Continuing Education Activity

The shoulder is the most commonly dislocated joint in the human body. Anterior shoulder dislocation is the most common form. Injury to the glenoid labrum due to dislocation is a prevalent finding. Dislocation leads to injury to the glenoid labrum, and injury to the labrum leads to joint instability, creating a vicious cycle. The Bankart lesion was first described in 1938 as an anterior labral injury causing anterior instability of the glenohumeral joint. This recurrent instability is troublesome for athletes performing overhead work. The diagnosis of anterior shoulder instability is made clinically when anterior instability tests are positive and magnetic resonance imaging (MRI) shows a glenoid labrum tear from the glenoid rim. MRI is an excellent diagnostic tool for detecting glenoid labral lesions. Advances in arthroscopic technique, instrumentation, and implant material play a significant role in treating glenoid labral lesions. Arthroscopic stabilization with suture anchors is the preferred method for many surgeons to treat anterior inferior glenoid labral tears.

Objectives:

• Identify the Bankart lesion as a cause of anterior shoulder instability.

• Evaluate the anterior shoulder instability clinically and radiologically.

• Explain the correct treatment for Bankart lesions and associated injuries.

• Review the multidisciplinary approach for the management of Bankart and associated injuries.

Introduction

The glenoid labrum is a fibrocartilaginous ring attached circumferentially to the glenoid rim contributing to the stability of the shoulder joint.[1] The glenoid labrum increases the glenoid surface vertically by 75% and horizontally by 57%, according to Saha et al.[2] Bankart's lesion represents an anterior and inferior labral detachment from the glenoid with an associated capsuloligamentous injury below the equator of the glenoid.[3] This result in anterior instability of the shoulder joint due to the loss of the following normal mechanisms, such as the choke block effect of the labrum, concavity compression mechanism of the rotator cuff, and function of the inferior glenohumeral ligament.[4] Traumatic subluxations or dislocations of the shoulder joint cause injury to the glenoid labrum.[5] Almost 87 to 100% of the index anterior shoulder dislocations are associated with Bankart lesions.[6]

Etiology

Lesions of the glenoid labrum are most commonly the result of traumatic shoulder dislocation.[7] The most common cause of traumatic shoulder dislocation is participation in collision or contact sports.[8] Primary or recurrent shoulder dislocations result in varying degrees of injury to the glenoid labrum, such as Bankart lesion, SLAP (Superior Labral lesion Anterior to Posterior) lesion, ALPSA (Anterior Labral Periosteal Sleeve Avulsion) lesion, and HAGL (Humeral Avulsion of Glenohumeral Ligament) lesion. Bankart lesion is specifically caused by anterior shoulder dislocation with the shoulder in external rotation and abduction.[9] 

Abnormal translation of the head of the humerus during dislocation results in excessive loading and stretching of the labrum and capsuloligamentous structures. This excessive stretch leads to a tear or avulsion of the labrum with associated capsular injury.[10]

Epidemiology

Shoulder dislocations occur in 1% of the population, most of which are anterior (90%).[11] Traumatic dislocations are the leading cause of shoulder injuries.[12] Most dislocations (95%) are traumatic and occur three times more often in men.[13] In young athletes, the recurrence rate is over 90% if not treated surgically.[12] 

An anterior shoulder dislocation is associated with a Bankart lesion in 87 to 100%, a Hill-Sachs lesion in 90%, a bony Bankart lesion in 73%, a rotator cuff injury in 13%, and a SLAP (Superior Labral lesion Anterior to Posterior) in 10%.[14][15][16] Perthes lesion, Anterior Labral Periosteal Sleeve Avulsion (ALPSA), Gleno-Labral Articular Disruption (GLAD), and Humeral avulsion of Glenohumeral Ligament (HAGL) occur in a minority of patients.[16][17]

Pathophysiology

Traumatic anterior shoulder dislocation results in various injuries to the shoulder joint (glenohumeral joint). Soft tissue injuries, such as glenoid labrum tears, capsular tears, glenohumeral ligaments, and rotator cuff injuries, may occur.[18] The bony injuries may involve the glenoid rim or the humeral head.[14] The soft tissue Bankart lesion is an injury to the anteroinferior glenoid labrum and capsule-ligament complex. It is a pure soft-tissue injury. Bankart lesion is caused explicitly by anterior shoulder dislocation with the shoulder in external rotation and abduction.[9] 

Abnormal translation of the head of the humerus during dislocation results in excessive loading and stretching of the labrum and capsuloligamentous structures.[10] This excessive stretch leads to a tear or avulsion of the labrum with associated capsular injury. In contrast, the bony Bankart lesion is an avulsion fracture of the glenoid rim with anteroinferior glenoid labrum and capsuloligamentous complex injury.[19] Bone loss alters the shape of the glenoid cavity as an inverted pear, and this will reduce the glenoid articular arc.[20] 

Burkhart studied the effect of a change in shape and reduced surface area of the glenoid on recurrence. The recurrence rate was higher in the groups with significant bone loss at the glenoid.[20] Hill-Sachs lesion is a posterosuperior osteochondral impaction fracture of the humeral head.[21] There are two types of Hill-Sachs lesions: one interlocked with the glenoid rim and one not interlocked when the shoulder is in a functional position (abduction and external rotation). They are referred to as "engaging" and "non-engaging," respectively.[4] 

In engaging Hill Sachs, the long axis of the bone defect is parallel to the anterior glenoid rim; hence it will engage with the glenoid rim.[14] The bone defect of the non-engaging- Hill Sachs is diagonal or not parallel to the anterior glenoid margin, so there is no engagement of the humeral head with the glenoid margin in functional positions, but engagement may occur in non-functional positions such as an extension or low abduction (<70 degrees).[14] The non-engaging variant is the most common, but an engaging Hill-Sachs causes the most recurrences.[14][22] Recently, Giovanni et al. proposed the concept of a glenoid track (on-track and off-track lesions).[14] According to this concept, "off-track" lesions usually engage even after soft tissue repair.[23]

History and Physical

Glenoid labral lesions present with signs and symptoms of recurrent shoulder instability with generalized shoulder pain.[5] A few patients may present with catching, locking, or popping sensations in the shoulder.[24] Most patients with a Bankart lesion report primary or recurrent anterior shoulder dislocation.

History

Evaluation of the Bankart’s lesion requires a thorough history, including the index dislocation, number of dislocations or subluxations, and their reduction method (self or medical personnel). Clinicians must enquire about the patient’s occupation, involvement in the contact sport, mechanism of trauma, and history of the epileptic disorder.[25] The history of a dislocation includes the following key points –

• Demographic details
• Occupation
• Level of activity- contact sport, recreational, none
• Index dislocation
• Age at first dislocation
• Number of dislocations/subluxations
• Mechanism of dislocation
• Presence of associated injury
• Reduction of dislocation- self or medical person
• Dislocation in sleep
• History of epileptic disorder  

Examination

Clinical examination is dedicated to diagnosing the presence of shoulder instability and associated injuries.

Signs of Anterior Instability

• Apprehension test – [Specificity-96%, Sensitivity-72%]
• Jobe’s relocation test - [Specificity-92%, Sensitivity-81%]
• Anterior drawer test - [Specificity-85%, Sensitivity-53%]
• Bony apprehension test - [Specificity-86%, Sensitivity-100%][26][27]

Signs of Posterior Instability

• Posterior apprehension- [Specificity-99%, Sensitivity-20%][28]
• Jerk test- [Specificity-98%, Sensitivity-73%]
• Porcellini test- [Specificity-99.3%, Sensitivity-100%][29]
• Kim test- [Specificity- 94%, Sensitivity- 80%][30]

Signs of Mid-range Instability

• Sulcus sign rules out multidirectional instability. [Specificity-97%, Sensitivity-28%][31]

Generalized Ligamentous Laxity

• Beighton score[32]

Evaluation

Investigations

Radiographs - It is important to obtain plain radiographs as part of the initial workup to rule out associated fractures and frank osseous defects such as bony Bankart, Hill-Sachs, glenoid fractures, coracoid fractures, and greater tuberosity fractures.[33]

• Anteroposterior view (AP view)
• True AP view
• Axillary view
• Scapular Y view
• Acromial outlet view

          Special views[33]

• West point axillary view- Bony Bankart's lesion
• Stryker's notch view – Hill-Sachs lesion

Magnetic Resonance Imaging (MRI)

MRI with or without contrast is the gold standard investigation for soft tissue injuries such as glenoid labrum and capsuloligamentous injury. It also helps in planning the management of shoulder instability. MRI findings will be hemorrhagic effusion and capsulolabral elevation from the anterior and inferior glenoid rim in an acute Bankart injury. MRI in the abduction and External rotation has improved sensitivity (94%) and specificity (82%) for detecting Bankart lesions than the traditional neutral position. Presence of associated lesions such as Perthe's lesion, Anterior Labral Periosteal Sleeve Avulsion (ALPSA), Gleno-Labral Articular Disruption (GLAD), and Superior Labral tear from Anterior to Posterior (SLAP), and Humeral avulsion of Glenohumeral Ligament (HAGL) can be diagnosed on MRI.[34]

MR-arthrogram is more specific and sensitive than MRI for detecting labral tears. The specificity and sensitivity are 96% and 93 %, respectively.[24]

Non- Contrast Computed Tomography (NCCT) with 3D reconstruction -  This investigation is very useful in quantifying the glenoid bone loss, the orientation of the articular surface, humeral bone loss, and the glenoid version.

Following are the indications for NCCT with 3D reconstruction[35]

• Mid-range instability on clinical examination.
• Glenoid bone loss suspicion on the radiograph.
• Large Hill-Sachs.
• A very large number of shoulder dislocations.
• Identification of "On Track" and "Off Track" Hill-Sachs lesion.

Measurements of glenoid and humeral bone loss on 3D reconstruction[14][19]

1. GT = 83% (D – d)
2. HSI = HS + BB

On Track = HSI < GT

Off Track = HSI > GT

Abbreviations

• GT - glenoid track.
• D – Diameter of inferior glenoid.
• d- Width of anterior glenoid bone loss.
• HSI- Hill-Sachs Interval.
• HS- width of Hill-Sachs lesion.
• BB- Width of Bone Bridge (distance of the lateral edge of Hill-Sachs from the medial edge of rotator cuff insertion).

Treatment / Management

Factors that determine the treatment of Bankart repair are:

• Age of the patient
• Level of physical activity
• Desired future activity level
• History of shoulder pain
• Recurrent shoulder instability
• Associated glenoid or humerus bone loss[23]

Conservative Management

The best candidates for nonoperative management are patients older than 30 with no obvious shoulder instability, preserved normal osseous restrain to instability, and no desire to participate in recreational activities. Patients with multidirectional instability (MDI), voluntary dislocators, and minimal demand are further prospects for nonoperative therapy.[36]

Operative Management

Indications for operative management- Young athletes (less than 30 years of age) with acute, primary, and traumatic anterior shoulder dislocations who wish to continue playing sports are the best candidates for surgical intervention.[37][38] Other indications are as follows-

• Post-traumatic recurrent shoulder instability limiting daily activities
• Post-traumatic anterior shoulder dislocation with an associated large rotator cuff tear, bony defect in the glenoid or the humerus head (Hill Sachs lesion)
• Persistent subluxation and pain even after adequate nonoperative management.
• Patients with a propensity for recurrent instability include athletes with overhead activities, construction workers, and climbers.

Relative Contraindications for Operative Management

• Uncooperative/ medically unstable patients
• Seizure disorder
• Primary collagen disorders, such as (Ehlers- Danlos or Marfan syndrome)
• Atraumatic shoulder instability
• A neurologic injury such as paralysis of the axillary nerve or suprascapular nerve
• Recurrent instability with post-traumatic arthritis[38]

Deciding the Surgery - The patient's expectations, age, and level of the sport (contact vs. non-contact) are the most crucial factors to consider when treating a labral injury.[39] If the patient is young and involved in contact sports (high demand), they will be considered for surgery.[40] The glenoid bone loss and engaging (off track)/non-engaging (on track) Hill Sachs lesions are assessed in all of these patients.[23] If the glenoid bone loss is less than 13.5%, isolated arthroscopic or open Bankart's repair with suture anchors will be sufficient.[41][42] This non-significant bone loss will not engage in almost all cases [23]. The glenoid bone loss of 13.5% to 17.3% is subcritical; in such cases risk of recurrence is taken into consideration, and high-risk patients (young athletes from contact sports, and the presence of engaging Hill-Sachs lesion) will be treated with arthroscopic or open Bankart's repair with remplissage.[42][43] 

When glenoid bone loss is 13.5% to 17.3% with a low risk of recurrence and is non-engaging, Hill Sachs patients are treated by isolated arthroscopic or open Bankart's repair.[44][45] Patients with 17.4% to 30% glenoid bone loss will need an open Latarjet procedure.[46] About 30% or more, glenoid bone loss mandates glenoid bone grafting (autograft- iliac crest or allograft-distal tibia allograft).[47]

Differential Diagnosis

Anterior Labrum Periosteal Sleeve Avulsion Lesion (ALPSA)

It is an anteroinferior glenoid labrum and capsuloligamentous avulsion with intact scapular periosteum. This lesion will heal at the nonanatomic position and presents as anterior shoulder instability.[48]

Perthes Lesion

The avulsion of the anteroinferior glenoid labrum from the glenoid rim but partially attached with the intact scapular periosteum. As a result, the avulsed labrum is present in an anatomical position but is nonfunctional. Hence, the patient will present with anterior shoulder instability.[49]

Prognosis

Surgical stabilization of anteroinferior glenoid labral lesions with arthroscopic or open procedures yields impressive results.[49] Arthroscopic procedures propose theoretical advantages of anatomical restoration of the glenoid labrum, selective soft tissue tensioning, improved range of motion, less post-operative pain, and preservation of subscapularis muscle over an open approach. Functional outcomes of the shoulder and return to the same level of sport are better with arthroscopically treated Bankart lesions.[38] 

The rate of return to the same level of sport after arthroscopically treated Bankart is 71% and 66% after the open procedure.[50]

Complications

Perioperative Complications

• Anchor failure
• Glenoid fracture
• Nerve injury (0.3%) - musculocutaneous or axillary nerve injury
• Hematoma formation
• Infection (0.2%)[50]

Postoperative Complications

Arthroscopic Bankart Repair

Recurrence - Arthroscopic Bankart repair shows a recurrence rate of 10.7% to 13.1%.[51][52] The rate of recurrence is higher in the following patients:

• Young age
• Excessive preoperative dislocations
• Significant bone loss
• Inferior capsule hyperlaxity

Decreased range of motion- reduction in external rotation is a common finding after arthroscopic Bankart repair.[53]

Open Bankarts Repair

• Recurrence: Open Bankart repair is associated with a low recurrence rate of 8%[54]
• Reduced range of motion- external and internal rotations are reduced - open Bankart repair shows more loss of rotations than arthroscopic Bankart repair
• Subscapularis rupture
• Prolonged operative time
• High incidence of sepsis[51]

Postoperative and Rehabilitation Care

Table 1. Rehabilitation protocol after arthroscopic Bankart repair[55]

Rehabilitation Protocol After Open Latarjet Procedure

• 0 to 6 weeks- Sling immobilization, passive external rotation- till neutral
• 7 to 12 weeks- overhead and external rotation stretching only
• 12 weeks to 4 months- Strengthening exercises
• 4 to 6 months - Weight training in the gym
• From 6 months - Fully unrestrained activities[56]

Deterrence and Patient Education

Educating the athletes about the mechanism of injury of Bankart lesions will help them avoid such injuries. Discussing the various methods of treatment of Bankart lesion and their pros/cons with the patient is necessary. The patient must be educated about the importance of physical therapy and rehabilitation protocol for a good recovery. Patients are encouraged to do shoulder muscle strengthening exercises, avoid provocation maneuvers of shoulder dislocations, do shoulder girdle strengthening exercises, avoid redislocations, and wear protective gear while playing.

Enhancing Healthcare Team Outcomes

Progress in arthroscopic techniques has improved the surgical care of Bankart lesions. Arthroscopic Bankart repair is less morbid than open repair. Bankart lesions are more troublesome for young athletes involved in overhead activities. Treatment of the Bankart lesion is complicated by associated injuries to the glenoid rim and humeral head. Glenoid bone loss and the humeral head defect will mandate additional procedures to prevent the recurrence after Bankart repair. Strict adherence to structured rehabilitation protocol is crucial for returning to sport. This is where an interprofessional team approach to management is vital.

The comprehensive management of such injuries requires interprofessional coordination between the orthopedic surgeon, musculoskeletal radiologist, nursing staff, and physiotherapist. The surgeon will take the lead on these cases, but all team members must contribute from their specialties to guide the patient outcome. Nursing will assist in patient evaluation, serve as the liaison between specialties, and counsel patients. They will also often assist during surgical repair. Pharmacists can have a minor role in ensuring proper post-operative pain control is appropriate and that there are no drug interactions while counseling the patient on their medications. The physical therapist is undoubtedly a key player in managing these injuries, either through conservative management to avoid surgery or post-operatively to restore function. Everyone on the interprofessional care team must maintain accurate and updated records so all caregivers have accurate information from which to make decisions, and open lines of communication among all team members are crucial to successful patient outcomes. [Level 5]