1 INSTABILITY: Dislocations & labral tears

Introduction The shoulder is a ball-and-socket with the head of the (upper bone) being the ball, and the glenoid (part of the shoulder blade or ) the shallow socket. The mismatch in size of these two surfaces allows the arm, on the one hand, the tremendous ability to move in almost any direction, but on the other hand, does make it more prone to instability i.e. coming fully out of joint (termed dislocation) or partially out of joint (subluxation) - a good analogy is a golf ball balancing on a tee, which even non-golfers will appreciate is not very stable, especially if there is a wind blowing, or the tee is broken or not level! In order to make the shoulder more stable, therefore, the socket is protected at its edge by a soft-tissue cartilage rim called the labrum which is a bit like the bumper of a car, it protects and deepens the glenoid, making it more broader and more concave. In addition, both joint surfaces are covered with articular cartilage, which acts to provide a smooth lubricated surface for movement and to allow some shock absorption, and the surrounding muscles, and tendons also provide stability and support.

Types of instability There are two major categories of unstable : i. Unidirectional instability. In this first category, an injury tears the labrum and stretches the capsule either at the front of the shoulder or – less commonly – at the back of the shoulder. Since the shoulder comes out in only one direction, this is called unidirectional instability: it dislocates either in the front (anterior dislocation) or in the back (posterior dislocation). When the labrum tears at the front, the term “” is used (Dr. Arthur Bankart described this labral tearing in anterior dislocations of the shoulder in 1923). ii. Multidirectional instability is different. This second category affects individuals with loose in general. Typically, the capsule of both shoulder joints is excessively large, allowing extra movement of the humeral head in every direction (translation). Individuals with excellent control of their and other adjacent muscles may still keep the ball centred in the socket. When these individuals relax their muscles, the ball can be moved a lot; but if there is no shoulder pain and the function is good with activity then their shoulders are considered lax, but not unstable. Multidirectional instability happens when the capsule is too large, elastic and the muscles are in suboptimal shape. Some individuals with marked laxity can dislocate and relocate their shoulders at will (voluntary instability).

What happens when the shoulder dislocates? In all cases, except those due to laxity/multidirectional instability, something has to give when a shoulder dislocates, and in general terms the damage can be to: • Soft tissue – on the socket side it is the labrum that tears and on the ball side it is the ligaments that tear - Humeral Avulsion of Glenohumeral ligaments (HAGL), or • Bone – damage on the socket side is termed a Boney Bankart lesion, and on the humeral head a Hill Sachs lesion, or • A combination of the two.

ëBMI Three Shires Hospital, Northampton ëRamsay Woodland Hospital, Kettering ëBMI Saxon Clinic, Milton Keynes ) 01604 633730 8 [email protected] : www.upperlimb.co.uk

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What’s a labral tear? The most common structure to be injured with a shoulder dislocation is the labrum (a labral tear is also called a Bankart tear). This occurs at the front of the shoulder with an anterior dislocation and at the back with a posterior dislocation. In some rare cases it can be at the back and front together. On the socket side the bone can sometimes fracture, and this is called a bony Bankart.

What’s a Hill Sachs lesion? This can best be described as a dent in the back of the humeral head. It results from the humeral head getting caught on the front of the socket as it comes out of joint. The sharp edge of the socket compresses the bone of the humeral head and distorts its normally round shape. The best analogy for this would be the dent that would occur in your car if you collided with a lamp post. Just like a car, these ‘dents’ do not mend themselves, and unfortunately these dents can predispose you to further dislocations.

What’s a HAGL lesion? This is the rarest type of injury with the most complex name – a Humeral Avulsion of Glenohumeral Ligaments lesion. In this case the consequence of the injury is a detachment of one or more of one of the ligaments at the front or bottom of the shoulder. This injury is more common in rugby, with the injury occurring when a tackler has his arm forced backwards at shoulder level, rather than in the overhead position.

Why don’t these tears heal themselves? When the labrum tear off the socket, joint fluid comes to lie in the tear. This fluid prevents blood clotting, and hence, if there is no clot formed, there can be no scar formation and no healing. Because of this, the recurrence rate in the under 25-year-old group is over 90%. Certainly, if it recurs once, it will probably continue to happen again and again, given the right circumstances. Over the age of 26 years the recurrence rate starts to fall, and indeed, recurrence is quite uncommon in the older age. One of the reasons for this, is that the consequences of a dislocation in an older patient are different, with tears occurring in the substance of the capsule itself or in the rotator cuff, or fractures of the humeral head and .

What ongoing symptoms might I get with shoulder instability? • Pain: this can start suddenly or slowly. It may hit you just as you throw a ball, for example. • Numbness all the way down your arm with throwing • A persistent sensation of the shoulder feeling loose, weak, “not right”, or repeatedly “giving way” • Repeated shoulder dislocations which you are able to relocate yourself or which you have to attend hospital to have put back in.

ëBMI Three Shires Hospital, Northampton ëRamsay Woodland Hospital, Kettering ëBMI Saxon Clinic, Milton Keynes ) 01604 633730 8 [email protected] : www.upperlimb.co.uk

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What investigations are useful? MR Investigations assess which structures are involved: • X-ray: useful to check the shoulder is fully in joint and to assess for a Hill Sachs or bony Bankart. • MRI scan: a frequently used investigation – covers most aspects. • MR arthrogram: The gold standard investigation for shoulder instability. Because of the many overlapping and interwoven structures in the shoulder, it is possible for a regular MRI scan to miss a small tear. Whilst even an MR arthrogram can miss the smallest of tears, it remains the best non-invasive investigation. • CT: This is used where there a high suspicion of damage to bone (CT is better than MRI for this). • Nanoscope: this is a new option where a very small 2mm camera is introduced under local anaesthetic into the shoulder as an outpatient Nanoscope procedure to visualise inside the joint.

What treatment options are there? Unfortunately, labral tears, Hill Sachs and HAGL’s do not heal themselves, but that said, some people can adapt very well by altering their activities and learning to use the shoulder in a safer, more comfortable manner. Physiotherapy may help improve mobility and strengthen shoulder muscles. If symptoms fail to settle with non-surgical treatments, surgery may be advised. Repeated shoulder dislocations can lead to cartilage damage and bone loss, which in turn can lead to pain, weakness, chronic instability and osteoarthritis, so shoulder stabilisation surgery is usually considered in the following cases: • Failure of non-operative treatment • Age: the risks of further dislocations are significantly higher in those <25 years of age • Activity Level: e.g. physical job or sporting activities requiring lots of shoulder activity • Acute injury: if someone presents with a fresh injury then this can an ideal opportunity to repair the damage, as that way the outcome will be more likely favourable.

What does surgery involve? In the last 20 years, techniques for repair of dislocating shoulders have improved considerably. For most problems, the problem can be dealt with arthroscopically (keyhole surgery) but, if complex, it may require open surgery, where a larger incision is required. Arthroscopic Shoulder Stabilisation & SLAP repair The aim of this procedure is to repair the torn labrum and ligaments in order to return tissues to their normal position and thereby tighten the shoulder preventing further dislocation. In respect of a SLAP tear the basic principle is to repair the torn labrum in order to restore the attachment of the long head of biceps tendon. In order to perform this surgery, you will usually have a regional anaesthesia involving a nerve block to the arm, supplemented with either sedation or a general anaesthetic. The operation is generally performed as a day case or overnight stay if performed later in the day. Usually three small (0.5 cm) wounds are made around the shoulder in order to allow the passage of the arthroscope (camera) and special instruments into the shoulder. Plastic anchors are inserted into the socket side (glenoid) after small holes have been drilled. Sutures attached to those anchors are then passed through the torn labrum and are then secured in such that the labrum is repaired back to the bone

ëBMI Three Shires Hospital, Northampton ëRamsay Woodland Hospital, Kettering ëBMI Saxon Clinic, Milton Keynes ) 01604 633730 8 [email protected] : www.upperlimb.co.uk

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Open Shoulder Stabilisation – Laterjet procedure In certain circumstances, arthroscopic stabilisation of an unstable shoulder is not possible. For example, when in addition to a torn labrum, a piece of bone has fractured off the socket (glenoid), or if there have been recurrent dislocations wearing away the socket, or if there is a large Hill Sachs lesion. In these cases, open surgery is necessary to compensate for the bone deficiency, with the transfer of a part of the coracoid bone (at the front of the shoulder) to replace the missing bone or deepen the socket. In addition, muscle attachments to the coracoid are transferred adding to the stability by acting like a sling in front of the shoulder (a Laterjet procedure). This surgery is performed under general anaesthetic, supplemented with a regional anaesthetic nerve block. A wound is made over the front of the shoulder usually 8–10 cm in length. Because it is a larger operation it can be more painful and a one-night stay in hospital afterwards is generally required.

Recovery after surgery In order for the soft tissues or bone to heal after surgery, the arm will be immobilised in a sling for 3–4 weeks. Because it can be difficult to control our motions while you sleep, you may be required to wear this sling to bed at night too. It will not possible to drive whilst the arm is in the sling. Surgery for shoulder instability is usually followed by a period of discomfort and shoulder stiffness that can be different for every patient. Some people have very little pain or stiffness, with most achieving good range of motion by 3 months after surgery. A strengthening programme is started around 6–8 weeks following surgery, with light weights. Non- contact sports are normally possible around 12 weeks post surgery, with contact sports around 4-5 months post operation. Rehabilitation may continue for 6-9 months following the procedure. Commitment to the physiotherapy programme is fundamental to the success of the surgery.

What are the risks of surgery? Complications can occur - fortunately, these are rare – they include: • Infection: this can range from a minor infection of the wound requiring only oral antibiotics, to a more serious deep infection which would likely require further surgery to help clear it. • Stiffness: joint problems including stiffness or arthritis can occur. • Failure of the repair: sometimes the bone quality means the anchor or suture slips, and if you fell after surgery this would risk damaging the repair. • Problems with anchors or sutures: there is the possibility that an anchor or a suture can loosen or cause irritation - this may necessitate further surgery. • Nerve injury: this is extremely rare but may result in temporary or permanent, partial or complete loss of feeling and/or movement in the arm. • Recurrence of instability: there remains a risk of redislocation – around 5%. • Failure to achieve the desired result is not strictly a complication but it can be a source of disappointment. My purpose in listing these complications is to inform, not frighten you. While it would be preferable if we could perform surgery without any risk, this is not the case. The complications are rare but regrettably, in spite of best efforts, they do occur. I feel it is only right you know.

How successful is the surgery? Surgery is successful about 85-95% of the time (no operation is 100% successful all the time). The operation is most successful at relieving pain, restoring stability and improving function. Whether you can return to your previous level is an individual matter and depends on the damage to your shoulder, how well it heals, how well you rehabilitate and how strenuous is your desired level of work or sports. Because of the many variables involved, I can make no guarantees other than to assure you I will deliver the very best medical care possible.

ëBMI Three Shires Hospital, Northampton ëRamsay Woodland Hospital, Kettering ëBMI Saxon Clinic, Milton Keynes ) 01604 633730 8 [email protected] : www.upperlimb.co.uk