Shoulder Instability Flashcards
What increases the recurrence rate in patients with TUBS?
▪ have a high recurrence rate that correlates with age at dislocation
up to 80-90% in teenagers (90% chance for recurrence in age <20)
What are the 4 Associated injuries with TUBS?
1- labral & 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
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
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
2- 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)
require 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%
Hill Sachs defect
is a chondral impaction injury in the posterosuperior humeral head secondary to contact with the glenoid rim.
is present in 80% 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
Lesser tuberosity fracture
is associated with posterior dislocations
3- Nerve injuries:Axillary nerve injury
is most often a transient neurapraxia of the axillary nerve
present in up to 5% of patients
4- Rotator cuff tears
30% of TUBS patients > 40 years of age
80% of TUBS patients > 60 years of age
What is the Antero-posterior 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Grade 2+: Humeral head translation over glenoid rim with spontaneous reduction once force withdrawn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 with locking
Sulcus Test Grading Scheme
Grade 1: Acromiohumeral interval <1cm
Grade 2: Acromiohumeral interval 1-2cm
Grade 3: Acromiohumeral interval >2cm
What is the ISIS score?
What to look for on physical exam for TUBS?
Load and shift
Grade I - increased translation, no subluxation
Grade II - subluxation of humeral head to, but not over, glenoid rim
Grade III - dislocation of humeral head over glenoid rim
apprehension sign
patient supine with arm in 90/90 position
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
sulcus sign
tested with patient’s arm at side
generalized ligamentous laxity
assess via Beighton’s criteria
shoulder specific laxity defined as
Hyper-external rotation at side > 85 degrees
Hyperabduction > 120 degrees (Gagey’s maneuver)
OR > 2+ load shift in 2 or more planes (anterior, posterior, inferior)
5 Risk factors for re-dislocation?
- age < 20 (highest risk)
- male
- contact sports
- Hyper-laxity
- Glenoid bone loss >20-25%
Any benefits for immobilization of the shoulder > 1 week for TUBS?
studies have not shown any benefit of immobilization > 1 week for decreasing recurrence rates
Indications for open Bankart repair?
- Bankart lesion with glenoid bone loss < 20-25%
- revision stabilization following failed arthroscopic Bankart repair without glenoid bone loss >20%
- humeral avulsion of the glenohumeral ligament (HAGL); can also be performed arthroscopically but is technically challenging
Indications for Latarjet procedure?
- Chronic bony deficiencies with >20-25% glenoid deficiency (inverted pear deformity to glenoid)
- 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)
2 Surgical options for >20-25% glenoid deficiency ?
- Latarjet
- Autograft (tri-cortical iliac crest) or allograft (iliac crest or distal tibia) for glenoid bone loss
Indications for Remplissage technique
- Engaging large (>25-40%) Hill-Sachs defect
- “off-track” Hill-Sachs lesions with <20-25% glenoid bone loss
Minimal number of anchors for Bankart labral repair?
≥ 3 anchors
How to avoid axillary nerve injury during open bankart repair?
avoid by abduction and ER of arm during procedure
What is the most common nerve injury seen in latarjet procedure and how to treat it?
▪ majority are traction or contusion neuropraxias and resolve spontaneously
treat with observation for 3-6 weeks; delayed EMG if deficits persist
musculocutaneous nerve is most common
occurs during instrumentation around the conjoint tendon
axillary nerve also at risk
occurs during graft fixation
What are some risk factors for recurrence after surgery of TUBS?
- unrecognized glenoid bone loss (especially with glenoid bone loss >20-25%)
- can be due to poor surgical technique (ie, < 3 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
8 complications after Bankart Repair?
- Recurrence
- Shoulder Pain
- Nerve injury
- Stiffness
- Infection
- Graft Lysis
- Hardware complications
- Chondrolysis
What are Beighton criteria’s
ON-Track and OFF-Track lesions
Glenoid track = area of contact between the humeral head and glenoid and is defined as ~83% of glenoid width
A Hill-Sachs defect that is smaller than the track (“on-track”) will maintain contact and is at lower risk of engagement and instability. Conversely, a Hill-Sachs defect that is larger than the glenoid track (“off-track”) will be at increased risk of engagement and instability (i.e. is an “engaging Hill-Sachs defect”).
Thus, there are two factors that contribute to determining if a bipolar bone lesion is on-track or off-track:
Anteroinferior glenoid bone loss
Hill-Sachs interval
Off-track lesions can result from either a large bony Bankart lesion or Hill-Sachs defect, or from a combination of a moderate-sized Hill-Sachs defect and moderate-sized bony Bankart lesion.
Determining on-track or off-track lesions was initially described on CT but can also be calculated on MRI. Two measurements are required 2:
Glenoid track: calculated on a sagittal oblique plane of the glenoid using the best-fit circle method
a best-fit circle is placed on the glenoid, matching the posterior and inferior borders
a horizontal line is drawn through the center of the best-fit circle reaching both anterior and posterior aspects (D)
a second horizontal line is drawn along the same plane from the anterior aspect of the circle to the anterior glenoid (d), i.e. measuring the width of anterior glenoid bone loss
Glenoid track = (0.83 x D) - d
Hill-Sachs interval = Hill-Sachs defect + bone bridge between the rotator cuff attachment and lateral aspect of the Hill-Sachs defect: measured in the axial plane
A bipolar lesion is said to be engaging if the Hill-Sachs interval is larger than the glenoid track.
non-engaging, on-track Hills-Sachs defect = Hill-Sachs interval < glenoid track
engaging, off-track Hills-Sachs defect = Hill-Sachs interval > glenoid track
3 Mechanisms for posterior shoulder dislocation?
- trauma (posterior dislocation)
- microtrauma (posterior instability) common in lineman, weight lifters, overhead athletes ; insidious onset and presentation
- seizures and electric shock
What are the associated conditions with posterior shoulder instability?
Difference in presentation between traumatic and chronic instability?
◦ chronic instability often presents with insidious onset, and vague symptoms (usually pain and not instability as opposed to anterior instability)
often in sporting or occupational activities that require repetitive pushing with the arm in forward flexed position foot ball lineman, weight lifters, etc
shoulder locked in an internally rotated position common in undiagnosed posterior dislocations
pain on flexion, adduction and internal rotation for posterior instability
What are the provocative tests - performed in the setting of chronic posterior instability ?
▪ Posterior load & shift test
place patient supine with arm in neutral rotation with 40 to 60° abduction and forward flexion, load humeral head and apply anterior and posterior translating forces noting subluxation
Jerk test
place arm in 90° abduction, internal rotation, elbow bent
apply an axial force along axis of humerus and adduct the arm to a forward-flexed position
a ‘clunk’ is positive for posterior subluxation
97% sensitive for posterior labral tear when combined with a Kim test
Kim test
performed by having the patient seated, arm at 90° abduction, followed by flexing the shoulder to 45 forward flexion while simultaneously applying axial load on the elbow & posterior-inferior force on the upper humerus.
test is positive when pain is present
posterior stress test
stabilize scapula and look for posterior translation with a posterior direct force
pain is elicited often, but this is not a specific finding
Posterior Load & Shift Grading
1+
apparent translation but not to rim
2+
translation to glenolabral rim
3+
translation over glenolabral rim
4+
translation with complete dislocation
Best view to demonstrate a posterior dislocation?
axillary lateral
View to check for posterior dislocation of the shoulder if patient can’t abduct arm?
Velpeau view if patient is unable to abduct arm for axillary view
Indications for CT in posterior dislocations of the shoulder?
Analyze the extent and location of bone loss in a chronic dislocation (>2 to 3 weeks)
What is the conservative management for (Posterior shoulder instability)
◦ acute reduction and immobilization in external rotation for 4 to 6 weeks
should be initially attempted for all acute traumatic posterior dislocations
most dislocations reduce spontaneously
technique
immobilize in 10-20 degrees of external rotation with elbow at side
after 6 weeks advance to physical therapy (rotator cuff strengthening and peri-scapular stabilization) and activity modification (avoid activities that place arm in high-risk position)
Physical therapy
may be a first line treatment for chronic posterior instability with rotator cuff strengthening, peri-scapular stabilizers may be considered for the in-season athlete
What are the surgical treatment options for posterior shoulder instability?
open or arthroscopic posterior labral repair (Bankart)
recurrent posterior shoulder instability despite appropriate course of physical therapy
continued pain with loading of arm in forward flexed position (bench press, football blocking)
negative Beighton’s score
outcomes
80% to 85% success at 5- to 7-year follow-up after open repair
similar outcomes with arthroscopic repair after shorter follow-ups
open or arthroscopic posterior capsular shift and rotator interval closure
Indications: positive Beighton score
posterior glenoid opening wedge osteotomyindications
excessive congenital glenoid retroversion
limited studies assessing outcomes with this approach
open reduction with subscapularis transfer (McLaughlin) or lesser tuberosity transfer to the defect (Modified McLaughlin)
indications
chronic dislocation < 6 months old
reverse Hill-Sachs defect < 40%
Hemiarthroplasty
indications
chronic dislocation > 6 months old
severe humeral head arthritis
collapse of humeral head during reduction
reverse Hill-Sachs defect > 40% of articular surface
Total shoulder arthroplasty
Indications: significant glenoid arthritis in addition to one of the hemiarthroplasty indications
What is the most common complication? What are the other complications? (Posterior shoulder instability)
Stiffness
most common complication after labral repair
Recurrence
2nd most common (7% to 50%)
Degenerative joint disease
3rd most common
Adhesive capsulitis
Overtightening of posterior capsule
may lead to anterior subluxation or coracoid impingement
Nerve injury
axillary or suprascapular
