By Tim Camps, Physiotherapist
Suffering from shoulder pain?
Subacromial Pain Syndrome (SAPS) is by far the most common shoulder injury. Prevalence ranges between 44-65% (Bhattacharyya et al. 2014). The term SAPS was defined as: all non-traumatic, usually unilateral, shoulder problems that cause pain, localized around the acromion, often worsening during or subsequent to lifting of the arm (Diercks et al. 2014).
What’s really going on?
The subacromial space (SAS) is a narrow tunnel found at the tip of your shoulder. The roof is created by the acromion (a superior projection of the scapula) and the coracoid process (a anterior projection of the scapula), the two are connected by the coraco-acromial ligament. The floor of the tunnel is created by the humerus as it joins the glenoid fossa, creating the glenohumeral (GH) joint. The SAS has a diameter ranging from 1-1.5 cm (Pesquer et al. 2018). Within the subacromial space we can find muscles and their tendons, bursae and the G-H joint capsule. Although the direct pathology is still unclear, it is hypothesized that the repetitive nature of SAPS causes a failed healing response, rather than acute inflammation or full-thickness rotator cuff tears (Del Buono et al. 2011).
There is constant, ongoing debate as to the causes of SAPS. Currently the evidence points towards it being multifactorial in nature. This summary on SAPS, is focused on highlighting factors we can functionally train to overcome and prevent the prevalence of shoulder pain.
The shoulder being a ball and socket joint allows for range of motion in several planes: flexion/extension, abduction/adduction, external/internal rotation and horizontal abduction/adduction. As we abduct our arm, the humerus naturally encroaches upon the SAS, causing compression of the underlying structures. It essential that during this motion we externally rotate our shoulder, which allows for the greater tuberosity to clear the SAS.
Try to feel the difference yourself! Try abducting your arm with both full internal, then external rotation. You’ll notice, that in full internal rotation you are only capable of reaching around 90 degrees of true GH abduction.
The scapula provides the surface for a total of 3 joints: the GH joint, the AC joint and the scapulo-thoracic joint. It also provides the attachment for 17 muscles! As we lift/move our arm, the scapula must create a complimentary movement to allow for the glenoid fossa to remain in a optimal position for the humerus. In the case of abducting our arm, the scapula must perform upward rotation, tilt posteriorly and externally rotate.
We can see that even within healthy shoulders, the space is continuously decreasing in size as we lift our arm. Lets dive a little deeper and take a closer look at the reasons behind how the SAS decreases beyond the normal values.
You’ve probably heard it time and time again, posture! Yes, it matters. Upper cross syndrome is a frequently encountered posture. Characteristic features include: forward head, protracted shoulders, increased thoracic kyphosis and a internally rotated shoulder. As we saw above, the internally rotated shoulder causes further unnecessary encroachment of the SAS.
Scapular dysfunction: as your scapula provides the surface to which the humerus attaches, its function/timing is crucial to shoulder dynamics. A great analogy is comparing your scapula to a marionette. If the strings (muscles) are pulled out of order, the movement you get is incoherent and abnormal. Meaning as you move your arm up, your shoulder blade may lag behind and the SAS remains consistently narrow. Patients presenting with SAPS, tend to show decreased upward rotation, posterior tilting and increased GH IR (Seitz et al. 2011). It has been shown that this decreases causes the humerus to encroach on the SAS at a earlier range of arm elevation (Lawrence et al. 2019).
Muscular imbalances: Muscles can be divided into phasic (tend to weaken) and tonic (tend to tighten). This pattern becomes evident with upper cross syndrome, where shortening of the pectoralis major/minor, upper trapezius and levator scapulae occurs. Followed by weakness of the deep neck flexors, rhomboids, serratus anterior and lower trapezius. As the shoulder allows for a great deal of mobility, it lacks passive stability. It is up to the surrounding musculature to provide that necessary active stability. The rotator cuff, a notorious group of 4 muscles (supraspinatus, infraspinatus, teres minor and subscapularis), which play a major role in depressing the humerus during arm elevation. Loss of humeral depression due to muscle weakness leads to mechanical compression of the structures in the SAS (Neviaser et al. 2012).
Having read the above reasons, it becomes quite evident just how connect all the structures are. It is therefore imperative to take a approach focusing on the entire chain, rather than towards one specific anatomical structure. Treat function and not the pathology!
What are the signs and symptoms?
1️. persistent pain without trauma at the anterior/lateral aspect (usually one sided)
2️. painful arc (pain while lifting arm between 70-120 degrees)
3️. pain while lying on affected shoulder
4️. pain with overhead activities
What Physiotherapy techniques do we offer to help?
Choices are made depending on severity, irritability, previous injuries, treatment goals and personal factors. Conservative treatment has shown to completely resolve 70-90% of all cases (Garofalo et al. 2011).
Ultrasound (for acute stages)
Manual techniques to regain range of motion: for the shoulder, cervical and thoracic spine
Dry Needling to promote healing, increase blood flow and wash away toxins
Personalized exercise program focused on shoulder strength, scapular kinematics and full chain dynamics (see below)
Posture retraining and advice for the work place
Motor pattern retraining and rehabilitation
Education on activity modification
Below you can find a general progression of exercises (lots of which can be easily implemented towards a home program). Giving you the tools to tune you’re own shoulder!
1.Isometric internal/external rotation at 0 degrees using elastic tubing
2️. Balll abc’s against the wall (at a pain free height)
3️. Pendulum swings with 5-10 pounds
4️. Scapular retractions with elastic tubing
1.️ Concentric internal/external rotation at varying degrees using elastic tubing/free weights
2️. PNF pattern chop & lifts
3️. Prone horizontal abduction with ER
4️. Unilateral kettle bell bell military press in half-kneeling position
1️. Speed training in external/internal rotation at varying degrees
2️. Stabilization with external perturbations
3️. Medicine ball push-ups
4️. Sport specific functional exercises