Shoulder Resources

Rotator cuff tears (R)(M) Rotator cuff tears (R)(M)


Rotator cuff tears and impingement

Function of the rotator cuff
The rotator cuff functions as a depressor of the humeral head to counteract the longitudinal pull of the deltoid, triceps, pectoralis minor and coracobrachialis. It plays its biggest role as a stabilizer between 30 and 75 degrees of humeral elevation, and by 120 degrees of elevation it is no longer a stabilizer.
Contraction of the rotator cuff compresses the humeral head in the glenoid, improving stability. Both the anterior and posterior cuffs must work to maintain stability; if one is dysfunctional increased translation ensues and compression is lost.
The supraspinatus is particularly important in compressing the humeral head into the glenoid. Note that it has been shown that abduction through a full range can occur after a suprascapular nerve block (Van Linge 1963).
The long head of biceps functions as a humeral head depressor,
Notes on applied anatomy
The vascular supply to supraspinatus is via the suprascapular artery. The blood supply is more tenuous on the articular side, and the collagen bundles there are also less regular and smaller.
The thickness of the rotator cuff is around 9-12mm.

Incidence
Cadaver studies show rate of 5-30%.
Increasing frequency with increasing age.
Partial thickness tears are more common in younger patients, implying progression to full thickness tear as the patient ages.
Patients older than 77 have greater than 50% rate of full thickness cuff tears which indicates to Rockwood that cuff tears may be a normal part of aging.
Rotator cuff disease is uncommon in primary glenohumeral osteoarthritis.

Aetiology
May be due to impingement of the rotator cuff on the coraco-acromial arch, particularly in the so-called impingement position (flexion, abduction and internal rotation). Neer felt that impingement occurs against the undersurface of the anterior 1/3 of the acromion and at times the AC joint. (Previously it had been suggested that the lateral acromion was responsible). Neer felt that the arm was used in a position of forward elevation rather than abduction.
The factors that cause impingement can be classified as intrinsic (intratendinous) and extrinsic (extratendinous). They can be further classified as primary, or secondary (the result of another process, such as instability).
Anatomical factors that predispose to cuff pathology include:
• Acromial shape – increasing curvature leads to increased pressure on the cuff.
• Anterior acromial spurs – seen in 7% of patients up to 50, but 30% of patients older than 50.
• Os acromiale - found in 8% of patients, 1/3 of these are bilateral.
May also be due to ischaemia, in the critical area of hypovascularity which is in the supraspinatus tendon around 1cm proximal to its insertion (demonstrated by Rathburn and Macnab).
Hawkins points out that these theories are complementary, with mechanical impingement on an area of hypovascular tissue.
Jobe suggested that in athletes involved in sports with overhead actions subtle glenohumeral instability could be the cause of rotator cuff tendinosis.
Muscle weakness, particularly in the supraspinatus, may lead to impingement.
Tendon degeneration may allow the humeral head to migrate superiorly, leading to impingement (Uhthoff).

Pathology
Apley describes a sequence of “wear, tear and repair”
Young patients with cuff tears have a vigorous healing response which is very painful (acute tendonitis) but relatively short lived. Older patients have a less vigorous response which is not as painful but more chronic (chronic tendonitis).
A complete tear (which usually occurs in the elderly) becomes painless quickly but never repairs.
Neer describes three stages of impingement:
• Oedema and haemorrhage
• Typical age less than 25
• DDx subluxation or AC joint arthritis
• Reversible clinical course
• Conservative treatment
• Fibrosis and tendinitis
• Typical age 25-40
• DDx frozen shoulder, calcific tendinitis
• Recurrent pain with activity
• Consider bursectomy, CA ligament division
• Bone spurs and tendon rupture
• Typical age >40
• DDx cervical radiculitis or neoplasm
• Progressive disability
• Anterior acromioplasty and cuff repair
Tears may develop acutely in young patients after trauma, or after degeneration in older patients.
Large tears of the cuff may eventually lead to serious impairment of shoulder biomechanics and eventually cuff tear arthropathy in 4% (Neer). A rapidly progressive cuff tear arthropathy is referred to as a Milwaukee shoulder.

Clinical features

Subacute tendonitis
Shoulder pain develops after strenuous activity. The pain is worse with overhead activity.
The shoulder is acutely tender along the anterior edge of the acromion, and tenderness over the greater tuberosity can be demonstrated particularly with the shoulder extended. When the humerus is flexed the supraspinatus tendon disappears under the acromion and the tenderness is diminished.
There is disruption of scapulothoracic rhythm with a painful arc which is improved if the arm if held in full external rotation throughout.
Note that both Neer and Hawkins' signs have low specificity.

Chronic tendonitis
The patient is older, usually 40-50.
May have had a history of recurrent subacute tendonitis.
Pain is characteristically worse at night; the patient can't lie on the affected side and often finds it more comfortable to sit.
Pain is worse with overhead activities.
Signs are similar to those of subacute tendonitis plus there is often involvement of biceps with rupture of the LHB.
Neer commented that 50% of his patients with cuff tear were unable to remember a definite injury. An injury may predispose to an “acute extension” of the tear, where prior to the injury there may have been only an incomplete thickness tear.

Cuff disruption
Patients with a partial tear may be able to abduct when the tear is injected with lignocaine. Diminishment of pain after injection with LA is referred to as a positive impingement test.
Patients with a complete tear will have the drop arm sign.

Radiology

Plain XR
Standard views are anteroposterior, trans-scapular lateral and an axillary view. The supraspinatus outlet view (Neer 1987) is a lateral radiograph of the erect scapula with a downward (caudal) tilt of 10 degrees, and this can help assess acromial morphology.
Bigliani classified acromial morphology as:
Type I – straight 17%
Type II – curved 43%
Type III – hooked 40%
Type III acromions have a much higher rate of RCT.
Wuh and Snyder have classified the acromion by thickness at the junction of anterior and middle thirds
Type A - less than 8mm thick
Type B - 8 to 12 mm thick
Type C – more than 12mm thick
This is helpful in avoiding iatrogenic acromion fracture during acromioplasty.
Routine XR are often negative even with a cuff tear. XR signs of cuff tear include:
• High riding humeral head (normal acromion-humeral gap is 7-14mm). Weiner and Macnab (JBJS A 1970) suggested that an interval of 5mm or less “should be considered compatible with a tear of the rotator cuff until proven otherwise”. Note that individuals who do excessive pitching at an early age may have overgrowth of the humeral head with decreased gap.
• Thinning of acromion or traction spur at the anterior acromion
• If long standing may be evidence of arthropathy
• Can be sclerosis, erosion or cystic change of insertion of the cuff into the greater tuberosity.

Ultrasound
This is operator dependent. Van Holsbeek quotes a 100% Sn and Sp for FTRCT and for PTRCT Sn 93% and Sp 100%.
The diagnosis of a large retracted tear is made when there is nonvisualization of the SS tendon and the deltoid muscle is closely opposed to the humeral cortex. This is a very reliable sign with a 100% PPV.
A focal full thickness tear is seen as a hypoechoic area extending through the rotator cuff; with subdeltoid bursal fluid supporting the diagnosis. If the tear is large enough the adjacent deltoid muscle may herniate into the tendon gap.
Partial thickness tears may appear hypoechoic or of mixed echogenicity.

MRI
Provides information about the state of the cuff, but up to 1/3 of individuals will have asymptomatic cuff tears on MRI. MRI is better than ultrasound in diagnosing partial thickness tears, but the two are similar in full thickness tears.
Rotator cuff tear size is graded as: small – less than 1cm; medium 1-3cm; large 3-5cm; massive – greater than 5cm.
MRI is useful in assessing the degree of atrophy and fibrosis in the cuff in the setting of massive cuff tears; if the muscle is fibrosed and retracted it is not likely to be repairable. If the patient has grade 3 rotator cuff strength and the MRI shows the cuff retracted to the glenoid rim with severe muscular atrophy this is almost certainly irreparable.
Differential diagnosis
Glenohumeral instability
Degenerative joint disease
AC joint pathology
Adhesive capsulitis
Nerve compression syndromes – particularly suprascapular nerve
Cervical spondylosis

Treatment
Conservative treatment
Patients should avoid the impingement position
Strengthening of the rotator cuff in the non-painful position
NSAIDS

Steroid injections
Icing
Ultrasound
The first phase of rehabilitation in tendinosis is rest and avoidance of the impingement position. Anti-inflammatories are prescribed. Subacromial lignocaine and steroid injections can be effective in pain relief. After the inflammation has settled range of motion exercises are started. Stretching is taught. The last phase is the strengthening phase, where rotator cuff, deltoid and scapula stabilizing exercises are prescribed. Overhead activities should be avoided, particularly initially. Any muscle imbalance, especially between external and internal humeral rotators, is addressed.

Non-surgical treatment is effective in up to 90% of patients. Poorer results are found in older patients and patients with curved acromions. Nonoperative treatment should be pursued for at least 6 months except for full thickness cuff tears. Bursal sided PTRCTs do not do well when treated nonoperatively.
If nonoperative treatment is being pursued, it is reasonable to get an US after 6-12 months to rule out progression of the tear which may make cuff repair impossible. Around 50% will progress.

Surgical treatment
Indicated in:
• Failure to respond to conservative treatment in tendinitis (Neer's stage II).
• Full thickness rotator cuff tears with pain or symptomatic weakness
Impingement
Neer advocates subacromial bursal excision and division of the CA ligament from the medial acromial border for stage II impingement if disability persists for one year, and doesn't advocate acromioplasty unless there is overhang and prominence of the underside of the acromion.
Hawkins mentions division of the CA ligament in patients with ongoing sx in Stage I who fail one year of conservative treatment, but emphasizes that the patient should have a period off sports first.
If the AC joint is symptomatic or preventing adequate view of the supraspinatus it needs debridement or excision.
Acromioplasty can be open or arthroscopic, and it has been shown on cadavers that a full and accurate arthroscopic decompression can be done. The results are similar.
Cuff tears
Surgery can be open or arthroscopic.
Arthroscopic surgery allows visualization of both sides of the cuff, and the ability to deal with other glenohumeral or labral pathology which is frequently co-existent.
The mini-open technique uses arthroscopy first to locate the tear, plus or minus deal with intra-articular pathology; a small deltoid splitting incision is then used to get access to the cuff. It minimizes detachment of the deltoid from the acromion. This decreases the risk of catastrophic deltoid dysfunction, but doesn't shorten the rehabilitation time, because this is dependent on rotator cuff healing. The tear should be small and easily mobilizable.
In open surgery bursal side PTRCTs can be seen, but not articular sided partial tears. Fukuda describes the colour test, where methylene blue is injected into the glenohumeral joint, and diffuses preferentially into areas of bursal sided partial tears. Open surgery is usually combined with acromioplasty and provides around 80-90% satisfactory results.
Partial thickness tears have a tendency to progress, with one study demonstrating 80% progression on ultrasound. Tears up to 50% cuff width should be treated with debridement (however note that after debridement there was no evidence of healing at second look arthroscopy); tears bigger than this should be treated with excision of the degenerate portion and cuff repair. This is backed up by a study looking at tears >50% thickness, where there were no recurrences in the group undergoing excision and repair, but progression to complete tear in 10% of patients treated only with debridement.
Debridement should usually be combined with subacromial decompression; acromioplasty if the acromion is hooked, CA ligament division and bursectomy if type I acromion. This leads to 75-80% satisfactory results. Acromioplasty is contraindicated in elite throwing athletes less than 35 who have a low rate of return to elite competition if this is done.
Surgery should be considered early in patients with complete cuff tears. Treatment consists of acromioplasty; excision of the coraco-acromial ligament and repair of any associated cuff tears. Surgery should only be considered if the patient is willing and able to undergo prolonged physiotherapy post-operatively. Debridement has inferior results compared with repair of the cuff; thus the trend is to repair any tear that causes pain or significant loss of function.
Technique of open cuff repair
Beach chair position
Variable skin incision – sabre cut vs. horizontal. Matsen prefers an oblique incision centred on the anterolateral corner of the acromion, perpendicular to the deltoid fibres.
Deltoid split for 2-3 cm from anterolateral corner of acromion, then along acromion to ACJ. The split should be in the tendon of origin found between the anterior and middle thirds. This tendon arises from the anterior lateral corner of the acromion. The spit is carried over the acromion and into the trapezius insertion.
Anteroinferior acromioplasty, to level of ACJ AFTER INSPECTION OF THE CUFF. If the cuff is not amenable to repair an acromioplasty will be deleterious. In this situation, the undersurface of the coracoacromial arch is smoothed off, and any debris, scar or thickened bursa in the subacromial space is removed. The top of the humeral head may also be smoothed off.
Excision of ACJ if:
• Symptomatic
• Osteophytes inferiorly
• Inadequate view
Bursectomy
Identification of tear
Debridement to adequate tissue
Mobilize tendons:
• Release subacromial adhesion
• Release intraarticular adhesions
• May need to release capsule
• Divide coracohumeral ligament
• Release rotator interval to base of coracoid. The complete release of the coracohumeral ligament and rotator interval is called the interval slide and should allow the supraspinatus to be mobilized 1-1.5cm laterally.
Repair with arm at side into bone trough.
The modified Mason-Allen stitch is preferred for attachment to the cuff (350N vs. 269N for mattress stitches).
Tendon to bone fixation with transosseous sutures
Sutures need to be braided, non-absorbable, pass through bone at least 1.5 to 2cm distal to tip of tuberosity with at least 1cm separation. Knots should be buried or tied laterally to avoid impingement.
If the biceps is torn, the proximal stump is resected and the distal stump tenodesed in the bicipital groove.
Reattach deltoid with nonabsorbable sutures.
Postoperative management
Passive ROM exercises are started immediately and continued for 6 weeks while the bone tendon interface heals. 140-40 aimed for. Active ROM exercises are then continued for another 6 weeks, before formal strengthening starts. Patients who have arthroscopic decompression and debridement alone can start active ROM immediately because the deltoid hasn't been detached and no tendon repairs need to be protected.
Results of open repair
85-95% satisfactory pain relief
85-95% significant improvement in shoulder function.
Patient satisfaction correlates most closely with pain relief

Salvage of massive cuff tears
A massive cuff tear is defined as one more than 5cm or involving two or more tendons. Prospective studies show these are worth repairing, with one study of 30 patients having significant improvements in pain, function and ROM at 6 ½ years.
Can the tear be repaired? This depends on whether the retracted tendon can be advanced. This is probably best assessed via an open procedure, where subdeltoid, subacromial and intraarticular adhesions can be looked for and addressed.
The supraspinatus can only be advanced 3cm before excessive tension develops in the neurovascular bundle.
Neer mentions transferring half of the subscapularis and infraspinatus tendons superiorly.
If unreconstructable an acromioplasty is contra-indicated because this will remove the remaining restraints to superior translation of the humeral head, and result in possible superomedial humeral head dislocation (Flatow). Degenerate cuff tissue should be debrided. Ellman and Gartsman have reported “reasonable” pain relief at up to 5 years with debridement alone, and emphasize that thorough debridement and synovectomy are needed, plus debridement of any acromial or AC joint spurs.
If reconstruction is required, then supraspinatus advancement, latissimus dorsi transfer, rotator cuff transposition, fascia lata autograft or synthetic tendon graft may be performed. The best results appear to be with latissimus dorsi transfer; auto and allografts have poor success rates.
The biceps tendon
This can be debrided or repaired as required. Tenodesis is recommended if the tendon is subluxing into the joint, or has more than 50% attenuation.
Revision rotator cuff surgery
Satisfactory results in only 60%.
Results of nonoperative management of full thickness tears of the rotator cuff (Bokor, CORR, 1993)
Spontaneous recovery to a comfortable and useful shoulder has been reported after a full thickness tear.
In Bokor's study patients who had a symptomatic full thickness tear were followed for an average of 7 y.
• 74% had no or little pain
• If seen after six months of symptoms this rate was only 56%
• This supports many investigators' recommendations to consider a short trial of conservative therapy
• Marked improvement in function
• Improvement in range of motion (loss of range of motion may be mainly due to pain)
The authors recognized that surgical treatment is the standard of care for most full thickness rotator cuff tears.

Treatment of rotator cuff arthropathy
Hemiarthroplasty with a large head, if the anterior deltoid is preserved. This fits into the acetabularized glenoid-coracoacromial arch, and provides predictable pain relief, although function isn't great. The glenoid should not be resurfaced.
Complications of acromioplasty/cuff repair
• Acromial fracture
• Deltoid dehiscence
• Weakness
• Failure of repair
• Deep and superficial wound infection
• Adhesive capsulitis
Subcoracoid impingement
This is associated with a laterally placed coracoid process that can impinge on the proximal humerus with forward flexion and internal rotation.
Patients tend to have more medial pain, referred to the arm and forearm.
The diagnosis can be made by performing a CT with the arm in the provocative position or by injection of local anaesthetic into the area.
Treatment is by resection of the lateral aspect of the coracoid process.

Internal impingement
Impingement of the posterior labrum and cuff can occur in throwing athletes with external rotation and anterior translation.
Isolated tears of the subscapularis tendon
Note: most subscapularis tears are associated with traumatic anterior dislocation and are often followed by symptoms of recurrent instability.
Gerber reported on 16 cases of isolated rupture in the JBJS(B) in 1991. All were in men and the average age was 50. The mechanism of injury was forceful hyperextension or external rotation of the adducted arm.
The tear was associated with pain when using the arm overhead and also below shoulder level. The tear was usually associated with increased external rotation of the shoulder, weakness of internal rotation and a pathological lift off test.
The patient complained of anterior shoulder pain and weakness of the arm when it was used above and below shoulder level (the latter would be unusual in supraspinatus tears). There was no associated shoulder instability.
The tear of the subscapularis was usually associated with medial subluxation of the biceps.

|<< Back to Resource List
 
 
© NEWSEC :: Phone: (02) 4323 2683