- A supraspinatus tendinopathy is a generic term that indicates a condition characterized by pain in and around a tendon associated with repetitive activities, and impaired function that happens when the healing process fails to properly regenerate the tendon of the supraspinatus muscle.
- This can occur due to a trauma or repeated microtrauma and present as a partial or full thickness tear.
- Most of the time the tear occurs in the tendon or as an avulsion from the greater tuberosity.
- Tendinopathies account for over 30% of musculoskeletal consultations, and shoulder pain is the third most common musculoskeletal complaint.
- Tendon injuries of the rotator cuff (RC) are among the most common problems of the shoulder, affecting people performing sports as well as repetitive activities related to work or daily living.
- Moreover, tendinopathies of the RC increase with aging, affecting more than 80% of the people over eighty years of age, with the supraspinatus tendon being the most commonly affected.
- Although supraspinatus tendinopathy is a frequent shoulder condition, to date a definitive understanding of the associated pathology remains elusive, and there is no agreement on treatment.
CLINICAL RELEVANT ANATOMY
- The shoulder joint is made up of three bones: the humerus, scapula and clavicle.
- The head of humerus and glenoid of the scapula form a ball-and-socket joint.
- The supraspinatus muscle is located on the back of the shoulder, forming part of the rotator cuff.
- The rotator cuff consists of Supraspinatus, Infraspinatus, Subscapularis and teres minor. The rotator cuff covers the head of the humerus and keeps it into place. These muscles help to lift and rotate the arm.
Origin: Supraspinous fossa of the scapula
Insertion: Greater tubercle of the humerus
Innervation: Suprascapular nerve (C5-C6)
Function: Abduction of the glenohumeral joint; assists the rotator cuff in stabilizing, control and movement the shoulder; assists in preventing sublaxation at the shoulder.
- The supraspinatus muscle originates from the posterior aspect of the scapula, superior to the scapular spine and inserts on the greater tuberosity of the humerus, blending partially with the tendon of the infraspinatus muscle.
- The tendon of the supraspinatus muscle is a specialized nonhomogeneous structure subjected to both compressive, and tensile forces.
- Moreover, in order to better resist compression, and to lubricate collagen bundles during shoulder movements, there is an increased number of glycosaminoglycans within the supraspinatus tendon when compared with the distal region of the biceps tendon.
- The etiology of supraspinatus tears is multifactorial, consisting of age-related degeneration, micro trauma and macro trauma.
- Injury and degeneration are the two main causes of supraspinatus tear.
- Supraspinatus tear is associated with older patients, a history of trauma and mostly affect the dominant arm.
- Supraspinatus tendon disorders have been classically described as degenerative processes starting from an acute tendinitis, progressing to tendinosis, and eventually resulting in partial or full thickness tendon rupture.
- However, currently the terms tendinitis and tendinosis should be avoided and the word tendinopathy should be preferred as recent research shows that there are minimal or no inflammatory cells in painful tendons.
- Lesions of the supraspinatus tendon seem to start where the loads are thought to be the greatest, in other words, at the articular surface of the anterior insertion on the humerus.
- Excessive mechanical loads at the supraspinatus tendon insertion have been thought to cause an increased rate of collagen synthesis and turnover that are often related to tendon tears and ruptures.
- Although supraspinatus tendinopathy etiology is still poorly understood, several intrinsic and extrinsic factors have been theorized as contributors to the development of supraspinatus tendinopathies.
- Structural and biological changes happen when tendinopathy develops. Cellular and extracellular modifications characterize tendon healing stages that continue over time.
- The model explaining tendinopathy development has been changing over the years. Currently, it is generally accepted that supraspinatus tendinopathy develops when excessive stresses exceed the healing capacity of the tendon cells (tenocytes), with the tendon failing to repair properly.
- > 40 years old
- Male > Female
- Body mass index
- Repetitive stress/lifting
- History of trauma
- Lack of blood supply
- Bony spurs
- Overhead activities and other people who do overhead work:
- Tennis players
- Baseball pitchers
- Traumatic injury e.g. fall (more common cause in younger individuals)
Signs and Symptoms
- Patients normally present with pain.
- worsening pain (in cases where tears are progressing)
- Most common symptom include pain when lifting and lowering your arm or with specific movement.
- Deep aching constant pain at rest, in night, predominantly when you lie on the affected shoulder.
- Traumatic tears: Sudden, intense pain often accompanied by a snapping sensation and immediate weakness in the upper arm.
- Location: anterolaterally and superiorly.
- Referred to the level of the deltoid insertion with full-thickness tears.
- Repetitive strain tear: Starts off mild and only when lifting your arm; over time the pain can become more noticeable at rest. Aggravated in overhead or forward-flexed position.
- Limited range of motion:
- Reduced forward elevation, external rotation and abduction
- Struggle with activities like reaching behind back, combing hair and overhead activities.
- Weakness when rotating or lifting your arm
- History will reveal you the provisional diagnosis in 60-80% cases.
- You observation, palpation and physical examination will give the confirmation.
- At the physical examination, pain commonly presents in the arc of motion between 60 ° and 120 ° of shoulder abduction/scapular plane abduction, but does not tend to radiate.
- Drop-arm test
- Jobe/supraspinatus/empty can test
- Full can test
- Subacromial grind test
- One can go for other investigations (X-ray, CT, MRI) for further confirmation of diagnosis and to check the grade of injury.
- Tenocytes are the most represented cell type in tendons and are responsible for maintenance of tendons’ health as they produce collagen and ECM secretion.
- The ECM is a complex structural entity that surrounds the tendon cells, providing the ability to the tendon to resist mechanical loads, influencing the viscoelastic properties, and assisting in healing from injury.
- It is formed by structural proteins (collagen and elastin), specialized proteins (fibrillin and fibronectin), and proteoglycans.
- Tendon injuries heal because of scar tissue processes that may last from twelve up to twenty-four months.
- However, the final repaired tissue differs from the native tissue, with a higher concentration of type III collagen, and a lower concentration of type I collagen, resulting in a lower tensile strength.
- Classically, scar formation goes through a three-phase healing process that starts off with an inflammation phase (acute phase) followed by a reparative phase, ending with a remodeling phase.
- Knowledge of pathophysiology, tissue properties, and tissue healing process are key factors when developing a targeted and safe rehabilitation program.
- Although a singular accepted treatment for supraspinatus tendinopathy has not been agreed upon.
Inflammatory phase/acute phase
- Aim: To decrease pain, inflammation and spasm.
- Management: Initially for two days rest with Ice Therapy. After two three days one can begin with Isometrics to maintain the muscle and tissue health for next 4-5 days.
- Complete immobilization of the tendon should be avoided as it may cause a protein synthesis reduction, an increase in collagenase activity, and a catabolic biological response.
Reparative Phase/ Scar Phase
- Aim: To promote healing without promoting Scar formation.
- Management : Eccentric Loading of supraspinatus
- Therapeutic modalities like Laser, therapeutic ultrasound commonly utilized for tendinopathies may help limit or reverse the degenerative process of tendinopathy by improving repair processes
- Since alterations of upper trapezius/lower trapezius, and upper trapezius/middle trapezius ratios, shoulder kinematics, and posterior capsule tightness , have been associated with many shoulder disorders, correction of posterior shoulder tightness and restoration of gleno-humeral joint and scapular kinematics are encouraged.
- The addition of manual therapies such as: friction massage, scapular and gleno-humeral mobilization, proprioceptive neuromuscular facilitation, and nerve gliding/sliding techniques seem to be beneficial for decreasing pain and improving range of motion.
- Aim: To improve tensile strength and flexibility.
- Management : Gradual Progressive Concenteric Loading.
- GAGs, Proteoglycan and Protein rich food or supplementation.
- Proper Hydration (Alive water)