Shoulder Dislocation and Shoulder Instability
The shoulder has the widest range of movement in the body; the price of that is low bony stability. The head of the arm bone balances in a shallow socket. When this balance is lost, either a dislocation (the head comes completely out of the socket) or instability (the joint becomes insecure and partially slips) occurs.
How Does the Shoulder Stay Stable?
Shoulder stability rests on two groups of structures. The passive structures are the cartilage rim that deepens the socket (the labrum), the joint capsule and the ligaments. The active structures are the rotator cuff muscles and the muscles that control the shoulder blade. During a dislocation the labrum and ligaments are most often injured.
The great majority of dislocations occur forwards: force applied while the arm is rotated outwards and raised is the typical mechanism. Posterior dislocations are rarer and may be seen in particular situations such as a seizure or an electric shock.
Symptoms
At the time of dislocation
- Severe pain and an inability to move the arm
- Obvious deformity of the shoulder, with the outer edge appearing squared off
- Holding the arm against the body and slightly rotated outwards
- Numbness in the arm (which may be due to stretching of a nerve)
Instability (recurrent insecurity)
- A sense that the shoulder will come out when the arm is brought into particular positions (apprehension)
- Insecurity during overhead movements and throwing
- Recurrent partial slipping (subluxation)
- Waking when the arm falls above the head during sleep
- Deep, ill-defined shoulder pain and early fatigue
Diagnosis
- History: age at and mechanism of the first dislocation, how many times it has recurred, who reduced it, and sporting and occupational requirements.
- Examination: range of movement, apprehension and relocation tests, assessment of general joint laxity.
- X-ray: to assess the bony structures and any accompanying fracture at the time of dislocation and afterwards.
- MRI / CT: MRI for labral and ligament injuries; CT where bone loss is suspected. The degree of bone loss directly determines the surgical method.
The age at first dislocation is decisive: in young and sporting patients the likelihood of recurrence is markedly higher than in those who dislocate for the first time at an older age. Where a first dislocation occurs at an older age, the likelihood of a rotator cuff tear increases and assessment is directed accordingly.
Treatment
After a first dislocation
A dislocation should be reduced by a physician under appropriate conditions. After reduction, a short period of protection is followed by range-of-movement and strengthening work. The programme targets the rotator cuff and shoulder blade muscles in particular.
Attempting to reduce the shoulder yourself or having it done by someone inexperienced carries a risk of fracture and of nerve or vessel injury; it is therefore not recommended.
Surgical treatment
Surgery is considered for recurrent dislocations, for a sense of insecurity that restricts daily life or sport, and where there is marked bone loss. Age, activity level, sport and the degree of bone loss are assessed together.
- Arthroscopic repair: the torn labrum and loosened capsule are fixed back to the rim of the socket with sutures. Preferred where bone loss is limited. See Shoulder Arthroscopy.
- Methods involving bone grafting: where there is marked bone loss at the rim of the socket, open procedures that widen the socket with bone may be considered.
Which method is appropriate is planned before surgery according to the bone loss seen on imaging and the patient’s requirements. Outcomes vary from person to person; no guarantee of a specific result or timeframe is given.
Return to Sport
Return is determined by criteria rather than the calendar: pain-free full range of movement, muscle strength close to the other side, shoulder blade control, and the ability to perform sport-specific movements safely. Return is planned more cautiously in contact sports and overhead disciplines. For detail see the Shoulder Arthroscopy Aftercare Guide.
When Should You Seek Assessment?
- If your shoulder has dislocated once (to assess the risk of recurrence)
- If you have a sense that the shoulder will come out during particular movements
- If your shoulder partially slips and returns on its own
- If there is loss of strength or insecurity during overhead movements
- If you have had a first dislocation at an older age (for rotator cuff assessment)
When to Seek Medical Help Without Delay
- Obvious deformity of the shoulder and an inability to move the arm at all
- Numbness, tingling, coldness or absence of a pulse in the arm
- Suspicion of a fracture together with the dislocation (severe pain, inability to bear weight)
- Numbness or loss of strength persisting after reduction
These findings require urgent assessment. Outside office hours, go to the nearest emergency department.
Frequently Asked Questions
My shoulder dislocated once — will it happen again?
The likelihood of recurrence depends most on the age at first dislocation and on activity level; the risk is markedly higher in young and sporting patients. Assessment and a programme after the first dislocation are therefore important.
Can I put a dislocated shoulder back myself?
This is not recommended. Inappropriate attempts can cause a fracture and injury to nerves or vessels. Support the arm, keep it still and go to a medical facility as soon as possible.
Can strengthening be enough without surgery?
In some patients — particularly those not playing contact sport and without bone loss — a targeted strengthening programme may be sufficient. Surgery is considered for recurrent dislocations and marked bone loss.
How long should I use a sling?
The duration varies with the type of dislocation and any accompanying injuries. Because prolonged immobility can lead to shoulder stiffness, the period of protection is determined by your physician and controlled movement is started early.
Why is bone loss important?
When bone loss at the rim of the socket exceeds a certain level, soft tissue repair alone may be insufficient and the likelihood of further dislocation rises. The bony structures are therefore assessed in detail before surgery.
I am older and have had a first dislocation — what changes?
With a first dislocation at an older age the likelihood of further dislocation is lower, but the likelihood of a rotator cuff tear is higher. If you remain unable to raise the arm, the tendons are assessed.
Academic Work
Assoc. Prof. Bertan Cengiz, MD has scientific work published in national and international peer-reviewed journals in the field of shoulder arthroscopy and upper limb surgery and related areas. The publication list and verifiable academic sources are available on the Publications page.
Related Pages
- Shoulder and Upper Extremity
- Shoulder Arthroscopy
- Rotator Cuff Tear
- Frozen Shoulder (Adhesive Capsulitis)
- Shoulder Arthroscopy Aftercare Guide
The information on this page is for general guidance and does not replace an in-person medical examination. Diagnosis and treatment require a physician’s clinical assessment. Outcomes of any treatment or surgical intervention may vary from person to person; no guarantee of a specific result or timeframe is given on this page.