The patient with the 30 shoulder dislocations.The (ISIS) instability severity index score and surgical decision making in traumatic shoulder instability.

The socket (glenoid) augmented with bone graft.

Bone graft is harvested from the pelvis
to augment the glenoid (socket)

 A dislocation can create a small impaction or  a large impaction fracture to the humerus (ball) creating a defect that decreases the overall articulating surface of the humerus making it prone to dislocations and engagement with the socket (glenoid).

The following case is a 40 y/o female with history of seizure disorder and history of multiple shoulder dislocations for a period of two years. She was unable to do any overhead activity because the shoulder will dislocated. At the time of presentation she had with over 30 dislocations. Shoulder dislocates easily (while putting clothes on) and usually once a week. Patient has been to the ER multiple times for reduction of her dislocation. She reported when she was seen in the office that her seizures have been under control for about 8 months. On exam:  L shoulder: Positive apprehension test, no sulcus sign, no generalized laxity. She has pain with FE pass 90 degrees. Has intact axillary nerve. Her muscle strength is 5/5 in all muscles of the rotator cuff. Negative Jerk's test for posterior instability. Her ISIS score was 6. Based on the score and the imaging studies we elected to proceed with an open stabilization procedure and augmentation of the glenoid with bone autograft (transfer of iliac crest bone to the glenoid; Eden hybinette procedure) . Alternatively a Latarjet (coracoid transfer) could have been performed

The patient is currently 3 years after her surgery and has no dislocations. Preoperative and postoperative xrays as shown below.

Apical oblique XR shows large Hill Sachs lesion over the superior-posterior aspect of the humerus

Hill Sachs lesion of significant depth

FOR A METHOD OF preoperative assessment of the possible engagement of Hill Sach lesions please click HERE

Bottom: Glenoid bone loss

Immediate postoperative radiograph (Grashey view) after bone augmentation of the glenoid

Axillary view of the glenoid after placement of the bone graft

3 year followup Grashey view of the shoulder.

The ISIS is a useful tool that guides physicians in the treatment of recurrent traumatic shoulder instability. The risk factors for recurrence of instability are taken into consideration when a decision needs to be made regarding the surgical approach. While arthroscopic procedures for treatment of recurrent instability are associated with less surgical trauma, there is a certain patient population that will have a high risk of recurrence of the instability after an arthroscopic procedure. The ISIS helps to identify those patients and treat them with an open stabilization procedure. The ISIS score analysis is reported below:

The instability severity index score. A simple pre-operative score to select patients for arthroscopic or open shoulder stabilisation.

Balg F, Boileau P. J Bone Joint Surg Br. 2007 Nov;89(11):1470-7.

• There is no simple method available to identify patients who will develop recurrent instability after an arthroscopic Bankart procedure and who would be better served by an open operation.
• We carried out a prospective case-control study of 131 consecutive unselected patients with recurrent anterior shoulder instability who underwent this procedure using suture anchors. At follow-up after a mean of 31.2 months (24 to 52) 19 (14.5%) had recurrent instability.
• The following risk factors were identified: patient age under 20 years at the time of surgery; involvement in competitive or contact sports or those involving forced overhead activity; shoulder hyperlaxity; a Hill-Sachs lesion present on an anteroposterior radiograph of the shoulder in external rotation and/or loss of the sclerotic inferior glenoid contour.
• These factors were integrated in a 10-point pre-operative instabilityseverity index score and tested retrospectively on the same population. Patients with a score over 6 points had an unacceptable recurrence risk of 70% (p < 0.001).
• On this basis we believe that an arthroscopic Bankart repair is contraindicated in these patients, to whom we now suggest a Bristow-Latarjet procedure instead.

instability severity index score is based on a pre-operative questionnaire, clinical examination, and radiographs:

Prognostic factors	Points
Age at Surgery (yrs)
≤ 20	2
> 20	0
Degree of sport participation (pre-operative)
Competitive	2
Recreational or none	0
Type of Sport (pre-operative)
Contact or forced overhead	1
Other	0
Shoulder Hyperlaxity*
Hyperlaxity (anterior/inferior)	1
Normal	0
Hill-Sachs lesion on AP radiograph
Visible on external rotation	2
Not visible on external rotation	0
Glenoid loss of contour on AP radiograph
Loss of contour	2
No lesion	0
Total (points)	10

A score of ≤ 6 points = an acceptable recurrence risk of 10% with arthroscopic stabilisation.
A score of > 6 points = an unacceptable recurrence risk of 70% and should be advised to undergo open surgery (i.e. Laterjet procedure).
* anterior hyperlaxity =  External rotation > 85° with the arm at the side
   inferior hyperlaxity = a positive hyperabduction test (the Gagey test as modified by Coste et al) in which a side-to-side difference > 20° is positive