Anterior Glenohumeral Instability

Upper Extremity RoundsSt. Michael’s HospitalMarch 2004

Objectives

Epidemiology Natural History Pathoanatomy Diagnosis

History, Physical Exam, Imaging Management Options

Consideration, Indications, Complications Surgical Procedures Cases

Introduction

Incidence – 2% over lifetime - Hovelius (CORR 1982); Simonet (CORR 1984)

Anterior dislocations account for ~95% of shoulder dislocations

Typically occurs in athletes who are < 25 years old Males are much more commonly affected than are

females (85-90%) Pathology most commonly found in shoulders following a

dislocation is a Bankart lesion Disruption of the labrum and the contiguous anterior band of the

inferior glenohumeral ligamentous complex (IGHLC) Bankhart lesion occurs > 85% of the time

Mechanism of Injury

Most common mechanism of injury is a fall onto an outstretched arm

Extremity is typically in an externally rotated and abducted position Places the anterior structures

at greatest risk for failure (especially the inferior glenohumeral ligament)

Other mechanisms: elevation combined with

external rotation direct blow

Classification

Instability can be classified by: direction of instability (anterior, posterior, multidirectional) degree of instability (subluxation, dislocation) etiology (traumatic, atraumatic, overuse) timing (acute, recurrent, fixed)

TUBS and AMBRI (Matsen) TUBS or “Torn Loose”

Traumatic aetiology, Unidirectional instability, Bankart lesion is the pathology, Surgery is required

AMBRI or “Born Loose” Atraumatic: minor trauma, Multidirectional instability may be

present, Bilateral: asymptomatic shoulder is also loose, Rehabilitation is the treatment of choice, Inferior capsular shift: surgery required if conservative measures fail

Prognostic variables

Gender – No correlation if look at <30 yrs of age group Hand dominance - No correlation consistently reported Initial Trauma - Controversial whether amount of initial

trauma correlates with recurrence Sports participation - Likely that level and type of sport

participation correlates with recurrence rate Initial X-ray Appearance – GT # low rate Period of immobilsation – Unclear whether period of

immobilization corrrelates with recurrence rate Age – Strong correlation between age and recurrence in

all studies

Age & Recurrence Rate

McLaughlin and Cavallaro (Am J Surg 1950) 573 patients - 90% in patients < 20 y, 60% in patients 20-40 y,

only 10% in patients > 40 y Rowe (Orthop Clin North Am 1980)

94% in patients < 20 y, 74% in patients 20-40 y Henry and Genung (Am J Sports Med 1982)

121 patients - 88% regardless of type of nonoperative treatment Simonet and Cofield (Am J Sports Med 1984)

116 patients - 66% in patients < 20 y, 40% in patients 20-40 y Arciero et al (Am J Sports Med 1984)

80% in 15 student-athletes with average age of 20 y

Natural History

Bilaterality - <30 y at time of first dislocation 18% bilaterality within 10 yrs (Hovelius, JBJS 1996)

Osteoarthritis - Risk of OA regardless of recurrence or surgery at 10 y mod. to severe 9% (Hovelius, JBJS 1996) mild 11% 17% (Lill, Chirurg 1998)

Functional Disability (Tsai et al, Am J Sports Med 1991) ~ 60% of patients with anterior instability complained of poor

strength, decrease range of motion, increased pain after conservative treatment

Anatomy

humeral head is retroverted 30o

typical neck-shaft angle is 130o

glenoid fossa average radius of curvature is 24 mm, only 2 mm less than humeral head

less than one-third of the humeral head articulates with glenoid during any given position of rotation

glenohumeral articulation is minimally constrained by bony anatomy alone

glenoid labrum is a fibrocartilaginous structure functionally deepens the glenoid fossa serves as an anatomic restraint to humeral head translation provides an anchor point for the glenohumeral ligaments

stability is conferred by a series of dynamic and static soft tissue restraints

Shoulder Stabilisers - Static Intracapsular pressure Suction effect: glenoid labrum acting on humeral head like a “plunger” Adhesion-cohesion: between 2 wet smooth surfaces Glenoid version Humeral retroversion: normal 21-30º, some studies have shown a

significant reduction in patients with recurrent anterior dislocation   Labrum: “chock block” to humeral head movement, increases depth of

the glenoid by 50% Ligaments – main static restraints

Coracohumeral ligament Superior glenohumeral ligament (SGHL) Middle glenohumeral ligament (MGHL) Inferior glenohumeral ligament complex (IGHLC) – “hammock” Posterosuperior capsule

Primary static stabilizer limiting anterior movement of the shoulder in 90 degrees of abduction is the IGHL complex

Shoulder Stabilisers - Dynamic

Rotator cuff Subscapularis muscle provides stability at lower degrees of

abduction but contributes little when shoulder is in 90o abduction Rotator cuff compresses humeral head into glenolabral socket,

contributing stability, esp. in middle ROM when ligaments are lax Proprioception

Lephart et al 1994 studied proprioception in three groups of patients: Normal, Unstable, Reconstructed shoulders

Proprioception was significantly reduced in unstable shoulders but returned to near normal in reconstructed shoulders

Long head of biceps: biceps is much more active in patients with recurrent dislocation

Pathophysiology

pathologic lesions leading to the unstable shoulder can be divided into two main groups:anterior labrumglenohumeral capsule

Anterior Labrum

Bankart lesion classically described as the detachment of the

anteroinferior labrum with its attached inferior glenohumeral ligament complex

Initially felt that this detachment was the “essential lesion”

Speer et al. Created Bankhart lesion from 12 o’clock to 6 o’clock

and found minimal translation (<4 mm) Capsular injury also required to dislocate shoulder

Glenohumeral Capsule

Turkel 1981 Selective cutting study showed importance of GH

ligaments Bigliani et al. 1992

Cadaveric bone-ligament-bone specimens of the IGHL were created and tested to failure

found that ligament failed off the glenoid in 40% of the specimens (Bankart) intrasubstance in 35% off the humeral side in 25%

Most importantly showed that the capsule underwent plastic deformation prior to failure in all specimens

PathoanatomyCapsule Bankart lesion

Capsular stretching Congenital laxity Wide rotator interval

Glenoid Bony Bankart (4%)Glenoid fractureGlenoid dysplasia

Labrum Bankart tear Posterior labral tear (10%)SLAP tear

Humerus Tear of the lig. insertion (HAGL) Greater tuberosity fracture Hill-Sachs lesion (77%)

Rotator cuff (13%)

Supraspinatus tear Subscapularis avulsion

Patient History

Mechanism of injury is critical in management of dislocated shoulder

Arm position at time of injury helpful in subtle forms of subluxation if the patient complains of symptoms in the cocking position,

anterior subluxation if the symptoms occur in the follow-through phase, posterior

subluxation Identify the amount of force required Number of dislocations suffered by the patient Age at the time of first dislocation is extremely important

most important prognostic indicator for patients with recurrent dislocations.

Exam - Acute Instability

Patients present with severe pain with arm held at side Normal contour of deltoid and acromion are usually lost Visual inspection, palpation, strength testing and a

thorough neurovascular examination Specific neurologic testing should include pre-reduction

evaluation of axillary, musculocutaneous, median, ulnar, and radial nerves.

Sensation over axillary nerve distribution (lateral aspect of the shoulder) has proven to be quite unreliable.

Isometric contraction of 3 deltoid heads (anterior, middle, and posterior), usually indicates an intact axillary nerve.

Exam - Recurrent Instability

Apprehension test Anterior release Anteroposterior translation

Grade 1+ translation to the glenoid rim Grade 2+ the head subluxes beyond

the rim but self-reduces when the force is released

Grade 3+ the head dislocates and does not spontaneously reduce

Sulcus Ligamentous laxity

Imaging

Acute Setting a true anteroposterior (AP) view, trans-scapular Y view,

and axillary view should be obtained to determine the direction of the dislocation

Radiographs should be performed before reduction is attempted unless the direction of dislocation is known from prior

dislocations the reduction is performed by an experienced

physician, trainer, or other health care worker. Post-reduction radiographs should confirm that the

reduction was successful and that there are no acute fractures

Imaging

Recurrent Instability Several special views may be more

helpful with recurrent instability AP radiograph in internal rotation,

Stryker-notch views are used to visualize Hill-Sachs lesion

West Point axillary view used to visualize anteroinferior glenoid (Bankart), avoids superimposition of the coracoid process & clavicle

Intra-articular lidocaine vs. IV sedation for closed reduction?Miller et. al. J Bone Joint Surg Am. 2002 Dec;84-A(12):2135-9. prospective, randomized study, skeletally mature patients, isolated

glenohumeral joint dislocation IV sedation or intra-articular lidocaine, modified Stimson method 30 patients

lidocaine group (n=15) - significantly less time in ER (av. time, 75 min vs 185 min in the sedation group, p < 0.01)

no significant difference between groups with regard to pain (p = 0.37), success of Stimson technique (p = 1.00), or time required to reduce shoulder (p = 0.42)

cost of IV sedation was $97.64/patient vs $0.52 for intra-articular lidocaine

Use of intra-articular lidocaine to facilitate reduction with the Stimson technique safe and effective method less money, time, and nursing resources

Orlinsky et. al. J Emerg Med. 2002 Apr;22(3):241-5. compare the analgesic effectiveness of intra-articular

lidocaine versus intravenous meperidine and diazepam Prospective randomized trial 54 patients with anterior shoulder dislocations 29 intra-articular lidocaine (IAL) 25 intravenous meperidine/diazepam (IVMD) IAL less effective than IVMD in relieving pre-reduction

pain (p = 0.045) IAL equally effective in overall pain relief (p = 0.98) IAL was more effective than IVMD in shortening recovery

time (p = 0.025) IVMD trend towards physician-perceived muscle

relaxation and patient's perception of analgesia adequacy

Kosnik et. Al. Am J Emerg Med. 1999 Oct;17(6):566-70. prospective, randomized, nonblinded clinical trial local intraarticular lidocaine injection (IAL) vs intravenous

analgesia/sedation (IVAS) Level 1, trauma center 49 patients: 20 - IVAS group, 29 - IAL group No difference between pain scores (IVAS 3.32+/-2.39 vs

IAL 4.90+/-2.34, P = .18) No difference between ease of reduction scores (IVAS

3.32+/-2.36 vs IAL 4.45+/-2.46, P = .12) IVAS tended to have higher success rate (20 of 20) than

IAL (25 of 29) (P = .16). Reduction rate as a function of time delay in treatment

patients presenting 5.5 h after dislocation more likely to fail treatment with IAL (P = .00001)

Half of the patients in the IAL group who had experience with IVAS did not favor IAL

Is Sling Appropriate? Non-operative management = Sling immobilzation with

the arm internally rotated No evidence Itoi et al. J Bone Joint Surg Am 2001; 83-A(5): 661-667

magnetic resonance imaging in patients Hatrick C, O'Leary S, Miller B, et al. ORS 2002.

load sensors in cadavers

Itoi et. al. J Shoulder Elbow Surg. 2003 Sep-Oct;12(5):413-5. Prospective, nonrandomized trial 40 patients initial shoulder dislocations

Immobilization in internal rotation (IR group, n = 20) Immobilization in external rotation (ER group, n = 20)

Recurrence rate @ 15.5 months 30% in the IR group 0% in the ER group

Difference in recurrence rate was even greater < 30 years 45% in the IR group 0% in the ER group

Role of Early Arthroscopic Repair?

Bottoni et. al. Am J Sports Med. 2002 Jul-Aug;30(4):576-80. Prospective, randomized clinical trial. Army Medical center. Compared nonoperative treatment with arthroscopic Bankart repair

for acute, traumatic shoulder dislocations in young athletes 14 nonoperatively treated patients - 4 weeks of immobilization +

supervised rehab. program 10 operatively treated patients - arthroscopic Bankart repair

(bioabsorbable tack) + same rehab protocol as nonop. patients Av. follow-up = 36 months, 3 patients lost to follow-up 9/12 nonoperatively treated patients (75%) developed recurrent

instability 6/9 required subsequent open Bankart repair for recurrent instability 1/9 operatively treated patients (11.1%) developed recurrent

instability

Kirkley A, Griffin S, Richards C, Miniaci A, Mohtadi N.Arthroscopy. 1999 Jul-Aug;15(5):507-14. Compare effectiveness of traditional treatment vs.

immediate arthroscopic stabilization in young patients with first traumatic anterior dislocation of the shoulder

Prospective, randomized, blinded trial 40 skeletally mature patients < 30 yr 20 pts, Immobilization for 3 wks + rehabilitation (group T) 20 pts, Arthroscopic stabilization (< 4 weeks of injury) +

immobilization/rehabilitation (group S) 2 yr follow-up Rate of redislocation: T = 47%, S = 15.9%, P = .03 Western Ontario Shoulder Instability (WOSI) index

showed significantly better results in the surgically treated group at the 33 months T = 633.93 v S = 287.1, P = .03

No significant difference in range of motion

Role of Arthroscopic Lavage?

Wintzell et. Al. J Shoulder Elbow Surg. 1999 Sep-Oct;8(5):399-402. Prospective randomized study, Sweden Compared treatment results of arthroscopic lavage with results of

conventional nonoperative treatment 30 consecutive patients, traumatic primary anterior shoulder

dislocation, 18-30 y, no history of shoulder problems 2-year follow-up

3 (20%) of 15 patients in the lavage group had a redislocated shoulder

9 (60%) of 15 patients in the non-operative group (P = .03) 2 in lavage group vs. 6 in control group had been operated on or

were scheduled for stabilizing surgery Functional outcome/Constant and Rowe shoulder scores did not

reveal any significant difference (P = .07) Joint effusion decreased more rapidly (33%) in arthroscopic lavage

group vs. non-operated group

Indications for Surgery

1) initial dislocation in a patient who participates in high-risk or high-demand activities in whom recurrent dislocation would be inopportune or dangerous professional athletes, mountain climbers, certain types of

construction workers 2) recurrence of dislocation or subluxation after trauma

treated adequately with nonoperative measures 3) pain due to recurrent transient shoulder subluxation

when the arm is used for overhead activities

Gill & Zarins. Am J Sports Med, Jan-Feb, 2003.

Algorithm for Anterior Shoulder Instability

J Am Acad Orthop Surg 1997;5:233-239

Nonanatomic Repairs

Bristow Transfer coracoid process to anteroinferior glenoid Sling effect and bone block

Putti-Platt “Pants-over-vest” repair capsule

Magnusen-Stack subscapularis tendon is detached from its insertion on the lesser

tuberosity, transferred laterally to the greater tuberosity Infrequent indications for using these procedures except

in revision surgery

Anatomic Repairs

Restoring normal anatomy is guiding principle in surgery to correct anterior shoulder instability If the labrum has been detached, it is reattached to the anterior

glenoid rim If the capsule has been stripped off the glenoid neck, the

capsule is reattached to the bony glenoid rim If greater than one-third of the glenoid fossa is involved, a bone

block procedure such as a Bristow or iliac crest bone graft may be considered

Guidelines Anatomic dissection at time of surgery Identification and repair of lesions responsible for instability Returning tissues to their anatomic locations Early postoperative range of motion

Surgical Issues

Incision subscapularis tendon/capsule Bankart repair Capsular shift

Complications Recurrent instability (10%) - most common causes

1. continued presence of avulsed anterior capsule and labrum from glenoid rim (unrepaired Bankart lesion)

2. excessive capsular laxity3. an enlarged "rotator interval”4. failure to diagnose correct direction(s) of instability

Other causes include presence of a Hill-Sachs lesion reduced humeral head retroversion excessive glenoid cavity retroversion avulsion of the anterior capsule from its lateral humeral attachment scarred or weakened subscapularis muscle or tendon.

Neurovascular injury – musculocutaneous, axillary Limitation of motion Problems from retained hardware Degenerative arthritis

Summary

Balance between the restoration of joint stability while minimizing loss of glenohumeral motion

Choice of treatment should be individualized patient's occupation, level of participation in sports, degree of

instability of the shoulder No single "essential lesion" as proposed by Bankart Bankart lesion is by far the most important Open stabilization remains the standard procedure for

treatment of anterior stabilization esp. for severe instabilities, revision procedures, athletes in

contact sports Follow “anatomic repair principles”

Case

25-year-old former collegiate football player presenting with 20 recurrent dislocations over the last 5 years

History

25-year-old, right-hand-dominant, former collegiate football player Suffered his first traumatic left shoulder dislocation at age 16 He had an emergency room assisted reduction and was placed in a

sling for 3 weeks Underwent physical therapy for 2 months but subsequently had

recurrent instability after returning to football Age18, he underwent an arthroscopic Bankart reconstruction with 3

metal suture anchors He began playing collegiate football, suffered a recurrent

dislocation, and eventually had to discontinue playing He has now had 20 recurrent dislocations over the last 5 years and

presents for evaluation and treatment

Physical Examination Active Shoulder Range of Motion:

Forward elevation180° bilaterally ER (side) 60° bilaterally ER (abduction) 90° bilaterally IR T-7 spinous process bilaterally

Right Shoulder Instability Exam Anterior load and shift 2+ Posterior load and shift 1+ Sulcus 1+ Negative apprehension, relocation, anterior release

Left Shoulder Instability Examination: Anterior load and shift 3+ Posterior load and shift 1+ Sulcus 1+ No signs of generalized ligamentous laxity. Positive apprehension, relocation, anterior release.

Normal neurological examination.

Imaging

Radiographs demonstrate a small Hill-Sachs lesion (yellow arrow) and the previously placed metal suture anchors (blue arrow).

Open anteroinferior capsular shift and Bankart procedure. Modified beach chair

position with the head elevated ~30°

Deltopectoral incision was used

Subscapularis was dissected off the underlying capsule

Bankart lesion Capsule dissected off the

humerus Fukuda retractor placed to

expose the glenohumeral joint

Large Bankart lesion was identified from the 6-9 o'clock position

Bioabsorbable suture anchors were used but had to be redirected carefully to avoid the previously placed metal suture anchors in the anteroinferior glenoid

Capsular Shift

Superolateral capsular shift (formal "T" capsulorrhaphy was not necessary) of the entire capsule

Arm placed in 30° abduction and 30° external rotation for capsular repair

Subscapularis Repair

Subscapularis was then anatomically repaired with #2 nonabsorbable sutures