Shoulder Instability

The Gleno-Humeral Joint has the largest range of movement of any joint in the body. In order to allow this range of movement the degree of stability of the joint is sacrificed. The bony socket (Glenoid) is small and relatively flat only made slightly cup shaped by the cartilage and a ring of soft tissue termed the labrum (lip). There is a greater reliance on the ligaments and muscles to prevent it coming out of joint or dislocating. If any of these structures are damaged or do not work properly the shoulder can become unstable or dislocate.

Instability or dislocations can occur as a consequence of a number of issues.

Traumatic.

A typical dislocation is a consequence of marked force applied to the arm, with the hand away from the body and in extension, as if starting to make an overarm throw or pitch. There is typically damage to the restraining structures. This usually involves a tear of the labrum (lip of the socket) and the capsule (lining of the joint) with possible bony damage to both the socket and the humeral head (ball).

The shoulder can be unstable or dislocate in any direction. The ball typically comes out of the front of the socket and lies in front or in front and below the shoulder. Dislocations where the shoulder comes out posteriorly (backwards) are uncommon and are typically associated with a seizure (fit) or electrocution.

Atraumatic.

Atraumatic dislocations or instability are typically a consequence of an underlying laxity of the soft tissue constraints or an abnormality of the shape of the Glenoid (socket).

Muscule patterning (muscle imbalance).

The muscles around the shoulder normally act to maintain the Gleno-Humeral Joint in place. Under certain circumstances they can contract abnormally acting to dislocate the Joint rather than keep it located.

Although the most common that the predominant cause of instability is traumatic damage it is common for there to be a combination of issues. In addition, the predominate type of instability may change with time.

Traumatic dislocations or instability:

Signs and symptoms:

Dislocation.

Typically there is an episode when the shoulder comes out of joint. This is associated with pain and deformity of the shoulder. It is often painful to move the arm at all and it is usually kept by the side. The normal curve of the shoulder is lost and the acromion is felt as a prominence with a fullness often felt anteriorly (at the front). The joint often needs to be reduced under medical supervision in the hospital. The dislocation may reduce spontaneously or may reduce when the arm is repositioned.

Dead arm.

There may not be a complete dislocation. Occasionally the arm may be injured sufficiently to damage the restraining structures but without the shoulder coming completely out of joint. There may be pain felt throughout the whole arm and the arm may feel ‘lame’ for a time.

Ongoing instability.

The shoulder may dislocate again or do so repeatedly. The joint may feel as if it is going to come out if the arm is placed in certain positions, so called apprehension. There may be pain rather than a sensation of instability with certain movements.

Diagnosis:

The diagnosis may be clear from the history and examination. Further imaging is usually undertaken to confirm the diagnosis and plan treatment.

X Rays (plain radiographs). These are important to diagnose a dislocation and to identify associated injuries as well as confirming the shoulder is back in joint.

Magnetic Resonance Imaging Arthrogram (MRI-A). This involves the injection of a contrast into the joint before the examination. This improves the detail of the exam and allows the identification of damage to the labrum as well as possible damage to other structures such as the rotator cuff tendons.

Computerised Tomography (CT scan) with or without contrast. This scan allows the imaging of the bony structures including potential damage to the socket. If an injection of contrast is used it can be used in the place of an Magnetic Resonance Imaging Arthrogram (MRI-A) to visualise damaged soft tissues and labrum.

Initial treatment:

Reduction.

The dislocated shoulder should be reduced as soon as is safely possible. Some people such as team physiotherapists may have been trained to reduce the shoulder at the side of the pitch. If there is no one available to reduce the shoulder then the patient should be taken to an emergency department.

The shoulder is typically X Rayed to exclude associated injuries. Painkillers and sedation or Entonox (Gas and Air) are often given to allow the shoulder to be reduced comfortably. The shoulder is typically much more comfortable once it is reduced back into the correct position. X Rays should be taken to confirm the reduction and check for any associated injuries. Very occasionally the shoulder cannot be reduced without a General Anaesthetic (being fully asleep).

Immobilisation.

There is some evidence that the risk of re-dislocation is reduced by immobilising the arm in external rotation (a hand shake position). Immobilisation in this position is difficult and poorly tolerated and the benefit is not marked. As a consequence it is usual to immobilise the arm in a broad arm sling or Polysling for up to 3 weeks.

Rehabilitation can be commenced as soon as this is comfortable.

Further treatment.

Once the shoulder has dislocated the risk of further dislocations increases. The degree of increased risk depends on a number of factors including; the amount of structural damage to the joint, the activities undertaken (eg: contact sports), the age and gender of the individual. In certain situations the risk of a further dislocation may be as high as 80%.

It is reasonable to consider surgical stabilisation after the first dislocation in certain circumsatnces. The alternative is to pursue rehabilitation allowing the shoulder to strengthen and become more comfortable avoiding at risk activities.

If the shoulder continues to dislocate or feels unstable it may be necessary to consider surgical intervention.

Surgical Stabilisation.

If the shoulder continues to be symptomatic and either dislocates or feels like it will dislocate again surgery may be necessary. The type of surgery will depend on the structural damage, which needs to be corrected. If the damage is largely soft tissue affecting the labrum and capsule then this can usually be addressed with a soft tissue procedure typically undertaken arthroscopically (keyhole). If the damage is principally to the bone of the glenoid or humeral head or both then it may be necessary to address this with a coracoid transfer operation or Latarjet.

Arthroscopic Shoulder Stabilisation (Bankart Repair)

Description:

Dislocations of the Shoulder (Gleno-Humeral) Joint are common. During the dislocation structural damage may occur to the joint. This damage may involve damage to the fibrous lip (labrum) of the socket (glenoid) or the bony socket (glenoid) itself. This damage may need to be repaired or reconstructed to stabilise the Gleno-Humeral Joint.

The soft tissue damage can usually be repaired or reconstructed as a keyhole (arthroscopic) procedure. The torn labrum is released and secured back to the to the edge of the socket (glenoid) with anchors which are fixed to the bone and to which sutures are attached that allow the labrum to be secured.

If the damage is more extensive with significant loss of bone this void is typically best addressed with a procedure that transfers bone from elsewhere to repair the socket (glenoid). This procedure is typically in the form of a Coracoid transfer or Latarjet stabilisation although alternative bone grafts can be used. This procedure is most reliably undertaken under direct vision as an open procedure.

There may be associated injuries to the Rotator Cuff or Superior Labrum (SLAP) that can be addressed at the same time.

The purpose of the surgery:

The aim of the surgery is to stabilise an unstable Gleno-Humeral Joint.

Alternative Treatment options:

Shoulder instability may be managed with rehabilitation to optimise muscle function in an attempt to satisfactorily improve stability. Activities can be modified to avoid those during which the Gleno-Humeral Joint feels unstable.

Anaesthetic:

The surgery is typically undertaken with the patient asleep with a nerve block to provide additional pain relief.

Incision and Dressings:

The majority of stabilisations can be performed as a keyhole (arthroscopic) procedure and are usually carried out through two or three small (5mm) incisions. These incisions are closed either with paper Butterfly sutures (SteriStripsTM) with or without dissolvable sutures which do not need to be removed. The wounds are then covered with a splash-proof OpsiteTM dressing. These dressings may in turn be covered by a large padded dressing immediately following the operation. This padded dressing is removed prior to being discharged home.

If there is bone damage then a larger incision is required (open technique) an incision approximately 5cm long is made over the front of the shoulder. This is typically closed with an absorbable suture under the skin. Paper Butterfly Stitches (SteriStripsTM) are usually used and the wound covered with padding and a splash proof OpsiteTM dressing.

Procedure:

The labrum (lip) of the socket is often detached and scarred down. This tissue is released and the damaged edge of the Glenoid (socket) is prepared. The labrum is then reattached to the Glenoid using sutures (stitches) attached to small anchors drilled into the bone of the Glenoid.

Rehabilitation:

Following the surgery immobilisation is required in a polysling. The sling should be worn as instructed in the post-operative guidance. The sling is usually worn for three weeks day and night and three weeks at night. The arm should be exercised as detailed in the post-operative rehabilitation guidelines. This typically involves avoiding movements that stress the repair too soon.

Please see the stabilisation rehabilitation guidelines.

Admission and Discharge:

You will normally be admitted the day of surgery and go home the same day. It may be necessary for you to stay in overnight particularly if you do not have a responsible adult to keep an eye on you overnight or if your operation is late on in the day.

Risks associated with the operation:

All operations are associated with a degree of risk but significant complications associated with an arthroscopic stabilisation are uncommon. The following risks are those that are serious or most commonly reported in the literature.

Infection (<1%). Infection in shoulder surgery is uncommon, particularly in keyhole (arthroscopic) surgery. If an infection were to develop it is typically a superficial infection, which can be treated with oral antibiotics. Rarely does an infection develop that requires re-admission to hospital and surgery to wash the infection out.

Anaesthetic Risks (Anaestheic complications are rare but include Heart Attack (Myocardial Infarction, MI), Stroke (Cerbero-Vascular Accident, CVA) and a clot in the leg (Deep Vein Thrombosis, DVT) or lungs (Pulmonary Embolus, PE).

Damage to nerve or blood vessels (Neuro-Vascular Damage) (<1%). Damage to nerves or blood vessels are rare. Damage to the axillary nerve may occur as it passes close to the joint. Damage to this nerve may result in weakness and difficulty bringing the arm out to the side (abduction).

Stiffness. After the surgery and a period of immobilisation the shoulder is likely to be stiff. This stiffness should improve with time and graduated rehabilitation. Initial stiffness may be protective of the repair. Initial stiffness may be protective of the repair. Rarely persistent stiffness or a frozen shoulder (Intrinsic Capsular Stiffness) develops and may require treatment.

Recurrence (5%). The aim of the surgery is to stabilise the shoulder (Gleno-Humeral) Joint. Despite a successful repair or reconstruction there is a small risk of recurrent instability. Typically this follows a further injury.

Further surgery (Re-operation)

Arthritis. While the surgery itself is unlikely to significantly predispose the shoulder to arthritis, a dislocation itself increases the probability of arthritis.

Open Bone Stabilisation (Latarjet)

Description:

Dislocations of the Shoulder (Gleno-Humeral) Joint are common. During the dislocation structural damage may occur to the joint. This damage may involve damage to the fibrous lip (labrum) of the socket (glenoid) or the bony socket (glenoid) itself. This damage may need to be repaired or reconstructed to stabilise the Gleno-Humeral Joint.

The soft tissue damage can usually be repaired or reconstructed as a keyhole (arthroscopic) procedure. The torn labrum is released and secured back to the to the edge of the socket (glenoid) with anchors which are fixed to the bone and to which sutures are attached that allow the labrum to be secured.

If the damage is more extensive with significant loss of bone this void is typically best addressed with a procedure that transfers bone from elsewhere to repair the socket (glenoid). This procedure is typically in the form of a Coracoid transfer or Latarjet procedure although alternative bone grafts can be used. This procedure is most reliably undertaken under direct vision as an open procedure.

The purpose of the surgery:

The aim of the surgery is to stabilise an unstable Gleno-Humeral Joint.

Alternative Treatment options:

Shoulder instability may be managed with rehabilitation to optimise muscle function in an attempt to satisfactorily improve stability. Activities can be modified to avoid those during which the Gleno-Humeral Joint feels unstable.

Anaesthetic:

The surgery is typically undertaken with the patient asleep with a nerve block to provide additional pain relief.

Incision and Dressings:

If there is bone damage then a larger incision is required (open technique) an incision approximately 5cm long is made over the front of the shoulder. This is typically closed with an absorbable suture under the skin. Paper Butterfly Stitches (SteriStripsTM) are usually used and the wound covered with padding and a splash proof OpsiteTM dressing.

Procedure:

The coracoid is exposed and the attachment of the Coraco-Acromial ligament is detached. The Pectoralis Minor (Pec Minor) insertion is released by trimming a portion of bone from the inside surface of the Coracoid. The Conjoint Tendon (Short Head of Biceps and Corachobrachialis), which is the main musculo tendinous attachment of the Coracoid, is preserved. The Subscapularis tendon is split, minimising potential damage to the muscle. The front of the GlenoHumeral Joint capsule (linning of the joint) is exposed and opened. The damaged front of the socket is thereby visible and can be prepared to accept the Coracoid. The Coracoid is turned on its side and fixed to the socket typically with two screws. The capsule and labrum can be repaired, as in a Bankart stabilsiation, keeping the bone block outside the joint.

The coracoid fills the bone defect of the socket as a static stabiliser. The Conjoint tendon then acts as a dynamic stabiliser of the shoulder as it is redirected across the front of the shoulder when it is in its most vulnerable position with arm away from the body with the hand extending backwards as if throwing.

Rehabilitation:

Following the surgery immobilisation is required in a PolyslingTM. The sling should be worn as instructed in the post-operative guidance. The sling is usually worn for 3 weeks day and night and 3 weeks at night. The arm should be exercised as detailed in the post-operative rehabilitation guidelines. This typically involves avoiding movements that stress the repair too soon.

Admission and Discharge:

You will normally be admitted the day of surgery and go home the same day. It may be necessary for you to stay in overnight particularly if you do not have a responsible adult to keep an eye on you overnight or if your operation is late on in the day.

Risks associated with the operation:

All operations are associated with a degree of risk but significant complications associated with an open Latarjet stabilisation are uncommon. The following risks are those which are serious or most commonly reported in the literature.

Infection (<1%). Infection in shoulder surgery is uncommon, particularly in keyhole (arthroscopic) surgery. If an infection were to develop it is typically a superficial infection, which can be treated with oral antibiotics. Rarely does an infection develop that requires re-admission to hospital and surgery to wash the infection out.

Anaesthetic Risks (Anaestheic complications are rare but include Heart Attack (Myocardial Infarction, MI), Stroke (Cerbero-Vascular Accident, CVA) and a clot in the leg (Deep Vein Thrombosis, DVT) or lungs (Pulmonary Embolus, PE).

Damage to nerve or blood vessels (Neuro-Vascular Damage) (<1%). Damage to nerves or blood vessels are rare. Damage to the axillary nerve may occur as it passes close to the joint. Damage to this nerve may result in weakness and difficulty bringing the arm out to the side (abduction).

Stiffness. After the surgery and a period of immobilization the shoulder is likely to be stiff. This stiffness should improve with time and graduated rehabilitation. Initial stiffness may be protective of the repair. Rarely persistent stiffness requires treatment.

Recurrence (<5%). The aim of the surgery is to stabilise the shoulder (Gleno-Humeral) Joint. Despite a successful repair or reconstruction there is a small risk of recurrent instability. Typically this follows a further injury.

Further surgery (Re-operation)

Mal-union and Non-union. The operation relies on the Coracoid bone block healing to the bone of the front of the Glenoid (socket). Despite careful preparation and surgical technique there is a risk that the Coracoid will not heal (non-union) or that it will heal in a suboptimal position (mal-union).

Arthritis. While the surgery itself is unlikely to significantly predispose the shoulder to arthritis, a dislocation itself increases the probability of arthritis.

Anterior Gleno-Humeral Joint Stabilisation Rehabilitation Protocol

Stabilisation surgery can be open or arthroscopic (key hole) and involve repair of the soft tissues and bony damage to the gleno-humeral joint. The principles of rehabilitation are similar. If there is any doubt please consult Mr. Packham.

Aims:

The aims of rehabilitation are to protect the repair in the early stages and to maximally optimise function in the long-term.

General Points :

• Do not push through pain.

• Do not sacrifice quality of movement for range of movement.

• Do not push into Abduction External Rotation (hand behind head, throwing or push up position) for at least 12 weeks post surgery.

Immobilisation:

• The patient is to wear a sling day and night for 3 weeks (apart from to undertake exercises).

• The patient is to wear the sling at night for a further 3 weeks, making a total of 6 weeks in total at night.

Post Operative Instructions:

0-3 weeks:

Care should be taken while dressing or if in doubt the sling should be worn under clothing.

Hand, Wrist and Elbow exercises.

Pendular exercises.

Encourage optimal Scapulo-Thoracic position.

Keep hand in the plain of the abdomen / stomach.

From 3-6 weeks:

Wean out of sling during the day– light activities within field of view only.

Gentle active and passive movements.

Gradually increase External Rotation to neutral (handshake position)

Proprioceptive exercises.

No long lever open chain exercises until 12 weeks

From 12 weeks onwards:

Isometric exercises in variable starting positions progressing to

Resisted movements through range and strengthening

Functional Milestones and Activity Time Scales:

Driving See general principles of rehabilitation.

Swimming 12 weeks plus.

Golf 12 weeks plus.

Contact sports 5 to 6 months.

Atraumatic instability:

Atraumatic dislocations or instability are typically a consequence of an underlying laxity of the soft tissue constraints or an abnormality of the shape of the Glenoid (socket). Patients are often very supple or double jointed. There may be an association with minor repetitive injury or trauma.

The signs and symptoms may be the same as for a traumatic dislocation or there may a pain or discomfort within the shoulder which may be vague and undefined. There may be a perceived looseness within the shoulder rather than frank instability or dislocations.

If the shoulder is dislocates then the immediate treatment is the same as in traumatic shoulder dislocation. The mainstay of treatment is rehabilitation from a specialist shoulder physiotherapist. This rehabilitation may focus initially away from the shoulder on the core abdominal muscles and buttocks on which the scapula-thoracic function depends. The shoulder will not be optimally stable unless the scapulo-thoracic function is optimal.

If the shoulder remains stable the surgical intervention may be necessary. This is typically in the form of an arthroscopic (keyhole) procedure which tightens lax tissue as well as addressing any structural damage

Shoulder stabilisation –capsular shift.

Muscle patterning (muscle imbalance).

The muscles around the shoulder normally act to maintain the Gleno-Humeral Joint in place. Under certain circumstances they can contract abnormally acting to dislocate the Joint rather than keep it located. This is the least common form of instability but its contribution to instability may subtle and may be missed.

Treatment is in the form of specific specialist rehabilitation to retrain the muscles to contract appropriately. Surgical intervention may exacerbate the abnormal muscle patterning.