Shoulder Instability Department of Orthopaedics, CKUH Sen-Jen Lee Reference: Orthopaedic Knowledge Update 6

Natural History The most common sequela of traumatic anterior shoulder instability is recurrence 90% for those 11 to 20 years of age Averaging between 55% and 66% 87% recurrent instability after nonsurgical treatment In the skeletally immature individual Bankart lesion (labral detachment of the inferior glenohumeral ligament complex, IGHLC) Length of immobilization, avoidance of overhead activity, and supervised physical therapy had no effect on outcome Patients over 40 years of age Neurologic injury and rotator cuff tears

Biomechanics Static Stabilizers Articular curvature between the glenoid and humeral head Superior glenohumeral ligament (SGHL) and coracohumeral ligament (CHL) To resist inferior translation Middle glenohumeral ligament (MGHL) To limit anterior translation IGHLC Primary restraint to anterior and posterior translation Secondary restraint to inferior translation

Biomechanics Dynamic Stabilizers Rotator cuff muscles Center the humeral head on the glenoid Maintain joint stability The capsuloligamentous structures (proprioception) provide afferent feedback for reflexive muscular control of the rotator cuff and biceps

Patient Evaluation History Physical examination Imaging Specific provocative tests Apprehension/relocation test and sulcus sign test Imaging Scapula (AP and lateral [y-view]) Axillary view West point axillary view CT arthrogram or MRI Examination under anesthesia and arthroscopy

Apprehension test Relocation test Load shift test Sulcus sign

True anteroposterior view West Point view (axillary)

Computed tomography scan of glenohumeral joint with significant anterior bone loss and presence of Hill-Sachs lesion. Magnetic resonance image with arthrogram of large Bankart lesion.

Arthroscopic Findings of Patients With Instability Bankart lesions: 87% Capsular insufficiency :79% Hill-Sachs lesions: 68% (posterosuperior humeral head impression fracture ) Glenohumeral ligament insufficiency: 55%

Clasification of Anterior Instability Direction Anterior Posterior Inferior Multidirectional Cause Traumatic Acute Repetitive Nontraumatic Degree Subluxation Dislocation Frequency Acute Recurrent Patient control Voluntary Involuntary

Matsen’s Classification of Anterior Instability AMBRI Atraumatic Multidirectional Bilateral Rehabilitation Inferior capsular shift TUBS Traumatic Unidirectional Bankar lesion Surgery

Redislocation Rates After Initial Dislocation (< 35 Y/O) Investigators Patients (%) No. of patients Age (years) Rowe 94 53 < 20 Mclaughlin 95 181 Simonet 66 32 Henry 88 121 < 32 Hovelius 64 102 < 22 Wheeler 92 38 Marans 100 21

Causes of Anterior Shoulder Instability Bankart lesion Avulsion of the anteroinferior capsulolabral complex Hill-Sachs lesion Compression fracture of the posterosuperior humeral head SLAP lesion Superior labrum anterior posterior HAGL lesion Humeral avulsion of glenohumeral ligaments ALPSA lesion Ant. labroligamentous periosteal sleeve avulsion Laxity of the joint capsule

Treatment of Anterior Glenohumeral Instability Nonsurgical treatment: Closed reduction Immobilization (3 to 6 weeks) rehabilitation Rate of recurrence : (less than 20 years old) 60% to 90%

Treatment of Anterior Glenohumeral Instability Arthroscopic Bankart repair versus nonoperative treatment for acute, initial anterior shoulder dislocations. 14 % versus 80% recurrent instability Arciero RA, wheeler JH, Ryan JB, et al: am J sports med 1994;22:589-594.

Treatment of Anterior Glenohumeral Instability Inferior capsular shift procedure for anterior-inferior shoulder instability in athletes. Satisfactory results: 94% Returned to sports: 92% (75% at the same level). The rate of recurrence: 3%. Bigliani LU, Kurzweil PR, Schwartzbach CC, et al: am JSports med 1994;22:578-584.

Treatment of Anterior Glenohumeral Instability Arthroscopic Bankart suture repair. Recurrent instability: 44% The authors recommend: caution in the use of arthroscopic stabilization for the competitive athlete. Grana WA, Buckley PD, Yates CK: am J sports med 1993;21:348-353.

Treatment of Anterior Glenohumeral Instability Reduction in Surgical time Blood loss Postoperative narcotic use Postoperative fevers Duration of hospitalization Work days missed Arthroscopic versus open Bankart procedures: A comparison of early morbidity and complications. Green MR, Christensen KP: arthroscopy1993;9:371-374.

Treatment of Anterior Glenohumeral Instability Treatment of instability of the shoulder with an exercise program. Response to treatment: Atraumatic versus traumatic instability: 80% versus 15% Burkhead WZ Jr, Rockwood CA Jr: J bone joint Surg 1992;74a:890-896.

Selective capsular tightening Selective capsular tightening. A, The inferior capsule is tightened with the arm in 10° flexion, 60° abduction, and 45° to 60° external rotation. B, The superior capsule is tightened with the arm in 0° abduction and 45° external rotation.

Treatment of Posterior Instability Nonsurgical treatment with exercise program. (First choice) Surgical treatment Provide bony stability: Posterior bone block, opening wedge osteotomy of the posterior glenoid (glenoplasty), and rotational osteotomy of the humerus Soft-tissue repairs: Posterior labral repair, a posterior capsular plication, and posterior capsulorrhaphy.

Instability in Throwing Athletes Anterior instability During the late cocking phase Posterior capsular tightness, pain, or impingement signs Posterior instability During the follow-through phase. "Dead arm" syndrome Transient neurological symptoms

Acromioclavicular Instability Mechanism Impact directly at the lateral edge of the acromion Classification (Rockwood) Type I: a sprain of the AC joint Type II: partial rupture of the AC ligaments and the coracoclavicular ligaments with subluxation of the AC joint Type III: dislocation of the AC joint with complete disruption of the coracoclavicular and AC ligaments Type IV: dislocation of the AC joint with posterior displacement of the clavicle into or through the trapezius muscle Type V: dislocation of the AC joint with marked superior displacement of the clavicle greater than twice the normal coracoclavicular distance Type VI: inferior dislocation of the AC joint with subcoracoid displacement of the clavicle

Rockwood classification of ligamentous injuries to the acromioclavicular joint.

Treatment A-C Instability Types I and II: nonsurgical Sling for 2 weeks Good results in over 90% of cases Type III: controversial Surgical treatment for acute injuries in laborers or high demand overhead athletes, and for chronic injuries in which initial nonsurgical treatment fails Types IV, V, and VI : surgical management AC fixation with pins or plates and coracoclavicular fixation with nonabsorbable suture or metallic screws

Chronic symptomatic A-C instability: The modified Weaver-Dunn procedure. (C-C fixation + transfer of the C-A ligament to the distal clavicle)

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