Shoulder pain is the third most common reported musculoskeletal condition in adults in the UK with 3% attending a primary healthcare facility with shoulder pain every year. 70% of people will experience at least one episode of shoulder pain in their lifetime.
The glenohumeral joint (shoulder joint) is a ball and socket joint consisting of the glenoid arising from part of the scapula (shoulder blade) and the head of the humerus (upper arm bone). There is also a joint between the end of the clavicle (collarbone) and a bony protuberance called the acromion at the top of the scapula called the acromioclavicular joint.
The ends of the bones which articulate to form joints are covered in hyaline cartilage. This layer creates a smooth low friction surface for which the bones move over one another. The nature of the glenohumeral joint with a shallow socket allows for a large range of motion into multiple different directions meaning that it is possible to achieve motion into forwards, backwards, sideways and rotational directions.
Shoulder joint stability is enhanced by the presence of a fibrocartilage ring called the labrum, which deepens the socket. It also gains extra reinforcement from the capsule and surrounding ligaments. The synovial membrane deep to the capsule secretes lubricating synovial fluid to keep the joint moving smoothly and the joint surfaces nourished.
The deep layer of muscles provide further stability and the most significant of these make up the rotator cuff group, which consist of four muscles arising from the scapula and connecting to the top of the humerus. The more superficial muscles include the deltoids, biceps, triceps, pectorals and trapezius muscles and these are more responsible for movement at the joint.
Tendinopathies of the rotator cuff can come about through overload or degenerative changes. Overload injuries commonly occur when an unusual activity is carried out that the muscles/tendons have not been conditioned for.
An example of this could be clearing out the shed over a weekend or travelling abroad and carrying a heavy suitcase. This can lead to acute irritation and micro-trauma of the tendon tissue, giving rise to pain and inflammation.
As we age, as well as joint degeneration occurring which we commonly known as osteoarthritis, tendons also change and become less resilient. Gradual micro-trauma and disrepair can reach a threshold and lead to a gradual onset of pain and loss of function. These cases are less likely to be related to a particular injury or activity.
Impingement occurs when soft tissue, most commonly the supraspinatus tendon (one of the rotator cuff muscles) or the bursa (a fluid filled sack which sits between tendon and bone to reduce friction) is pinched during motion of the shoulder. This may arise from suboptimal posture leading to a muscle imbalance between the chest muscles and back muscles, pulling the shoulder further forwards and creating a smaller gap for the soft tissue.
There can also be anatomical causes of impingement such as a downward-sloping clavicle leading to a smaller gap for the soft tissue as the shoulder moves. Often, structures becoming irritated and inflamed further reduces the space and can worsen symptoms if not treated.
Adhesive capsulitis occurs when the joint capsule becomes thickened, scarred and shrinks around the joint.
The condition will go through three stages:
The entire process can take up to two years. The cause of adhesive capsulitis is unclear but risk factors include: being over 40 years of age, recent surgery or injury, and being diabetic (10 – 20% of people with diabetes with experience this condition). It is also more likely to occur in women, with 70% of sufferers being female.
Osteoarthritis can occur at the glenohumeral (shoulder) joint and the acromioclavicular joint (joint at the top of the shoulder). It is an age-related process which leads to a thinning of the hyaline cartilage, synovial changes and bony irregularity caused by the body’s attempt to lay down extra bone to heal the overloaded joint surfaces.
This can result in pain, stiffness and loss of function. This often leads to weakness and tightness of the surrounding muscles which can cause further overload to the joint. Pain caused by osteoarthritis often comes on gradually as a vague local ache and can be associated with morning stiffness of the joints as well as a feeling or sound of crepitus (grinding or clicking).
Although this blog has discussed the most common shoulder complaints, pain can arise due to other conditions including inflammatory arthritis, shoulder instability, other muscle or tendon injuries or referral from the neck, to name a few.
Here at Pure Sports Medicine we have a huge amount of collective experience in assessing and treating shoulder pain, tailoring our approach appropriately for each individual.
Often a combined approach of two or more professions yields the best outcome for a wide range of shoulder complaints.
If you are suffering from shoulder pain and would like to see one of our Specialists, please contact your closest clinic here.