Subacromial Bursitis

Shoulder Bursitis

The shoulder is a ball and socket joint formed by the upper arm bone (humerus), shoulder blade (scapula) and the collar bone (clavicle).  These 3 bones are connected with a series of muscles, tendons and ligaments.  This allows a large range of movement, but at the expense of stability. 

 

Picture from: http://morphopedics.wikidot.com/shoulder-joint-instability-syndromes  

 

The shoulder moves in many directions:

·         forwards and backwards (flexion and extension)
·         towards and away from the body (adduction and abduction)
·         rotation (internal and external rotation) and
·         across the body and behind the body (horizontal adduction and abduction)

The main shoulder joint in the glenohumeral joint formed by the shoulder blade and arm bone, but it is important to assess the acromioclavicular joint and scapulothoracic joint in a person with shoulder pain.

Stability in the shoulder (glenohumeral joint) comes from muscular control, pressure within the joint and the labrum (lining) of the joint.  The rotator cuff muscles, infraspinatus, teres minor, supraspinatus and subscapularis, are the primary muscle stabilisers.  They help to hold the ball (head of humerus) in the socket (scapula), and also rotate the arm. 

 The shoulder joint also has a number of bursa – small fluid filled sacs designed to minimise friction between surfaces.  The subacromial bursa sits underneath the acromion of the scapula and above the tendon of supraspinatus.   

Bursitis is a painful inflammation of the bursa.  Subacromial bursitis is reported in up to 2% of upper limb pain in the general population[1].   Because the shoulder joint is already a small, confined space, any extra fluid such as swelling in this space often leads to impingement – when you lift your arm the bursa is pinched or impinged between the acromion (scapula) and the arm bone (humerus).  The supraspinatus tendon is also often irritated. 

There are many causes of bursitis, and often a multi-faceted treatment approach is needed.  The aims of treatment should be to improve shoulder posture and manage load on the shoulder to reduce pain and inflammation; and to optimise flexibility, control and strength for best biomechanics.

In the early stages hot or cold packs can help reduce pain as can resting from aggravating activities.  Massage and soft tissue treatment (trigger pointing, myofascial release, dry needling etc) are useful to improve flexibility around the shoulder joint and reduce impingement.  Patients should discuss pain relief (analgesia) and anti-inflammatories with their doctor or pharmacist.    

As pain settles, rehab increases with techniques (e.g. taping) and exercises focussed on:

·         improving range of movement

·         controlling the shoulder blade during posture and arm movement

·         restoring spinal flexibility

·         strengthening the rotator cuff

·         complex shoulder movements and tasks

·         returning to sport and/or work

Exercises should always be prescribed by a qualified physiotherapist.  You will find a range of exercises on the internet, but you need an individualised and progressive program to ensure a safe and successful recovery. 

Corticosteroid injections (CSI) can also be used if physiotherapy is not completely successful in reducing pain.  I personally think that CSI should be ultrasound guided to ensure accurate placement – see this link for a recent study that supports this http://europepmc.org/abstract/MED/23698243 .  Clinically patients often feel worse for a couple of days after the injection, possibly due to the increase in fluid volume in the area.  Rehab is essential after CSI to ensure the shoulder returns to full function and to prevent recurrence.   Bursitis usually responds to conservative management, although surgery can be performed to remove the bursa in chronic cases. 

 

References:

1.            Walker-Bone, K., et al., Prevalence and impact of musculoskeletal disorders of the upper limb in the general population. Arthritis Care & Research, 2004. 51(4): p. 642-651.