The shoulder is the most mobile joint in your body. To allow such movement, the ball (humeral head) has to sit in a very shallow socket (glenoid) – a situation that mimics a golf ball balanced on a tee. (You will know that a golf ball can be easily knocked off a tee!). Stability of your shoulders therefore relies on intact soft tissue and bony stabilizers and fine co-ordination of the muscles around your shoulder. Injury, abnormal development or incorrect movement patterns can expose your shoulder to instability. An unstable shoulder may either come partially out (subluxtion) or totally dislocate. Approximately 90% of the time, the humeral head dislocates anteriorly.
Sudden onset of pain, deformity with inability to move your shoulder. Normally dislocation follows a specific injury – e.g. a rugby tackle/ski fall. Some patients notice numbness and or tingling in their shoulder and arm. Occasionally patients hear or feel a crack or a pop. Repeated dislocations usually occur more easily than the first episode and patients may learn to reduce their shoulder themselves. Complete dislocations normally require help for the shoulder to be put back in joint (normally this is done in hospital with sedation). Subluxations tend to go back into the correct position on their own.
If you dislocated or subluxed your shoulder in a traumatic manner, then it is very likely you will have sustained a tear to your glenoid labrum (this is present in 85% of cases). Your labrum acts as a chuck to stop your humeral head from rolling forwards off your socket - an injured labrum no longer provides this bumper. The labrum gets torn when your humeral head is forced out of the socket, tearing it off from the edge of the glenoid socket. This anterior-inferior labral tear is called a Bankart lesion. Sometimes the labrum is torn in different places around your socket and, more rarely still, all the way around. (See diagram below)
Left untreated this torn labrum tends to heal in the wrong place making you vulnerable to recurrent instability
Sometimes, there is also damage to the bone. This can affect both the socket (Bony Bankart) and/or the humeral head (Hill-Sachs defect).
A Bony Bankart equates to a chipped golf tee, so your humeral head has less of a platform on which to rest. This may happen as an acute fracture, or, with several dislocations, you may suffer gradual erosion of the front-lower portion of your socket.
The HIll-Sachs lesion occurs when your dislocated humeral head is resting against the sharp front edge of your socket. The humeral head bone is softer, so it gets a dent in its posterior surface. If you have a large Hill-Sachs, this can cause your humeral head to slide out of joint as you rotate your arm outwards.
Both Bony Bankart and Hill-Sachs lesions can compromise the success of keyhole stabilisation so, if they are large enough, you may require a Latarjet procedure (a bone block open stabilization operation) rather than a keyhole procedure.
Red = Bony Bankart viewed from above and face-on to the socket = chipped golf tee
Blue = Hill Sachs Lesion = dent in posterior part of humeral head
The acute dislocation is an urgent issue and your shoulder must be relocated swiftly. This is best done in the Emergency Department under appropriate sedation and image control.
Following reduction of your shoulder; which should be confirmed on x-rays; you will need to rest your shoulder, take painkillers and anti-inflammatories and wear a sling. This will help you recover after your injury
Sling – you will normally be given a simple sling and you should wear this for the first week or two after your dislocation. If it’s your first dislocation you may be given a special (abduction external rotation) sling to wear for three weeks to improve the position of your torn labrum tissues as it heals. This probably reduces your re-dislocation rate, although not everyone is convinced of this and the practice is not widespread.
Physiotherapy helps to restore your range of motion. It is also important for optimising the co-ordination of your shoulder girdle muscles and the stability of your core.
Your risk of re-dislocation depends on several factors:
1. Your age at first dislocation (younger = higher risk)
<20 years old – up to 90% risk of re-dislocation
20-25years old – up to 80% risk
>40 years old – as low as 6% risk (but more chance of having a rotator cuff tear that may need fixing)
2. The structural damage sustained in your shoulder
This includes: labral tear, bony injury, rotator cuff and capsular injuries. The more the damage, the greater the chance of further dislocations
3. Your sport and the level you play it
Contact sports and overhead sports are higher risk
Competitive athletes are at higher risk
The shoulder joint can get damaged with each traumatic dislocation. This potentially exacerbates: Glenoid bone loss, Labral and capsular damage, Articular cartilage damage (arthritis), Nerve damage
For young active patients, the evidence is clear that surgical stabilisation optimises functional outcome
The success rates of keyhole stabilisation reduces with increasing joint damage and numbers of previous dislocations
If you are recommended for surgery there are two main types:
Arthroscopic Shoulder Stabilisation / Labral Repair
Open Stabilisation / Latarjet Procedure
Both have high success rates - the choice of which to have depends on your structural injuries, your age and sport.
After surgery, you will require a period in a sling and have restrictions on movement and function. You will require a physiotherapy rehabilitation programme.
Return to sport will vary, but it's unlikely before 5 months. Contact and overhead sport may take a little longer.
Traumatic shoulder dislocation is a common problem. The risk of re-dislocation is very high in young active patients. Repeated dislocations increase the damage to your shoulder and worsen outcomes from surgery.
Surgery aims to restore stability to your shoulder. Re-dislocation rates are low after surgery in the short term (Keyhole surgery success 85-95% at two years; Open stabilization (Latarjet) approximately 95% at 2 years). 80% can expect to return to sport after surgery. If you continue to pursue competitive collision sport you may re-injure a fully healed shoulder and suffer a repeat dislocation.
Teenagers who play collision sports have a higher recurrence rate after surgery. In some series this rate is as high as 25%.
Some patients suffer instability without a history of trauma - patients with ‘atraumatic’ shoulder instability do not generally experience the same structural injuries as their traumatic counterparts.
Atraumatic instability is more common in teenagers and young adults. It is much more common in females. Many have a degree of hypermobility (double jointedness) or problems with their tissue strength. Most have problems with muscle patterning around their shoulder and many have difficulty with their shoulder joint position sense (proprioception). Most ‘atraumatic instability’ patients improve with a focused therapy programme. Joint laxity tends to improve with age, but the period during which the shoulder is unstable can be very troubling for patients: often it's painful and requires repeated visits to hospital for relocation as well as intensive physiotherapy. Thankfully, the problem normally sorts itself out by the age of 25.
Surgery is not the best first option. Specialist physiotherapy is the first line treatment. Occasionally surgery is indicated to tighten up the 'loose joint' so that the physiotherapy can be more effective.
Making the right choice about the best treatment for you means getting the right information. During your consultation, please do feel free to ask Mr Granville-Chapman to explain anything that you do not fully understand, and for his advice about the pros and cons of any treatment.