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By: Paul Messner, Registered Physiotherapist
Hello, I’m Paul, and this is my latest contribution to Physiomobility blog. I recently took two courses from Dr. Lyn Watson – Shoulder Specialist Physiotherapist. I learned a thing or two. I say so to emphasize I will be summarizing some of her findings. The bread and butter of her research is on posterior instability of the shoulder (laxity at the back of the joint). This is less common than anterior instability and can be easily missed (Kaplan et al, 2005).
How Did I Treat Shoulder Posterior Instability?
I treated a patient with this problem using Dr. Watson’s protocol (not the same Dr. Watson as in Sherlock homes). By the end of our sessions, the frequency of clunking and clicking had significantly reduced (not bad for $ 1600 worth of courses). If you are not familiar with a randomized control trial (RCT) – it yields the highest level of clinical evidence. Lyn Watson’s rehab protocol for posterior instability is the only published RCT showing effective results. Basically, the protocol works.
What are the signs and symptoms of posterior instability?
Pain or clicking doing a push up, assuming yoga positions such as downward dog, pitching a baseball (more so the deceleration phase opposed to the cocking phase), hitting a back-hand stroke or serve in tennis, removing a shirt (by crossing your arms and pulling the shirt up from the bottom like women tend to do in movies, not the guy method). You may also experience shoulder irritation reaching across the body towards your opposite shoulder (Tannenbaum et al, 2011) , driving a car, sleeping on your side (even if not lying on the bad shoulder)…. There are more but I’ll stop here.
How Does Shoulder Instability Occur?
Some people have congenitally lax shoulders. Combining this with excessive bench press at the gym, the joint may become more lax (sorry guys). Other examples of repetitive movements stressing the back of the shoulder include swimming, golfing, throwing a hook punch etc. Falling off a bicycle and bracing yourself with your arm stretched in front would be a traumatic example. “American football” and of course rugby can wreak havoc to one’s shoulder. (Lyn Watson is from Australia so American football means football).
How is Shoulder Instability managed?
For the sake of time and sparing of wordy descriptions of exercises that would need to be seen and done to fully understand, I’ll skip that part. A patient’s shoulder may sit lower than it should, placing it in a biomechanical disadvantage. The key concept is learning to elevate the shoulder using the upper trapezius muscle to optimize the shoulder position (AKA humeral head centralization) (Watson et al, 2016). The shoulder is a ball and socket joint with the analogy of a golf ball positioned on a tee. You won’t be able to drive the ball unless it is centered in the tee / your shoulder is weaker when mispositioned. Positioning the shoulder to where it is strongest is the ideal place to perform strengthening exercises. Learning to use the shoulder muscles to properly position the shoulder and strengthening in this position is the answer (along with some nice massage of course). The end result, creating a muscular barrier to block the shoulder from translating back.
Where things could go wrong…
Sound clinical reasoning in regards to posture is paramount when treating a patient with posterior instability. It is common that the patient presents with a winged shoulder blade (technically the correct term is anterior tipping, but I won’t go there now). In most cases, this is important to correct. However, with posterior instability, squeezing shoulder blades together for “proper posture” will exacerbate the problem. The body assuming this forward tipped shoulder posture is an adaptive mechanism preventing the shoulder from dislocating backwards. Basically, it’s lax at the back, the body moves the shoulder forward to steer clear. The course of action is to strengthen the back of the shoulder in this adaptive position. “Do NOT correct the tilt,” as Lyn Watson would say. This was one of the most valuable things I learned.
Some final words:
Shoulder posterior instability can lead to additional shoulder problems. Becoming aware of the problem is an important step (Watson et al, 2016).
Information in this blog was adapted from Dr. Lyn Watson’s Lectures and Level 2 Shoulder Physiotherapy Course Manual – Lyn Watson & Simon Balster 2017.
- Kaplan LD, Flanigan DC, Norwig J, Jost P, Bradley J. Prtevalence and variance of shoulder injuries in elite collegiate football players. Am J Sports Med, 2005; 33(8): 1142-1146
- Tannenbaum E, Sekiay JK. Evaluation and management of posterior shoulder instability. Sports Health. 2011 ;3(3);253-263
- Watson L, Balster S, Warby SA, Sadi J, Hoy G, Pizzari T. A Comprehensive rehabilitation program for posterior instability of the shoulder. J Hand Therapy. 2017; 30: 182-192.