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Abstract
The glenohumeral joint is multiaxial joint of the ball and socket type possessing three degrees of freedom between the roughly hemispherical humeral head and shallow scapular glenoid fossa, an arrangement allowing much motion but reducing security The glenohumeral stability is provided by the interrelated passive mechanisms, including the joint conformity, finite joint volume, adhesion/cohesion, ligamentous and capsular restraints, bony restraints and glenoid labrum, and active mechanism that the dynamic glenohumeral stability is provided by the long head of the biceps and the muscles of the rotator cuff.
These passive and active mechanisms work together to couple biomechanical stability with the extreme mobility this minimally constrained joint. The diagnosis of the anterior shoulder instability is based on a thorough history, physical examination, and stability assessment which includes specific provocative maneuvers and neurologic examination. Radiological studies are helpful in making an accurate diagnosis of shoulder injuries which includes plain x-ray, C.T, MRI, and diagnostic arthroscopy.
Because of the multifactorial nature of instability, as well as the lack of a single consistent “essential pathologic lesion,” the surgeon must consider all potential contributing factors and correct the relevant pathoanatomy encountered in that individual case.
The Bankart lesion with avulsion of the anterior capsulolabral complex has traditionally been regarded as the essential lesion of the anterior traumatic dislocation of the shoulder. Capsular laxity, RI lesions, and SLAP lesions, glenoid bone lesions and Hill-Sachs lesions are also causes of recurrent anterior shoulder dislocation. The arthroscopic procedures in the management of anterior glenohumeral instability include; Fixation of the Bankart lesion either with transglenoid suture or suture anchors and biodegradable tacks, reinforced capsular shift for capsular laxity and RI repair, thermal shrinkage, tissue tucks as adjunct procedures. The arthroscopic management of anterior glenohumeral instability represents an effective alternative for addressing and treating the pathology associated with this condition. Patient selection criteria, operative techniques, and implants all continue to evolve and have resulted in improved rates of success. Arthroscopic procedures benefit patients by avoiding the common morbidities associated with the disruption of the anterior soft tissues including a loss of external rotation associated with open procedures.
The diagnosis and management of posterior shoulder instability remain challenging. Posterior instability is uncommon, and the diagnosis may be subtle.
The most common presenting complaint is pain. Thorough evaluation and appropriate imaging will demonstrate the pathoanatomy, which can be variable and may involve soft-tissue and/or bony elements. Careful classification of the instability will yield insight into the natural history and help guide treatment. In the great majority of individuals, nonsurgical treatment is the preferred initial management. In those who fail conservative measures, surgery may be indicated. Careful preoperative planning, surgery targeted at the specific pathology, and thoughtful aftercare can maximize the chance for success and minimize the risk of complications.
The best outcomes appear to follow open or arthroscopic soft tissue procedures to repair posterior labral pathology and for retention of the posteroinferior capsulolabral complex patterns of instability and may require adjuvant retentioning of the inferior and posterior aspect of capsule and closure of the rotator interval .osseous procedures should be reserved for the very rare patient with definite evidence of marked glenoid erosion or glenoid retroversion that is thought to contribute to the instability.
Individuals with voluntary instability, multidirectional instability, or bony defects will require a more careful assessment of the cause of the instability. If an extended rehabilitation program is unsuccessful, combined soft- tissue and bony procedures may be needed to restore stability.