Introduction
Rotator Cuff Tendinopathy is a common condition representing 30-70% of shoulder pain disorders. This condition is more significant after the age of 50 and can be attributed to multiple factors. Rotator Cuff Tendinopathy has adverse consequences on the quality of life and is associated with long-term disability, retirement and high rates of chronicity (40-50%).
While structural-oriented treatment may be effective in acute stages of musculoskeletal disorders (MSD), the outcomes are relatively poor in chronic stages. This proposes a question of what are the reasons beyond the development of chronic pain and disability in Rotator Cuff Tendinopathy. This simply leads us to consider CNS-related factors.
Rehabilitation strategies should include motor control training in the rehabilitation of chronic RCT.A study features different structural and global approaches to rehabilitate CNS reorganization, including sensorimotor training, pain education and postural exercises.
RC Tendons
There is a wide debate in the literature regarding shoulder pain terminology. Whether it is rotator cuff tendinopathy, sub acromial pain syndrome or sub acromial impingement syndrome we have to acknowledge the fact that shoulder pain is multifactorial and can be attributed to multiple reasons. However, in a clinical setting it is better to have objective measures to differentiate between rotator cuff tendinopathy and sub acromial pain syndrome. This is particularly helpful for rehabilitation decision-making.
Tendon overload/degeneration is likely to be a cause of sub acromial pain. Tendons, especially Supraspinatus tendon, also could be compressed mechanically in the sub acromial space. However, bony pathologies cannot be attributed as the sole cause of pain. Surgical approaches combined with rehabilitation was found to be no more effective than rehabilitation alone. Therefore, researchers suggest abandoning the ”impingement” terminology.
Intrinsic factors contributing to RC tendons degeneration/loading are:
- Vascularity
- Morphology
- Mechanical
- Ageing
- Genetic
Neovascularization, referring to increased blood supply in tendons causing pain, was evident in the lower limb. Despite this finding, we still need more studies to confirm neovascularity as a contributing factor to RCT. The less vascularity in shoulder tendons and the difficulty in obtaining diagnostic images similar to lower limb tendons propose challenges to study this factor
Although there is a wide agreement towards adapting the terminology ”Tendinopathy” instead of ” tendonitis”, inflammation was reported. Tendon thickening was also present in tendinopathy as a result of abnormal collagen laydown. However, it starts thinning with progressive tendon disease which may lead to tear. But thickening isn’t always a sign of tendinopathy as it was evident in overhead athletes and spinal cord injuries.
Compression is likely to be the reason of pain in three circumstances:
- Thicker tendon e.g.: overuse or disease
- Smaller distance between Acromion and Humerus AHD (7-8mm). Normally AHD= 10-15 mm.
- Occupation ratio: Supraspinatus Tendon: AHD. If the tendon occupies > AHD.
AHD is at its smallest between 0-90°. Therefore pain above 90° is likely to be of other reasons.
For rehabilitation decision making purposes, diagnosing shoulder pain could be classified as following:
| Recommendations for Diagnosis | ||
| Sub acromial Pain Syndrome (SPS)/ Partial Thickness Tear | Full Thickness Tear (FT-RCT) | |
| Confirm (Rule In): Specifity ≥ 80%. +Likelihood ratio ≥ 2.0. | Single Tests 1-Painful Arc 2-Resisted External Rotation (Pain or Weakness) 3-Full can 4- Drop Arm. Combo Tests 1-Hawkins 2-Pianful Arc 3-ER resistance (Pain/weakness). All 3+: +LR of 10.56 All 3-: -LR of 0.17 | Single Test: 1-Painful Arc 2-Resisted ER (marked weakness) 3-Drop Arm 4-ER lag-massive tear 5-Atrophy(infraspinatus) 6-IR lag& lift off 7-Belly off-subscapularis Combo Tests: 1- Age ≥ 65 you 2-ER (marked weakness) 3- Night Pain All 3 + :+LR of 9.84 All 3 – : -LR of 0.54 |
| Screen out (Rule Out): Sensitivity ≥ 80%. -LR ≤ 0.5 | Single Tests: 1-Painful Arc 2-Resisted ER: Pain or Weakness 3-Hawkins 4-Neer 5-Full Can 6-Empty can/Jobe test ComboTets: 3/5 1-Hawkins 2-Neer 3-Painful Arc 4-Empty Can 5-ER resistance If ≥ 3+ /5 : +LR of 2.93 If < 3+ / 5: – LR of 0.34 | Single Tests: 1-Resisted ER→marked weakness 2-IR lag and lift off 3-Full Can 4-Empty Can Combo Tests: 1-Drop Arm 2-Painful Arc 3-ERRT All 3 + R/In: + LR of 15.57 All 3 – R/Out: -LR of 0.16 |
Scapula
In healthy individuals, scapular movement is controlled through balanced activation patterns as follows:
- Prime Movers
- Dynamic Stabilizers
- Postural Muscles
Since Scapula plays an integral role in bridging shoulder complex to the spine, overloading the RC tendons to maintain GH stability is possible. Therefore it is essential to integrate scapular rehabilitation in the RCT management program.
When it comes to deciding which scapular-focused exercise to include in the rehabilitation program, clinicians should consider the following:
1- Neuromuscular Coordination and correcting scapular position consciously.
2-Restoring muscle balance rather than strengthening.
3-Integrating functional-specific or sport-specific exercises.
Recommendations for balancing muscle activation patterns
- To address middle and lower trapezius muscles hypo activity/weakness, it is recommended to add external rotation in different positions e.g. diagonal pattern and with shoulder elevation.
- Shoulder ER diagonal
- Shoulder ER with elevation
- Shoulder Elevation and ER on ball
- Forward shoulder elevation
Elevation Exercises are preferred over isolated protraction when targeting serratus anterior muscle.
- Adding an external rotation component and/or performing exercises in a lying position with the head resting are suggested for decreasing upper trapezius hyperactivity.
- Shoulder ER in lying position
- Open chain exercises with external rotation has been shown to decrease hyperactivity of pectoralis minor.
- Overhead exercises or closed chain positions such as overhead retractions, overhead shrugging and wall slide are recommended to decrease levator scapula hyperactivity.
- Integrating core and peripheral muscles could be helpful in RCT rehabilitation, considering kinetic chain role of the scapula. Serratus Anterior activation could be targeted by conscious contraction of core abdominal muscles and during high load exercises.
Proprioception
Pain, despite having a negative effect on muscle strength and performance had a positive effect on movement sense. Fatigue was also studied to see the effect it has on proprioception, and found to have no effect on proprioception, movement speed or accuracy.
Although some studies reported enhancement in proprioception, the available evidence is not sufficient to conclude whether proprioception deficits are linked to chronic RCT. Future studies should focus on getting an in-depth insight of the central influence of pain rather than the peripheral effects only. This also should be reflected on clinical practice, in terms of prescribing exercises that address both central and peripheral impairments
Central Sensitization
In response to pain, many people develop neuroplastic changes in the peripheral and central nervous systems. Neuroplasticity is associated with functional and chemical changes that induce sensitization rather than habituation. As a result, innocuous stimulus such as touch might be perceived as noxious ”painful”
Systematic reviews reported significant presence of central sensitization (CS) in a subgroup of chronic shoulder pain, but its specific role hasn’t yet been investigated sufficiently
Patients with chronic pain could be identified if they are having CS or not using a simple algorithm. Disproportionate, diffused pain are the most distinguishing criteria of CS. Central Sensitization Inventory and Scoring is also used to detect individuals with CS Additionally, we can subcategorize individuals with CS-dominance as either persisters or avoiders. Persisters will resume their normal activities after pain subsides, while avoiders will restrict or decrease their level of movement.
Regardless of CS-dominance, pain neuroscience education has been shown to be effective in chronic pain management. In addition, avoiders might benefit from graded exposure to exercises whereas pacing strategies might be helpful for persisters.
It is suggested to start with general exercises, especially if the patient has high levels of pain, then progressing to more specific exercise. General fitness exercises as well as manual therapy have shown analgesic effects in patients with chronic pain syndromes.
Conclusion
Each patient is unique and it is important to remember that Rotator Cuff Tendinopathy is not caused by only one injury mechanism and that different factors may be involved in each patient. Every patient should receive a thorough clinical examination and the treatment plan should be based on those findings while considering evidence based treatments for each factor.
Source: Physiopedia