Instability Severity Index Score (Shoulder, ISIS)
Instability Severity Index Score (ISIS; Balg & Boileau 2007): sums six preoperative factors for anterior shoulder instability and flags a score >6 as high recurrence risk after an arthroscopic Bankart repair, favoring an open procedure.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Age ≤20 years at surgery
- Yes
- Competitive sport participation
- Yes
- Hill-Sachs on AP external-rotation radiograph
- Yes
- Glenoid loss of contour on AP radiograph
- Yes
Result: ISIS 8 of 10 (score >6): high recurrence risk after arthroscopic Bankart; an open procedure is favored.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- 0-6
- Lower recurrence risk after arthroscopic Bankart repair; arthroscopic stabilization is a reasonable option.
- 7-10
- High recurrence risk (>70% in the original series) after arthroscopic Bankart repair; an open procedure (Latarjet or open Bankart) is favored.
What you enter
- Age ≤20 years at surgery
- Competitive sport participation
- Contact or forced-overhead sport
- Shoulder hyperlaxity (anterior or inferior)
- Hill-Sachs on AP external-rotation radiograph
- Glenoid loss of contour on AP radiograph
How this is calculated
Balg F, Boileau P. The instability severity index score. A simple pre-operative score to select patients for arthroscopic or open shoulder stabilisation. J Bone Joint Surg Br. 2007;89(11):1470-1477. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.