Roy J-S1,2, Michener L3, Cools A4, Sole G5, Struyf F6
1Laval University, Department of Rehabilitation, Quebec City, Canada, 2Centre for Interdisciplinary Research in Rehabilitation and Social Integration, Quebec City, Canada, 3University of Southern California, Division of Biokinesiology and Physical therapy, Los Angeles, United States, 4Ghent University, Department of Rehabilitation Sciences and Physiotherapy, Ghent, Belgium, 5University of Otago, School of Physiotherapy, Dunedin, New Zealand, 6University of Antwerp, Department of Rehabilitation Sciences and Physiotherapy, Antwerp, Belgium
- Describe and critically evaluate the evidence on anatomical, biomechanical, sensorimotor and psychosocial factors contributing to chronicity following rotator cuff (RC) tendinopathy.
- Discuss methods used by physiotherapists to evaluate these factors.
- Incorporate the current evidence of the contribution of proprioception, glenohumeral and scapular rehabilitation, and pain management in the rehabilitation of patients with RC tendinopathy.
Shoulder pain related to RC tendinopathy is common, and associated with substantial functional limitations. Of great concern to clinicians, researchers and patients alike, is that RC tendinopathy often becomes chronic. In fact, clinical trials suggest that, regardless of modality, long-term outcome is poor for more than 30% of patients with RC tendinopathy. It is therefore essential to better understand the factors associated with the development and chronicity of RC tendinopathy to promote optimal recovery. Five factors that have a role in the chronification of RC tendinopathy will be discussed.
RC tendons: Two predominant theories of RC tendon injury are tendon overload and compression between the humeral head and scapula. Debated evidence supports both mechanisms, but this evidence has limitations. External mechanistic causes of spinal posture, scapular motion, scapular and RC muscle weakness, posterior shoulder tightness, and shoulder capsular laxity. Physiotherapists can address these modifiable factors. Tendon intrinsic aspects of vascularity, aging, micro- and macro-morphology are related to tendinopathy. Understanding of mechanisms related to tendinopathy can aid in directing diagnosis and rehabilitation of patients with RC tendinopathy.
Brain: A potential influence in the chronification of RC tendinopathy is the presence of central motor alterations. In studies looking at motor cortex representations of RC muscles, individuals with RC tendinopathy have been shown to present decreased corticospinal excitability of the infraspinatus muscle. This decreased excitability is associated with the duration of symptoms and the narrowing of the subacromial space. Therefore, these central changes have a role in the chronicity of symptoms and in the maintenance of shoulder motor control deficits, and need to be considered in the rehabilitation process.
Scapula: The scapula plays an important role in normal shoulder function providing a stable base for the glenohumeral joint during daily activities. Malpositioning of the scapula, aberrant scapular movement patterns, and deviations in the muscle recruitment patterns have been identified in patients suffering from chronic shoulder pain. In view of the established association between scapular dyskinesis and RC disease, there is a need for a science based rehabilitation program, and for appropriate exercise selection to restore normal neuromuscular coordination, muscle balance, and muscle strength.
Proprioception: Impaired proprioception has traditionally been considered as a contributing factor for various shoulder disorders, however there is limited evidence that active joint positions sense may be reduced in patients with RC tendinopathy. An experimental study showed that proprioception, defined with threshold to detection of movement, might be more sensitive (improved) in the presence of sub-acromial pain, indicating a potential protective role to avoid pain. Proprioception may thus be a contributor towards a more sensitised nervous system that could potentially lead to chronicity of symptoms.
Central sensitization: There exists a potential mismatch between the origin of pathology and the perception of pain. Indeed, it is thought that the transition from acute to chronic pain arises from neuroplastic changes in the peripheral and central nervous system. Recent literature reviews have demonstrated that sensitization of the central nervous system plays an essential role in chronic pain conditions such as RC tendinopathy. Therefore, the effective diagnosis and treatment of RC tendinopathy should not only rely on detailed knowledge of the peripheral pathologies but also on current knowledge of pain neurophysiology.
Implications / Conclusions
Each presentation of RC tendinopathy is unique, as there is not a single mechanism or associated factor that contributes to the development. Therefore, clinicians must keep in mine that one of several factors may explain the symptoms for a given patient. Treatment selection must be based on a thorough clinical examination of the impairments and level of irritability of the individual patient. For some factors like scapular dysfunction, studies already provide a rationale for exercise selection. For other factors like central neural and proprioceptive deficits or central sensitization, new rehabilitation approaches may be needed. They include proprioceptive exercises with a wider approach that considers effects of a sensitised nervous system, and the use of non-invasive brain stimulation to prime the motor cortex during the retraining of appropriate control of movement.
- Rotator cuff
Relevance to physical therapy globally
Shoulder pain caused by rotator cuff tendinopathy is common, associated with substantial functional limitations and its incidence in the workplace is increasing despite efforts in prevention. Clinical trials suggest that, regardless of modality, long-term outcome is negative for more than 30% of patients with rotator cuff tendinopathy. It is therefore essential to better understand the factors associated with the occurrence (aetiology) and maintenance (chronicity) of RC tendinopathy to promote prevention and optimal recovery.
Knowledge users (clinicians), researchers, undergraduate and graduate students
Programme subject to change