated comparable biomechanical fixation strength to double-row techniques.17,25
In large and massive tears, double-row repair provides a higher rate of intact tendon healing than does traditional single-row repair; however, this benefit has not translated into clinically confirmed functional improvement or costeffective results.7,12
Recent study suggests that single-row repair may be preferable in certain situations, particularly when there is less than 10 mm of remnant tendon length.22
In the setting of a full-thickness rotator cuff tear, we perform a double-row suture anchor repair, a tension band repair, or a hybrid repair (double row and tension band) based on the clinical situation and surgeon preference.
ANATOMY
The rotator cuff is a complex of four muscles arising from the scapula and inserting onto the tuberosities of the proximal humerus.
The supraspinatus and infraspinatus muscles make up twothirds of the posterior rotator cuff. The two tendons fuse together and have a direct bony insertion.
When performing a double-row rotator cuff repair, knowledge of the dimensions of the rotator cuff insertion or “footprint” is critical.
The footprint of the supraspinatus is triangular in shape, with an average maximum medial to lateral length of 6.9 mm and an average maximum anteroposterior (AP) width31 of 12.6 mm.
The infraspinatus has a long tendinous portion in the superior half of the muscle, which curves anteriorly and extends to the anterolateral area of the highest impression of the greater tuberosity.31
The footprint of the infraspinatus is trapezoidal in shape, with an average maximum medial to lateral length of 10.2 mm and an average maximum AP width31 of 32.7 mm.
Suture anchor repair constructs using a single row of anchors have been shown to restore only 67% of the original footprint of the rotator cuff.2
Adding a second row of anchors increases the contact area of the repair by 60%.41
PATHOGENESIS
The etiology of rotator cuff tears is multifactorial.
The major factors are age-related degenerative changes of the tendon and physiologic loading.
The theory of age-related accumulative damage is supported by histologic findings of decreased fibrocartilage at the cuff insertion, decreased vascularity, fragmentation of the tendon with cellular loss, and disruption of Sharpey fiber attachments to bone.
Clinical studies support the aging theory as a primary cause of rotator cuff disorders.44
In a review of 586 consecutive patients with unilateral shoulder pain, rotator cuff tears were found to be correlated with increasing age, with an almost perfect 10-year difference between patients with no tear, a unilateral tear, and bilateral tears.
The average age of patients presenting with rotator cuff-derived pain with no tear was 48.7 years old; unilateral tear, 58.7 years old; and bilateral tears, 67.8 years old.
Physiologic loading of the tendon has also been postulated as a mechanism for cuff tearing.
Localized degeneration of the articular region of the tendon, most commonly in the supraspinatus, is indicative of a tendon loading etiology.
Uniform changes throughout the entire tendon, which are not commonly found, would be more suggestive of an age-related degenerative process.
Age and loading likely have a multiplicative effect, with tendons in an older person both being more susceptible to damage from normal physiologic loading and exhibiting a worse healing response.
Genetics may also have a significant role in the predisposition for rotator cuff tears.
A strong relationship between rotator cuff tearing and family history has been shown.37
One study found a relative risk of 2.42 for full-thickness rotator cuff tears in siblings of patients with cuff tears versus controls.14
This increased risk in siblings implies that genetic factors may play a role in the development of rotator cuff tears.
NATURAL HISTORY
Information about the natural history of rotator cuff disease is fundamental to understanding treatment indications.
Because symptomatic tears are often treated, our understanding of the natural history of rotator cuff disease is based on the study of asymptomatic rotator cuff tears.
Asymptomatic tears are extremely common in the population, and many of these are at risk for the development of symptoms over time.
In one study, over 51% of patients with a previously asymptomatic rotator cuff tear and a contralateral symptomatic tear developed symptoms in the asymptomatic tear over an average of 2.8 years.45
Once a tear became symptomatic, 50% progressed in size. Only 20% of those remaining asymptomatic progressed in size.
No tears were found to decrease in size over time, suggesting that there was a limited intrinsic healing potential for the rotator cuff and that a significant percentage of patients with asymptomatic tears were at risk for symptom development.
Pain development in shoulders with an asymptomatic rotator cuff tear is associated with an increase in tear size.27,32,45
In addition, the potential for healing after surgery may be influenced by the irreversible muscle and tendon changes that occur in delayed repairs and in older patients.
Clinical evidence of spontaneous healing of partial-thickness tears also appears limited.
Partial-thickness tears are likely to progress to full-thickness tears over time and tear progression is associated with symptom development.27
In a cohort of subjects with an asymptomatic rotator cuff tear who were prospectively monitored, 40% of partialthickness tears progressed to full-thickness tears with pain development.27
PATIENT HISTORY AND PHYSICAL FINDINGS
Patients with rotator cuff disorders often complain of pain and/or weakness.
The development of symptoms is often insidious.
There may be a recollection of minor trauma (eg, episode of heavy lifting, catching a heavy object).
Pain is usually localized to the anterior or anterolateral aspect of the shoulder, often extending down the front or side of the shoulder to the elbow.
Pain exacerbated with use, especially with overhead activities, is common.
Sleep disruption is also common in patients with symptomatic rotator cuff disease.
Weakness is a complaint for patients with symptomatic fullthickness rotator cuff tears.
When asymptomatic, a rotator cuff tear is often associated with a clinically insignificant loss of shoulder function compared with an intact rotator cuff.18
Large tears in asymptomatic or symptomatic individuals are more likely to manifest in weakness21,29; however, pain from tendinitis or small tears may also simulate lack of strength.
Similarly, patients with large or massive tears may have very reasonable function.
More commonly, however, these patients report overhead weakness and fatigue.
If gross weakness is recognized suddenly after a trauma, a rotator cuff injury should be suspected and investigated.
In the setting of chronic rotator cuff tears, inspection of the shoulder will often reveal atrophy of the supraspinatus and infraspinatus.
Prior surgical incisions should be noted. If previous open rotator cuff repair with deltoid detachment was performed, deltoid integrity should be assessed, along with axillary nerve function.
Range-of-motion testing should be performed both actively and passively.
Passive range of motion is often preserved except in the setting of chronic large tears where static superior head migration leads to limited forward elevation with inferior capsule contracture.
Posterior capsular contracture is also a common finding with both small and large tears.
Active motion is often limited in scapular plane elevation. This may be due to either weakness or pain.
Shoulder strength should be evaluated with manual muscle testing.21
Various arm positions will isolate the rotator cuff and specifically test these muscles for dysfunction.
The supraspinatus, infraspinatus, and teres minor can be isolated with resisted scapular plane elevation at 90 degrees in neutral rotation, resisted external rotation in full adduction and slight internal rotation, and external
rotation in 90 degrees of abduction and 90 degrees of adduction, respectively.
The belly press, lift-off, or bear hug tests can be used to test subscapularis function.
Belly press test: Inability to maintain maximum internal rotation without the elbow dropping posterior to the midsagittal plane of the trunk indicates impaired subscapularis function.
Lift-off test: Inability to maintain active maximal internal rotation with hand off the lumbar spine without extending the elbow indicates impaired subscapularis function.
Bear hug test: Inability to maintain resisted internal rotation with the palm of the hand on the involved side placed on the opposite shoulder and the elbow positioned anterior to the body indicates impaired subscapularis function.
Electromyographic analysis has shown that the belly press activates the upper subscapularis, whereas the lift-off activates the lower subscapularis.
Special tests have been developed to aid in diagnosis:
The Neer impingement test (forward elevation in internal rotation) and the Hawkins impingement test (elevation to 90 degrees, cross-body adduction, and internal rotation) were designed to elicit symptoms by impinging the rotator cuff on the undersurface of the acromion and coracoacromial ligament.
The hornblower’s sign indicates teres minor dysfunction or tearing if there is weakness or inability to achieve full external rotation in an abducted position.
A positive result (weakness or pain) with the empty can test (Jobe sign) indicates dysfunction of the supraspinatus tendon.
Inability to maintain the shoulder in a fully externally rotated position indicates a positive external rotation lag sign and significant dysfunction or tearing of the infraspinatus tendon.
Variable accuracy of these tests has been shown when used in isolation, but accuracy may be improved when used in combination with other provocative examinations.34
IMAGING AND OTHER DIAGNOSTIC STUDIES
Four standard shoulder radiographs should be taken for every patient evaluated for shoulder pain: AP, true AP with active shoulder abduction to 30 degrees in the scapular plane, axillary lateral, and scapular Y views.
The decision to obtain further imaging studies is based on radiographic findings along with data obtained from the history and physical examination.
In a patient with a small full-thickness rotator cuff tear, radiographs are usually normal.
With increasing tear chronicity, sclerotic and cystic changes of the greater tuberosity are often noted.
With increasing tear size, proximal humeral migration can be found on the AP and true AP views. Tears extending into the infraspinatus tendon are associated with greater humeral migration than is seen with isolated supraspinatus tears.19
Proximal migration is best identified on the true AP view as loss of a concentric reduction of the proximal humeral and glenoid centers of rotation.
Humeral elevation may be static or dynamic depending on the chronicity of the tear. Static elevation is associated with contracture of the inferior capsule.
Magnetic resonance imaging (MRI) of the shoulder in patients with rotator cuff tears evaluates both the tendon and muscle quality.
Full-thickness tears show increased signal intensity at the tendon insertion on T2-weighted images.
MRI has been shown to have over 90% sensitivity and specificity in detecting tears without previous surgery.
Fatty infiltration and atrophy of the rotator cuff musculature can also be identified on MRI.
Increased fatty infiltration of the rotator cuff muscles has been correlated with poorer tendon healing and worse final postoperative outcomes after repair.
In the hands of a skilled ultrasonographer, ultrasound has a sensitivity and specificity similar to that of MRI to identify rotator cuff tears as well as fatty infiltration of muscles.35,39,42Related posts:
Arthroscopic Treatment of Posterior Shoulder Instability
Management of Glenohumeral Instability with Humeral Bone Loss
Athletic Pubalgia and Adductor Injuries
Repair of Acute and Chronic Patella Tendon Tears
Anterior Cruciate Ligament Reconstruction in the Skeletally Immature Patient
Modified Brostrom and Brostrom-Evans Procedures
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
