Multi Directional Instability of the Shoulder

MDI: 

MDI Multi Directional Instability Louis Peter Re , MD

MDI: 

MDI Multidirectional shoulder instability is defined as symptomatic instability in two or more directions. Nonspecific activity-related pain and decreased athletic performance are common presenting complaints. It is critical to distinguish increased laxity from instability.

MDI: 

MDI If surgical management is required, capsular plication has been used successfully Advanced arthroscopic techniques offer several advantages over traditional open approaches and may have similar outcomes. The role of rotator interval capsular plication is controversial, but it may be used to augment capsular plication in patients with specific patterns of instability. Despite encouraging results, outcomes remain inferior to those associated with traumatic unidirectional instability.

MDI: 

MDI diagnosis and management remain challenging dynamic and static stabilizers are able to compensate for other deficient structures. Structural deficiencies become apparent only when compensatory mechanisms fail. Standardized criteria that define MDI do not exist in the literature Neer and Foster1 described MDI as anterior and posterior instability associated with involuntary in- ferior subluxation or dislocation. MDI has also been defined as instability in two or three directions. The lack of a pre- cise definition for MDI underscores the need for detailed inclusion and exclusion criteria.

MDI: 

MDI It is critical to distinguish laxity from instability Instability is characterized by the presence of symptoms in conjunction with abnormal laxity Instability can be caused by re- petitive microtrauma or a single ma- crotrauma.

MDI: 

MDI Historically, the acronyms TUBS (traumatic, unilateral, Bankart lesion, surgery) and AMBRI (atraumatic multidirectional, bilateral, rehabilitation, inferior capsular shift) we define MDI as symptomatic instability in two or more directions with or without associated hyperlaxity.

Glenohumeral Stability: 

Glenohumeral Stability Static and dynamic stabilizers interact to provide joint stability Static and Dynamic Stabilizing Structures of the Glenohumeral Joint Static stabilizers Glenoid concavity and version Labral height Glenohumeral ligaments Dynamic stabilizers Scapulothoracic musculature Rotator cuff Proprioceptive and neuromuscular control

Glenohumeral Stability: 

Glenohumeral Stability

Clinical Presentation: 

Clinical Presentation Most patients present with insidious onset and nonspecific, activity-related pain in the second to third decade of life. Identification of specific inciting activities can provide insight into the direction and severity patients either learn to avoid certain positions or develop compensatory routines to avoid inciting activities. higher in persons involved in repetitive overhead activities, particularly in sports such as volleyball, swimming, or gymnastics. Collagen disorders can also be a contributing factor and should be considered in patients who present with MDI because surgical stabilization is less successful in patients with these disorders.

Clinical Presentation: 

Clinical Presentation it is prudent to reconsider MDI in the patient with unidirectional instability in the absence of an anatomic lesion should also be suspected in young patients (aged <40 years) with a history of a failed instability procedure. In general, patients with willful dislocation respond poorly to surgical stabiliza- Patients who demonstrate positions that reproduce their instability (ie, positional instability) but who attempt to avoid these positions generally respond well to surgical stabilization

Physical Examination: 

Physical Examination Generalized hyperlaxity is also evaluated elbow or metacarpophalangeal joint hyperex- tension, genu recurvatum, patellar instability, and the ability to place the thumb on the ipsilateral forearm. Surgical stabilization is less successful in patients with connective tissue disorders (eg, Ehlers-Danlos syndrome).

Physical Examination: 

Physical Examination Anterior Apprehension Test Relocation Test

Physical Examination: 

Physical Examination Posterior Apprehension Test

Physical Examination: 

Physical Examination sulcus sign is a dimple that appears distal to the lateral acromion when inferior traction is applied to the arm Humeral head displacement >2 cm from the acromion is considered indicative of a high degree of glenohumeral laxity The presence of the sulcus sign with 90∞ of abduction is indicative of considerable inferior capsular laxity.

Physical Examination: 

Physical Examination sulcus sign is a dimple that appears distal to the lateral acromion when inferior traction is applied to the arm

Physical Examination: 

Physical Examination The load-and-shift test is also frequently used to evaluate glenohu- meral translation The humeral head is centered in the glenoid by applying a small axial load. The proximal humerus is then translated to determine laxity. grade 1, translation to the glenoid rim grade 2, dislocation with spontaneous re- duction grade 3, dislocation without spontaneous reduction.

Physical Examination: 

Physical Examination The hyperabduction test developed by Gagey and Gagey is useful for evaluating laxity of the inferior glenohumeral ligament Laxity of the inferior glenohumeral ligament is indicated bypassive abduction past 105degrees

Imaging: 

Imaging standard radiographs reveal abnormal glenoid version, dysplasia, hypoplasia, or bone loss that may contribute to patterns of instability.

Imaging: 

Imaging Axillary Stryker notch

Imaging: 

Imaging Reformatted CT can be used to fur- ther delineate abnormal findings. MRI provides excellent detail of soft tissue and is frequently used to evaluate patients with shoulder in- stability. Magnetic resonance ar- thrography may be more useful than MRI labral tears patulous capsule, increased glenohumeral volume, and labral abnormalities are seen in MDI patients

Imaging: 

Imaging MR ARTHROGRAM

Nonsurgical Management: 

Nonsurgical Management For most MDI patients, reha- bilitation remains the treatment of at initial presentation treatment of scapulothoracic dyskinesia - improving the dynamic positioning of the glenoid strengthening of the rotator cuff may also improve concavity compression

Nonsurgical Management: 

Nonsurgical Management treatment of scapulothoracic dyskinesia - improving the dynamic positioning of the glenoid

Nonsurgical Management: 

Nonsurgical Management Burkhead and Rockwood (1992) demonstrated the efficacy of nonsurgical man- agement in a study of 115 patients (140 shoulders) with traumatic or atrau- matic shoulder instability. Good or excellent results were reported in 83% of patients with atraumatic instability treated with muscle-strengthening exercises. Good or excellent results were reported in 35 of 39 patients with MDI

Nonsurgical Management: 

Nonsurgical Management Misamore et al (2005) reported less encouraging long-term results in patients who were initially treated with rehabilitation. In a cohort of young, athletic patients, 19 of 36 experienced poor results only 8 were free of all pain and instability at a mean 8-year follow-up

Surgical Management: 

Surgical Management Reconstructive techniques include gle- noid osteotomy, labral augmentation, and capsuloligamentous reconstruction. Capsuloligamentous techniques, which include open inferior capsular shift, thermal capsulorraphy, and arthroscopic placation, are most frequently used.

Open Inferior Capsular Repair: 

Open Inferior Capsular Repair In 1980, Neer and Foster1 described humeral-based inferior capsular shift for management of MDI.. T-shaped incision is made between the middle and inferior glenohumeral ligaments Capsular flaps are carefully elevated from the neck of the humerus and are advanced to reduce posterior capsular redundancy and eliminatethe inferior capsular pouch

Open Inferior Capsular Repair: 

Open Inferior Capsular Repair

Open Inferior Capsular Repair: 

Open Inferior Capsular Repair approximately 95% in two studies that examined the efficacy of the Bankart and inferior capsular shift proce- dures Altchek et al4 reported that 33 of 40 patients (83%) returned to full sport Only 25 of 36 athletes (69%) were able to re- turn to premorbid levels of sporting activity following an inferior capsu- lar shift procedure.

Thermal Capsulorrhaphy: 

Thermal Capsulorrhaphy Thermal capsulorrhaphy was an attractive al- ternative because it could be performed quickly and easily and provided immediate visual feedback in terms of capsular shrinkage How- ever, chondrolysis, thermal nerve injury, and high failure rates have been reported. Hawkins et al reported failure rates of approximately 60% in some patient populations. Given these findings, thermal capsulorrhaphy is not recommended for management of MDI

Arthroscopic Capsular Plication: 

Arthroscopic Capsular Plication Diagnostic arthroscopy should be used to identify a patulous capsule and labral abnormalities Af-ter capsular abrasion, the repair sequence begins in the direction of primary instability Each plication decreases capsular volume and the size of the working area. Consequently, it is important to proceed from inferior to superior

Arthroscopic Capsular Plication: 

Arthroscopic Capsular Plication A suture is passed though the cap- sular tissue and can be sutured directly to the labrum or a suture anchor can be used. Flanigan et al demonstrated that 5 and 10mm capsular plications resulted in a mean volume reduction of 16.2% and 33.7%, In another cadaver study, multiple pleated anterior, inferior, and poste- rior capsular plications resulted in a significantly larger decrease in capsular volume compared with open inferior capsular shift

Arthroscopic Capsular Plication: 

Arthroscopic Capsular Plication

Axillary Nerve Injury: 

Axillary Nerve Injury The course of the axillary nerve is in close proximity to the inferior glenohumeral pouch, and injury to this nerve has been reported after open, thermal, and arthroscopic procedures. Typically, the teres minor branch is most at risk this branch is a mean 12.4 mm from the glenoid in the 6 o’clock position. It passes a mean of 2.5 mm deep to the capsule abduction, external rotation, and slight traction results in the largest margin between the axillary nerve and capsule

Rotator Interval Closure: 

Rotator Interval Closure biomechanical role in glenohumeral stability remains controversial Harryman et al reported a decrease in posterior and inferior translation with OPEN medial-lateral coracohumeral ligament imbrication traditional superior-inferior arthroscopic interval capsular closure techniques have failed to replicate these findings, Two studies used a human cadaver model to assess the use of arthroscopic superior glenohumeral ligament to middle glenohumeral ligament rotator interval closures and reported a decrease in anterior glenohumeral translation. Tensioning the closure in 30∞ of external rotation should minimize motion limitations.

Postoperative Rehabilitation: 

Postoperative Rehabilitation The shoulder is placed in approximately neutral rotation for 4 to 6 weeks using an immobilizer with an abduction pillow We do not routinely alter the position of immobilization based on the direction of primary instability. Patients are instructed to perform improvised elbow, wrist, and hand motions. After the immobilizer is discontinued, patients begin strengthening exercises full activity approximately 6 months postoperatively if they demonstrate full strength and have completed a sport-specific training program.

Summary: 

Summary Considerable advances have been made in the diagnosis and management of MDI since its seminal description. However, the lack of pathognomonic, clinical, or radiographic findings makes diagnosis and treatment challenging.Rehabilitation of dynamic stabilizers is the goal of initial nonsurgical management, but if these efforts fail, surgical options can be used. Satisfactory surgical outcomes have been achieved with open and arthroscopic techniques; however, given the persistent discrepancy between the reported surgical out- comes of unidirectional instability and MDI, continued research is warranted. Favorable results can be reliably obtained with careful examination and diagnosis, meticulous surgical technique, and thorough rehabilitation.