ANTERIOR DISLOCATION OF GLENOHUMERAL JOINT: PATHOLOGIC LESIONS
Commonly
seen in traumatic anterior dislocation of the shoulder is a Bankart lesion,
which is an avulsion of the anterior inferior glenohumeral ligaments along with
the anterior inferior labrum. In most cases of recurrent anterior instability
associated with an avulsion of the anterior inferior labrum and glenohumeral
ligaments, a Bankart-type procedure is performed in which these tissues are
sewn back to the original attachment site along the anterior and inferior rim
of the glenoid.
If there is an acute fracture of the glenoid rim associated
with a first-time or recurrent dislocation, then open reduction and internal
fixation of the fragment can restore both the glenoid fossa surface area and
the attached ligaments. If there is bone deficiency that is not associated with
a bone fragment that can be reduced and fixed to achieve these surgical goals,
then a bone graft procedure is preferred. Several types of bone substitution
procedures are available for these types of surgery. The most popular of these
bone transfer procedures uses the coracoid process and the associated tendons
(short head of the biceps and the coracobrachialis) placed along the anterior
inferior glenoid defect and held in place with screw fixation. This procedure
(Bristow or Laterjet) provides both restoration of the bone loss of the glenoid
and a dynamic stabilization by the sling effect of the transferred tendon and
muscle tissue.
All of these types of shoulder stabilization procedures can be
done by either open or arthroscopic methods. In addition, there is, in many
cases, a variably sized impaction-type fracture in the posterosuperior aspect
of the humeral head that is termed a Hill-Sachs lesion. This lesion occurs
in anterior dislocation when the softer bone of the humeral head is impacted
against the harder bone of the anterior glenoid rim. These lesions may be large
and are occasionally treated with placement of a humeral head allograft or
small partial head prosthetic replacement into this defect. Hill-Sachs lesions
can also be treated by suturing the posterior rotator cuff and capsule
tissue into the defect.
