Shoulder Capsule / Rotator Interval Capsule

- Rotator Interval Capsule:
    - rotator interval is a triangular portion of shoulder capsule which lies between the supraspinatus and subscapularis tendons;
    - capsular anatomy: (Static Stabilizers / Capsule of the Shoulder)
          - interval capsule is reinforced by the superior glenohumeral and coracohumeral ligaments; 
          - references:
                  - Capsular ligaments of the shoulder. Anatomical and functional study of the anterior superior capsule
                  - Capsular restraints to anterior-posterior motion of the abducted shoulder: a biomechanical study. 
                  - The Vascular Anatomy of the Glenohumeral Capsule and Ligaments: An Anatomic Study.
                  - Static capsuloligamentous restraints to superior-inferior translation of the glenohumeral joint.
                  - The role of the rotator interval capsule in passive motion and stability of the shoulder.
          - superior glenohumeral ligaments:
                  - has two sites of origin: supraglenoid tubercle - just anterior to long head of biceps origin on superior labrum and the base of coracoid;
                  - arthroscopically it may be hidden by the biceps tendon;
                  - inserts on proximal aspect of lesser tuberosity;
                  - at 0 deg abduction, superior & MGHL develops most strain, and together w/ the coracohumeral ligament stabilize the shoulder in adduction;
                  - it helps to prevent posterior and inferior instability;
                  - reference:
                       - Tensile properties of the superior glenohumeral and coracohumeral ligaments.
          - coacohumeral ligament:
                  - arises as an extraarticular ligament on the lateral surface of coracoid and inserts into the greater and lesser tuberosities, spanning bicipital groove;
                  - sectioning of coracohumeral ligaments produces anteroinferior instability;
                  - represents folded thickening of glenohumeral capsule in area of rotator interval between subscapularis & supraspinatus;
                  - w/ body upright & arm in dependent position, coracohumeral & MGHL play important roles in resisting inf translation.
                  - references:
                       - The structure and function of the coracohumeral ligament.  An anatomic and microscopic study.  
                       - Tensile properties of the superior glenohumeral and coracohumeral ligaments.
    - acts to limit flexion and external rotation;
    - tears of the rotator interval capsule:
          - may mimic rotator cuff tears;
          - impingment signs may be present along w/ biceps tendon tenderness;
          - may allow extravasation of dye into subacromial space, as well as the subscapularis fossa (w/ dye seen anterior to the subscapularis);
                 - leakage into the subscapularis fossa may require shoulder movement;
          - Harryman, et al, the authors report that sectioning of the rotator interval capsule allowed 50% posterior translation and 100% inferior translation;
    - management:
          - in cadaver experiments, imbrication of interval capsule helped to eliminate posterior and inferior instability;
          - if superior capsular structures are shortened w/o addressing the redundancy of the inferior capsule, may tend to push the humeral head inferiorly;
    - references: 
          - The role of the rotator interval capsule in passive motion and stability of the shoulder.  
          - The anatomy and histology of the rotator interval capsule of the shoulder. 

- Surgical Closure of the Rotator Interval:
        - Isolated closure of rotator interval defects for shoulder instability. 
        - Rotator interval lesion
        - Arthroscopic treatment of anterior-inferior glenohumeral instability. Two to five-year follow-up. 
        - Thermal versus suture treatment of symptomatic capsular laxity. 
        - Arthroscopic rotator interval repair in glenohumeral instability: description of an operative technique. 
        - The addition of rotator interval closure after arthroscopic repair of either anterior or posterior shoulder instability: effect on glenohumeral translation and range of motion. 
        - Arthroscopic rotator interval closure: effect of sutures on glenohumeral motion and anterior-posterior translation.
        - Arthroscopic rotator interval closure in shoulder instability repair: A retrospective study

        - effects on multidirectional instability: 
                 - Biomechanical analysis comparing a traditional superior-inferior arthroscopic rotator interval closure with a novel medial-lateral technique in a cadaveric multidirectional instability model.
                 - Effects of Capsular Plication and Rotator Interval Closure in Simulated Multidirectional Shoulder Instability
                 - The effects of thermal capsulorrhaphy and rotator interval closure on multidirectional laxity in the glenohumeral joint: a cadaveric biomechanical study. 

        - effects of rotator interval on posterior capsule:
                 - Letter to the Editor: The Use of Rotator Interval Closure in the Arthroscopic Treatment of Posterior Shoulder Instability

 Arthroscopic Rotator Interval Closure by Purse String Suture for Symptomatic Inferior Shoulder Instability




Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, June 25, 2012 3:57 pm