I have had this question from multiple patients. Their shoulder does not feel stable and, in many of the cases, it is not. I have gotten use to relocating a slightly subluxed shoulder and the patient feels much better afterwards. However, many times they will come back the next visit with it in that same subluxed position. Eventually it will start to stay in place, but it could take several visits. Shoulder instability is a tough condition to manage, but it can be managed. From the high-level swimmer to the hypermobile flute player, they have all returned to their activities with a little help from their physical therapist. Read on to learn more about shoulder instability. Let’s start with anatomy!
The shoulder joint
The main shoulder joint is called the glenohumeral joint. It is a large and complex joint that is made when the humerus (upper arm bone) and the scapula (shoulder blade) come together. It is a ball and socket joint. However the ball is much bigger than the socket. Think of a golf ball on a tee. The golf ball is the head of the upper arm bone and the tee is the outside part of the shoulder blade.
This allows the shoulder to have the most movement of any joint in the body. However, it also has the least stability and this is what tends to get the shoulder joint in trouble.
There are several ligaments and muscles that surround the shoulder joint. These add stability to the joint. The rotator cuff and scapular stabilizers are two groups of muscles that are very important in adding stability to the shoulder. The rotator cuff is comprised of 4 muscles – supraspinatus, infraspinatus, teres minor, and subscapularis. The main purpose of these muscles is to stabilize the shoulder joint – to keep the golf ball on the tee. The scapular stabilizers are muscles that attach to the scapular and are very important in keeping the scapula in a stable position.
What is shoulder instability?
Shoulder instability is when the ball starts to move to undesirable locations on or off the socket. This is due to laxity or looseness of the shoulder joint. This looseness could be the result of lax ligaments, muscular imbalances, posture, repetitive activities, or a traumatic event. This laxity of the structures around the shoulder joint allow it to move around more than it should. Usually the ball will slip forward of it’s socket. However it can also slip backward and downward. When the shoulder is unstable in multiple directions, it is called multidirectional instability.
Shoulder laxity can result in subluxation or dislocation. Subluxation is considered a partial dislocation. It is when the ball of the shoulder joint is out of place but it is still touching the socket. A dislocation is when the ball is no longer touching the socket. It may or may not go back into place without assistance.
The different causes of instability
As mentioned previously, there are several reasons that the shoulder is unstable. The main mechanisms of injury are:
- Traumatic – This is usually the result of a sports injury or fall.
- Atraumatic – This is due to a repetitive pitching-type motion. This causes a gradual weakening of the stabilizing structures in the front and below the joint. This is commonly associated with the following sports:
- Baseball
- Softball
- Tennis
- Swimming
- Gymnastics
- Congenital instability – This is a structural issue in the joint. It could be an abnormality in the bone or ligaments.
What are the symptoms of shoulder instability?
There are many symptoms of shoulder instability. These include:
- Pain or feelings of instability in the shoulder with
- Pushing, pulling, or lifting heavy objects
- Overhead activities
- During or after sports or exercise
- Feeling that the shoulder is shifting
- Slipping in and out of socket
- Fear of certain shoulder positions
- Clicking and popping
- Number and tingling in the arm
- Shoulder weakness
- Fatigue with activity
Who gets shoulder instability?
Shoulder instability usually affects a younger population. It is more common under the age of 40 since our joints tend to get stiffer as we age. It is a common sports injury and tends to be more prevalent in males.
Can my shoulder instability cause other injuries?
Shoulder subluxations and dislocations can cause other damage to the joint. This includes damage to bone, muscle, joint capsule, and labrum. Imaging including an x-ray and MRI would be needed to determine the extent of joint damage.
Who do I see?
- Physical therapist – A physical therapist is going to be an integral part of the healing process. Whether or not the person has additional shoulder injuries, they will need physical therapy. Physical therapists can aid in decreasing pain and swelling, increasing strength and stability, and returning to sport safely. It is important to have a physical therapist assist in determining when the person is appropriate to return to sport and provide direction in how to prevent the injury from reoccurring.
- Orthopedist – An orthopedist is also going to be needed. Imaging would be required to confirm the extent of the injury, especially, if other structures are involved. The orthopedist would discuss options including surgery if it is appropriate to the injury.
What can I do?
- Relative rest – Resting the area to decrease further pain and damage from occurring is one of the best ways to treat shoulder instability. Basically, stay away from the activities that are causing symptoms. This gives the shoulder time to rest and heal. If you keep doing what is causing the injury, it is not going to get better. This might include not participating in your sport or activity for a period or time. If you are not able to participate in your activity, then you can supplement with non-irritating activities such as biking, walking, or running while your shoulder is healing.
- Ice – Ice can help decrease pain and swelling in the tendon. Ice the painful area for 15 to 20 minutes at a time. I would recommend using an ice pack several times per day if the pain is constant or is preventing you from participating in an activity. Ice immediately after activity.
- Posture – Having forward rounded shoulders causes muscular imbalances in the shoulder. It stretches out the rotator cuff and scapular stabilizing muscles which are important for shoulder stabilization. It also shortens and causes the pectoralis major, pectoralis minor, and the biceps to get tight. If these muscles are tight, it will roll the shoulder forward. Below is a video showing how to stretch the pecs and biceps and also how to use a wall to check your posture.
- Strengthen the rotator cuff and scapular stabilizers – The role of the rotator cuff is to keep the ball in the socket of the shoulder joint. These muscles are very important and need to be strengthened in the case of shoulder instability. The scapular stabilizers are the muscles around the shoulder blade which help stabilize the shoulder joint while your arm is performing different activities. These muscles need to be strong to perform repetitive or stronger tasks without injury. The videos below review some strengthening exercises for the rotator cuff and the scapular stabilizers. Using loop resistance bands and resistance bands can increase strength and difficulty.
In review
- The main shoulder joint is called the glenohumeral joint.
- It is a large and complex joint that is made when the humerus (upper arm bone) and the scapula (shoulder blade) come together.
- The shoulder has the most movement of any joint in the body.
- However, it also has the least stability and this is what tends to get the shoulder joint in trouble.
- Shoulder instability is when the ball starts to move to undesirable locations on or off the socket.
- This is due to laxity or looseness of the shoulder joint.
- Usually the ball will slip forward of it’s socket.
- However it can also slip backward and downward.
- Shoulder laxity can result in subluxation or dislocation.
- There are different causes of instability
- Traumatic
- Atraumatic
- Congenital
- Shoulder subluxations and dislocations can cause other damage to the joint.
- A physical therapist and an orthopedist would be needed to treat this condition.
- There are things that you can do.
- Relative rest
- Ice
- Posture
- Strengthening rotator cuff and scapular stabilizers
As always, If you have questions about the content of this post or any other musculoskeletal questions, please e-mail me.
Additional resources
https://www.physio-pedia.com/Shoulder_Instability