- Stage 1, commonly affecting patients younger than 25 years, is depicted by acute inflammation, edema, and hemorrhage in the rotator cuff. This stage usually is reversible with nonoperative treatment.
- Stage 2 usually affects patients aged 25-40 years, resulting as a continuum of stage 1. The rotator cuff tendon progresses to fibrosis and tendonitis, which commonly does not respond to conservative treatment and requires operative intervention.
- Stage 3 commonly affects patients older than 40 years. As this condition progresses, it may lead to mechanical disruption of the rotator cuff tendon and to changes in the coracoacromial arch with osteophytosis along the anterior acromion. Surgical l anterior acromioplasty and rotator cuff repair is commonly required.
Although rotator cuff tears are more common in the older population, impingement and rotator cuff disease are frequently seen in the repetitive overhead athlete. The increased forces and repetitive overhead motions can cause attritional changes in the distal part of the rotator cuff tendon, which is at risk due to poor blood supply. Impingement syndrome and rotator cuff disease affect athletes at a younger age compared with the general population.
Secondary impingement may be the most common cause in young athletes who frequently place large, repetitive overhead stresses on the static and dynamic glenohumeral stabilizers, resulting in microtrauma and attenuation of the glenohumeral ligamentous structures, which leads to subclinical glenohumeral instability. Such instability places increased stress on the dynamic stabilizers of the glenohumeral joint, including the rotator cuff tendons.
Arthroscopic studies of these patients note impingement between the posterior superior edge of the glenoid and the insertion of the rotator cuff tendon with the arm placed in the throwing position (abducted and externally rotated). Lesions were noted along the area of impingement at the posterior aspect of the glenoid labrum and articular surface of the rotator cuff. This concept is believed to occur most commonly in throwing athletes and must be considered when assessing for impingement.
- Patients younger than 40 years - Usually glenohumeral instability, and acromioclavicular joint disease/injury
- Patients older than 40 years - Consider glenohumeral impingement syndrome/rotator cuff disease and glenohumeral joint degenerative disease
- Individuals at highest risk for shoulder impingement are laborers and those working in jobs that require repetitive overhead activity.
- Athletes (eg, swimming, throwing sports, tennis, volleyball)
- Athletic activity
- Onset of symptoms in relation to specific phases of the athletic event performed
- Duration and frequency of play
- Duration and frequency of practice
- Level of play (eg, little league, high school, college, professional)
- Actual playing time (eg, starter, backup, bench player) and position played
- Lack of periodization in training - Athlete participating in same overhead sport year-round
- Sudden onset of sharp pain in the shoulder with tearing sensation is suggestive of a rotator cuff tear.
- Gradual increase in shoulder pain with overhead activities is suggestive of an impingement problem.
- Chronicity of symptoms
- Pain usually is reported over the lateral, superior, anterior shoulder; occasionally refers to the deltoid region.
- Posterior shoulder capsule pain usually is consistent with anterior instability, causing posterior tightness.
- Setting during which symptoms arise (eg, pain during sleep, in various sleeping positions, at night, with activity, types of activities, while resting)
- Quality of pain (eg, sharp, dull, radiating, throbbing, burning, constant, intermittent, occasional)
- Quantity of pain (on a scale of 0-10, 10 being the worst)
- Alleviating factors (eg, change of position, medication, rest)
- Aggravating factors (eg, change of position, medication, increase in practice, increase in play, change in athletic gear/foot wear, change in position played)
- Functional symptoms - Patient changed mechanics (eg, throwing motion, swim stroke) to compensate for pain
- Associated manifestations (eg, possibly chest pain, dizziness, abdominal pain, shortness of breath)
- Provocative position
- Pain with humerus in forward-flexed and internally rotated position suggests rotator cuff impingement.
- Pain with humerus in abducted and externally rotated position suggests anterior glenohumeral instability and laxity.
- Other history - Inquire about previous or recent trauma, stiffness, numbness, paresthesias, clicking, weakness, crepitus of instability, and neck syndromes
- Men should have their shirts off and women should wear a tank top for the examination.
- Visualize entire shoulder girdle and scapular area. Inspect for scapular winging (long thoracic nerve palsy) by having the patient perform a wall push-up.
- Note muscle mass asymmetry/atrophy and bony asymmetry.
- Active range of motion (AROM) is tested if possible. If not possible, passive range of motion (PROM) is performed, as follows:
- Forward flexion (average range is 150-180°)
- Abduction (average range is 150-180°)
- External rotation (average range with arm in adduction is 30-60°)
- External rotation (average range with arm in abduction is 70-90°)
- Internal rotation (average range, which is measured by how high the patient can reach around the back with the ipsilateral thumb [ie, ipsilateral hip, T12, L5], is above T8)
- Adduction (average range is 45°)
- Extension (average range is 45°)
- Note the following:
- Stiffness with external/internal rotation is best tested with arm in 90° of abduction.
- External and internal rotation are best tested in the supine position with the scapulothoracic articulation stabilized.
- Most high-level pitchers have increased external rotation and decreased internal rotation in the pitching arm compared to the nonpitching arm. This may not be pathologic in the high-level athletic population.
- A painful arc of motion may be experienced with elevation above the shoulder level in patients with impingement.
- Palpate along the joints, noting the biceps tendons, supraspinatus and subscapularis tendons, and anterolateral corner of the acromion. Check for bony pain over anterior portion of acromion in region of potential os acromiale.
- The entire shoulder girdle is palpated (noting tenderness, deformities, and atrophy) from acromioclavicular joint, clavicle, glenohumeral joint, scapula, scapulothoracic articulation, anterior/posterior shoulder capsule, supraspinous fossa, infraspinous fossa, and humerus (especially proximally).
- Manual muscle testing
- Concentrate on assessing the shoulder girdle muscles, especially external/internal rotation and abduction.
- Supraspinatus may be isolated by having the patient rotate the upper extremity so that the thumbs are pointing toward the floor and apply resistance with the arms at 30° of forward flexion and 90° of abduction (called the supraspinatus isolation test or empty can test because the position assimilates emptying a can).
- Pain is felt with tendonitis or partial injury to the supraspinatus tendon in the supraspinatus isolation test, but weakness also may be found accompanying partial-thickness or full-thickness disruption of the supraspinatus tendon.
- Weakness also may be found with tendonitis, due to muscle inhibition from painful stimuli.
- Special tests: Any test performed should compare both shoulders either to detect bilateral pathology or to establish a control for comparison with the affected shoulder.
- Impingement signs
- Neer test: Forcefully elevate an internally rotated arm in the scapular plane, causing the supraspinatus tendon to impinge against the anterior inferior acromion.
- Hawkins-Kennedy test: Forcefully internally rotate a 90° forwardly flexed arm, causing the supraspinatus tendon to impinge against the coracoacromial ligamentous arch. Note: Pain and a grimacing facial expression indicate impingement of the supraspinatus tendon, indicating a positive Neer/Hawkins impingement sign.
- Impingement test: Inject 10 mL of 1% lidocaine solution into the subacromial space. Repeat testing for an impingement sign. Elimination or significant reduction of pain constitutes a positive impingement test.
- Drop arm test: The patient places the arm in maximum elevation in the scapular plane and then lowers it slowly (the test can be repeated following subacromial injection of lidocaine). Sudden dropping of the arm suggests a rotator cuff tear.
- Supraspinatus isolation test/empty can test: The supraspinatus may be isolated by having the patient rotate the upper extremity so that the thumbs are pointing to the floor and apply resistance with the arms in 30° of forward flexion and 90° of abduction (assimilates emptying of a can). This test is positive when weakness is present (compared to the unaffected side), suggesting disruption of the supraspinatus tendon.
- Impingement signs
- Tests for instability
- Sulcus sign: Grasp the patient's elbow and apply inferior traction. Dimpling of the skin subjacent to the acromion (the sulcus sign) indicates inferior humeral translation, suggesting multidirectional instability.
- Apprehension test: Most effectively performed with the patient in the supine position stabilizing the scapula. Gently bring the affected arm into an abducted and externally rotated position. Patient apprehension and guarding by not allowing further motion by the examiner denotes a positive test that is consistent with anterior shoulder instability.
- Relocation test: Usually, this test is performed in conjunction with the apprehension test. After putting patient in an apprehensive position, apply a posteriorly directed pressure to the anterior proximal humerus, simulating a relocation of the glenohumeral joint that presumably was dislocated partially from the apprehension test. Posterior translation of the humeral head on the glenoid may be felt. A positive test may be noted when the patient becomes at ease with application of pressure on the anterior proximal humerus, suggesting anterior shoulder instability.
- Other tests may be performed on the shoulder to rule out other pathology affecting the biceps tendon, glenoid labrum, cervical spine, sternoclavicular joint, acromioclavicular joint, and scapulothoracic joint. A survey of other joint ROM also should be performed to assess for generalized ligamentous laxity.
- Neurovascular examination
- To complete the shoulder examination, a full neurologic examination must be performed, along with assessment of all upper extremity vascular pulses.
- Neurologic examination should include all neurologic segments from C5 through T1 myotomes (dermatomes with the corresponding stretch reflexes).
- Primary impingement
- Increased subacromial loading
- Acromial morphology (A hooked acromion, presence of an os acromiale or osteophyte, and/or calcific deposits in the subacromial space make patients more predisposed for primary impingement.)
- Acromioclavicular arthrosis (inferior osteophytes)
- Coracoacromial ligament hypertrophy
- Coracoid impingement
- Subacromial bursal thickening and fibrosis
- Prominent humeral greater tuberosity
- Trauma (direct macrotrauma or repetitive microtrauma)
- Overhead activity (athletic and nonathletic)
- Secondary impingement
- Rotator cuff overload/soft tissue imbalance
- Eccentric muscle overload
- Glenohumeral laxity/instability
- Long head of the biceps tendon laxity/weakness
- Glenoid labral lesions
- Muscle imbalance
- Scapular dyskinesia
- Posterior capsular tightness
- Trapezius paralysis
- Standard radiographic studies (4 views to rule out glenohumeral/acromioclavicular arthritis)
- Anterior-posterior (AP) view of the glenohumeral joint
- Internal rotation view of the humerus with 20° upward angulation to show acromioclavicular joint
- Axillary view is most useful to rule out subtle signs of instability (eg, glenoid avulsion, Hill-Sachs lesion) and to visualize presence of an os acromiale.
- Supraspinatus outlet view is most useful to assess the supraspinatus outlet space. If the space is less than 7 mm, then an increased risk for impingement syndrome exists. Also, assess morphology of the acromion (hooked acromion more at risk for impingement).
- MRI is considered the imaging study of choice for shoulder pathology.
- No radiation
- Able to detect intrasubstance tendon degeneration or partial rotator cuff tears
- Able to detect inflammation, edema, hemorrhage, or scarring
- Able to be used with an intra-articular contrast agent (eg, gadolinium), improving the MRI ability to detect partial rotator cuff tears
- Not able to accommodate patients with claustrophobia
- Not able to accommodate larger patients
- Not able to accommodate patients with pacemakers or other metal implants or particles
- Dependent on quality of the MRI machine
- Dependent on skill of technician performing the imaging and the radiologist interpreting the images
- Dye is injected into the glenohumeral joint and postinjection radiographs are filmed to assess the integrity of the glenohumeral joint.
- This study frequently is used in evaluating rotator cuff tears.
- If dye escapes out of the joint and into the subacromial space, it is diagnostic of a full-thickness rotator cuff tear.
- Can be used in conjunction with CT scan or MRI to evaluate intra-articular pathology (eg, Bankart tears)
- Low cost
- Size of the tears cannot be quantified.
- Patient is exposed to radiation.
- Contrast dye exposure
- Invasive procedure
- Diagnostic arthroscopy
- Minimally invasive visual surgical procedure to assess shoulder pathology
- Able to visualize and assess majority of shoulder lesions
- May give the patient and physician a chance to diagnose and treat the pathology in one procedure
- Workup for other more systemic processes may be included as clinically indicated.
During the acute to subacute phase, when pain and inflammation are predominant, a subacromial injection may be diagnostic and therapeutic as an adjunct to a rehabilitation program. Injection of 10 mL of 1% lidocaine solution (without epinephrine) into the subacromial space should relieve shoulder pain if pain and inflammation truly is originating from the supraspinatus outlet/subacromial space. Adding a low dose intermediate-acting injectable corticosteroid may provide a therapeutic effect. Betamethasone, triamcinolone, and methylprednisolone commonly are used. One mL of any of these available injectable corticosteroids mixed with 9 mL of 1% lidocaine solution (without epinephrine) commonly is used.
- Systemic effects include flushing, menstrual irregularity, impaired glucose tolerance, osteoporosis, psychological disturbance, steroid arthropathy, steroid myopathy, and immunosuppression.
- Local effects include postinjection flare.
- Usually, adverse effects are due to overdose and allergic reactions, which definitively can be minimized by double-checking the administered dose and inquiring about and checking on medication records for medication allergies.
- Effects of overdose and allergic reactions may be catastrophic and may include cardiac, respiratory, and cerebral compromise.
- Lie the patient down in the supine position. Elevate the patient's legs.
- Strongly reassure patient that recovery is fast.
- If patient briefly loses consciousness, protect the airway and give oxygen at 35% concentration.
Recovery Phase: Physical Therapy
The goal of this phase is to maintain a high level of training and prevent reoccurrence. Emphasis is placed on longer, more intense workouts and proper arthrokinematics of the shoulder. Analysis and modification of techniques and mechanics may reexacerbate symptoms. Make refinements in intensity and coordination. Patient education again is reemphasized, maintaining proper mechanics, strength, and flexibility and understanding the pathology. The patient also should have a good understanding of the warnings signs of early impingement and continue with a home exercise program with proper warm-up and strengthening techniques.
In general, conservative measures are continued for at least 3-6 months or longer if the patient is improving, which is usually the case in 60-90% of patients. If the patient remains significantly disabled and has no improvement after 3 months of conservative treatment, the clinician must seek further diagnostic work-up, and reconsider other etiologies or refer for surgical evaluation.
Appropriate surgical referrals are patients with subacromial impingement syndrome refractory to 3-6 months of appropriate conservative treatment. Surgery may be particularly beneficial in patients with full unrestricted PROM, positive response to injection of lidocaine into the subacromial space, a type III acromion having a large subacromial spur and those in whom changes are noted in the rotator cuff tendon on MRI scanning.
In a systematic review, Dorrestijn et al attempted to compare the effects of conservative and surgical treatment for subacromial impingement syndrome with regard to improvement of shoulder function and reduction of pain.4 Of 4 randomized controlled trials that met the investigators' criteria, 2 were of medium methodologic quality and 2 were of low methodologic quality, but there were no differences in outcome between the treatment groups. Their findings led Dorrestijn et al to note the scarcity of high-quality randomized controlled trials does not allow conclusive evidence for differences in pain outcomes and shoulder function in conservatively and surgically treated patients with subacromial impingement syndrome.
In another study, Ketola et al found no evidence that arthroscopic acromioplasty provides any additional value in the treatment of shoulder impingement syndrome.5 In a randomized, controlled trial in 140 patients, follow-up at 24 months showed no statistically significant difference in self-reported pain between patients who received only a supervised exercise program and those who underwent acromioplasty followed by an exercise program. In addition, acromioplasty added considerably to the cost of treatment.5
- Surgical Evaluation
- Initial examination under anesthesia (general anesthesia vs. regional block) and diagnostic arthroscopy
- Evaluation of shoulder ROM and stability
- In patients with limited motion, manipulation of the shoulder is performed. Diagnostic arthroscopy also may be performed, but arthroscopic subacromial decompression is generally not performed in patients with significant preoperative stiffness due to the increased risk of postoperative adhesive capsulitis
- Document any instability
- Arthroscopic evaluation
- Particular attention is directed to the rotator cuff, especially the supraspinatus tendon near its insertion onto the greater tuberosity
- Visualize the subscapularis tendon.
- Assess for labral pathology or changes suggesting glenohumeral instability.
- A partial tearing of the supraspinatus tendon along its articular surface is a common finding in symptomatic throwing athletes. The fragmented and torn tissue is debrided, leaving all intact rotator cuff tendon. This allows a more accurate determination of the size and thickness of the tear on the articular side of the rotator cuff and may help reduce symptoms of catching and pain.
- Following glenohumeral arthroscopy, the bursal side of the rotator cuff is then evaluated with arthroscopy
- The bursal surface of the rotator cuff is assessed for evidence of fraying as well as the amount of clearance between the anterior inferior acromion and the supraspinatus tendon.
- Also noted are any signs of fraying or wear changes on the undersurface of the coracoacromial ligament.
- If no evidence of rotator cuff disruption is noted, the coracoacromial ligament is smooth with adequate space between the anterior inferior acromion and rotator cuff, then the diagnosis of subacromial impingement is unlikely. In this case, subacromial decompression is not performed.
- In case of a small partial-thickness rotator cuff tear on the articular surface, without evidence of impingement, only glenohumeral debridement of this tear is performed. However, if the patient has changes suggestive of impingement syndrome, arthroscopic subacromial decompression (acromioplasty- resection of the anterior inferior portion of the acromion) is performed as well.
- If following subacromial decompression, a rotator cuff repair is necessary, it may be continued with arthroscopic assistance or it may be necessary to convert the rotator cuff repair to an open procedure.
- Postoperative care
- Postoperatively, a radiograph (supraspinatus outlet view) should be obtained to document the adequacy of the subacromial decompression. The appearance on this radiographic view should be of a type I acromial arch without any residual spurring.
- Following subacromial decompression, the patient is placed in a sling but is encouraged to remove the sling when comfortable and begin AROM and PROM exercises. When pain has decreased significantly and ROM has returned toward normal, a program of strengthening similar to the previously mentioned conservative management may be instituted. Patients cannot begin sports-specific activities until they have full AROM in the operated shoulder and normal strength, generally a time course of approximately 3-4 months.
- Surgical Outcome
- Results are generally good for properly selected middle-aged patients with evidence of impingement on history and physical examination and at the time of arthroscopy.
- General consensus in the literature is that arthroscopic subacromial decompression results in a good return to the previous level of function in approximately 85-90% of patients; however, results are generally poor in young high-performance athletes who participate in overhead activities.
- Hepatotoxicity: Liver function profile must be monitored in patients taking NSAIDs, periodically every 1-2 months, especially in high-risk individuals.
- Renal toxicity: Renal function profile must be monitored periodically every 1-2 months, especially in high-risk individuals.
- GI toxicity: Symptoms may include nausea, diarrhea, acid reflux, and periumbilical cramping. The physician may consider administering NSAIDs in conjunction with GI protective medications (eg, misoprostol, omeprazole, H2-blockers) and instruct patients to take NSAIDs with food. If GI symptoms persist for more than 2 weeks or if the patient has evidence of complication (eg, iron deficiency anemia, GI bleeding, unexplained weight loss, dysphagia), endoscopic evaluation is indicated
- Aplastic anemia: Monitor CBC, especially platelets, periodically for 1-2 months.
- Anaphylaxis: Inquire about and check medical records for history of allergic reactions.
Nonsteroidal Anti-inflammatory Medications (NSAIDs)
If shoulder impingement syndrome is not diagnosed and treated promptly and correctly, it can progress to rotator cuff degeneration and eventual tear. Other complications may include progression to adhesive capsulitis, cuff tear arthropathy, and reflex sympathetic dystrophy. Complications also may result from surgery, injection, physical therapy, or medication.
Primary prevention should be considered an integral part in the treatment of impingement syndrome. Education of patients at risk can do much to circumvent the development of impingement syndrome. Athletes, particularly those involved in throwing and overhead sports, and laborers with repetitive shoulder stress should be instructed in proper warm-up techniques, specific strengthening techniques, and have a good understanding of the warning signs of early impingement.
In general, prognosis for prompt and correct diagnosis and treatment of shoulder impingement syndrome is good and 60-90% of patients improve and are symptom-free with conservative treatment. Surgical outcomes are promising in patients who fail conservative therapy.
No immediate catastrophic sequela exists if diagnosis of shoulder impingement syndrome or rotator cuff tear is missed; however, the patient may become disabled progressively without prompt and correct diagnosis and treatment. Other complications may include progression to adhesive capsulitis, cuff tear arthropathy, and reflex sympathetic dystrophy. Complications also may result from surgery, injection, physical therapy, or medications. With complaint of any shoulder pain, the clinician must rule out disorders (eg, infection, tumor, dislocation, fracture, vascular injury, peripheral neurologic injury, cervical spine neurologic injury) that may have catastrophic consequences if action is not taken immediately. These diagnoses must be kept in mind in the differential and tested when assessing a shoulder problem in any patient.
- Shoulder impingement syndrome is managed similarly in all populations. How aggressive the management of this syndrome is depends upon the patient's activity level, reliance on the shoulder for occupation/athletics (recreational or competitive), age, and comorbid medical illnesses.
- In pregnancy, nursing mothers, young children, and patients with comorbid medical illnesses, caution must be used when administering medication to ensure the chosen medication is compatible for the patient.
- Patient's age, medical illnesses, low activity level, poor healing potential, poor anesthetic candidate, and pregnancy status may preclude the patient from being a surgical candidate.