Subacromial impingement syndrome

Classification of subcarpal tunnel syndrom

Subcarpal tunnel syndrome, also known as subcarpal tunnel syndrome, was first classified in 1972 by Dr. Charles Neer, who divided it into four types:

• Type I mainly affects patients under the age of 25 and is often associated with overuse injuries. It is characterized by tendonitis, swelling and moderate pain in the shoulder joint during exercise, with no loss of muscle strength or restriction of movement.
• Type II is more advanced and usually affects patients between 25-40 years of age. It is characterized by increased pain, inflammation, loss of mobility, and the lesions show fibrosis and irreversible changes to the rotator cone tendons.
• Type III occurs in people over the age of 40 and is characterized by partial tearing of the rotator cone.
• Type IV also affects people over the age of 40 and is characterized by a complete tear of the rotator ring.

Currently, subacromial tightness syndrome is referred to as the first phase of rotator cone disease. It can occur as a conflict and inflammation of the infrapatellar bursa, it can be as a partial rotator cone lesion, as a massive rotator cone lesion - more than two tendons and more, and it can also be as an arthropathy due to chronic rotator ring damage.

Causes of subcarpal tightness syndrome

Repeated overhead movements with the upper limb in some sports can cause narrowing of the subacromial space. This causes damage to the rotator ring with the onset of local inflammation with swelling and pain. This, of course, causes an increase in subarbar tightness reducing the regenerative capacity.

Primary factors are related to congenital or acquired structural changes that mechanically narrow the subarbar space. Among them may be a rotator-ring tendon conflict between the coracoacromial ligament, the shoulder-clavicular joint and the shoulder process, osteophyte formation, abnormal bone alignment after a fracture.

Secondary factors are related to biomechanical changes, such as abnormal kinematics due to changes in the balance of muscle strength (weakening of the rotator cone muscles). Degeneration of the supraspinatus muscle makes it too weak (it is disused or hurts). Therefore, there is an upward movement of the head of the humerus as the shoulder muscle pulls it up, which reduces the sub-bar space causing tightness. This is why exercise is so important, because strengthening the rotator muscles lowers the head of the humerus relative to the shoulder process and reduces friction. This is why exercise is such an important component of rehabilitation.

Symptoms of subacromial tightness syndrome

Patients with subacromial tightness syndrome are generally over the age of 40 and suffer from persistent pain in the shoulder girdle area without any previous injury. Most often, it is a degenerative condition that develops in secret over weeks or months, rather than the result of a sudden injury. Therefore, patients often have difficulty determining the exact onset of symptoms. The main symptom is pain when lifting the shoulder at an angle of 70-120°, as well as when sleeping on the affected shoulder or with the arm under the head. Shoulder pain in this case can have acute or chronic symptoms. Most often it occurs locally, with radiation along the medial or lateral part of the arm. The sensation of shoulder pain can be particularly annoying when performing activities with the arms up, such as reaching for objects above the head, or at least combing the hair.

Diagnosis of subacromial tightness syndrome

There are many conditions of the shoulder that can resemble the symptoms that subacromial tightness syndrome produces. A detailed history and clinical examination are necessary for a proper diagnosis. No single test is accurate enough to conclusively diagnose subacromial tightness syndrome, but using a combination of specific tests increases the likelihood of a correct diagnosis.

Examples of tests in the diagnosis of subcarpal tunnel syndrome:

• Neer's test - positive if passive forward bending >90° causes pain,
• Hawkins test - positive if internal rotation and passive forward flexion up to 90° causes pain,
• Jobe's test - pain with internal rotation with resistance and forward flexion to 90° indicates pathology of the supraspinatus muscle,
• Painful arc test - pain with shoulder inversion in the plane of the scapula from 60° to 120°,
• Yocum's test - positive if pain appeared with elbow elevation, when the hand on the same side rested on the opposite shoulder.

Helpful in the diagnosis of subcarpal tunnel syndrome are imaging studies, such as an X-ray, which can show us, among other things, degenerative changes, osteophytes, calcification of the coracohumeral ligament, cystic changes in the greater tuberosity, the shape of the shoulder process of the scapula, whether it is of the hooked type, for example. The orthopedist may also order an MRI - magnetic resonance imaging - which is useful in assessing the extent of rotator cone pathology.

How to treat subacromial tightness syndrome?

Shoulder pain caused by subacromial tightness syndrome generally does not go away on its own, especially if the cause is not removed and we continue to be physically active. That's why it's a good idea to consult a sports orthopedist for diagnosis and treatment. In the meantime, we can reduce the pain and apply ice packs to the sore shoulder. However, be sure to reduce physical activity, as the exercises we do may interfere with the healing process and cause further damage. Subacromial tightness syndrome begins with conservative treatment (unless we have damage to the rotator cone), which can take about a year until we see marked improvement. Conservative treatment of the syndrome consists of: rest, reduction of pain and swelling, and restriction of physical activity, especially with overhead movements. For subacromial tightness syndrome, painkillers such as Paracetamol are not particularly effective, and can only be used at the beginning of treatment or if symptoms are severe. Anti-inflammatory drugs like Olfen or Diclofenac work better.

The doctor may also give an injection of Glucocorticosteroid (Diprofos), which is often used for its anti-inflammatory and analgesic effects. The effect of the injection is usually very effective, but temporary. It can last for several months, but also only a few weeks. The injection is usually used when shoulder pain has persisted for a long time and physical therapy has been unsuccessful, or in athletes who need to speed up the healing process. Platelet-rich plasma injections are sometimes used. The basis of conservative treatment is exercise-based physiotherapy. Exercise therapy should focus on controlling the shoulder, strengthening the rotator cone and the muscles that stabilize the scapula. Good shoulder and scapular posture increases the gap where the tendon and bursa are located and reduces pressure. When exercise proves ineffective, when conservative treatment fails to reduce pain and restore shoulder function, surgery should be considered. Several surgical techniques are available and are used depending on the nature and severity of the injury.

Physiotherapy in the treatment of subcarpal tightness syndrome

Sample exercises are presented by Rehasport physiotherapist Natalia Reke.

Strengthening of the external rotators of the shoulder joint
Starting position: lying on the side with the arm and elbow close to the body, elbow bent 90 degrees, in the hand a weight (0.5-2kg).
Execution: external rotation of the arm by lifting the hand with the weight toward the ceiling.
Compensation: excessive adduction of the shoulder blade to the spine.

Activation of the lower stabilizers of the scapula.
Starting position: lying on the stomach with the arm close to the body, elbow straight, in the hand a weight (0.5-2kg).
Execution: lowering and adducting the scapula to the spine with simultaneous elevation of the arm with the weight toward the ceiling.
Compensations: excessive internal rotation of the scapula, lifting the scapula away from the chest.

Automobilization of the thoracic segment of the spine
Starting position: lying on the back with a roller (roller) under the thoracic spine.
Execution: on an inhalation, lift the arms (weights/elastic tape can be added) behind the head and straighten the thoracic spine.
Compensation: extending the chin toward the ceiling.

Activation of the rotator ring m. during flexion with resistance
Starting position: standing with an elastic band in a loop between the wrists/forearms, elbows bent 90 degrees.
Execution: maintaining the position of the forearms and elbows with simultaneous lifting of the arms.
Compensation: tilting back the torso, wrists parallel to elbows.

Stretching the front chest wall
Starting position: standing in lunge with forearm resting against the wall/frame, elbow bent 90 degrees.
Execution: pushing the forearm against the wall (horizontal adduction of the arm) for 10 sec, then inhaling and exhaling and deepening the outward rotation of the body (away from the wall) or static maintenance of the stretching position for a minimum of 30 seconds.
Compensations: hanging on the wall with the body, body extended further than the upper limb being stretched.

Alternative exercise to stretching against the wall
Starting position: standing with arms at chest level with tape held in hands.
Execution: horizontal lunge with pulling the shoulder blades together by stretching the elastic band.
Compensation: lifting the shoulders.

Surgical treatment

The gold standard in the surgical treatment of subarbar tightness syndrome is shoulder arthroscopy. During this procedure, decompression of the subacromial space is performed through acromioplasty, which is the trimming and milling of the shoulder process. In the case of partial or complete rupture of the rotator cone, and if conservative treatment does not give satisfactory results, an arthroscopic procedure is performed to repair the damaged rotator cone muscle tendon using bone anchors. This is a repair or refixation, which involves attaching the severed tendon back to the humerus. For the most severe cases of massive rotator cone damage, new surgical techniques are being proposed, such as upper joint capsular reconstruction, which involves sewing a “patch” into the acetabulum with the head of the humerus holding it up. The final solution is the use of a special so-called inverted shoulder joint endoprosthesis.

Prognosis

Treatment of subcarpal tightness syndrome in most cases is conservative, its basis being physiotherapy based on exercise and manual therapy. In the vast majority of patients, very good clinical results are obtained after conservative treatment. In more difficult cases, such as with partial or complete rupture of the rotator cone, arthroscopic rotator-ring repair surgery, which is performed, also yields satisfactory results. In both cases, return to daily physical activity and sports is as possible. To a large extent, the results of treatment depend on the patient's self-discipline.

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Bibliography:

• "Subacromial Impingement Syndrome" - Harrison, Alicia K. MD; Flatow, Evan L. MD - American Academy of Orthopaedic Surgeon: November 2011 - Volume 19 - Issue 11 - p 701-708
• "Anatomical and biomechanical mechanisms of subacromial impingement syndrome" - Lori A.Michenera, Philip W., McClureb, Andrew R., Kardunac - Clinical Biomechanics - Volume 18, Issue 5, June 2003, Pages 369-379
• National Library of Medicine - "Subacromial impingement syndrome" - Masood Umer, Irfan Qadir, and Mohsin Azam - 2012
• Ortho Bullets - "Subacromial Impingement" - Matthew J. Steffes MD, Jay Keener MD - American Shoulder and Elbow Surgeons - 2021