08 Nov Shoulder Instability: Causes, Rehab, and Treatment
Do your shoulders feel like they are loose? Has your shoulder suddenly popped out of its socket, and back into place? Have you ever been in a position where you raise your arm up and say to yourself, “Wow it felt like my shoulder was going to come out of place!”? If you answered yes to any of these questions, you may have what is known as ‘shoulder instability’. This happens to occur in many individuals, as the shoulder is the most mobile joint in our entire body, and as a result, its stability is often sacrificed. Sometimes, certain injuries may accompany an episode of instability that can be categorized either as a subluxation (transient slip in and out of a joint), or dislocation (a joint moves and stays out of place). How do we avoid these episodes of instability from occurring? [P]Rehab!! Follow along in this article, as we will discuss how and why shoulder instability occurs, what common signs and symptoms of shoulder instability are, and the ultimate guide of how to prevent shoulder instability!
The Complexity of the Shoulder Girdle: Sacrificing Stability For Mobility!
The shoulder is the most mobile joint in our body that can move within all planes of movement. Moreover, our upper extremities are required to undergo high levels of demand on a daily basis. Carrying groceries, reaching overhead into the cabinet to grab a bowl, or pushing your lawnmower, the shoulder and other upper extremity joints are constantly being used! The shoulder joint relies on a complex, dynamic stabilization team consisting of the shoulder girdle joints, as well as the surrounding soft tissue structures (ligaments, tendons, and muscles).
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Shoulder injury rates such as instability, rotator cuff tendinopathy, biceps tendinopathy, and subacromial impingement syndrome are all high for many reasons, one of the most common being a lack of adequate strength and motor control of the shoulder girdle. Depending on the type of tissue that is injured, as many of which may be injured with shoulder instability, healing timelines, as well as rehabilitation implications, will differ. For example, if someone has an injury to the rotator cuff tendons from repetitive poor shoulder stability, versus an individual who suffers a SLAP tear (superior labrum anterior-posterior), timelines, as well as outcomes, will naturally be different. Learn more about these concepts in our blog article below.
What Is Shoulder Instability?
Shoulder instability is a common diagnosis that is seen throughout the orthopedic setting. As previously discussed, the glenohumeral joint allows for such a large amount of joint mobility to function properly, and inherently, this is the most unstable and frequently dislocated joint in our body. For the scope of this article, we will be mostly discussing anterior shoulder instability in more traumatic cases, yet we will also discuss atraumatic cases of shoulder instability, which can occur in other planes of movement such as inferior (downwards) or posterior (backward). Anterior shoulder instability is when the head of the humerus excessively moves anteriorly (forward) within the glenoid (shoulder joint cavity). Literature from Wilk et. al in addition to other studies have corroborated that this is the most common form of shoulder instability, accounting for up to 95% of all shoulder dislocations.
Traumatic instability tends to be more common in active populations, with sports being at the top of that list. Specifically, collision sports, such as football and hockey have higher instances. Depending on if someone has a traumatic episode leading to instability, or if that individual has feelings of unstable shoulders since he or she was young that is more atraumatic in nature, the signs and symptoms, as well as treatment strategies, will differ. Follow along as we touch on how to not only rehab from shoulder instability but also prevent it in the future!
Types of Shoulder Dislocations
This picture above depicts how our shoulder may dislocate in either an anterior direction (forward) or posterior direction (backward). To reiterate from what was discussed previously, anterior is the most common based on frequency, yet posterior dislocations may happen in some instances such as a fall onto an outstretched hand (FOOSH) or in some instances from convulsions when one is trying to brace him or herself.
Types of Shoulder Instability: Traumatic Versus Atraumatic
Shoulder instability can either be traumatic, in which there was a specific, acute incident that resulted in a shoulder dislocation followed by instability, or atraumatic, which is usually related to a genetic predisposition. There are two acronyms that have been well established within the literature, such as in an article by Varacallo et al that helps differentiate these types of shoulder instabilities as well as recommended treatment strategies:
- T – Traumatic
- U – Unilateral
- B – Bankart Lesion
- S – Surgical Intervention Recommended
- A – Atraumatic
- M – Multidirectional
- B – Bilateral
- R – Rehabilitation Intervention Recommended
- I – Inferior Capsular Shift (sometimes*)
Looking at the highlighted portions above, what is important to note is the treatment differences between traumatic versus atraumatic shoulder instability. In most situations, a traumatic shoulder dislocation will warrant surgical intervention due to damage to either the soft tissue, bone, or both. On the contrary, someone who has atraumatic shoulder instability is more likely to follow specific rehabilitation guidelines including motor control interventions, strengthening, dynamic stabilization, and neuromuscular re-education to enhance their shoulder health. Regardless, rehabilitation will be a key aspect of care for shoulder instability, whether it is traumatic or atraumatic. Learn even more about shoulder instability on our [P]Rehab Audio Experience Podcast Episode with Dr. Makhni!
Traumatic Shoulder Instability
The most vulnerable position for the shoulder is when the humeral head (head of the shoulder) is forced into the extremes of shoulder abduction and external rotation, or horizontal abduction, which is when the shoulder will most often translate anteriorly. Moreover, an episode of trauma to the shoulder may also result from a FOOSH injury. If someone does have a FOOSH injury, healthcare practitioners will also be looking at the elbow, wrist, and hand, as these areas of the body are also vulnerable to this specific mechanism of injury (MOI). For example, someone may experience posterolateral rotatory instability at the elbow resulting in a radial head subluxation/dislocation episode, or a scaphoid fracture at the hand, which has one of the highest rates of mal-union (healing in a less than optimal position) in our body. It becomes essential to seek medical consultation if having wrist pain as a feeling of a simple sprain to you may actually be a fracture that is undiagnosed, which can lead to issues down the road. Specifically, at the shoulder, there frequently is an injury to either the labrum, joint capsule, and/or articular cartilage, which may warrant surgical intervention in some situations.
Surgical intervention becomes even more so warranted if someone is having repeated dislocations, as this is indicating the stability of that shoulder is severely lacking. Inherently this makes sense right? If we are losing a lot of the feedback from soft tissue structures that help stabilize our shoulder, instability is going to be the result! Also, there are a series of risk factors for repeated shoulder dislocations, with one of the highest being age under 20. If an individual is young and active with sports, surgery for a traumatic dislocation is usually warranted for superior outcomes. However, with that being stated, general treatment strategies for first-time dislocations is actually nonoperative. It is important to educate patients that if they have a second episode of a dislocation, seeking medical consultation quickly after that episode is imperative. This is well supported in an article by Srinivasan and Pandey on the Current Concepts of Shoulder Instability.
Some common injuries to the shoulder that occur in conjunction with a traumatic dislocation are a Bankart Lesion, Hills-Sach Lesion, or a SLAP tear. For the scope of this article, we will not go into detail on these pathologies specifically, but more to come in future posts!
Some of the common signs and symptoms of traumatic shoulder instability include:
- Considerable pain
- Visible deformity of the humeral head positioning in relation to the glenoid
- Muscle spasm
- An acute inflammatory response with swelling and potential ecchymosis (discoloration)
- Guarding injured arm in an internally rotated and adducted position against the side of the body
Atraumatic Shoulder Instability
Atraumatic, or multidirectional instability (MDI) can be identified as shoulder instability in more than one direction of motion. These individuals have a congenital predisposition, and as a result, exhibit ligamentous laxity (looseness of the ligamentous surrounding the shoulder) due to excessive collagen elasticity of the capsule. Often times, these individuals have a higher Beighton Index Score, which assesses if someone has joint hypermobility.
With that being said, hypermobility is different from instability. Someone can be considered hypermobile, yet if they have good control and stability of their body, that indicates they are stable!
With MDI, usually, individuals may hear associated clicking or popping in their shoulders and will have an excessive amount of mobility in the shoulders. An article by Rodeo et al reported that this type of patient turns over collagen at a much higher rate than individuals without MDI. This implicates that the ligaments and other soft tissue structures supporting the shoulder may not be as strong and may lack the resistive components the shoulder requires to remain stable.
Some of the common and signs and symptoms of atraumatic shoulder instability include:
- Excessive range of motion
- Weakness in the rotator cuff, deltoid, and scapular stabilizers
- Evidence of poor dynamic stabilization
- Reports of clicking, popping in the shoulders
- Episodes of the shoulder “giving way”
- Apprehension in positions of abduction and external rotation
Shoulder Instability: How Do We Fix It?
The early approach to rehabilitation will differ based on if an individual has had a surgical consultation or if there was more of an insidious onset of shoulder instability. For those who have had surgery, the initial management is to protect the soft tissue structures with immobilization to allow for normal tissue healing, yet balance this protection against risks of stiffness, especially the posterior capsule of the shoulder. In those individuals who have more atraumatic shoulder instability, immobilization will not be required, yet activity modification is warranted to avoid provocative motions that exacerbate symptoms of instability during early aspects of care.
Treatment Decision Making
Like other clinical conditions, you want to start by putting the fire out and allowing that area of the body to calm down before moving on to more progressive interventions. Next, we will go through a progression of exercises for shoulder instability, starting with basics in the open chain and eventually moving towards more challenging, closed chain exercises!
Exercises For Shoulder Instability: Open Chain Drills
Open chain exercises are performed with no support to the hand and have increased load to the shoulder due to the weight of the arm and the effect of gravity. Below we will highlight a progression of exercises in the open chain that are great for shoulder instability! Exercises include static isometrics, dynamic isometrics, scapulothoracic joint exercises, open chain plyometrics, and rack carry variations! Each of these exercises enhance the motor control, stability, and strength of the shoulder girdle in various ways, all of which are important to consider when designing a rehabilitation program.
Static Isometrics: Shoulder IR Isometric
When first starting exercises for shoulder instability, go back to the basics! In this early phase, submaximal isometrics are great for the rotator cuff. This should be pain tolerant for patients. Particularly, the subscapularis plays a role in providing anterior glenohumeral joint stability, which can be a major player during rehab for those who have suffered anterior shoulder instability and/or dislocations.
This is a nice activation exercise for one of our four rotator cuff muscles. Rehab programs typically start by strengthening the weaker rotator cuff muscles. A study by Jaggi and Lambert describes how some individuals who are unable to have selective recruitment of their rotator cuff musculature can consider starting with exercises that engage their core musculature, such as standing on uneven surfaces, standing on one leg, or sitting on a physioball. By doing this, postural tone will increase which helps to inhibit some of our global musculature including our lats or pec major that we do NOT want to take over our movements, and allow our deep stabilizing muscles around the glenohumeral joint engage properly!
Dynamic Isometrics: Shoulder External Rotation Walk Out
Walkouts are a great way to enhance rotator cuff strengthening, especially early on when performing isometrics. If someone is lacking strength and/or is having symptoms after an injury such as shoulder instability, walkouts are a great place to start. With this exercise, focus on squeezing your shoulder back with good posture. From there, activate your shoulder external rotators by slightly bringing the band away from your midline with your elbow staying close to your side. While keeping your core engaged and all of the musculature engaged, slowly sidestep away from the anchored band for the prescribed distance, then slowly sidestep back in and repeat.
Placing a towel in-between your body and your elbow is excellent when working on rotator cuff strengthening in standing as well as side-lying, as this places the glenohumeral joint in a more optimal position, allowing for more motor unit recruitment!
Scapulothoracic Joint Motor Control: Prone T – Off Table
The Prone T is a great way to begin engagement of the scapular retractors, including the middle trapezius and rhomboid muscles that are essential for scapulothoracic joint motor control. Also, notice how Mike’s thumb is facing the ceiling. What this action does is externally rotates the shoulder. That will help engage more of our posterior cuff and lower trapezius as well! This was explained well in an article by Reinold et al in 2009, where you can also find additional information on glenohumeral and scapulothoracic exercises, including EMG activity for specific exercises. You can also work on Prone I’s which also targets our scapular retractors, and Prone Y’s, which are shown next in a plyometric fashion.
Plyometric Shoulder Y – Swissball
The plyometric Y on a physioball will work on the dynamic stability and strength of the scapular stabilizers and rotator cuff. To perform this exercise, have a weighted ball in each hand and extend your arms up overhead to make a “Y” position. While keeping your body still, bounce the ball up and down slightly dropping it and catching it right away. If a weighted ball is too heavy, start with something lighter like a tennis ball and progress from there! Keep your chin tucked, quadriceps, and glutes engaged to keep a solid upright position over the physioball.
Carry – 90/90 Bottoms Up, Unilateral
Rack carries are an awesome way to build dynamic shoulder stability for those individuals who are lacking that stability the shoulder craves. There are many variations of these carries that you can find in our exercise library!
This variation is much more difficult than it looks. By holding the kettlebell by the handle, it becomes much more difficult to stabilize! Compensations that occur with this is arching of the back or allowing the arm to fall down from this position. Ensure that you maintain an upright posture, draw in your deep core stabilizers, engage your scapular retractors and depressors, and then walk for the prescribed amount of time!
To make this more challenging:
- Try holding a heavier kettlebell
- Try to tape a line down or image a straight line, and only walk on that straight line, which will add a dynamic balance component to this exercise
- Hold another weight in the opposite arm down by your side to create an off-weighting component to this exercise, further challenging balance as well as stability!
If this exercise is too challenging, start with traditional suitcase carries, which is having the arm down by the side, and work your way up to overhead positions!
Learn How To Assess and Improve Overhead Shoulder Mobility!
Exercises For Shoulder Instability: Closed Chain Stabilization
Closed chain exercises facilitate initiation and setting of the rotator cuff musculature as well as the scapulothoracic joint stabilizers, both of which are essential for shoulder stabilization. Moreover, closed chain exercises also enhance muscular co-activation as well as joint proprioception, which is critical for those who lack shoulder stability. Initially, for shoulder instability, exercises should be performed with a fixed base of support and can be progressed to more unstable surfaces once a patient has established improvements in their stability. Also, when starting closed chain exercises, you will want to start in more gravity eliminated positions, and progress to more demanding positions from there.
The wall push up is a great closed chain exercise to start after being in a quadruped position. Once someone can perform this with proper form and it becomes easier, they can progress to an incline position, and eventually into a full plank position on the floor! This exercise is great to work on recruitment of the serratus anterior. You can click on that link to gain access to other, excellent serratus anterior exercises as well!
An article by Struyf et al in 2013 highlighted that overhead athletes with internal shoulder impingement and anterior shoulder instability tend to have higher recruitment of their upper trapezius muscles and lower recruitment of the lower and middle trapezius as well as the serratus anterior. With that information, it is important to train our scapulothoracic joint stabilizers, especially in athletes that are aspiring to return to sport.
Wall Clock – Quadruped
Begin near a wall in a quadruped position with your knees on the ground under your hips and your hands underneath your shoulders. With one arm against the wall, push into the wall with your arm straight out from shoulder height, while performing different motions in reference to a clock. By having one hand on the ground, you are having to stabilize with your shoulder girdle musculature.
This is an all-around great exercise to work on for closed chain shoulder stabilization. There are many ways to progress and regress this exercise as well. It can become more challenging by adding an activity for the arm that is not in the closed chain, such as band pulls, isometric overhead shoulder holds, and so forth. Also, one can work on lifting the opposite leg away from the leg closer to the floor for further hip, core, and shoulder engagement. Think about pushing the floor away from you with your shoulders and hips with this and not allowing yourself to “sink in” towards the floor.
Tall Plank Circles – BOSU
Adding in stability drills on uneven surfaces is essential to challenge the proprioception of the shoulder joint. Place a BOSU with the blue side down. Grab onto each side with your arms underneath your shoulders, your legs straight out from your hips and your toes pushing into the ground with a flat back. From this plank position, roll the edge of the ball around in a clockwise or counterclockwise direction while maintaining the plank position.
Plyometric Push Up – Bosu Blue Side Landing
This is a great exercise to work on the power as well as stability of the shoulder. Place a BOSU on the ground with the blue side up. Place your hands on the ball about shoulder-width apart with your elbows straight, feet straight out, and your toes pushing into the ground. Perform a normal push up and at the bottom explode up by pushing off of the ball as quick as you can. Land in the push-up position and repeat.
Shoulder instability is a common diagnosis that can be managed conservatively or surgically. Rehabilitation and proper exercise prescription, as well as dosage, are essential for optimal outcomes. Recurrence rates may be high if this condition is either mismanaged or not addressed after an initial incident.
Some of the key takeaways from this article are:
- Anterior shoulder dislocations are the most common type, accounting for up to 95% of traumatic instability episodes of the shoulder.
- Shoulder instability may be traumatic or atraumatic.
- In most cases, if traumatic, there will be associated injuries to anatomical structures of the shoulder, warranting surgery.
- If atraumatic, it usually is related to a genetic predisposition where there is naturally more laxity and as a result, a lack of stability in the shoulders, which can be initially treated conservatively with rehabilitation.
- When going through exercise progressions, start with low demanding exercises and progress towards higher level, more demanding exercises, that places the shoulder in more vulnerable positions
- A variety of both open and closed chain exercises are essential to work on muscular co-activation, static and dynamic stability, motor control, and strength for individuals with shoulder instability
- Be sure to always work on exercises that are specific for you as an individual, and relate it back to function!
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Overhead Stability For Fitness Athletes [P]Rehab Program
Overhead stability requires multiple moving body parts working together in synchrony. Without adequate motion, stability, strength, and power in the right places, you run the risk of exposing other body regions to excessive strain. As a result, you may be limiting yourself to reach your true performance potential as a fitness athlete. With that being said, addressing overhead stability requires a multi-dimensional approach, while taking out the guesswork and truly identifying your limiting factor to performance. We have blended science with our clinical expertise to provide you with the ultimate proven solution, we know it will help you too! Learn more HERE!
About The Author
[P]Rehab Head of Content
Sherif graduated from Temple University with a Bachelor’s of Science Degree and a concentration in Kinesiology. He then received his Doctorate of Physical Therapy Degree from DeSales University, graduating with honors of the professional excellence award and research excellence award. After his graduate studies, he served as Chief Resident of the St. Luke’s Orthopedic Physical Therapy Residency Program. Sherif is a Board Certified Orthopedic Clinical Specialist. Sherif focuses on understanding how movement impairments are affecting function while also promoting lifestyle changes in order to prevent recurrences of injury. His early treatment interests include running-related injuries, adolescent sports rehab, and ACL rehab in lower extremity athletes. He also has been involved in performance training for youth soccer players. Outside of working as a physical therapist, he enjoys traveling, running and cycling, following Philadelphia sports teams, and spending time with his family.
- Wilk, K. E., Macrina, L. C., & Reinold, M. M. (2012). Nonoperative rehabilitation for traumatic and atraumatic glenohumeral instability. Shoulder Instability: A Comprehensive Approach, 108-125. doi:10.1016/b978-1-4377-0922-3.00019-8
- Pandey, R., & Srinivasan, S. (2017). Current concepts in the management of shoulder instability. Indian Journal of Orthopaedics, 51(5), 524. doi:10.4103/ortho.ijortho_224_17
- Buss, D. D., Lynch, G. P., Meyer, C. P., Huber, S. M., & Freehill, M. Q. (2004). Nonoperative Management for In-Season Athletes with Anterior Shoulder Instability. The American Journal of Sports Medicine, 32(6), 1430-1433. doi:10.1177/0363546503262069
- Jaggi, A., & Lambert, S. (2010). Rehabilitation for shoulder instability. British Journal of Sports Medicine.
- Reinold, M. M., Escamilla, R., & Wilk, K. E. (2009). Current Concepts in the Scientific and Clinical Rationale Behind Exercises for Glenohumeral and Scapulothoracic Musculature. Journal of Orthopaedic & Sports Physical Therapy, 39(2), 105-117. doi:10.2519/jospt.2009.2835
- Jaggi, A., & Alexander, S. (2017). Rehabilitation for Shoulder Instability – Current Approaches. The Open Orthopaedics Journal, 11(1), 957-971. doi:10.2174/1874325001711010957