Advances in the Understanding and Treatment of Rotator Cuff Disease
Abstract
Abstract
Shoulder pain and dysfunction increase with age, and one of the major causes of shoulder pain is changes in the rotator cuff tendons secondary to ageing, such as irritation of the rotator cuff tendons, partial tears of the tendons and full-thickness tears of the tendons. The exact reasons for this gradual tendon degeneration, which leads to tears, have been the subject of debate. As more scientific evidence has been acquired, the impact of these changes on what is perceived to cause the degeneration has led to changes in how the diseased tendons are treated. This article focuses on the major theories regarding the cause of tendon degeneration and on the evolution of and advances in treatment of rotator cuff abnormalities.
Keywords
Shoulder, rotator cuff, impingement, surgery, suture anchors, double row, failure
Disclosure: The authors have no conflicts of interest to declare.
Received: 28 July 2009 Accepted: 6 August 2009
Correspondence: Edward G McFarland, c/o Elaine P Henze, BJ, ELS, Medical Editor and Director, Editorial Services, Department of Orthopaedic Surgery, Johns Hopkins Bayview Medical Center, 4940 Eastern Ave, #A665, Baltimore, MD 21224-2780, US. E: ehenze1@jhmi.edu
Like many other conditions that become more common as a person ages, rotator cuff degeneration and symptoms can present as early as the fourth decade of life and increase linearly with age thereafter.1–3 Shoulder pain and rotator cuff disease have been shown to be factors in time off work and economic impact.4,5 However, despite the prevalence of abnormalities of the rotator cuff with ageing, not all individuals have symptoms. One magnetic resonance imaging (MRI) study found that by 60 years of age, some cuff abnormality is present even in individuals without shoulder pain: 54% of 60-year-old asymptomatic individuals had some evidence of partial- or fullthickness rotator cuff tears.6 In addition, although it has been shown that some small, full-thickness rotator cuff tears may get larger over time,7 the natural history of rotator cuff tears remains unknown.
This article addresses recent advances in the understanding and treatment of rotator cuff disease, including its causes, current treatments and potential future treatments.
What Causes Rotator Cuff Disease?
The cause of rotator cuff tendon degeneration and tears has been debated for approximately 100 years.8 It is commonly accepted wisdom in the orthopaedic community that normal tendons do not tear easily; for example, in trauma victims under 18 years of age, the bone to which the tendon attaches breaks before the tendon tears. As an individual matures, tendons throughout the body become more susceptible to tearing (even after relatively minor trauma). This observation is supported by the fact that tears of all tendons in the body, including the quadriceps, Achilles and biceps tendons, increase linearly with age. Although traumatic injury to the rotator cuff is one of the major causes of tendon tears, it is clear that, in many cases, the tendon was already weakened or even partially torn before the injury.
Since 1972, the prevailing theory of the cause of rotator cuff tears has been tendon ‘impingement’ on other structures. 9 Although not the originator of this idea, Dr Charles Neer 10 created a classification of injury that provided a rubric for the treatment of such tears. He suggested that rotator cuff abnormality and symptoms were primarily a result of rotator cuff tendons, especially the supraspinatus, rubbing against the anterolateral acromion and the coracoacromial ligament. If patients with impingement had no rotator cuff tear or only partial tearing of the tendon, he recommended partial acromioplasty and release of the coracoacromial ligament. In patients with a fullthickness rotator cuff tear, he recommended the same treatment with the addition of repair of the torn rotator cuff tendon back to the bone. 9 Interestingly, one study has shown that in symptomatic patients who did not have full-thickness rotator cuff tears, approximately 85% had satisfactory results in terms of pain relief with surgery. 11 However, in patients who had surgical repair of the rotator cuff tendon with an acromioplasty and release of the coracoacromial ligament, over 90% had a satisfactory result with pain relief as the measure.11
However, since then clinicians have come to appreciate that rotator cuff disease and symptoms are more complex than just impingement of the rotator cuff against the acromion. First, it became apparent that there was an imprecise relationship between the presence of a rotator cuff tear and symptoms: 12,13 many patients with torn rotator cuff tendons (and sometimes with multiple torn tendons) experience no symptoms. 14,15 Studies of rotator cuff repairs have shown that re-tearing of rotator cuff tendons after surgery is very common;however, despite this finding, typically more than 90% of patients are satisfied with the surgery whether or not the tendon heals back to the bone. 13,16 For ‘massive tears’ of the rotator cuff, which are defined as the presence of more than one rotator cuff tendon tear or a single tendon defect that is 3x4cm, studies have shown a re-tear rate of up to 90%. 13,16 Nevertheless, patients are generally satisfied with their surgical procedure, particularly in terms of pain relief.
Second, clinicians found that the coracoacromial ligament was not a vestigial structure (like the appendix), but that it helped restrain superior migration of the humeral head in relationship to the glenoid. 17 As a result, in some patients with large to massive rotator cuff tears, release of the coracoacromial ligament actually causes abnormal superior migration of the humeral head, which can lead to loss of range of shoulder motion and decreased function. After attempts to reconstruct this ligament once it was released proved fruitless, it became apparent that the ligament should not be excised, particularly in large rotator cuff tears.
