Definition
Bankart and Hill-Sachs lesions are injuries involving the shoulder gleno-humeral joint consequent to one or multiple shoulder dislocations. These injuries affect the glenoid fossa on the scapular side (Bankart lesion) but can also cause damage to the head of the humerus (Hill-Sachs 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.
Two different types of Bankart lesions have been described, one with and one without the fracture of the glenoid.
A Bankart lesion without a fracture of the glenoid is in most cases a lesion of the glenoid labrum (the glenoid rim) that is caused by a shoulder dislocation and/or repeated anterior shoulder subluxations. The damage of the glenoid labrum can lead to the partial detachment of the labrum from the glenoid at its antero-inferior portion.
The osseous Bankart lesion occurs in patients with a full anterior shoulder dislocation, resulting in a more significant injury due to the detachment of the antero-inferior labrum associated with the glenoid rim fracture. Radiological images are critical for detecting an osseous Bankart lesion of the glenoid bone and allow for the measurement of bone loss.
If a shoulder dislocation is produced by high-energy trauma, it can additionally impact on the humeral head. A Hill-Sachs lesion, or Hill-Sachs impaction fracture is an injury to the postero-lateral side of the humeral head. This injury is also caused by a shoulder dislocation. The name of this pathology derives from the American radiologists who first described it in 1940.
The Hill-Sachs lesion has an incidence of 35% of all anterior dislocations and up to 80% in recurring dislocations.
Both pathologies can be associated with axillary nerve injury and various fractures to the humeral head and humerus bone.
Causes
The same mechanisms responsible for a shoulder dislocation are amongst the causes leading to Bankart and Hill-Sachs lesions. These pathologies are 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.
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
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 scans do 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 intensive physical therapy. However, with non-operative treatment there is a higher risk of recurrent dislocations. If the shoulder dislocates again, surgery is needed.
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.
The 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.
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 can begin. Rehabilitative management consists of a number of approaches:
Massage
Joint mobilisation
Ice/heat treatment
Physical exercise (pendular movements, shoulder shrug, rotation)
Education in sport and daily activities
Return to sport plan
Anti-inflammatory treatment (NSAIDs)
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.