A Conservative Approach to Treatment and Management of Rotator Cuff Impingement: A Literature Review

By Brett Taylor

Faculty Advisor: Rodger Tepe, PhD

A senior research project submitted in partial requirement

for the degree Doctor of Chiropractic

March 11, 2011

ABSTRACT

Objective: To present the various conditions of the shoulder/shoulder girdle, whether congenital, arthritis, muscle insufficiency or diversity of injuries and what, if any, conservative treatment can be applied by the chiropractic physician or physical therapist.

Clinical Features: Patients with varied symptoms including: soreness, pain or insufficiencies of the rotator cuff manifesting from acromial spurring or diminished space for supraspinatus excursion between the humeral head and acromion, weakness of abductor, external or internal muscles of the cuff or rotator cuff injuries.

Interventions and Outcome: Conservative treatment with spinal manipulative therapy, muscle stretching and strengthening, cryotherapy, ultrasound, range of motion exercises, taping and cross-friction massage have been shown to result in favorable outcomes in many patients, which eliminates the need for invasive surgery.

Conclusion: This literature review shows the benefit of conservative care for rotator cuff impingement and rotator cuff tears. Persistence of the patient in following through with the proposed treatment plan before the decision of undergoing invasive surgical repair is an important component of successful outcomes.

Key Indexing Terms: Shoulder, Shoulder Impingement Syndrome, Rotator Cuff

Impingement, Rotator Cuff Injury.

Taylor: Shoulder Impingement Syndrome: Literature Review 1

INTRODUCTION

Shoulder impingement syndrome and rotator cuff conditions are among the most

1, 2, 3, 4, 5 common causes of shoulder pain and dysfunction in adults. Shoulder pain is the third most common musculoskeletal symptom encountered after back and neck pain 6 accounting for almost 3 million patient visits each year in the United States.7 Conditions affecting the shoulder are a common complaint presenting to the primary health care physician, particularly the chiropractor 8, 9 and are amendable through conservative treatment. Shoulder impingement syndrome and shoulder pain are third only to headache

8, 9 and back pain in frequency seen in the practitioner’s office, yet, despite this, there is lack of prior reporting of impingement syndrome in the chiropractic literature. Half of these patients have 1 episode of shoulder pain yearly.10 Studies show that conservative management of shoulder impingement syndrome resolves the problem in 70-90% of patients, 9, 11 although, in certain cases, surgical intervention is required. 5 Successful management of impingement syndrome is dependent on an accurate diagnosis, which is attained by knowledge of the regional anatomy, the biomechanics of shoulder motion and the correct interpretation of the pathology determined through a detailed history, physical examination and diagnostic studies. 12

The glenohumeral articulation has more overall movement than any other joint in the body due to the minimal bony stability in the shoulder permitting a wide range of motion

(ROM). In order to achieve peak performance, there must be optimal balance between mobility and stability. 2, 12 Due to the limited bony structures, the shoulder is inherently

Taylor: Shoulder Impingement Syndrome: Literature Review 2 unstable, thus the soft tissue structures (static and dynamic stabilizers) are the major

12 glenohumeral stabilizers. However, excessive or repetitive strain of the shoulder complex can impair the balance between mobility and stability, placing the shoulder at

3, 12, 13 risk for a variety of disorders.

The purpose of this paper is to discuss the typical causes of shoulder pain and the conservative management in a chiropractic setting, common and beneficial exercises employed to strengthen and repair the rotator cuff, and when surgery is necessary/unnecessary.

DISCUSSION

Anatomical considerations: The shoulder joint is a multiaxial spheroid joint. The minimal bony stability in the shoulder permits the greatest range of motion of any other joint in the human body. The soft tissue structures are the major glenohumeral stabilizers. Stability is provided both statically by the capsule and labrum, and dynamically by the rotator cuff musculature. Dysfunction of any of these structures can lead to pain, weakness, and instability. Several interconnecting ligaments and layers of muscles join these bones, providing the rather unstable joint with a great amount of strength. 2, 12 Due to the curvature of the articular surfaces of the shoulder, the joint is not congruent and is referred to as “loose packed.” It is only when the humerus is abducted and externally rotated that it becomes “close packed” and a congruent joint. 2

The rotator cuff consists of four muscles, which reinforce the fibrous capsule and

Taylor: Shoulder Impingement Syndrome: Literature Review 3 control three basic motions: abduction, internal rotation and external rotation. The supraspinatus lies above the joint providing abduction, while the infraspinatus and teres minor muscles cross the joint posteriorly allowing for external rotation; all three muscles insert onto the greater tubercle of the humerus. The subscapularis, allowing for internal rotation, is the fourth rotator cuff muscle, attaching from the anterior surface of the scapula, crossing the glenohumeral joint anteriorly and inserting onto the lesser tubercle of the humerus. 2, 9, 12 The muscles of the rotator cuff balance the forces of other shoulder muscles, most importantly the deltoid muscle. Contraction of the deltoid muscle in the absence of supraspinatus function leads to superior translocation of the humeral head, making wide abduction difficult.

14 Clark and Harryman reported that tendons of the rotator cuff muscles fuse into one structure near or at their insertion into the tuberosities of the humerus. Therefore, the contraction loads of one cuff muscle can effect the attachment of neighboring tendons. 15

This interconnection may be important in the pathogenesis of cuff tears. 15 It was also noted that the coracohumeral ligament and fibers from adjacent cuff tendons reinforce the supraspinatus tendon. 14 The vascular supply to the rotator cuff tendons is different from that of typical synovial avascular tendons or paretenon-covered vascular tendons. 16 The rotator cuff tendons receive their blood supply through the bursal surface,

16 musculotendinous junction, and the periosteum. A “critical zone” of decreased vascularity near the insertion of the supraspinatus tendon has been identified.8 However, other investigators have noted an adequate vascular supply on the bursal surface with relative hypovascularity on the articular surface of the rotator cuff

Taylor: Shoulder Impingement Syndrome: Literature Review 4

Muscles. 16 This finding is consistent with reported higher incidence of the articular

17 surface tears of the cuff.

In 1972, Neer 18 first introduced the concept of rotator cuff impingement to the literature, stating that it resulted from mechanical impingement of the rotator cuff tendon beneath the anterior/inferior portion of the acromion, especially when the shoulder is placed in the forward-flexed and internally rotated position. 19 He reported that about

90% of rotator cuff tears are a result of subacromial impingement from supraspinatus outlet narrowing.

The supraspinatus outlet is a space formed on the upper rim, humeral head, and the glenoid by the acromion, coracoacromial arch and acromioclavicular joint. This outlet accommodates the passage and excursion of the supraspinatus tendon. Abnormalities of the supraspinatus outlet have been attributed as a cause of impingement syndrome and

20 21 rotator cuff disease, as has rotator cuff weakness.

Anatomical variants of the acromion have been shown to correlate with impingement.

5, 22 The acromion has been classified into three types based on the shape of its inferior surface: flat (type I), curved (typed II) and hooked (typed III). 1 The latter two types have been implicated as a causative factor in the development of impingement syndrome leading to rotator cuff pathology. 17

Research carried out by Neer on impingement was based on cadaveric dissections and clinical and surgical experience. 18 ,3, 12 He established a classification system that defines three stages in the spectrum of rotator cuff impingement that follow a pattern of severity.

Stage 1 is depicted by acute inflammation, edema and hemorrhage in the rotator cuff. In

Taylor: Shoulder Impingement Syndrome: Literature Review 5 stage 2, the rotator cuff tendon progresses to fibrosis and tendinitis. As this condition progresses, it may lead to mechanical disruption of the rotator cuff tendon and to changes in the coracoacromial arch with osteophytes along the anterior acromion. These changes are consistent with stage 3 of the Neer classification. In all Neer stages, etiology is impingement of the rotator cuff tendons under the acromion and a rigid coracoacromial

18 arch, eventually leading to degeneration and tearing of the rotator cuff tendon. Stage II warrant a possibility of surgery. Stage III, surgery is crucial.

Rotator cuff pain is frequently described as a dull ache of insidious onset, extending over the lateral arm and shoulder. Overhead activities exacerbate the pain, and the pain frequently increases at night and may awaken the individual from sleep. Weakness with the inability to abduct and elevate the arm is seen in more advanced cases; patients frequently describe difficulties combing hair, holding a hair dryer, and removing the wallet from their back pocket. Immediate onset of weakness, especially in association with trauma, may indicate an acute tear. Individuals with rotator cuff disorders can be divided into 2 groups according to their presenting symptoms: 1) those with impingement-type symptoms, frequently manifested as pain at night and at rest as well as a painful arc of motion, which can often be successfully treated by conservative measures; those with symptoms of a torn rotator cuff tendon, manifested as painful weakness and atrophy, which frequently do not respond fully to conservative measures alone and for which surgical intervention should be considered. 9

Impingement syndrome is a chronic process that manifests as shoulder pain and is, at least initially, reversible with rest or other conservative measures. Left untreated, the

Taylor: Shoulder Impingement Syndrome: Literature Review 6 pain can progress to permanent changes and eventual tearing of the rotator cuff, resulting in painful weakness. Impingement syndrome is classified into external, internal, and secondary impingement.

External impingement: External or outlet impingement, the most common form, is caused by compression of the rotator cuff tendons as they pass underneath the coracoacromial arch. 23 Narrowing of the humeroacromial motion interface, which lies between this arch and the humeral head, causes compression of the intervening rotator cuff tendons. Inflammation of the subacromial bursa can ensue, leading to pain and further compression due to secondary swelling. Narrowing of the humeroacromial interface can occur for a variety of reasons, such as acromioclavicular (AC) joint osteophytes, acromial bone spurs, or malunions after proximal humeral fractures, especially if there has been displacement of the greater tuberosity. 24 Neer has described several stages of external impingement, and he estimated it as the cause of 95% of rotator cuff tears in his practice. 23 Stage I affects younger patients, is fully reversible, and has hemorrhage and edema as anatomic correlates. Stage II is a disease affecting patients of middle age, is only partially reversible, and presents as tendon degeneration and fibrosis, also called tendinosis. Stage III occurs in elderly patients and is characterized by further

25 tendon degeneration and rupture.

Internal impingement-Internal impingement has been described more recently and occurs primarily in athletes who participate in overhead and throwing sports activities. 26

Its anatomic correlate consists of undersurface fraying of the infraspinatus tendon,

Taylor: Shoulder Impingement Syndrome: Literature Review 7 wherein it contacts the posterior glenoid as the arm is placed in maximum abduction and external rotation, such as the late cocking phase of throwing. Although this contact may often be present physiologically, the repetitive injury and eccentric loading associated with throwing can lead to labral and rotator cuff tears.

Secondary impingement-Secondary or nonoutlet impingement is a dynamic process caused by mild glenohumeral instability. Subtle subluxation of the humeral head brought on by activity can severely narrow the humeroacromial interface and thus lead to impingement symptoms. Posterior capsular contractures, such as occur with frozen shoulder, can cause obligate anterosuperior humeral head translation with forward flexion of the humerus. This also can narrow the acromiohumeral interval and result in secondary impingement.

Treatment

Patients presenting with supraspinatus tendinitis, supraspinatus strain and impingement syndrome respond well to cross friction massage and trigger point therapy of the bicipital and supraspinatus tendons, and supraspinatus, infraspinatus, rhomboid and trapezius muscles. This is followed by stretching of these muscles and cryotherapy. A course of shoulder mobilization exercises aimed at increasing the restricted shoulder

ROM is introduced in the second treatment as well as spinal manipulative therapy applied to the involved segmental spinal levels. All of these treatments and modalities are futile without proper ergonomic advice regarding the use of patient’s arms in day to day activities in muscle activation and movements at home and work. After the patients show improvement, they are given rehabilitation home exercises, which include ROM exercises, shoulder girdle stretching and strengthening. 25

Taylor: Shoulder Impingement Syndrome: Literature Review 8

The treatment choice for shoulder impingement syndrome is conservative and varies with the stage of the complaint, the level of progression and the level of shoulder motion involved in the patient’s daily activity. 9, 20

According to several authors, 60-90% of cases are successfully resolved with conservative management and rehabilitation when treatment is continued for at least 3-6 months or longer.

27 In a study carried out by Wen et al., the success rate of conservative management in patients with impingement syndrome was 73.8% regardless of the acromial morphology present. If the patient remains significantly disabled and has no improvement after conservative treatment, surgical treatment may be considered. Early therapeutic goals include the reduction of inflammation, swelling and pain. Cryotherapy is particularly beneficial during the acute inflammation stage or for the chronic recurrent exacerbation.

25 Stretching and strengthening of the rotator cuff muscles should be performed while avoiding the impingement positions and, once pain and inflammation have reduced, active and passive ROM exercises should be incorporated with gentle oscillation and

9, 25 mobilization. One recent in vivo study shows, for the first time, that adducting muscle forces lead to a significant increase of the subacromial space width compared to

26 abducting muscle activity. Thus, future physical therapy protocols should focus on increasing the depressor effect of adducting muscles in the postoperative and conservative treatment of impingement syndrome of the shoulder. This early rehabilitative activity allows for neurological reintegration of neuromuscular structures.

25 The pumping action of moving muscles expedites lymphatic flow, the input of

Taylor: Shoulder Impingement Syndrome: Literature Review 9 nutritional blood-borne factors and the withdrawal of inflammatory cellular debris and chemotactic factors. In those whose work or lifestyle involves repetitive overhead activity, the rotator cuff muscles are being placed in the impingement position frequently and they must be balanced. This requires anterior and posterior strength and flexibility.

13, 25 In a large majority of the cases, patients will only improve to a certain extent without proper compliance to necessary rehabilitative exercises or stretches while not changing their work habits, e.g. overhead activity.

The chiropractic physician will also want to assess the five joint complexes (the glenohumeral joint, the acromioclavicular joint, the sternocostal joints, the costovertebral joints and the scapulothoracic articulation) that are part of the kinetic chain affecting the

25 shoulder as well as assessing the spine for involvement.

Impingement and injury to the rotator cuff muscles could result in damage to the neural

25, 28 mechanoreceptors that mediate normal proprioceptive sensation of the shoulder.

This deficit could lead to slow protective reflexes, where contraction of the muscles occurs too late to protect the joint. Thus, the resultant proprioception deficit could contribute to chronic instability and further injury of the shoulder joint. Thus, kinesthetic and proprioceptive exercises should be incorporated into the shoulder rehabilitation program.

Patients with grade I primary shoulder impingement respond well to soft tissue therapy in application of ischemic pressure to the supraspinatus and infraspinatus muscles, as well as the rhomboids, upper trapezius, and levator scapulae. The application involves palpating the muscle bellies, musculotendinous junction, and applying a

Taylor: Shoulder Impingement Syndrome: Literature Review 10 sustained pressure onto areas of muscle spasm until a release of the barrier of resistance is felt. A release is defined as the relaxation of the muscle spasm with a decrease in the sensitivity and muscle tone after palpating the area. The pressure is applied repetitively, using the thumb or a myofascial T-bar until the muscle tension has been relaxed. 29

Scapular retraining may be implemented to improve control of scapular movement, particularly to avoid excessive elevation and protraction, so as to optimize the functional position of the shoulder. The therapist or chiropractor should passively guide the participant from a neutral shoulder girdle posture to an adducted, depressed position, then to an upwardly rotated, elevated position. The participant patient should then perform the movement actively for several repetitions followed by a 10 second hold in the adducted, depressed posture. This should be repeated 5 times. Postural taping should also be worn full time for approximately two weeks. The chiropractor or therapist should first apply a protective skin barrier followed by non-rigid strapping tape for postural adjustments. The shoulder taping technique should encourage a retracted, depressed scapular posture and thoracic extension increasing the interval between the acromion and the head of the humerus.

Longitudinal and transverse friction massage is applied to the posterior musculotendinous junction of the infraspinatus muscle, the postero/inferior aspect of the coracoacromial ligament, and the insertion of the supraspinatus on the greater tuberosity of the humerus. The friction massage application is achieved by palpating the capsular or tendinous adhesions and frictioning over its surface with the practitioner’s reinforced index finger, or with help of a myofascial T-bar. This is maintained until friction

Taylor: Shoulder Impingement Syndrome: Literature Review 11 anesthesia is achieved and the patient cannot feel any discomfort. A new point is then palpated and the process is again repeated. At the end of treatment sessions, ice application is advised at a frequency of 3 applications of 15 minutes with two 20 minute breaks. 29

Ultrasound phonophoresis is then applied to the areas that previously underwent friction massage. It can be applied with a continuous wave form for 7 minutes at a setting of 2.2 W/cm to the rotator cuff insertion on the anterior-inferior aspect of the humerus and posterior inferior aspect of the acromioclavicular joint. Ultrasound is often routinely used and can help with a quicker recovery from deep tissue massage, often alleviating or minimizing any post-treatment soreness. 29

Peripheral manual manipulation (high-velocity thrust) can be applied to the glenohumeral joints in external rotation and inferiorly to the acromioclavicular joint and anteriorly to posterior to the sternoclavicular joint. An activator tool can be used while the humerus is in external rotation or inferiorly through the acromioclavicular joint.

Also, to mobilize the thoracic and cervical spines, the patient can be adjusted in the upper thoracic levels.

Lastly, the patient is given a basic exercise program with initial emphasis on isometric strengthening of the supraspinatus and infraspinatus muscles. Implement these exercises only when a reduction of pain and improved range of motion is noted in the shoulder.

The frequency of exercises should be 4 sets of 10 repetitions, 2 to 3 times per day.

Shoulder shrugs, wall push-ups and scapula retraction exercises should also be performed

Taylor: Shoulder Impingement Syndrome: Literature Review 12 at the same frequency. All exercises in the beginning should be done with a Theraband to utilize isotonic or isometric muscle strengthening. Postural advice must also be given to the patient.

CONCLUSION

Shoulder pain from rotator cuff injury and shoulder impingement syndrome are common complaints presenting to the primary health care practitioner and one of the most common of the musculoskeletal disorders. The relationship between repetitive motion and impingement syndrome is possibly more complex than simple cause and effect. Thus, the goal of the practitioner should be to identify work-related and patient related factors that may contribute to the development of impingement and rotator cuff disease. The practitioner should also be comfortable recognizing the injury and associated maladaptions, including glenohumeral and scapular motion and stability, trunk and lower extremity mechanics, and activity-specific stresses that contribute to the patient’s pain. Fortunately, most rotator cuff injuries can be successfully treated conservatively and investigating the treatment options for shoulder complaints is crucial for developing optimal treatment approaches for those patients presenting with shoulder pain as a result of impingement syndrome and rotator cuff disease for a better long term prognosis. When the correct diagnosis is reached, a coordinated effort of conservative management by both the physician and patient enables most patients to return to their prior level of activity.

Taylor: Shoulder Impingement Syndrome: Literature Review 13

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22. Roodman WU. Etiologies of shoulder impingement syndrome in competitive swimmers. Chiro Sports Med 1989;3:27-31. 23. Shrode LW. Treating shoulder impingement using the supraspinatus synchronization exercise. JMPT 1994;17(1):43-53. 24. Praemer A, Furner S, Rice D. Musculoskeletal conditions in the United States. 2nd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 1999. 25. Neer C. Impingement lesions Clin Orthop 1983;173:70-7. 26. Walch G, Liotard J, Boileau P, Noel E. Postero-superior glenoid impingement: another impingement of the shoulder. J Radiol 1993;74:47-50. 27. Beredjiklian PK, Iannotti JP, Norris TR, Williams GR. Operative treatment of malunion of a fracture of the proximal aspect of the humerus. J Bone Joint Surg Am 1998;80:1484-97. 28. Moreau CE, Moreau SR. Chiropractic management of a professional hockey player with recurrent shoulder instability. JMPT 2001;24(6):425-30 29. Pribicevic M, Pollard H: Rotator Cuff Impingement. JMPT 2005;27:580-590.

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