summary Traumatic Anterior Shoulder Instability, also referred to as TUBS (Traumatic Unilateral dislocations with a Bankart lesion requiring Surgery), are traumatic shoulder injuries that generally occur as a result of an anterior force to the shoulder while its abducted and externally rotated and may lead to recurrent anterior shoulder instability. Diagnosis is made clinically with the presence of positive anterior instability provocative tests and confirmed with MRI studies that may reveal labral and/or bony injuries of the glenoid and proximal humerus (Hill-Sachs lesion). Treatment may be nonoperative or operative depending on the chronicity of symptoms, the presence of risk factors for recurrence, and the severity of labral and/or glenoid defects. In high-risk populations, surgery is often offered after a single dislocation event. Epidemiology Incidence one of most common shoulder injuries 1.7% annual rate in general population Demographics have a high recurrence rate that correlates with age at dislocation up to 80-90% in teenagers (90% chance for recurrence in age <20) Risk factors markedly higher incidence in military patients contact athlete patients Etiology Pathophysiology mechanism of injury anteriorly directed force on the arm when the shoulder is abducted and externally rotated pathoanatomy "on-track" versus "off-track" concept of Hill-Sachs lesion (instability as a bipolar concept) Hill-Sachs defect is "off-track" and will "engage" on the glenoid if the size of the Hill-Sachs defect > glenoid articular track (HSI > GT) conversely, the Hill-Sachs defect is "on track" and will NOT "engage" if the size of the Hill-Sachs defect < glenoid articular track (HSI < GT) Glenoid Track (GT) = 0.83D-d (D = diameter of inferior glenoid, d = width of anterior glenoid bone loss) Hill-Sachs Interval (HSI) = HS+BB (HS = width of the Hill-Sachs, BB = width of bony bridge) may have implications regarding surgical management goal is to convert on off-track lesion into an on-track lesion Associated injuries orthopaedic labrum & cartilage Injuries bankart lesion is an avulsion of the anterior labrum and anterior band of the IGHL from the anterior inferior glenoid. is present in 80-90% of patients with TUBS humeral avulsion of the glenohumeral ligament (HAGL) occurs in patients slightly older than those with Bankart lesions also found in female collegiate athletes associated with a higher recurrence rate if not recognized and repaired an indication for possible open surgical repair glenoid labral articular defect (GLAD) is a sheared off portion of articular cartilage along with the labrum presence is a risk factor for failure following arthroscopic stabilization procedures anterior labral periosteal sleeve avulsion (ALPSA) can cause torn labrum to heal medially along the medial glenoid neck associated with higher failure rates following arthroscopic repair common finding in patients with recurrent instability managed nonoperatively 97% of patients with recurrent instability have either a Bankart or ALPSA lesion fractures & bone Defects bony bankart lesion is a fracture of the anterior inferior glenoid present in up to 49% of patients with recurrent dislocations higher risk of failure of arthroscopic treatment if not addressed defect >20-25% is considered "critical bone loss" and is biomechanically highly unstable stability cannot be restored with soft tissue stabilization alone (unacceptable >2/3 failure rate) requires bony procedure to restore bone loss (Latarjet-Bristow, other sources of autograft or allograft) recent studies suggest critical bone loss may be as low as 13.5% each dislocation event causes, on average, 6.8% bone loss glenoid takes on an inverted-pear appearance as bone loss increases 89% failure rate following arthroscopic repair in patients with this glenoid morphology Hill-Sachs defect is a chondral impaction injury in the posterosuperior humeral head secondary to contact with the glenoid rim. is present in 80%-100% of traumatic dislocations and 25% of traumatic subluxations is not clinically significant unless it engages the glenoid greater tuberosity fracture is associated with anterior dislocation in patients > 50 years of age increases risk of recurrence lesser tuberosity fracture is associated with posterior dislocations nerve injuries axillary nerve injury is most often a transient neurapraxia of the axillary nerve present in up to 5% of patients rotator cuff tears 30% of TUBS patients > 40 years of age 80% of TUBS patients > 60 years of age medical global hyperlaxity (i.e. Ehlers-Danlos Syndrome, collagen disorders) often associated with atraumatic instability global hyperlaxity confers an odds ratio (OR) of 2.68 for the development of anterior shoulder instability individuals with global hyperlaxity have a 3x higher rate of recurrent instability patients with global hyperlaxity are less likely to develop capsulolabral lesions Anatomy Glenohumeral anatomy Static restraints bony anatomy capsule glenohumeral ligaments labrum labrum contributes 50% of additional glenoid depth Dynamic restraints rotator cuff muscles long head of biceps tendon Anterior static shoulder stability is provided by Anterior band of IGHL (main restraint) provides static restraint with arm in 90° of abduction and external rotation MGHL provides static restraint with arm in 45° of abduction and external rotation SGHL provides static restraint with arm at the side Classification Anteroposterior Translation Grading Scheme Grade 0 Normal glenohumeral translation Grade 1+ Humeral head translation up to glenoid rim Grade 2+ Humeral head translation over glenoid rim with spontaneous reduction once force withdrawn Grade 3+ Humeral head translation over glenoid rim without spontaneous reduction Sulcus Test Grading Scheme Grade 1 Acromiohumeral interval < 1cm Grade 2 Acromiohumeral interval 1-2 cm Grade 3 Acromiohumeral interval > 2cm Instability Severity Score Variable Parameter Score Age < 20 years > 20 years 2 0 Degree of sports participation Competitive Recreational/none 2 0 Type of sport participation Contact/forced overhead Other 1 0 Shoulder Hyperlaxity Hyperlaxity (anterior/inferior) Normal 1 0 Hill sachs on AP x-ray Visible on external rotation Not visible on external rotation 2 0 Glenoid contour loss on AP x-ray Loss of contour No lesions 2 0 Clinical Implications Total Possible = 10 An acceptable recurrence risk of 10% with arthroscopic stabilization. < 6 points A score of > 6 points has an unacceptable recurrence risk of 70% and should be advised to undergo open surgery (i.e. Laterjet procedure). > 6 points Presentation History patients often recount a traumatic event leading to a dislocation important to clarify whether patient needed a formal reduction, or if they spontaneously reduced Symptoms traumatic event causing dislocation feeling of instability shoulder pain complaints caused by subluxation and excessive translation of the humeral head on the glenoid Physical exam load and shift Grade 0 - normal glenohumeral translation Grade I - translation to the glenoid rim, without dislocation Grade II - shifts over glenoid rim, spontaneously reduces Grade III - shifts over glenoid rim, does not spontaneously reduce apprehension sign patient supine with arm 90 degrees abducted and 90 degrees externally rotated positive when patients experiences apprehension positive sign in mid-ranges of abduction is highly suggestive of concomitant glenoid bone loss relocation sign decrease in apprehension with anterior force applied on shoulder during apprehension testing sulcus sign tested with patient's arm at side generalized ligamentous laxity increased risk of recurrent instability in patients with hyperlaxity assess via Beighton's criteria (score > 4) shoulder specific laxity defined as hyperexternal rotation at side > 85 degress hyperabduction > 105 degrees (Gagey's maneuver) OR > 2+ load shift in 2 or more planes (anterior, posterior, inferior) Imaging Radiographs see imaging of shoulder recommended views a complete trauma series needed for evaluation true AP scapular Y axillary optional views West Point view shows glenoid bone loss Stryker view shows Hill-Sachs lesion CT scan +/- arthrogram indications helpful for evaluation of bony injuries and calculation of glenoid bone loss arthrogram usually reserved for patients who are unable to undergo MRI i.e. patients with pacemakers and/or cochlear implants due to limited soft-tissue contrast, CT arthrogram not as effective at visualizing internal soft-tissue derangements as MR arthrogram MRI indications best for visualization of labral tear has been validated as an imaging modality through which to assess bone loss abduction and external rotation (ABER) sequences can be utilized to better visualize the antero-inferior glenoid labrum MR Arthrogram increases sensitivity and specificity (86-91% and 86-96%) for detecting soft-tissue injuries when compared to conventional MRI (44-100% and 66-95%) Treatment Nonoperative acute reduction, ± immobilization, followed by therapy indications management of first-time dislocators remains controversial current ASES recommendations are for surgical intervention for athletes aged 14 to 30 at the end of their competitive season if they have positive apprehension testing and bone loss reduction simple traction-countertraction is most commonly used other reduction techniques include: Kocher: arm at side in external rotation is forward-flexed and then internally rotated Hippocratic: traction against a heel placed in the patients axilla Stimson's: weight is hung from the affected arm of a patient in the prone position immobilization studies have not shown any benefit of immobilization > 1 week for decreasing recurrence rates some studies show immobilization in external rotation decreases recurrence rates in patients < 40 thought to reduce the anterior labrum to the glenoid leading to more anatomic healing subsequent studies have refuted this finding and the initially published results have not been reproducible physical therapy strengthening of dynamic stabilizers (rotator cuff and periscapular musculature) outcomes goal is return to sport within 7 to 21 days military and overhead and/or contact athletes experience an unacceptably high rate of recurrent instability risk factors for re-dislocation are age < 20 (highest risk) male contact sports hyperlaxity glenoid bone loss >20-25% greater tuberosity fractures Operative Arthroscopic Bankart repair +/- capsular plication indications relative indications first-time traumatic shoulder dislocation with Bankart lesion confirmed by MRI in athlete younger than 25 years of age high demand athletes recurrent dislocation/subluxation (> one dislocation) following nonoperative management < 20-25% glenoid bone loss remplissage augmentation with arthroscopic Bankart may be considered if Hills-Sachs "off-track" techniques at least three (preferably four) anchor points shoulder be used paramount that labrum is fully mobilized prior to repair outcomes results now equally efficacious as open repair with the advantage of less pain and greater motion preservation increased failure rates seen in patients with global hyperlaxity, glenoid bone loss, or too few fixation points too many anchors does pose a risk for fracture through the anchor holes (postage stamp fracture) Open Bankart repair +/- capsular shift indications Bankart lesion with glenoid bone loss < 20-25% revision stabilization following failed arthroscopic Bankart repair without glenoid bone loss >20% can be considered when there is a concomitant acute glenoid fracture, or if the patient is hyperlax and requires a formal capsular shift during the same procedure humeral avulsion of the glenohumeral ligament (HAGL) can also be performed arthroscopically but is technically challenging technique generally accessed through a deltopectoral approach can fix bony bankart with screws or suture in a linear or bridge technique outcomes results are equivalent to arthroscopic repair, although patients have more pain and less range of motion postoperatively patients with greater than 13.5% glenoid bone loss have higher rates of recurrent instability Latarjet (coracoid transfer) or Bristow Procedure indications chronic bony deficiencies with >20-25% glenoid deficiency (inverted pear deformity to glenoid) in the setting of glenoid bone loss, excessive stress is transferred to labrum and attenuated anterior soft tissues, increasing the risk of failure of labral repair alone transfer of coracoid bone with attached conjoined tendon and CA ligament Latarjet procedure performed more commonly than Bristow Latarjet triple effect = bony (increases glenoid track), sling (conjoined tendon on top of subscapularis), capsule reconstruction (CA ligament) technique deltopectoral approach subscapularis is split outcomes over recurrent instability rate ranges from 0% to 8% good to excellent outcomes are seen in over 90% of patients Autograft (tricortical iliac crest or distal clavicle) or allograft (iliac crest or distal tibia) indications bony deficiencies with >20-25% glenoid deficiency (inverted pear deformity to glenoid) revision of failed latarjet technique can be performed arthroscopic or open distal tibia gaining popularity since graft is a true osteochondral graft outcomes 89% healing rate at a mean of 1.4 years Remplissage + Bankart Repair indication engaging large (>25-40%) Hill-Sachs defect "off-track" Hill-Sachs lesions with <20-25% glenoid bone loss technique posterior capsule and infraspinatus tendon sutured into the Hill-Sachs lesion may be performed with concomitant Bankart repair by decreasing size of Hill-Sachs, converts on off-track lesion into an on-track lesion outcomes when compared to latarjet with 2-year outcomes, remplissage + bankart had lower recurrent instability rates (1.4% vs. 3.2%) despite greater bipolar bone loss Bone graft reconstruction for Hill Sachs defects indication engaging large (>40%) Hill-Sachs lesions technique allograft reconstruction arthroplasty rotational osteotomy outcomes Tendon transfers indication chronic, irreparable subscapularis tear technique latissimus dorsi may better replicate line of pull of native subscapularis pectoralis major - sternal head outcomes Historical procedures: Putti-Platt / Magnuson-Stack / Boyd-Sisk indications led to over-constraint and arthrosis technique goal is to tighten subscapularis Putti-Platt is performed by lateral advancement of subscapularis and medial advancement of the shoulder capsule Magnuson-Stack is performed with lateral advancement of subscapularis (lateral to bicipital groove and at times to greater tuberosity) Boyd-Sisk is transfer of biceps laterally and posteriorly outcomes high rate of post-operative stiffness and subsequent osteoarthritis typical presentation of open procedure performed in 1970s-80s, now with presenting complaint of pain and stiffness from glenohumeral OA, especially lack of ER, and signigicant posterior glenoid wear and retroversion high rate of recurrent instability with Boyd-Sisk Techniques Acute Reduction +/- Immobilization followed by physical therapy indications acute dislocations presenting to the emergency departments techniques relaxation of patient with sedation or intraarticular lidocaine is essential various methods for reduction exist scapular manipulation Kocher Stimson pros/cons timely reduction can help to style the development of further bone loss or joint contractures complications unsuccessful in 5-10% of cases biceps tendon, joint capsule, fracture fragments most common blocks to reduction nerve injury axillary nerve if excessive traction is utilized recurrent instability risk factors include young patient age, bone loss, contact sport participation, global hyperlaxity Arthroscopic Bankart Repair + Capsular plication indications recurrent anterior instability anterior instability in young athletes current trend is towards surgical management after first-time dislocation event, as recurrent instability is associated with greater degrees of glenoid bone loss, which may preclude arthroscopic stabilization approach shoulder arthroscopic approach technique drive through sign might be present prior to labral repair and capsulorraphy studies support use of > 3 anchors (< 4 anchors is a risk factor for failure) complications recurrence, most often due to unrecognized glenoid bone loss or lack of concomitantly addressing "off-track" HS lesion stiffness, especially in external rotation, further loss of ER may occur with the addition of remplissage over-tightening increases the risk of post-capsulorrhaphy arthropathy, especially in older patients axillary nerve injury axillary nerve is on average 12mm from infra-glenoid tubercle chondrolysis (from use of thermal capsulorraphy which is no longer used) Open Bankart repair +/- capsular shift indications often employed in the setting of failed arthroscopic stabilization some surgeons prefer an open procedure if the patient is found to have a HAGL lesion approach shoulder anterior (deltopectoral) approach technique subscapularis transverse split or tenotomy open labral repair and capsulorraphy capsular shift inferior capsule is shifted superiorly complications recurrence most often due to unrecognized glenoid bone loss subscapularis injury or failed repair post-operative physical exam will show a positive lift off and excessive ER stiffness caused by overtightening of capsule leads to loss of external rotation treat with Z lengthening of subscapularis axillary nerve injury iatrogenic injury with surgery (avoid by abduction and ER of arm during procedure) arthritis usually wear of posterior glenoid may have internal rotation contracture seen with Putti-Platt and Magnuson-Stack procedures Latarjet or Bristow Procedure indications indications vary based on geographic region European surgeons aggressively employ the latarjet young, high-demand contact athletes or athletes of consequence (mountain climbers, big wave surfers) recurrent anterior instability with critical (>20-25%) or subcritical (>13.5%) bone loss patients at high-risk of failure with soft-tissue procedures alone (ISIS > 4-6 points) approach shoulder anterior (deltopectoral) approach can be performed arthroscopically technique coracoid transfer to anterior inferior glenoid bone defect traditional or congruent arc technique for coracoid graft placement after harvest, coracoid is passed through a split in the distal 1/3 or middle 1/2 subscapularis traditional versus congruent arc technique in the congruent arc technique, the undersurface of the coracoid ends up articulating with the humeral head graft can be placed intraarticularly (capsular repaired to CA ligament stump) or extraarticularly (capsule repaired to native glenoid rim) concerns exist for increased rates of subsequent osteoarthritis with intraarticular placement, although this isn't fully supported by high-quality literature no difference in outcomes between open and arthroscopic procedures, although literature has identified a profound learning curve for the arthroscopic latarjet complications generally higher than arthroscopic or open Bankart, some studies report up to 25% incidence of complications nonunion graft lysis up to 90% of patients undergo some degree of resorption within the first six months hardware problems stiffness, particularly in external rotation glenohumeral osteoarthritis will rapidly occur with lateral overhang of graft into the joint space occurs in up to 38% of patients nerve injury majority are traction or contusion neuropraxias and resolve spontaneously treat with observation for 3-6 weeks; delayed EMG if deficits persist musculocutaneous nerve occurs during instrumentation around the conjoint tendon pieces conjoint tendon, on average, 5.6 cm distally to the tip of the coracoid axillary nerve occurs during graft fixation located, on average, 12mm from infra-glenoid tubercle Autograft (tricortical iliac crest or distal clavicle) or allograft (iliac crest or distal tibia) indications area of research ideal patient for latarjet versus bone block is yet to be identified indications similar to those of latarjet critical or subcritical glenoid bone loss patients at high risk of failure with soft-tissue procedures alone loss graft resoprtion overall when compared to latarjet can be used to revise a failed latarjet some surgeons recommended use of Bovie electrocautery or checkpoint during dissection to ensure that musculocutaneous nerve is not inadvertently injured approach shoulder anterior (deltopectoral) approach arthroscopic technique can use autograft of allograft iliac crest, allograft glenoid or allograft distal tibia can secure with screws or buttons complications hardware failure subscapularis repair failure Remplissage + Bankart Repair indications medium to large engaging/off-track Hill-Sachs lesion some surgeons have begun using remplissage in the setting of subcritical bone loss, as in these patients rates of recurrent instability following arthroscopic management alone approaches 20% approach arthroscopic percutaneous additional posterolateral portal made under visualization technique goal is to fill Hill-Sachs with capsule and infraspinatus tendon can use knotted or knotless configurations most surgeons recommend passing sutures prior to anterior labral repair, and then tying once anterior labral repair is complete new knotless anchors allow for passage and construction of a "double-pulley" configuration, with final tensioning completed after additional intraarticular work complications stiffness, specifically loss of external rotation most patients lose 5-15° of external rotation recurrence 5% at two years Bone graft reconstruction for Hill-Sachs defects indications large Hill-Sachs (>40% of articular surface) approach open anterolateral deltopectoral arthroscopic technique autograft iliac crest allograft (humeral head, talus, femoral head) fresh-frozen osteochondral allograft complications graft lysis disease transmission from allograft osteoarthritis Historical procedures: Putti-Platt / Magnuson-Stack / Boyd-Sisk indications historically indicated for recurrent instability rarely indicated now approach open anterior (deltopectoral) approach technique Putti-Platt is performed by lateral advancement of subscapularis and medial advancement of the shoulder capsule Magnuson-Stack is performed with lateral advancement of subscapularis (lateral to bicipital groove and at times to greater tuberosity) Boyd-Sisk transfer of biceps laterally and posteriorly outcomes Putti-Platt and Magnuson-Stack both lead to decreased external rotation and increased loading on the posterior glenoid, which can lead to post-capsulorraphy arthropathy Complications Recurrence often due to unrecognized glenoid bone loss treated with a soft tissue only procedure (especially with glenoid bone loss >20-25%) can be due to poor surgical technique (ie, < 4 suture anchors) increased risk with preoperative risk factors including age < 20, male sex, contact/collision sport, ligamentous laxity, and unrecognized glenoid and/or humeral head bone loss (critical bone loss or "off-track" lesion) medical management should be exhausted prior to surgery in patients with seizures, as there is a high recurrence risk even when bony augmentation techniques are used unrecognized pan-labral tear high incidence of posterior and/or combined front-to-back tears in the military population Shoulder pain overtightening during labral repair can lead to post-capsulorrhaphy arthropathy Nerve injury musculocutaneous (most common) axillary Stiffness especially in external rotation (particularly with Latarjet and additional remplissage) Infection Graft lysis (Latarjet) present in up to 90% of patients at six-months Hardware complications anchor pull-out (Bankart repair) screw pull-out (Latarjet) Chondrolysis historically due to use of thermal capsulorraphy (now contraindicated) or intra-articular pain pumps (now contraindicated)