A dislocation can occur as a result of injury or be an inherent problem as a result of “lax” joints.
Traumatic Dislocation – This occurs when a strong enough force to pull or push the humerus bone out of its socket is experienced eg: a rugby tackle or fall. The first dislocation would typically need to be put back into joint(reduced) in A&E, a sling worn for a period of time, followed by a course of physiotherapy.
Atraumatic Dislocation – This occurs in people with generalised lax joints. A change in muscle activity around the shoulder mostly proceeds the dislocation, eg: taking up a new activity/sport. This alteration in muscle balance can be enough to pull the joint out of its resting position.
There will often be one position in particular in which the joint is likely to dislocate. The shoulder rarely dislocates fully but “sub-luxes” from the glenoid.
With any dislocation the movement of the humerus over the glenoid rim can cause a ‘chip’ in the head of the humerus. This is termed a Hill Sachs lesion.
JPG 8.12 and 8.11
Physiotherapy to address the imbalance is the initial line of treatment.
This sort of dislocation can begin as a “party trick” but become a problem when the ligaments and capsule stabilising the shoulder become progressively weaker.
If physiotherapy fails to improve the condition, surgery may be needed.
Capsular Shrinkage – This is used in multi-directional instability ie when the shoulder can sub-lux in more than one direction.
Two incisions are made at the front and one at the back. Heat is used in the form of a radiofrequency to shrink the capsule.
ANTERIOR INFERIOR CAPSULAR SHIFT
To restore normal volume of the capsule (or lining) of the glenohumeral (or shoulder joint) and restore normal tension and length of the stretched ligaments following recurrent dislocation.
Patients with recurrent instability and/or dislocation which is caused by multi-directional joint laxity rather than a localized defect (usually as a result of several dislocations)
Superficial muscles are separated and deep muscles are divided. The capsule of the joint is opened. All these structures are repaired at the end of the procedure.
The capsule of the joint is dissected from the muscle anteriorly and inferiorly and divided by an –I incision. The two flaps of capsule are overlapped which shifts the inferior capsule and reduced the overall volume of the joint capsule. Two suture anchors are inserted into the anterior margin of the glenoid bone, allowing the tissues to heal in this position. These embedded ‘anchors ‘ grip the bone and allow the overlapped capsule to be tightened against the glenoid bone.
Possible associated procedures
- Examination under Anaesthesia
- Arthroscopic assement of the glenohumeral joint and sub acromial bursa
- Bankart Repair ( link)
Main Possible Complications
- Damage to nerve and blood vessels
- Recurrence of anterior instability
- Shoulder stiffness
After your operation
- The arm will be rested in a controlled position in a sling or brace. The physiotherapist and nursing staff will show you how to adjust and safely remove and re apply this.( Link to ULTRASLING II ER and living with a sling)
- You will not need an x ray.
- You will typically be able to go home the same day or the day after surgery.
- You can expect to need painkillers for the first 2 weeks after surgery to control the background pain. You will also need to take painkillers an hour before each physiotherapy or heavy exercise session for up to 6 weeks longer.
- You will be shown specific shoulder and arm exercises by your physiotherapist before you leave the hospital. These exercises are very important and must be carried out accurately after leaving hospital on a daily basis at home; ideally 3 times a day. It is very important that you DO NOT EXTERNALLY ROTATE the shoulder during the first 4 weeks after surgery. Make sure that you are shown this by your physiotherapist before leaving hospital.
- The stitches must be removed or the wound inspected (if absorbable sutures are used) at 14 days after surgery; either with your GP’ practice nurse or at the hospital.