A total of forty consecutive patients suffering from recurrent traumatic anterior shoulder instability underwent stabilisation with a glenoid based inferior capsular shift. The patients were followed up prospectively by an independent observer (JM) using the Constant-Murley score and objective evaluation of shoulder movement and strength with an isometric dynamometer. The mean follow-up period was 50 months (range, 2 to 6.8 years). Three patients (7.5%) suffered a repeat, high energy, traumatic dislocation following an early return to sports activities. "Cybex" testing documented a minimal average loss of external rotation movement (4.4 degrees) and strength (4.3%) with the arm in neutral, which was higher with the arm at 90 degrees of abduction (i.e., 13.7 degrees and 15.6%, respectively). The deficit in internal rotation strength was similarly lower in neutral position (2%), when compared to the deficit with the arm at 90 degrees of abduction (13.5%). There was no measurable loss of internal rotation motion. Our study supports the use of a glenoid based inferior capsular shift, as there is a low recurrence rate and minimal deficit in shoulder movement and strength.