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

Authors: Balg F, Boileau P.

References: 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 instability severity 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


 Age at Surgery (yrs)


   ≤ 20


   > 20




 Degree of sport participation (pre-operative)



    Recreational or none




 Type of Sport (pre-operative)


    Contact or forced overhead





  Shoulder Hyperlaxity*


    Hyperlaxity (anterior/inferior)





  Hill-Sachs lesion on AP radiograph


    Visible on external rotation

    Not visible on external rotation




  Glenoid loss of contour on AP radiograph


    Loss of contour


    No lesion



  Total (points)


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



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