Bankart lesion and Hill-Sachs lesion
MRI of a Bankart lesion

Definition

The labrum of the shoulder joint can be torn as a consequence of a forceful shoulder dislocation. When the damage only involves the labrum it is called a Bankart lesion. A Hill-Sachs lesion occurs when the lesion to the labrum presents simultaneously with a structural defect of the bone of the humeral head.

Illustration of a Bankart lesion

Pathology

A Bankart lesion consists of a tear of the glenoid labrum. When the humeral head pops out of the joint during a forceful, mostly anterior, shoulder dislocation, it may tear the capsule surrounding the shoulder joint and cause the detachment of the labrum from the glenoid. If a shoulder dislocation is produced by high-energy trauma, it can additionally impact on the humeral head. The abrupt displacement of the humerus causes the cartilage covering the humerus head to hit the glenoid. This leads to the formation of an indentation fracture to the humerus head generating the so called Hill-Sachs lesion. The lesion may vary in size and requires surgical treatment only if being from 1/8 to over 1/4 of the size of the labrum. This lesion occurs mostly in young individuals and shows an incidence of 35% of all anterior dislocations and up to 80% in recurring dislocations. Such lesions can be associated with axillary nerve injury and various fractures to the humeral head and bone.

Classification

Fractures of the humerus shaft can display various patterns: transverse, oblique, spiral, and comminuted. In addition they are differentiated depending on whether the fracture is displaced or undisplaced, relative to the loss of bone alignment and closed or open fracture. The AO (Arbeitsgemeinschaft für Osteosynthesefragen) Foundation, an international organisation founded in Switzerland, focussing on research and education for the management of orthopaedic injuries), is one of most used systems available to characterise humerus shaft fractures. According to the AO humerus shaft fractures are divided into their level of comminution:

Type A - No comminution

Type B - Presence of butterfly fragment (wedge-shaped fragment of bone

Type C - Comminution

An anterior shoulder dislocation may lead to a Bankart lesion

Causes

The same mechanisms responsible for a shoulder dislocation are amongst the causes leading to Bankart and Hill-Sachs lesions. These pathologies are most often diagnosed together with an anterior shoulder dislocation and in patients with recurrent shoulder dislocations. 

Bankart and Hill-Sachs lesions are frequent in young men involved in contact sports and elderly women over 60 years due to falls.

Risk factors

Any sport or physical activity that predisposes to a shoulder dislocation presents a risk for Bankart and Hill-Sachs lesions. This includes individuals actively playing contact sports (football, rugby, hockey) and throwing activity (tennis, baseball, cricket). The increased incidence of falls onto the shoulder represents a higher risk in older people. The intrinsic poor vascularity of the glenoid labrum exposes this area to injury when strained. These pathologies can easily arise in patients with a congenital joint laxity, a condition named Ehlers-Danlos Syndrome that weakens the ligaments stabilising the joints.

Shoulder pain and instability are symptoms of a Bankart lesion, Hill-Sachs lesion

Symptoms

The most common symptom of Bankart and Sachs-Hill lesions is a feeling of instability of the shoulder joint particularly if these pathologies occur after repetitive dislocations. The patient may display excessive translation of the humeral head within the glenoid joint. Pain and a catching sensation with shoulder subluxation are also frequently described. Patients often state that when moving the arm behind the head they feel that shoulder is close to dislocate.

Diagnosis

Top: X-ray of a Hill-Sachs lesion. Note the dent on the humeral head. Bottom: MRI showing a Bankart lesion

A medical history sets the beginning of a clinical investigation to evaluate the possible causes, injuries and previous shoulder dislocations that have lead to a recurrent shoulder dislocation. A high-energy trauma event particularly in active young individuals presents a higher risk for a Bankart or Hill-Sachs lesion, thus requiring a thorough medical analysis. Clinical examination provides a good indication for a dislocated shoulder and possibly other associated pathologies. Specific functional tests employed include the apprehension test, relocation test and sulcus sign. However, radiological imaging is required for the exact diagnosis of a Bankart and Hill-Sachs lesion. A Bankart lesion of the labrum is visualised at best by MRI using a contrast agent. X-rays and CT scansdo not detect easily a Bankart lesion as it involves soft tissue but are useful to diagnose a Hill-Sachs lesion to the humeral head and possible collateral fractures.

Treatment

Nonoperative treatment

The first approach of conservative treatment for a Bankart lesion due to shoulder dislocation is a closed reduction of the shoulder followed by temporary immobilisation with a sling until the inflammation has subsided. The patient requires treatment with pain killers and NSAID’s in the acute phase and subsequently undergo intensive physical therapy. However, with non-operative treatment there is a higher risk of recurrent dislocations. If the shoulder dislocates again, surgery is needed.

Example of arthroscopic surgery

Surgical treatment

Surgery for a Bankart lesion is highly recommended for active athletes, even after a single dislocation, especially those involved in contact sports, which increase the likelihood of a second shoulder dislocation and shoulder joint injury. Similarly to SLAP injuries, surgery consists in the repair of the labrum followed by the reattachment of the glenohumeral ligament to the glenoid rim mostly via arthroscopic surgery. The success rate of surgical repair is approximately 90% and patients are able to return to their sport activities.

With a Hill-Sachs lesion that occupies >30% of the humeral head surface, as established by CT or MRI scan, surgery is required due to the high instability of the shoulder. Surgical techniques vary: Allograft (transplant of a small bone tissue) into the lesion of the humeral head; remplissage (French translation for “fill-in”) in which a burr is introduced to decorticate the Hill-Sachs lesion and a large rotator cuff anchor is inserted into the bony defect; humeral rotation osteotomy or removal of bone parts; hemiarthroplasty and total shoulder arthroplasty are only used in patients over 50 years of age.

Shoulder shrug exercise

Rehabilitation

A number of exercises are available to strengthen the rotator cuff and the musculature of the shoulder and shoulder blades. Stretching is useful to restore flexibility and the range of movement of the shoulder joint. Following surgery the patient wears a sling for about three weeks until physiotherapy begins. In the recovery phase applications of cold pads, administration of pain killers and anti-inflammatory therapy with NSAIDs is standard rehabilitative management to improve symptoms. Physiotherapy consists of a number of methods:

Massage

Joint mobilisation

Ice/heat treatment

Physical exercise (pendular movements, shoulder shrug, rotation)

Education in sport and daily activities

Return to sport plan

Antiinflammatory treatment (NSAIDs)

Exercise with an elastic band strengthen the shoulder muscles

Prevention

The best prevention for a shoulder dislocation and consequent Bankart and Hill-Sachs lesions consists of physical training to strengthen the muscles around the shoulder and core. It is also recommended soon after recovery to avoid excessive training or intense activities potentially leading to recidivism.

In patients with increased risk due to strenuous sport activities, it is advised to wear proper safety equipment (braces) and padding during training. Where possible avoid falls in the elderly to prevent a shoulder dislocation.