Shoulder joint pain: treatment and causes.

The shoulder joint is an articulation between the head of the humerus and the glenoid cavity of the scapula. This gives rise to the alternate name for the shoulder joint – the glenohumeral joint.

The head of the humerus is much larger than the glenoid fossa, giving the joint a wide range of movement at the cost of instability. To help reduce the difference in surface size, the glenoid fossa is deepened by a fibrocartilage rim known as the glenoid labrum. The joint capsule is a fibrous sheath which encloses the structures of the joint. The joint capsule is lax and allows greater mobility, especially abduction. The synovial membrane lines the inner surface of the joint capsule and produces synovial fluid to reduce friction between the articular surfaces.

The ligaments involved in helping to stabilise the joint are the 3 part glenohumeral ligament that acts to stabilise the anterior aspect of the joint; the coracohumeral ligament which supports the upper part of the joint capsule; the transverse humeral ligament which holds the long head of biceps tendon in the intertubercular groove and the coracoacromial ligament that extends between the acromion and coracoid process of the scapula, forming the coracoacromial arch over the shoulder joint. This resists upwards movement of the humeral head.

Bursae are small fluid filled sacs that help to reduce friction between muscle insertions and the underlying bones. There are 2 main bursae, the Subacromial and Subscapular bursae. Their function is to reduce friction for the rotator cuff tendons and specifically the subscapularis tendon respectively.

The joint is surrounded by a membrane (the synovium) that produces synovial fluid, which helps to nourish the cartilage and lubricate the joint.

The shoulder is a very mobile joint and the main movements of the shoulder are:

1. Flexion

2. Extension

3. Abduction

4. Adduction

5. Internal and external rotation and circumduction.
   

Flexion a forward’s movement of the upper limb is produced by pectoralis major, anterior deltoid and coracobrachialis.

Extension, a backwards movement is produced by posterior deltoid, latissimus dorsi and teres major.

Abduction, an outwards movement, is produced by supraspinatus (0-15 degrees), middle fibres of deltoid (15-90 degrees), after 90 degrees the scapula needs to rotate to achieve full range and the trapezius and serratus anterior produce this range.

Adduction, an inwards movement, is produced by pectoralis major, latissimus dorsi and teres major. Medial rotation, a turning inwards of the arm, is produced by subscapularis, pectoralis major, latissimus dorsi, teres major and anterior deltoid. Lateral rotation, a turning outwards, is produced by infraspinatus and teres minor. Circumduction, moving the arm in a circle, is produced by a combination of movements.

Common Shoulder joint pain and injuries can be broken into 5 sub-categories:

1.Trauma Fractures

Fractures can involve the clavicle (collarbone), proximal humerus (top of the upper arm) and scapula (shoulder blade). Fractures of the clavicle or the proximal humerus can be caused by a direct blow to the area from a fall, collision, or motor vehicle collision. Anyone can experience shoulder fractures, but they’re most common in kids and teens who experience traumas and adults older than 65 who experience falls. People with osteoporosis are more likely to sustain a fracture.

The scapula is protected by the chest and surrounding muscles and not easily fractured. Fractures of the scapula are usually caused by high-energy trauma, such as a high-speed motor vehicle collision and often occur with injuries to the chest as well.

Dislocation

Anterior (forwards) dislocations of the shoulder are caused by the arm being forcefully twisted outward (external rotation) when the arm is above the level of the shoulder. These injuries can occur from different causes, including a fall or a direct blow to the shoulder.

Posterior (backwards) dislocations of the shoulder are much less common than anterior dislocations of the shoulder. Posterior dislocations often occur from seizures or electric shocks when the muscles of the front of the shoulder contract and forcefully tighten.

Dislocations of the acromioclavicular joint can be caused by a fall onto the shoulder or from lifting heavy objects.

Shoulder separation

 This is where trauma causes damage to the acromioclavicular joint where the collar bone (clavicle) meets the shoulder blade (scapula). If the damage is severe the shoulder blade may separate from the collar bone.

Ligament sprains/tears

The ligaments of the shoulder area can be injured because of sudden overstretching, such as a backward force on the arm. Other causes are from a fall, car accidents, sports injuries or a blow to the shoulder blade. They can vary from a mild sprain or overstretch, to a complete tear or rupture.

Labral tear

There are several types of shoulder labral tears:

A SLAP lesion (superior labrum, anterior [front] to posterior [back]) is a tear of the labrum that usually occurs in the upper part of the socket and may also involve the upper part of the long head of the biceps tendon.

A tear of the front part of the labrum at the bottom of the socket is called a Bankart lesion. This usually happens from an anterior shoulder dislocation (a dislocation when the humeral head comes out of the front of the socket).

A tear of the labrum can also occur in the back part of the socket. This is called a posterior labral tear. It can be a traumatic tear due to injury, or it may be degenerative due to normal wear and tear.

Muscle strains/tears

A shoulder strain occurs when muscles or tendons are overused or stretched beyond their limit, causing tearing (partial or complete). This can happen to anyone during everyday tasks but are more commonly related to sports and certain occupations, where the muscle becomes overloaded and then more likely to be injured usually through a sudden forced over stretch, but it can also be the result of muscle fatigue. They can also be caused by direct trauma such as a fall or car accident. Strains are graded from grade 1 where a few fibres are torn, to a grade 3 with a complete rupture. Symptoms vary between a cramp, tightness, pain on stretch or muscle contraction through to stabbing/burning pain, bruising and swelling, to difficulty moving the arm.

The rotator cuff is a group of muscles (supraspinatus, infraspinatus, subscapularis and teres minor). They come from the scapula (shoulder blade) and are attached to the humerus, upper arm bone, by tendons. It is one of the most important components of the shoulder, and it plays an essential role in lifting the arm upwards. The rotator cuff muscles work together to facilitate the main functions of the shoulder:- to stabilise the top of the humerus in the socket; lifting the shoulder out to the side; external rotation or the shoulder and allowing free movement during arm elevation.

Rotator Cuff tears are a common cause of shoulder pain among adults. When a rotator cuff tears, the shoulder becomes destabilized and weak.

As we age the blood flow that allows normal repair to the tendons decreases and can lead to tendonitis or tearing. Most rotator cuff tears are caused by the normal wear and tear that goes along with aging, people over 40 are at most risk. People who do repetitive lifting or overhead activities as part of the job are at risk and athletes are also vulnerable to overuse tears. Although overuse tears caused by sports activity or overhead work also occur in younger people, most tears in young adults are caused by a traumatic injury, such as a fall.

Symptoms of a rotator cuff tear include:

·       Pain at rest and at night, particularly if lying on the affected shoulder

·       Pain when lifting and lowering your arm or with specific movements

·       Weakness when lifting or rotating your arm

·       Crepitus, or a crackling sensation, when moving your shoulder in certain positions

2. Shoulder impingement

Shoulder impingement syndrome is a common and painful condition resulting from a structural narrowing of the subacromial space (anterior and posterior), sub coracoid space or a suprascapular nerve impingement at the spino-glenoid notch.

 The narrowing can be because of malformation, bony spurs in the inferior acromial arch area, or from where other structures are thickened or swollen eg tendons, bursae, ligaments or from poor function. At shoulder height (60-120 degrees) the space is naturally most reduced. Often there is a painful arc of movement in this range of abduction but usually only with active or resisted abduction and not passive movement.

Pain is usually felt in the top and outer side of the shoulder with abduction, at night or when lying on the affected side and there may be weakness of the shoulder.

Over time, impingement can lead to inflammation of the rotator cuff tendons, causing tendonitis, or inflammation of the bursae, causing bursitis. Impingement will also lead to thinning and tearing of the rotator cuff tendons if not treated.

3. Degenerative

Osteoarthrosis

OA, degenerative joint disease or wear and tear is more commonly found in the acromioclavicular joint than the glenohumeral joint. Some of the cartilage covering the ends of the bones roughens (bony osteophytes) and thins so the joint doesn’t move as smoothly as it should causing pain, loss of movement and function. Moving the shoulder may produce a clicking or grinding noise or sensation, called crepitus.

 Shoulder OA is not as common as OA of the hip or knee.  It is estimated that nearly 1 in 3 people over the age of 60 have shoulder OA to some degree. It is more common in women than men.

Secondary OA can occur because of previous injury, infection or a rotator cuff tear for example.

4. Inflammation/infection

Rotator cuff Tendinopathy/Tendonitis

Each of your shoulders is made up by a group of muscles and tendons called a rotator cuff. This is a group of four muscles that originate from the scapula (shoulder blade), insert and cover the top of the upper humerus bone as a thick cuff. The four muscles first come together in the shoulder as tendons and create the cuff that deepens the socket and stabilises your humerus in the glenoid cavity. It also gives the shoulder the strength and motion to rotate and lift your arms.

Rotator cuff tendinopathy is when a rotator cuff tendon in your shoulder has tiny tears in it or is inflamed and hurts. Sometimes called tendinosis, this type of shoulder pain is more common in people over age 40. If it’s not treated, it can lead to stiffness or weakness in your shoulder and other long-term problems. This condition is often seen alongside shoulder impingement.

It is caused by overuse or general wear and tear from repeated overhead activities can lead to recurrent injury and rotator cuff problems. This includes common activities like weightlifting, swimming, tennis, golf, and many physical jobs. While historically this was called tendinitis, that term is now used for more sharp, inflammatory shoulder pain.

Symptoms include pain and swelling in the front and side of your upper arm; pain on moving your arm and down; a clicking sound; stiffness; pain when reaching backwards; loss of range and strength in the arm and pain when sleeping.

Long head of Biceps Tendinopathy

Long head of biceps tendonitis is inflammation of the upper part of the Biceps tendon at the shoulder. It represents about 5% of cases of proximal biceps dysfunction. The most common symptoms are of pain in the front of the shoulder with weakness (the biceps contribute 10% of the total power for shoulder abduction in external rotation).

Most people will have other shoulder issues as well: -including rotator cuff tendinitis or chronic tendinopathy; subscapularis injuries; impingement; instability or dislocation of the long head of biceps tendon etc

Symptoms include anterior shoulder pain radiating into the front of the arm (atraumatic). Pain tends to be worse with overhead activities (sports or work related). Clicking or an audible popping at the front of the shoulder and pain felt at rest and at night.

Bursitis

This is an inflammation of a bursa. Bursae are small fluid filled sacs that help to reduce friction between tendons and bones.  They can become inflamed, painful, swollen and warm due to a sudden injury (traumatic bursitis) eg fall or direct blow; from recurrent minor trauma (chronic bursitis), this is most common; due to infection from bacteria eg skin break or sometimes as part of Rheumatoid arthritis or Gout.

The Subacromial-subdeltoid (SASD) bursa, subcoracoid, coracoclavicular and subscapular are the bursae that can cause problems in the shoulder joint. Younger and middle-aged people are more likely to have acute bursitis than an older person with chronic rotator cuff syndrome. Bursitis is often seen with tendonitis. Pain in SASD is usually felt in the upper front and the outside of the upper arm, is often worse at night and with overhead activity and has a big impact on activities of daily living, work and sports.

Symptoms include swelling, excessive warmth in the area, tenderness or pain and sometimes fever.

Frozen Shoulder

A Frozen shoulder, also called adhesive capsulitis, involves stiffness and pain in the shoulder joint. Signs and symptoms typically begin slowly, then worsen. Gradually, symptoms get better, usually within 1 to 3 years.

 It is the second most common cause of shoulder problems after a rotator cuff tear. It tends to affect people between the ages of 40 and 60 years and is more common in women than men.

The progression is usually divided into 3 stages:

1. Freezing stage where all movement causes pain and range starts to become limited in all directions. (tends to last from 2-9 months)

2. Frozen stage where the pain eases but the movement becomes less.

(tends to last from 4-12 months

3. Thawing stage where movement starts to improve. (tends to last 5-24 months)

When a frozen shoulder occurs, the capsule surrounding the joint begins to tighten and contracts. The cause is unknown but seems to be linked with diabetes, hypothyroidism and cardiac disease and may be secondary to when the shoulder movement is restricted post-surgery, after fracture or injury. It can be treated successfully with shoulder exercises and pain relief, but occasionally arthroscopic surgery is necessary.

It is unusual for frozen surgery to re-occur in the same shoulder, but people can develop it in the other shoulder, often within five years.

Infection

Infection of the shoulder joint is a rare occurrence, with an incidence of about 0.5% after total shoulder replacement.

The most common bacteria responsible for an infection in the joint are Staphylococcus aureus, Staphylococcus epidermidis, and Propionibacterium acnes.

Infection can also develop from an open wound following trauma or after an operation.

 Bacteria can also spread from inside the body while suffering from a cold or infection in another joint or body part.

Signs of an infection in the shoulder joint may include warmth, redness, pain, swelling, fever, and loss of joint movement. Pain is often worse at night. The key to treating a shoulder joint infection successfully is catching it early, starting treatment  to stop the risk of joint damage.

Avascular necrosis is a condition whereby the blood supply is cut off, for a significant period. It is more common in the hip but can occur in the shoulder too. It can cause destruction of a joint. It tends to affect the 30–50-year ages. Risk factors include injury such as fracture, dislocation, excessive alcohol over use or prolonged use of corticosteroid medication, cancer treatments involving radiotherapy can affect the bone and blood vessels, high cholesterol and some diseases eg sickle cell anaemia and Gaucher’s disease.

Rheumatoid Arthritis

This is an autoimmune disorder, it means your body attacks your own healthy cells, which may include the lining of the joint. The small joints in the hands and feet are usually the first to be attacked. The inflammatory arthritis can be present in both shoulders at the same time. Generally, when the disease causes problems in your shoulder, it means it is advanced. The main treatment for Rheumatoid arthritis is with DMARDS (disease-modifying antirheumatic drugs) but if these are not helping injections, surgery including replacements may be considered.

5. Post-surgery

Rotator cuff repair

This is the most common type of surgery on the shoulder. Repair is usually completed where individuals haven’t improved after an injury eg a tear or when inflammation is not improving with other treatments. Except for larger tears it is usually performed arthroscopically.

Arthroscopy

This is a surgical procedure and involves a tiny camera being inserted into the joint via several small incisions. This then allows the surgeon to see what is happening inside the joint and determine the likely cause of a problem.  During an arthroscopy, as well as determining the problem, the surgeon can also perform debridement, trimming or re-shaping of the cartilage or bone as required in impingement type syndromes.  Similar repair or removing damaged tissue can be used for labral cuff tear.

Arthroscopy for Impingement Syndrome

The procedure used is called a subacromial decompression. The aim of the surgery is to increase the space between the rotator cuff and the area of the shoulder called the acromion. This is to stop any pinching of the tendons.

Arthroscopy for frozen shoulder

The aim is to loosen the contracted fibrous capsular tissue and allow the shoulder to move more freely again.

Arthroscopy for SLAP repair

This is used to restore the labrum to its position at the rim of the shoulder joint.

Arthroscopy for repeated shoulder dislocation

The aim is to repair torn or over stretched ligaments so that they can stabilise the shoulder better. There are many types of repair. A Bankart repair involves attaching the labrum to the joint capsule to help keep the head of humerus in place. Sometimes surgery is needed to tighten the joint capsule, bone may be added around the shoulder to deepen the socket. The Bristow-Latarjet procedure is often used for recurrent anterior dislocations and involves transferring the coracoid and the muscles attached to it, to the front of the glenoid cavity. This replaces missing bone and the muscle acts as extra tissue to try and prevent further dislocations.

Acromioclavicular joint (ACJ) repairs

Problems of wear and tear (OA), post injury or because of repetitive movement can cause damage to the ACJ. Open surgery is sometimes used to remove the end of the clavicle (collar bone) and increase the space at the joint. Sometimes plates and screws are used, or ligaments reconstructed if there is instability of the joint.

Total shoulder replacement

A Total shoulder replacement is a procedure used to reduce pain and restore mobility in patients with end-stage shoulder arthritis; sometimes after a severe shoulder fracture or rotator cuff injury; failed fracture surgery or after bone necrosis in the shoulder joint. 

Most usually the ball and socket are replaced with a metal ball and plastic socket. Where the upper part of the humerus bone is broken and the socket undamaged, a hemiarthroplasty (partial replacement) may be done instead. A reversed shoulder replacement is used where there is severe labral and rotator cuff damage and then the synthetic ball is placed where the socket was and the synthetic socket where the ball was.

Repair post fracture

Shoulder fractures can be divided into 3 areas- the top of the humerus, the clavicle or the scapula. Shoulder fractures are less common than dislocations or separated shoulders. Some people only need a sling, cast or brace, others will need open reduction with internal fixation of the fracture and in severe cases a joint replacement may be needed. They generally take 3-4 months to heal.

Shoulder treatments at Team Rehab UK

Your physiotherapist will access you and determine what the likely cause of your shoulder pain is. They may feel that additional investigations are necessary such as X-rays or scans and can contact your doctor to request these as appropriate.

Your treatment programme will be tailored to you but is likely to include some of the following strategies.  Advice, strengthening, stretching and proprioceptive/functional exercises, management strategies, mobilisations- soft tissue, joint mobs.

If you're experiencing shoulder pain or discomfort, don't wait to seek help.

At Team Rehab, our expert physiotherapists are dedicated to diagnosing and treating shoulder issues with personalised care. Contact us today to schedule an appointment and start your journey towards pain-free movement and optimal shoulder health. Reach out to Team Rehab now and let us help you get back to doing the things you love!

Read also: Sports Massage in Northampton

FAQ Section:

1. What is the glenohumeral joint?

The glenohumeral joint, commonly known as the shoulder joint, is the articulation between the head of the humerus and the glenoid cavity of the scapula. This joint allows for a wide range of movement, making the shoulder one of the most mobile joints in the body.

2. What are the main ligaments that stabilize the shoulder joint?

The shoulder joint is stabilized by several ligaments, including the glenohumeral ligament (which has three parts), the coracohumeral ligament, the transverse humeral ligament, and the coracoacromial ligament. These ligaments help to maintain joint stability during movement.

3. What are bursae and what role do they play in the shoulder joint?

Bursae are small fluid-filled sacs that reduce friction between muscles and bones. In the shoulder, the subacromial and subscapular bursae help reduce friction for the rotator cuff tendons and the subscapularis tendon, respectively, aiding in smooth movement of the shoulder.

4. What are common causes of shoulder fractures?

Shoulder fractures can occur due to direct blows from falls, collisions, or motor vehicle accidents. They are most common in children, teens, and adults over 65. Conditions like osteoporosis can increase the likelihood of fractures in the clavicle, proximal humerus, and scapula.

5. What is shoulder impingement syndrome?

Shoulder impingement syndrome is a painful condition caused by the narrowing of the subacromial space, which can result from bony spurs, thickened tendons, or swollen bursae. This narrowing causes pain during movements like abduction and can lead to inflammation or tearing of the rotator cuff tendons if untreated.