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Self-management of shoulder disorders—Part 1
ARTICLE IN PRESS Journal of Bodywork and Movement Therapies (2005) 9, 189–197
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SELF-MANAGEMENT: CLINICIAN SECTION
Self-management of shoulder disorders—Part 1$ Craig Liebenson, DC
Introduction
Epidemiology
Shoulder pain is a common ailment. Shoulder stability requires proper function of the rotator cuff and surrounding muscles which attach the arm to the torso. A properly functioning shoulder allows for movement with sufficient stability when pushing, pulling, swimming, throwing, lifting, or reaching overhead. Injury to the shoulder joint may limit movement and/or cause pain with activities. Since the shoulder has such great mobility, injury or dysfunction are common. Typical disorders include rotator cuff tendonitis or tears, shoulder impingement syndrome (pain while reaching overhead), shoulder instability, or severe limitation of the shoulder’s mobility (frozen shoulder or adhesive capsulitis). While many shoulder problems are frustrating and may take several months to heal, many spontaneously get better on their own. Trauma to the shoulder or recurring shoulder pain may be an indication that there is a more serious problem and additional investigation is required. This is the first part of a three-part series focusing on self-management approaches for common shoulder ailments. This first part will present the scope of the problem and typical mechanisms of injury that occur. Subsequent articles will discuss the examination and self-care approaches.
The incidence of shoulder pain is quite high in the general population. The point prevalence of shoulder pain is estimated to be 4–20% at any given time (% of people with a problem at one particular time) (Palmer, 2000; Vecchio et al., 1995). The 1 year prevalence is 16–40% (number of individuals who will have discomfort during a 1 year period) (Takala et al., 1982). Most people under the age of 40, with a shoulder problem, have rotator cuff lesions (Palmer et al., 2000; Vecchio et al., 1995). People over 40 years of age (mean of 55–60 years old) are more likely to suffer from adhesive capsulitis, while those over 65 are more likely to have a painful rotator cuff tear (Bulgen et al., 1984; van der Windt et al., 1995, 1996). Various risk factors for future shoulder problems have been identified. Fatigue, sleep problems, reduced sports activity, and high psychosomatic score in 15–18 year olds predict future shoulder pain (7 years later) (Siivola et al., 2004). Feuerstein et al. (2000) followed acute (o6 weeks from onset) upper quarter pain patients for up to 1 year to identify what factors were predictive of future outcome. The findings are summarized in Table 1. The RR is the Risk Ratio of incidence rates for a condition in two distinct populations. Thus, individuals with a catastrophizing pain coping style were found to be 1.87 times more likely to develop persistent upper quarter pain after 1 year than those who did not catastrophize.
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Table 1 Risk factors for prolonged upper quarter pain (Feuerstein et al., 2000). 1 month Upper extremity co-morbidity (RR 1.58) Pain severity (RR 1.45) Ergonomic risk factor (RR 1.07) Low job support (RR 1.03) Catastrophizing pain coping style (RR 1.54) 3 months
Pain severity (RR 10.46) Job stress (RR 1.20) Catastrophizing pain coping style (RR 1.98) Figure 1 Shoulder girdle anatomy. 12 months ] of pain treatment episodes (RR 1.77) Past recommendations for surgery (RR 6.43) Catastrophizing pain coping style (RR 1.87)
Pathogenesis and pathophysiology
Self-management of shoulder disorders—Part 1
Pain generators Shoulder disorders such as frozen shoulder, impingement syndrome, and instability disorders (e.g. labral tears) are quite common. The shoulder girdle functions as part of a kinetic chain linking the thorax to the hand. Many of the muscles of this region attach to the cervical spine, humerus, thorax, and even pelvis. The shoulder itself has only one articular attachment to the torso—via the sterno-clavicular (SC) joint. It is an inherently unstable joint, a large ball and a small socket in contrast to the hip which has a big socket. The ball and socket of the shoulder is likened to a golf ball on a tee or more accurately a ball balancing on a seals nose (see Figs. 1 and 2). A variety of structures can become strained or impinged in the shoulder girdle due to repetitive strain (overuse) or injury (see Figs. 3–6). The subacromial bursa, supraspinatus tendon, biceps tendon, and anterior labrum are all vulnerable to either impingement or instability.
Figure 2 Ball and socket of the glenohumeral joint.
Mechanism of injury—scapular dyskinesis Scapular dyskinesis (SD) is considered a nonspecific muscle response to various shoulder conditions (Kibler and McMullen, 2003). SD is associated with
Figure 3 Cross-sectional anatomy including many key pain generators.
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Figure 4 Long head of the biceps tendon: zone of impingement in the bicipital groove where rupture occurs modified from Neer, 1983. Impingement lesions. J. Orthopaedic Related Research 173, 70–77.
Figure 5 Supraspinatus tendon zone of overload.
impingement or instability by altering the normal mechanics and load distribution properties of the shoulder girdle. It is defined as an observable postural and movement dysfunction of the scapulae. Incoordination of scapular muscles, in particular inhibition of the serratus anterior and lower trapezius are the most likely contributers (McQuade et al., 1998). A reduction of the subacromial space is considered an important factor in the pathogenesis of impingement syndrome (Michener et al., 2003; Neer, 1972). Acromion or scapular morphology can also predispose to impingement (Bigliani et al., 1991; Anetzberger and Putz, 1996). Either abduction or protraction movements can also narrow the anterior opening of the subacromial space (Graichen et al., 1999, 2005; Solem-Bertoft et al., 1993).
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Figure 6 SLAP tear of biceps insertion on labrum adapted from Blackburn and Guido (2000). Rehabilitation after ligamentous and labral surgery of the shoulder: guiding concepts. J. Athletic Training 35(3), 373–381.
Postural component One postural sign of SD is prominence of the inferior-medial border of the scapulae (see Fig. 7) (Kibler and McMullen, 2003). Another sign is superior elevation of the entire scapulae (see Fig. 8) (Kibler and McMullen, 2003). Spinal posture influences the biomechanics of the shoulder (Kebaetse et al., 1998). Muscle force is 16.2% less in the 901 abducted arm position in individuals with a slouched vs. erect thoracic posture. There is a 23.61 decrease in shoulder abduction range of motion (ROM) in the slouched posture. Scapular kinematics is significantly influenced by thoracic spine posture. For instance there is less scapular posterior tilt (posterior and caudal movement of the scapulae) when slouched. Impingement patients have been shown to have reduced scapular posterior tilt during shoulder elevation when compared to asymptomatic individuals (Lukasiewicz et al., 1999). One aspect of a slumped posture is rounding of the shoulder forward (see Fig. 9). This stretches the anterior capsule and tightens the posterior capsule. Harryman et al. (1990) reported that posterior capsular tightness results in anterosuperior migration of the humeral head, thus leading to subacromial impingement (see Fig. 10). Bullock et al. (2005) have shown that an erect sitting posture increases active shoulder flexion
Self-management of shoulder disorders—Part 1
Self-management of shoulder disorders—Part 1
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Self-management of shoulder disorders—Part 1
Figure 7 Winged scapulae reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca, C., Cervico. Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998.
Figure 8 Shrugged (Gothic) shoulder girdle reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca, C., Cervico. Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998.
ROM in subjects with impingement syndrome. In the slouched posture mean shoulder flexion ROM was 109.71 whereas in erect posture it was 127.31.
Scapulohumeral rhythm and movement dysfunction From a functional perspective, one of the pivotal biomechanical events for the shoulder girdle is the scapulohumeral rhythm (SHR) (Burkhart et al., 2000; Kamkar et al., 1993). The SHR is the pattern of joint and muscular activity occurring during shoulder abduction, scaption, or flexion. Its purpose is to keep the glenoid fossa in a biomechanically optimal position to receive the humeral head. If the arm is internally rotated, abduction will be
C. Liebenson
Figure 9 Forward drawn shoulder girdle reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca. C., Cervico.Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998.
limited by the greater tubercle striking the acromion process and coracoacromial ligament. This will result in impingement of the subacromial bursa or supraspinatus tendon. Over time, impingement will lead to rotator cuff or biceps tendinosis and even instability. Total abduction is normally 1801. The glenohumeral contribution is 1201 and the scapulothoracic contribution is 601. Thus, there is 21 of glenohumeral motion for each 11 of scapulothoracic motion. In the first 30–601—the setting phase—virtually all the movement is glenohumeral. After that, abduction occurs roughly equally between the two functional joints. Two other joints also participate in this symphony of motion—the sternoclavicular and acromioclavicular. As the arm moves into abduction the scapulae rotates upwardly (inferior/medial border moves laterally) in order to position the glenoid fossa at the proper angle to receive the humeral head (see Fig. 11). The serratus anterior, upper trapezius, and lower trapezius help achieve this. The opposite movement downward rotation is promoted by the rhomboid major and levator scapulae. For the prime abductors of the shoulder, the deltoid and supraspinatus, to operate near capacity, the trapezius and serratus anterior must act synergistically. The upward rotation of the scapulae allows the deltoid and supraspinatus to keep a proper length–tension relationship, so they don’t lose their strength. Excessive downward rotation of the scapulae will promote SD. Normally, the shoulder girdle does not elevate in the first 601 of the SHR, which is called the setting phase’’. When the SHR is faulty usually the setting phase is reduced or absent and the patient is predisposed to subacromial impingement through ’’
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Figure 12 Setting phase during arm abduction reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca, C., Cervico.Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998. Figure 11 Force couples of major scapular and humeral muscles.
Biomechanics of throwing the following mechanisms (see Fig. 12). Rotator cuff fatigue can cause the humeral head to migrate superiorly (Chen et al., 1994–1995; Fleisig et al., 1996). This situation results in impingement as the deltoid force vector predominates over the rotator cuff and scapular fixator force vector (see Fig. 13). Similarly, lower trapezius and serratus anterior fatigue decreases acromial elevation (McQuade et al., 1998; Wadsworth and Bullock-Saxton, 1997). As the shoulder fatigues the SHR also changes from a 2:1 to a 1:1 ratio (McQuade et al., 1998). Such alterations in the SHR have been shown to be prevalent in individuals with stiff, painful shoulders (Babyar, 1996).
Overhead activities like swimming, weight lifting, throwing, tennis, volleyball, etc. cause repetitive strain to the shoulder girdle (Figs. 14 and 15). The scapular muscles play a vital role during arm motions, in particular the overhead throwing motion (DiGiovine et al., 1992). Proper scapular movement and stability are imperative for a healthy shoulder (Kibler, 1991, 1998). These muscles work in a synchronized fashion and act as force couples about the scapula, providing both movement and stabilization. Muscle imbalance due to overactive scapular elevators and underactive scapular depressors will cause impingement. Recent work has documented that overhead athletes with impingement syndrome have a delay in muscle
Self-management of shoulder disorders—Part 1
Figure 10 Posterior capsule tightness leading to impingement adapted from Blackburn, T.A., Guido, J.A., 2000. Rehabilitation after ligamentous and labral surgery of the shoulder: guiding concepts. J. Athletic Training 35(3), 373–381. (A) Normal, (B) tight.
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C. Liebenson latency of middle and lower trapezius during a sudden downward falling arm movement when compared to athletes without impingement (Cools et al., 2003). Throwing and serving motions involve the entire kinetic chain as the body attempts to optimize power and speed (Kibler, 1995). This activity progresses from the ground up (Fleisig et al., 1996; Kibler, 1995). The leg and trunk must provide a stable base for arm motion (Young et al., 1996). The majority of the force generated is provided by the leg and trunk (Kibler, 1995). Contralateral hip–pelvis control creates a stable post around which ideal trunk momentum develops (Young et al., 1996). A weak link’’ in the kinetic chain will cause compensatory activity that can lead to overload of the shoulder. Contralateral hip deficits (mobility and/or strength, particularly in rotation) are often seen with throwers, tennis players and others whose activity is primarily repetitive, unilateral and overhead (Kibler, 1998). The contralateral hip/ pelvis is used to push off from for pulling exercises (e.g. lawn mower) and for posting’’ during the ’’
Self-management of shoulder disorders—Part 1
’’
Figure 13 Inman force couple between deltoid and rotator cuff from Rowe, C.R. The shoulder, New York, 1988, Churchill Livingstone.
Figure 14 Throwing motion and glenohumeral stress modified from Fleisig GS, Andrews JR, Dillman, C.J., et al., 1995. Kinetics of baseball pitching with implication about injury mechanisms. Am J. Sports Med. 23, 233–239.
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Figure 16 Humerus outside the plane of the scapula adapted from Harding, W.G., 1993. Keep your shoulders in the safe zone’’. Phys. and Sports Med. 21, 93–94. (A) Opening up too soon—arm out of the plane of the scapulae, (B) in the plane of the scapulae. ’’
Most throwers exhibit an obvious motion disparity whereby external rotation is excessive and internal rotation is limited at 901 of abduction. (Bigliani et al., 1997; Brown et al., 1988; Johnson et al., 2003; Wilk et al., 1993). Most throwers exhibit significant laxity of the glenohumeral joint, which permits excessive ROM. The hypermobility of the thrower’s shoulder has been referred to as thrower’s laxity.’’ (Wilk et al., 1993) The laxity of ’’
landing phase of pushing exercises (e.g. punches, throwing, etc.). If there is a loss of control in the left hip of a right-handed thrower, the right shoulder or elbow face an increased injury risk. Ipsilateral hip deficits are also important as this is the leg that one balances on and pushes off from during throwing/hitting/pushing motions. The ipsilateral leg is also the leg which receives the body’s momentum during pulling actions.
Self-management of shoulder disorders—Part 1
Figure 15 Swimming motion and subacromial impingement adapted from Johnson, J.E., Sim, F.H., Scott, S.G., 1987. Swimming related injuries. Mayo Clin. Proc. 62289-304.
ARTICLE IN PRESS C. Liebenson
’’
Summary Shoulder girdle disorders are frequently related to faulty posture or motor control. Typical patterns of muscle imbalance, such as weakness of the lower
scapular fixators (serratus anterior and lower trapezius), and shoulder external rotators along with tightness of the scapulae elevators (upper trapezius, levator scapulae) and shoulder internal rotators are common. Overhead activities can be particularly strenuous for the shoulder and precipitate injury via repetitive strain, especially when SD is present. Subsequent articles in this series will detail the examination and rehabilitation of shoulder function.
References Allegrucci, M., Whitney, S.L., Lephart, S.M., et al., 1995. Shoulder kinesthesia in healthy unilateral athletes participating in upper extremity sports. Journal of Orthopaedic & Sports Physical Therapy 21, 220–226. Anetzberger, H., Putz, R., 1996. The scapula: principles of construction and stress. Acta Anatomica 156, 70–80. Babyar, S.R., 1996. Excessive scapular motion in individuals recovering from painful and stiff shoulders: causes and treatment strategies. Physical Therapy 76, 226–238. Bigliani, L.U., Ticker, J.B., Flatow, E.L., Soslowsky, L.J., Mow, V.C., 1991. The relationship of acromial architecture to rotator cuff disease. Clinics in Sports Medicine 10, 823–838. Bigliani, L.U., Codd, T.P., Connor, P.M., et al., 1997. Shoulder motion and laxity in the professional baseball player. American Journal of Sports Medicine 25, 609–613. Brown, L.P., Niehues, S.L., Harrah, A., et al., 1988. Upper extremity range of motion and isokinetic strength of the internal and external shoulder rotators in major league baseball players. American Journal of Sports Medicine 16, 577–585. Bulgen, D.Y., Binder, A.I., Hazleman, B.L., Dutton, J., Roberts, S., 1984. Frozen shoulder: prospective clinical study with an evaluation of three treatment regimens. Annals of the Rheumatic Diseases 43, 353–360. Bullock, M.P., Foster, N.E., Wright, C.C., 2005. Shoulder impingement: the effect of sitting posture on shoulder pain and range of motion. Manual Therapy 10, 28–37. Burkhart, S.S., Morgan, C.D., Kibler, W.B., 2000. Shoulder injuries in overhead athletes. The dead arm’’ revisited. Clinics in Sports Medicine 19, 125–158. Chen, S.K., Wickiewicz, T.L., Otis, J.C., et al., 1994–1995. Glenohumeral kinematics in a muscle fatigue model: a radiographic study. Orthopedic Transactions 18, 1126. Cools, A.M., Witvrouw, E.E., Declercq, G.A., Dannaeels, L.A., Cambier, D.C., 2003. Scapular muscle recruitment patterns: trapezius muscle latency with and without impingement symptoms. American Journal of Sports Medicine 31, 542–549. DiGiovine, N.M., Jobe, F.W., Pink, M., et al., 1992. An electromyographic analysis of the upper extremity in pitching. Journal of Shoulder and Elbow Surgery 1, 15–25. Feuerstein, M., Huang, G.D., Miller, J., Haufler, A.J., 2000. Development of a screen for predicting clinical outcomes in patients with work-related upper extremity disorders. Journal of Occupational and Environmental Medicine 42, 749–761. Fleisig, G.S., Barrentine, S.W., Escamilla, R.F., Andrews, J.R., 1996. Biomechanics of overhand throwing with implications for injuries. Sports Medicine 21, 421–437. Graichen, H., Bonel, H., Stammberger, T., Haubner, M., Englmeier, K.-H., Reiser, M., Eckstein, F., 1999. Subacromial ’’
the anterior and inferior glenohumeral joint capsule may be appreciated by the clinician during the stability assessment of the overhead thrower’s shoulder joint. Wilk et al. (1993, 1995) demonstrated that the external rotation strength of the pitcher’s throwing shoulder is significantly weaker (Po0:05) than the non-throwing shoulder, by 6%. Conversely, internal rotation strength of the throwing shoulder was significantly stronger (Po0:05), by 3%, compared with the non-throwing shoulder. In addition, adduction strength of the throwing shoulder is also significantly stronger than in the non-throwing shoulder, by approximately 9–10%. A proper balance between agonist and antagonist muscle groups is thought to provide dynamic stabilization to the shoulder joint. The external rotator muscles should be at least 65% the strength of the internal rotator muscles. (Wilk and Arrigo, 1993; Wilk et al., 1995, 1997). The thrower relies on enhanced proprioception to influence the neuromuscular system to dynamically stabilize the glenohumeral joint in the presence of significant capsular laxity and excessive ROM. Allegrucci et al. (1995) tested shoulder proprioception in 20 healthy overhead throwing athletes participating in various sports. The investigators noted that the dominant shoulder exhibited diminished proprioception compared with the non-dominant shoulder. Occasionally, throwers who exhibit internal impingement will allow their arm to lag behind the scapula, thus throwing with excessive horizontal abduction and not throwing with the humerus in the plane of the scapula (see Fig. 16). Jobe et al., 1989, 1990 and Jobe, 1997 referred to this as hyperangulation’’ of the arm. Practically speaking this dysfunction leads to the pitcher or thrower turning his/her chest towards the target ( opening up’’) too soon. The elbow should not go behind the back when the arm is cocked, but it should stay in the plane of the torso and scapulae while the body rotates on the back hip/leg. This type of fault leads to excessive strain on the anterior capsule and to internal impingement of the posterior rotator cuff. (Jobe, 1995, 1996, 1997) Correction of throwing pathomechanics is critical to returning the athlete to asymptomatic and effective throwing. ’’
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space width changes during abduction and rotation–a 3-D MR imaging study. Surgical Radiologic and Anatomy 21, 59–64. Graichen, H., Hinterwimmer, S., von Eisenhart-Rothe, R., Vogl, T., Englmeier, K.H., Eckstein, F., 2005. Effect of abducting and adducting muscle activity on glenohumeral translation, scapular kinematics and subacromial space width in vivo. Journal of Biomechanics 38, 755–760. Harryman II, D.T., Sidles, J.A., Clark, J.M., et al., 1990. Translation of the humeral head on the glenoid with passive glenohumeral motion. Journal of Bone and Joint Surgery 72A, 1334–1343. Jobe, C.M., 1995. Posterior superior glenoid impingement: expanded spectrum. Arthroscopy 11, 530–536. Jobe, C.M., 1996. Superior glenoid impingement [Current concepts]. Clinical Orthopedics 330, 98–107. Jobe, C.M., 1997. Superior glenoid impingement. Orthopedic Clinics of North America 28, 137–143. Jobe, F.W., Bradley, J.P., Tibone, J.E., 1989. The diagnosis and nonoperative treatment of shoulder injuries in athletes. Clinics in Sports Medicine 8, 419–438. Jobe, F.W., Tibone, J.E., Jobe, C.M., et al., 1990. The shoulder in sports. In: Rockwood, Jr, CA., Matsen, III, F.A. (Eds.), The Shoulder. W. B. Saunders, Philadelphia, pp. 961–990. Johnson, E.G., Godges, J.J., Lohman, E.B., Stephens, J.A., Zimmerman, G.J., 2003. Disability self-assessment and upper quarter muscle balance between female dental hygienists and non-dental hygienists. Journal of Dental Hygiene 77 (4), 217–223. Kamkar, A., Irrgang, J.J., Whitney, S.L., 1993. Nonoperative management of secondary shoulder impingement syndrome. Journal of Orthopedic & Sports Physical Therapy 17 (5), 212–224. Kebaetse, M., McClure, P., Pratt, N.A., 1998. Thoracic position effect on shoulder range of motion, strength, and threedimensional scapular kinematics. Archives of Physical Medicine and Rehabilitation 80, 945–950. Kibler, W.B., 1991. Role of the scapula in the overhead throwing motion. Contemporary Orthopedics 22, 525–532. Kibler, W.B., 1995. Biomechanical analysis of the shoulder during tennis activities. Clinics in Sports Medicine 14, 79–85. Kibler, W.B., 1998. The role of the scapula in athletic shoulder function. American Journal of Sports Medicine 26, 325–337. Kibler, W.B., McMullen, J., 2003. Scapular dyskinesis and its relation to shoulder pain. Journal of the American Academy of Orthopedic Surgery 11, 142–151. Lukasiewicz, A.C., McClure, P., Michener, L., et al., 1999. Comparison of 3-dimensional scapular position and orientation between subjects with and without shoulder impingement. Journal of Orthopedic & Sports Physical Therepy 29, 574–586. McQuade, K.J., Dawson, J.D., Smidt, G.L., 1998. Scapulothoracic muscle fatigue associated with alterations in scapulohumeral rhythm kinematics during maximum resistive shoulder elevation. Journal of Orthopedic & Sports Physical Therapy 28, 74.
197 Michener, L.A., McClure, P.W., Karduna, A.R., 2003. Anatomical and biomechanical mechanisms of subacromial impingement syndrome. Clinical Biomechanics 18, 369–379. Neer II, C.S., 1972. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. Journal of Bone and Joint Surgery 54, 41–50. Palmer, K., Walker-Bone, K., Linaker, C., Reading, I., Kellingray, S., Coggon, D., Cooper, C., 2000. The Southampton examination schedule for the diagnosis of musculoskeletal disorders of the upper limb. Annals of the Rheumatic Diseases 59, 5–11. Siivola, S.M., Levoska, S., Latvala, K., Horkio, E., Vanharanta, H., Keinanen-Kiukaanniemi, S., 2004. Predictive factors for neck and shoulder pain: a longitudinal study in young adults. Spine 29, 1662–1669. Solem-Bertoft, E., Thuomas, K.A., Westerberg, C.E., 1993. The influence of scapular retraction and protraction on the width of the subacromial space. An MRI study. Clinical Orthopaedics 296, 99–103. Takala, J., Sievers, K., Klaukka, T., 1982. Rheumatic symptoms in the middle aged population in southwestern Finland. Scandinavian Journal of Rheumatology 47 (Suppl), 15–29. van der Windt, D.A., Koes, B.W., de Jong, B.A., Bouter, L.M., 1995. Shoulder disorders in general practice: incidence, patient characteristics, and management. Annals of the Rheumatic Diseases 54, 959–964. van der Windt, D.A., Koes, B.W., Boeke, A.J., Deville, W., De Jong, B.A., Bouter, L.M., 1996. Shoulder disorders in general practice: prognostic indicators of outcome. British Journal of General Practice 46 (410), 519–523. Vecchio, P., Kavanagh, R., Hazleman, B.L., King, R.H., 1995. Shoulder pain in a community-based rheumatology clinic. British Journal of Rheumatology 34, 440–442. Wadsworth, D.J.S., Bullock-Saxton, J.E., 1997. Recruitment patterns of scapular rotator muscles in freestyle swimmers with suabacromial impingement. International Journal of Sports Medicine 18, 618–662. Wilk, K.E., Arrigo, C., 1993. Current concepts in the rehabilitation of the athletic shoulder. Journal of Orthopedic & Sports Physical Therapy 18, 365–378. Wilk, K.E., Andrews, J.R., Arrigo, C.A., et al., 1993. The strength characteristics of internal and external rotator muscles in professional baseball pitchers. American Journal of Sports Medicine 21, 61–66. Wilk, K.E., Andrews, J.R., Arrigo, C.A., 1995. The abductor and adductor strength characteristics of professional baseball pitchers. American Journal of Sports Medicine 23, 307–311. Wilk, K.E., Arrigo, C.A., Andrews, J.R., 1997. Current concepts: The stabilizing structures of the glenohumeral joint. Journal of Orthopedic & Sports Physical Therapy 25, 364–379. Young, J.L., Herring, S.A., Press, J.M., et al., 1996. The influence of the spine on the shoulder in the throwing athlete. Journal of Back and Musculoskeleton Rehabilitation 7, 5–17.
Self-management of shoulder disorders—Part 1
Self-management of shoulder disorders—Part 1
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SELF-MANAGEMENT: CLINICIAN SECTION
Self-management of shoulder disorders—Part 1$ Craig Liebenson, DC
Introduction
Epidemiology
Shoulder pain is a common ailment. Shoulder stability requires proper function of the rotator cuff and surrounding muscles which attach the arm to the torso. A properly functioning shoulder allows for movement with sufficient stability when pushing, pulling, swimming, throwing, lifting, or reaching overhead. Injury to the shoulder joint may limit movement and/or cause pain with activities. Since the shoulder has such great mobility, injury or dysfunction are common. Typical disorders include rotator cuff tendonitis or tears, shoulder impingement syndrome (pain while reaching overhead), shoulder instability, or severe limitation of the shoulder’s mobility (frozen shoulder or adhesive capsulitis). While many shoulder problems are frustrating and may take several months to heal, many spontaneously get better on their own. Trauma to the shoulder or recurring shoulder pain may be an indication that there is a more serious problem and additional investigation is required. This is the first part of a three-part series focusing on self-management approaches for common shoulder ailments. This first part will present the scope of the problem and typical mechanisms of injury that occur. Subsequent articles will discuss the examination and self-care approaches.
The incidence of shoulder pain is quite high in the general population. The point prevalence of shoulder pain is estimated to be 4–20% at any given time (% of people with a problem at one particular time) (Palmer, 2000; Vecchio et al., 1995). The 1 year prevalence is 16–40% (number of individuals who will have discomfort during a 1 year period) (Takala et al., 1982). Most people under the age of 40, with a shoulder problem, have rotator cuff lesions (Palmer et al., 2000; Vecchio et al., 1995). People over 40 years of age (mean of 55–60 years old) are more likely to suffer from adhesive capsulitis, while those over 65 are more likely to have a painful rotator cuff tear (Bulgen et al., 1984; van der Windt et al., 1995, 1996). Various risk factors for future shoulder problems have been identified. Fatigue, sleep problems, reduced sports activity, and high psychosomatic score in 15–18 year olds predict future shoulder pain (7 years later) (Siivola et al., 2004). Feuerstein et al. (2000) followed acute (o6 weeks from onset) upper quarter pain patients for up to 1 year to identify what factors were predictive of future outcome. The findings are summarized in Table 1. The RR is the Risk Ratio of incidence rates for a condition in two distinct populations. Thus, individuals with a catastrophizing pain coping style were found to be 1.87 times more likely to develop persistent upper quarter pain after 1 year than those who did not catastrophize.
$
This paper may be photocopied for educational use.
Tel.: +1 310 470 2909; fax: +1 310 470 3286.
E-mail address: [email protected]. 1360-8592/$ - see front matter & 2005 Published by Elsevier Ltd. doi:10.1016/j.jbmt.2005.04.004
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Table 1 Risk factors for prolonged upper quarter pain (Feuerstein et al., 2000). 1 month Upper extremity co-morbidity (RR 1.58) Pain severity (RR 1.45) Ergonomic risk factor (RR 1.07) Low job support (RR 1.03) Catastrophizing pain coping style (RR 1.54) 3 months
Pain severity (RR 10.46) Job stress (RR 1.20) Catastrophizing pain coping style (RR 1.98) Figure 1 Shoulder girdle anatomy. 12 months ] of pain treatment episodes (RR 1.77) Past recommendations for surgery (RR 6.43) Catastrophizing pain coping style (RR 1.87)
Pathogenesis and pathophysiology
Self-management of shoulder disorders—Part 1
Pain generators Shoulder disorders such as frozen shoulder, impingement syndrome, and instability disorders (e.g. labral tears) are quite common. The shoulder girdle functions as part of a kinetic chain linking the thorax to the hand. Many of the muscles of this region attach to the cervical spine, humerus, thorax, and even pelvis. The shoulder itself has only one articular attachment to the torso—via the sterno-clavicular (SC) joint. It is an inherently unstable joint, a large ball and a small socket in contrast to the hip which has a big socket. The ball and socket of the shoulder is likened to a golf ball on a tee or more accurately a ball balancing on a seals nose (see Figs. 1 and 2). A variety of structures can become strained or impinged in the shoulder girdle due to repetitive strain (overuse) or injury (see Figs. 3–6). The subacromial bursa, supraspinatus tendon, biceps tendon, and anterior labrum are all vulnerable to either impingement or instability.
Figure 2 Ball and socket of the glenohumeral joint.
Mechanism of injury—scapular dyskinesis Scapular dyskinesis (SD) is considered a nonspecific muscle response to various shoulder conditions (Kibler and McMullen, 2003). SD is associated with
Figure 3 Cross-sectional anatomy including many key pain generators.
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Figure 4 Long head of the biceps tendon: zone of impingement in the bicipital groove where rupture occurs modified from Neer, 1983. Impingement lesions. J. Orthopaedic Related Research 173, 70–77.
Figure 5 Supraspinatus tendon zone of overload.
impingement or instability by altering the normal mechanics and load distribution properties of the shoulder girdle. It is defined as an observable postural and movement dysfunction of the scapulae. Incoordination of scapular muscles, in particular inhibition of the serratus anterior and lower trapezius are the most likely contributers (McQuade et al., 1998). A reduction of the subacromial space is considered an important factor in the pathogenesis of impingement syndrome (Michener et al., 2003; Neer, 1972). Acromion or scapular morphology can also predispose to impingement (Bigliani et al., 1991; Anetzberger and Putz, 1996). Either abduction or protraction movements can also narrow the anterior opening of the subacromial space (Graichen et al., 1999, 2005; Solem-Bertoft et al., 1993).
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Figure 6 SLAP tear of biceps insertion on labrum adapted from Blackburn and Guido (2000). Rehabilitation after ligamentous and labral surgery of the shoulder: guiding concepts. J. Athletic Training 35(3), 373–381.
Postural component One postural sign of SD is prominence of the inferior-medial border of the scapulae (see Fig. 7) (Kibler and McMullen, 2003). Another sign is superior elevation of the entire scapulae (see Fig. 8) (Kibler and McMullen, 2003). Spinal posture influences the biomechanics of the shoulder (Kebaetse et al., 1998). Muscle force is 16.2% less in the 901 abducted arm position in individuals with a slouched vs. erect thoracic posture. There is a 23.61 decrease in shoulder abduction range of motion (ROM) in the slouched posture. Scapular kinematics is significantly influenced by thoracic spine posture. For instance there is less scapular posterior tilt (posterior and caudal movement of the scapulae) when slouched. Impingement patients have been shown to have reduced scapular posterior tilt during shoulder elevation when compared to asymptomatic individuals (Lukasiewicz et al., 1999). One aspect of a slumped posture is rounding of the shoulder forward (see Fig. 9). This stretches the anterior capsule and tightens the posterior capsule. Harryman et al. (1990) reported that posterior capsular tightness results in anterosuperior migration of the humeral head, thus leading to subacromial impingement (see Fig. 10). Bullock et al. (2005) have shown that an erect sitting posture increases active shoulder flexion
Self-management of shoulder disorders—Part 1
Self-management of shoulder disorders—Part 1
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Self-management of shoulder disorders—Part 1
Figure 7 Winged scapulae reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca, C., Cervico. Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998.
Figure 8 Shrugged (Gothic) shoulder girdle reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca, C., Cervico. Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998.
ROM in subjects with impingement syndrome. In the slouched posture mean shoulder flexion ROM was 109.71 whereas in erect posture it was 127.31.
Scapulohumeral rhythm and movement dysfunction From a functional perspective, one of the pivotal biomechanical events for the shoulder girdle is the scapulohumeral rhythm (SHR) (Burkhart et al., 2000; Kamkar et al., 1993). The SHR is the pattern of joint and muscular activity occurring during shoulder abduction, scaption, or flexion. Its purpose is to keep the glenoid fossa in a biomechanically optimal position to receive the humeral head. If the arm is internally rotated, abduction will be
C. Liebenson
Figure 9 Forward drawn shoulder girdle reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca. C., Cervico.Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998.
limited by the greater tubercle striking the acromion process and coracoacromial ligament. This will result in impingement of the subacromial bursa or supraspinatus tendon. Over time, impingement will lead to rotator cuff or biceps tendinosis and even instability. Total abduction is normally 1801. The glenohumeral contribution is 1201 and the scapulothoracic contribution is 601. Thus, there is 21 of glenohumeral motion for each 11 of scapulothoracic motion. In the first 30–601—the setting phase—virtually all the movement is glenohumeral. After that, abduction occurs roughly equally between the two functional joints. Two other joints also participate in this symphony of motion—the sternoclavicular and acromioclavicular. As the arm moves into abduction the scapulae rotates upwardly (inferior/medial border moves laterally) in order to position the glenoid fossa at the proper angle to receive the humeral head (see Fig. 11). The serratus anterior, upper trapezius, and lower trapezius help achieve this. The opposite movement downward rotation is promoted by the rhomboid major and levator scapulae. For the prime abductors of the shoulder, the deltoid and supraspinatus, to operate near capacity, the trapezius and serratus anterior must act synergistically. The upward rotation of the scapulae allows the deltoid and supraspinatus to keep a proper length–tension relationship, so they don’t lose their strength. Excessive downward rotation of the scapulae will promote SD. Normally, the shoulder girdle does not elevate in the first 601 of the SHR, which is called the setting phase’’. When the SHR is faulty usually the setting phase is reduced or absent and the patient is predisposed to subacromial impingement through ’’
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ARTICLE IN PRESS Self-management of shoulder disorders—Part 1
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Figure 12 Setting phase during arm abduction reproduced with permission from Liebenson, C.S., LeFebvre, R., DeFranca, C., Cervico.Thoracic spine: making a rehabilitation prescription. Lippincott/Williams and Wilkins, 1998. Figure 11 Force couples of major scapular and humeral muscles.
Biomechanics of throwing the following mechanisms (see Fig. 12). Rotator cuff fatigue can cause the humeral head to migrate superiorly (Chen et al., 1994–1995; Fleisig et al., 1996). This situation results in impingement as the deltoid force vector predominates over the rotator cuff and scapular fixator force vector (see Fig. 13). Similarly, lower trapezius and serratus anterior fatigue decreases acromial elevation (McQuade et al., 1998; Wadsworth and Bullock-Saxton, 1997). As the shoulder fatigues the SHR also changes from a 2:1 to a 1:1 ratio (McQuade et al., 1998). Such alterations in the SHR have been shown to be prevalent in individuals with stiff, painful shoulders (Babyar, 1996).
Overhead activities like swimming, weight lifting, throwing, tennis, volleyball, etc. cause repetitive strain to the shoulder girdle (Figs. 14 and 15). The scapular muscles play a vital role during arm motions, in particular the overhead throwing motion (DiGiovine et al., 1992). Proper scapular movement and stability are imperative for a healthy shoulder (Kibler, 1991, 1998). These muscles work in a synchronized fashion and act as force couples about the scapula, providing both movement and stabilization. Muscle imbalance due to overactive scapular elevators and underactive scapular depressors will cause impingement. Recent work has documented that overhead athletes with impingement syndrome have a delay in muscle
Self-management of shoulder disorders—Part 1
Figure 10 Posterior capsule tightness leading to impingement adapted from Blackburn, T.A., Guido, J.A., 2000. Rehabilitation after ligamentous and labral surgery of the shoulder: guiding concepts. J. Athletic Training 35(3), 373–381. (A) Normal, (B) tight.
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C. Liebenson latency of middle and lower trapezius during a sudden downward falling arm movement when compared to athletes without impingement (Cools et al., 2003). Throwing and serving motions involve the entire kinetic chain as the body attempts to optimize power and speed (Kibler, 1995). This activity progresses from the ground up (Fleisig et al., 1996; Kibler, 1995). The leg and trunk must provide a stable base for arm motion (Young et al., 1996). The majority of the force generated is provided by the leg and trunk (Kibler, 1995). Contralateral hip–pelvis control creates a stable post around which ideal trunk momentum develops (Young et al., 1996). A weak link’’ in the kinetic chain will cause compensatory activity that can lead to overload of the shoulder. Contralateral hip deficits (mobility and/or strength, particularly in rotation) are often seen with throwers, tennis players and others whose activity is primarily repetitive, unilateral and overhead (Kibler, 1998). The contralateral hip/ pelvis is used to push off from for pulling exercises (e.g. lawn mower) and for posting’’ during the ’’
Self-management of shoulder disorders—Part 1
’’
Figure 13 Inman force couple between deltoid and rotator cuff from Rowe, C.R. The shoulder, New York, 1988, Churchill Livingstone.
Figure 14 Throwing motion and glenohumeral stress modified from Fleisig GS, Andrews JR, Dillman, C.J., et al., 1995. Kinetics of baseball pitching with implication about injury mechanisms. Am J. Sports Med. 23, 233–239.
ARTICLE IN PRESS Self-management of shoulder disorders—Part 1
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Figure 16 Humerus outside the plane of the scapula adapted from Harding, W.G., 1993. Keep your shoulders in the safe zone’’. Phys. and Sports Med. 21, 93–94. (A) Opening up too soon—arm out of the plane of the scapulae, (B) in the plane of the scapulae. ’’
Most throwers exhibit an obvious motion disparity whereby external rotation is excessive and internal rotation is limited at 901 of abduction. (Bigliani et al., 1997; Brown et al., 1988; Johnson et al., 2003; Wilk et al., 1993). Most throwers exhibit significant laxity of the glenohumeral joint, which permits excessive ROM. The hypermobility of the thrower’s shoulder has been referred to as thrower’s laxity.’’ (Wilk et al., 1993) The laxity of ’’
landing phase of pushing exercises (e.g. punches, throwing, etc.). If there is a loss of control in the left hip of a right-handed thrower, the right shoulder or elbow face an increased injury risk. Ipsilateral hip deficits are also important as this is the leg that one balances on and pushes off from during throwing/hitting/pushing motions. The ipsilateral leg is also the leg which receives the body’s momentum during pulling actions.
Self-management of shoulder disorders—Part 1
Figure 15 Swimming motion and subacromial impingement adapted from Johnson, J.E., Sim, F.H., Scott, S.G., 1987. Swimming related injuries. Mayo Clin. Proc. 62289-304.
ARTICLE IN PRESS C. Liebenson
’’
Summary Shoulder girdle disorders are frequently related to faulty posture or motor control. Typical patterns of muscle imbalance, such as weakness of the lower
scapular fixators (serratus anterior and lower trapezius), and shoulder external rotators along with tightness of the scapulae elevators (upper trapezius, levator scapulae) and shoulder internal rotators are common. Overhead activities can be particularly strenuous for the shoulder and precipitate injury via repetitive strain, especially when SD is present. Subsequent articles in this series will detail the examination and rehabilitation of shoulder function.
References Allegrucci, M., Whitney, S.L., Lephart, S.M., et al., 1995. Shoulder kinesthesia in healthy unilateral athletes participating in upper extremity sports. Journal of Orthopaedic & Sports Physical Therapy 21, 220–226. Anetzberger, H., Putz, R., 1996. The scapula: principles of construction and stress. Acta Anatomica 156, 70–80. Babyar, S.R., 1996. Excessive scapular motion in individuals recovering from painful and stiff shoulders: causes and treatment strategies. Physical Therapy 76, 226–238. Bigliani, L.U., Ticker, J.B., Flatow, E.L., Soslowsky, L.J., Mow, V.C., 1991. The relationship of acromial architecture to rotator cuff disease. Clinics in Sports Medicine 10, 823–838. Bigliani, L.U., Codd, T.P., Connor, P.M., et al., 1997. Shoulder motion and laxity in the professional baseball player. American Journal of Sports Medicine 25, 609–613. Brown, L.P., Niehues, S.L., Harrah, A., et al., 1988. Upper extremity range of motion and isokinetic strength of the internal and external shoulder rotators in major league baseball players. American Journal of Sports Medicine 16, 577–585. Bulgen, D.Y., Binder, A.I., Hazleman, B.L., Dutton, J., Roberts, S., 1984. Frozen shoulder: prospective clinical study with an evaluation of three treatment regimens. Annals of the Rheumatic Diseases 43, 353–360. Bullock, M.P., Foster, N.E., Wright, C.C., 2005. Shoulder impingement: the effect of sitting posture on shoulder pain and range of motion. Manual Therapy 10, 28–37. Burkhart, S.S., Morgan, C.D., Kibler, W.B., 2000. Shoulder injuries in overhead athletes. The dead arm’’ revisited. Clinics in Sports Medicine 19, 125–158. Chen, S.K., Wickiewicz, T.L., Otis, J.C., et al., 1994–1995. Glenohumeral kinematics in a muscle fatigue model: a radiographic study. Orthopedic Transactions 18, 1126. Cools, A.M., Witvrouw, E.E., Declercq, G.A., Dannaeels, L.A., Cambier, D.C., 2003. Scapular muscle recruitment patterns: trapezius muscle latency with and without impingement symptoms. American Journal of Sports Medicine 31, 542–549. DiGiovine, N.M., Jobe, F.W., Pink, M., et al., 1992. An electromyographic analysis of the upper extremity in pitching. Journal of Shoulder and Elbow Surgery 1, 15–25. Feuerstein, M., Huang, G.D., Miller, J., Haufler, A.J., 2000. Development of a screen for predicting clinical outcomes in patients with work-related upper extremity disorders. Journal of Occupational and Environmental Medicine 42, 749–761. Fleisig, G.S., Barrentine, S.W., Escamilla, R.F., Andrews, J.R., 1996. Biomechanics of overhand throwing with implications for injuries. Sports Medicine 21, 421–437. Graichen, H., Bonel, H., Stammberger, T., Haubner, M., Englmeier, K.-H., Reiser, M., Eckstein, F., 1999. Subacromial ’’
the anterior and inferior glenohumeral joint capsule may be appreciated by the clinician during the stability assessment of the overhead thrower’s shoulder joint. Wilk et al. (1993, 1995) demonstrated that the external rotation strength of the pitcher’s throwing shoulder is significantly weaker (Po0:05) than the non-throwing shoulder, by 6%. Conversely, internal rotation strength of the throwing shoulder was significantly stronger (Po0:05), by 3%, compared with the non-throwing shoulder. In addition, adduction strength of the throwing shoulder is also significantly stronger than in the non-throwing shoulder, by approximately 9–10%. A proper balance between agonist and antagonist muscle groups is thought to provide dynamic stabilization to the shoulder joint. The external rotator muscles should be at least 65% the strength of the internal rotator muscles. (Wilk and Arrigo, 1993; Wilk et al., 1995, 1997). The thrower relies on enhanced proprioception to influence the neuromuscular system to dynamically stabilize the glenohumeral joint in the presence of significant capsular laxity and excessive ROM. Allegrucci et al. (1995) tested shoulder proprioception in 20 healthy overhead throwing athletes participating in various sports. The investigators noted that the dominant shoulder exhibited diminished proprioception compared with the non-dominant shoulder. Occasionally, throwers who exhibit internal impingement will allow their arm to lag behind the scapula, thus throwing with excessive horizontal abduction and not throwing with the humerus in the plane of the scapula (see Fig. 16). Jobe et al., 1989, 1990 and Jobe, 1997 referred to this as hyperangulation’’ of the arm. Practically speaking this dysfunction leads to the pitcher or thrower turning his/her chest towards the target ( opening up’’) too soon. The elbow should not go behind the back when the arm is cocked, but it should stay in the plane of the torso and scapulae while the body rotates on the back hip/leg. This type of fault leads to excessive strain on the anterior capsule and to internal impingement of the posterior rotator cuff. (Jobe, 1995, 1996, 1997) Correction of throwing pathomechanics is critical to returning the athlete to asymptomatic and effective throwing. ’’
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space width changes during abduction and rotation–a 3-D MR imaging study. Surgical Radiologic and Anatomy 21, 59–64. Graichen, H., Hinterwimmer, S., von Eisenhart-Rothe, R., Vogl, T., Englmeier, K.H., Eckstein, F., 2005. Effect of abducting and adducting muscle activity on glenohumeral translation, scapular kinematics and subacromial space width in vivo. Journal of Biomechanics 38, 755–760. Harryman II, D.T., Sidles, J.A., Clark, J.M., et al., 1990. Translation of the humeral head on the glenoid with passive glenohumeral motion. Journal of Bone and Joint Surgery 72A, 1334–1343. Jobe, C.M., 1995. Posterior superior glenoid impingement: expanded spectrum. Arthroscopy 11, 530–536. Jobe, C.M., 1996. Superior glenoid impingement [Current concepts]. Clinical Orthopedics 330, 98–107. Jobe, C.M., 1997. Superior glenoid impingement. Orthopedic Clinics of North America 28, 137–143. Jobe, F.W., Bradley, J.P., Tibone, J.E., 1989. The diagnosis and nonoperative treatment of shoulder injuries in athletes. Clinics in Sports Medicine 8, 419–438. Jobe, F.W., Tibone, J.E., Jobe, C.M., et al., 1990. The shoulder in sports. In: Rockwood, Jr, CA., Matsen, III, F.A. (Eds.), The Shoulder. W. B. Saunders, Philadelphia, pp. 961–990. Johnson, E.G., Godges, J.J., Lohman, E.B., Stephens, J.A., Zimmerman, G.J., 2003. Disability self-assessment and upper quarter muscle balance between female dental hygienists and non-dental hygienists. Journal of Dental Hygiene 77 (4), 217–223. Kamkar, A., Irrgang, J.J., Whitney, S.L., 1993. Nonoperative management of secondary shoulder impingement syndrome. Journal of Orthopedic & Sports Physical Therapy 17 (5), 212–224. Kebaetse, M., McClure, P., Pratt, N.A., 1998. Thoracic position effect on shoulder range of motion, strength, and threedimensional scapular kinematics. Archives of Physical Medicine and Rehabilitation 80, 945–950. Kibler, W.B., 1991. Role of the scapula in the overhead throwing motion. Contemporary Orthopedics 22, 525–532. Kibler, W.B., 1995. Biomechanical analysis of the shoulder during tennis activities. Clinics in Sports Medicine 14, 79–85. Kibler, W.B., 1998. The role of the scapula in athletic shoulder function. American Journal of Sports Medicine 26, 325–337. Kibler, W.B., McMullen, J., 2003. Scapular dyskinesis and its relation to shoulder pain. Journal of the American Academy of Orthopedic Surgery 11, 142–151. Lukasiewicz, A.C., McClure, P., Michener, L., et al., 1999. Comparison of 3-dimensional scapular position and orientation between subjects with and without shoulder impingement. Journal of Orthopedic & Sports Physical Therepy 29, 574–586. McQuade, K.J., Dawson, J.D., Smidt, G.L., 1998. Scapulothoracic muscle fatigue associated with alterations in scapulohumeral rhythm kinematics during maximum resistive shoulder elevation. Journal of Orthopedic & Sports Physical Therapy 28, 74.
197 Michener, L.A., McClure, P.W., Karduna, A.R., 2003. Anatomical and biomechanical mechanisms of subacromial impingement syndrome. Clinical Biomechanics 18, 369–379. Neer II, C.S., 1972. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. Journal of Bone and Joint Surgery 54, 41–50. Palmer, K., Walker-Bone, K., Linaker, C., Reading, I., Kellingray, S., Coggon, D., Cooper, C., 2000. The Southampton examination schedule for the diagnosis of musculoskeletal disorders of the upper limb. Annals of the Rheumatic Diseases 59, 5–11. Siivola, S.M., Levoska, S., Latvala, K., Horkio, E., Vanharanta, H., Keinanen-Kiukaanniemi, S., 2004. Predictive factors for neck and shoulder pain: a longitudinal study in young adults. Spine 29, 1662–1669. Solem-Bertoft, E., Thuomas, K.A., Westerberg, C.E., 1993. The influence of scapular retraction and protraction on the width of the subacromial space. An MRI study. Clinical Orthopaedics 296, 99–103. Takala, J., Sievers, K., Klaukka, T., 1982. Rheumatic symptoms in the middle aged population in southwestern Finland. Scandinavian Journal of Rheumatology 47 (Suppl), 15–29. van der Windt, D.A., Koes, B.W., de Jong, B.A., Bouter, L.M., 1995. Shoulder disorders in general practice: incidence, patient characteristics, and management. Annals of the Rheumatic Diseases 54, 959–964. van der Windt, D.A., Koes, B.W., Boeke, A.J., Deville, W., De Jong, B.A., Bouter, L.M., 1996. Shoulder disorders in general practice: prognostic indicators of outcome. British Journal of General Practice 46 (410), 519–523. Vecchio, P., Kavanagh, R., Hazleman, B.L., King, R.H., 1995. Shoulder pain in a community-based rheumatology clinic. British Journal of Rheumatology 34, 440–442. Wadsworth, D.J.S., Bullock-Saxton, J.E., 1997. Recruitment patterns of scapular rotator muscles in freestyle swimmers with suabacromial impingement. International Journal of Sports Medicine 18, 618–662. Wilk, K.E., Arrigo, C., 1993. Current concepts in the rehabilitation of the athletic shoulder. Journal of Orthopedic & Sports Physical Therapy 18, 365–378. Wilk, K.E., Andrews, J.R., Arrigo, C.A., et al., 1993. The strength characteristics of internal and external rotator muscles in professional baseball pitchers. American Journal of Sports Medicine 21, 61–66. Wilk, K.E., Andrews, J.R., Arrigo, C.A., 1995. The abductor and adductor strength characteristics of professional baseball pitchers. American Journal of Sports Medicine 23, 307–311. Wilk, K.E., Arrigo, C.A., Andrews, J.R., 1997. Current concepts: The stabilizing structures of the glenohumeral joint. Journal of Orthopedic & Sports Physical Therapy 25, 364–379. Young, J.L., Herring, S.A., Press, J.M., et al., 1996. The influence of the spine on the shoulder in the throwing athlete. Journal of Back and Musculoskeleton Rehabilitation 7, 5–17.
Self-management of shoulder disorders—Part 1
Self-management of shoulder disorders—Part 1