Tendinopathy is a generic term without aetiological, biochemical or histological implications and is used to describe pathology in, and pain arising from, a tendon. The theories of the pathogenesis of rotator cuff tendinopathy may be divided into extrinsic and intrinsic causes and combinations of both. Intrinsic tendinopathy is defined as tendon pathology that originates within the tendon, usually as a consequence of overuse or overload (including compression). Increases and changes in collagen, proteoglycans, vascularity and cells have been described in tendon pathology. Evidence suggests that intrinsic degeneration within the rotator cuff is the principal factor in the pathogenesis of rotator cuff tears (Hashimoto et al 2003). Extrinsic factors include irritation or compression of the superior aspect of the tendons under the coraco-acromial arch, or of the articular side of the tendons from internal impingement onto the glenoid labrum.
The pathophysiology of rotator cuff disease has historically been viewed in 3 stages ranging from impingement syndrome to partial- and full-thickness rotator cuff tears (Neer 1983), or more recently using the contiuum model from reactive, to dysrepair and on to degenerative tendinopathy (Lewis 2010). Rotator cuff pathology is associated with advancing age, and thus a degnerative mechanism is likely to the primary cause of this condition.
Patients may present with impingement-type symptoms, pain at night and during overhead movement, as well as a painful arc. Some may have features of a torn rotator cuff tendon, manifest by painful weakness and atrophy. Shoulder pain persists or recurs in 40 to 50% of individuals within one year after initial presentation (Chard 1991; Croft 1996; van derWindt 1996). It also has a substantial detrimental impact upon quality of life (MacDermid 2004).
Anatomy of GHJ
Assessment and Diagnosis
Rotator cuff disorders are the most common cause of shoulder pain seen by physicians and its incidence is expected to grow as the population ages, but is increasingly active and less willing to accept functional limitations (Gomoll 2004). A wide range of conditions are included under this umbrella term including, rotator cuff tendonitis or tendinopathy, supraspinatus, infraspinatus, subscapularis or biceps tendonitis, subacromial bursitis, partial and complete rotator cuff tears. There is currently no uniformity in how these conditions are labeled and defined (Green 1998). Among published trials for rotator cuff disease, inclusion criteria most commonly include the presence of positive impingement signs including a painful arc with abduction and pain with resisted movements, and/or normal passive range of motion (Green 1998).
Historically, musculoskeletal assessment of the shoulder has been based around a premise that it is possible to isolate individual structures and apply a mechanical procedure that either compresses or stretches the tissue of interest or requires it to contract. However, it is unlikely that any test would not stretch or compress adjacent structures or cause them to contract during the procedure. Research has shown that although these tests have a high sensitivity and reproduce symptoms, they have an associated low specificity which substantially reduces their utility in deriving a specific diagnosis. The gold standard for diagnostic comparison with the clinical tests has traditionally been direct intra-operative observation, or indirect methods such as MRI or ultrasound. However the ability to achieve an accurate structural diagnosis is further challenged by the poor correlation between radiological imaging findings and symptoms.
Other diagnostic or classification systems for shoulder pain need to be investigated. One such approach, the Shoulder Symptom Modification Procedure was described by Lewis (2009) where symptom modifcation using various physical procedures is the aim of the assessment, and the findings can be used to direct treatment.
The diagnosis of rotator cuff disease is predominantly made by history and physical examination. Plain radiographs may exclude other causes of shoulder pain such as glenohumeral osteoarthritis, the presence of calcific deposits which are usually situated just proximal to the rotator cuff insertion or an acromial spur that might impinge on the rotator cuff. Elevation of the humeral head which together with narrowing of the subacromial space might indicate the presence of a large rotator cuff tear. Specific ‘outlet view’ x-rays may be useful in defining the shape of the acromion and may be helpful in surgical planning. Imaging modalities such as ultrasound and MRI are both equally useful for detecting full thickness rotator cuff tears but have lesser accuracy for detection of partial-thickness tears (Dinnes 2003).
Based upon magnetic resonance imaging scans, asymptomatic partial- and full-thickness rotator cuff tears have been demonstrated to occur in 4% of individuals < 40 years old and in more than 50% of individuals > 60 years old (Sher 1995). It is clear from these studies that the shoulder can continue to function well, despite significant structural changes , and that the presence or degree of shoulder pain is not directly related to the degree of structural pathology. A host of factors are likely to be involved in the development of chronic shoulder pain, including altered pain processing (Littlewood et al 2013, Rio et al 2013), as well as personal and social factors.
While a large proportion of patients with rotator cuff disease may be asymptomatic, one study found that 50% of individuals with asymptomatic rotator cuff tears followed up developed pain within five years (Yamaguchi 2001).
The objectives of treatment of symptomatic rotator cuff disease are to relieve pain, and restore movement and function of the shoulder. Conservative treatments are the first line option, including physiotherapy, nonsteroidal- anti-inflammatory drugs (NSAIDs), and corticosteroid injections if pain is a significant factor.
A recent systematic review of exercise for subacromial impingment concluded that exercise was a very effective management approach, however no specific exercise protocol could be recommended due to the lack of details provided in the studies (Hanratty et al 2012). Successful exercise programmes include strengthening for the rotator cuff muscles, and stabilising muscles of the scapula, as well as stretches and mobilising exercises to restore full range of movement.
Manual physiotherapy also seems to have a role in reducing pain and increasing mobility of the shoulder (Camarino and Marinkos 2009).
A specific exercise approach for those with massive or complete (surgically irreparable) rotator cuff tears, the Torbay protocol, has been described and successfully evaluated by Ainsworth (2006) . The details of the protocol have been made available to download here.
Surgery (decompression +/- rotator cuff repair) should be reserved for those who fail to respond to non-operative treatment (Gomoll 2004). Surgical procedures that may be used to treat rotator cuff disease include subacromial bursectomy, debridement of partial tears, subacromial decompression (acromioplasty) and/or removal of calcific deposits. Often a combination of procedures is performed. A Cochrane review (Coughlan et al 2008) reported that there is little evidence to support or refute the effectiveness of surgery for rotator cuff disease. This review found “Silver” level evidence from three trials that there is no difference in outcome between surgery and active non-operative treatment for impingement, and from six trials that there are no differences in pain, function or participant evaluation of success for arthroscopic compared to open subacromial decompression.
Ketola et al (2013) recently published a five-year follow up of 190 patients with subacromial impingment who were randomised to receive supervised exercise either with or without arthroscopic acromioplasty surgery. Both groups improved significantly over two and five years, but there was no significant difference in any of the outcome measures (pain, disability, working ability, pain at night, shoulder function) between those who had surgery and those who did not. Overal 75% of patients had recovered well, with the remainder continuing to have some pain and disability. Interestingly 30% of those in the study had developed pain in the opposite shoulder at the five-year follow-up. The authors conclude that there is no indication for acromioplasty surgery for uncomplicated subacromial impingement.
Studies of large populations and in workplace settings have identified that work-based activities such as vibration, repetitive overhead movements, lifting heavy loads, working in awkward postures and high psychosocial job demand, can all be related to the development of shoulder pain (Miranda et al 2008, van Rijn et al 2010). Ergomonic interventions in the workplace are very important in helping to prevent the development of rotator cuff disorders in the working population.
What is important for the clinician and the individual with shoulder pain is to have access to effective treatment that shortens the duration of symptoms and disability, and prevents recurrence. The answer to finding the right treatment for the individual at whatever degree or stage their rotator cuff tendinopathy is at, is not fully substantiated by the research yet. However, achieving better treatment pathways for shoulder pain will be of great value in terms of reduced morbidity and costs to both the individual and the community.
Ref: Coghlan JA, Buchbinder R, Green S, Johnston RV, Bell SN. Surgery for rotator cuff disease. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD005619. DOI: 10.1002/14651858.CD005619.pub2
Hashimoto T, Nobuhara K, Hamada T. (2003). Pathologic evidence of degeneration as a primary cause of rotator cuff tear. Clin Orthop Relat Res (415):111-20.
Lewis, J.S. (2009). Rotator cuff tendinopathy. Br J Sports Med 43:236-241. doi:10.1136/bjsm.2008.052175
Littlewood C, Malliaras P, Bateman M, Stace R, May S, Walters S. 2013 The central nervous system – An additional consideration in ‘rotator cuff tendinopathy’ and a potential basis for understanding response to loaded therapeutic exercise. Man Ther. doi: 10.1016/j.math.2013.07.005. [Epub ahead of print]
Miranda H, Punnett L, Viikari-Juntura E, Heliövaara M, Knekt P. 2008 Physical work and chronic shoulder disorder. Results of a prospective population-based study. Ann Rheum Dis; 67(2):218-23.
Rio E, Moseley L, Purdam C, Samiric T, Kidgell D, Pearce AJ, Jaberzadeh S, Cook J.The Pain of Tendinopathy: Physiological or Pathophysiological?Sports Med. 2013 Sep 12. [Epub ahead of print]
van Rijn RM, Huisstede BM, Koes BW, Burdorf A. 2010 Associations between work-related factors and specific disorders of the shoulder-a systematic review of the literature. Scand J Work Environ Health. 2010; 36(3):189-201.