We studied a group of 12 subjects with chronic posttraumatic scapulo-humeral instability who underwent arthroscopic coracoid transposition using Latarjet's technique. All patients were followed-up after the operation for a mean of 1.7 years (minimum 1 year, maximum 3 years). The follow-ups consisted of a clinico-functional evaluation with a apprehension test and isokinetic studies of strength and joint movements during internal and external rotation of the abducted shoulder, both on the healthy side and on the operated side. The isokinetic evaluation consisted of 5 repetitions of internal-external rotation at ana angular velocity of 60 degrees/sec. The results showed that the operated shoulder was slightly weaker than the healthy one, but that the difference was not statistically significant according to Student's t test for paired data. The profile of the trace did not show macroscopic differences between the two sides. At clinical assessment 11 of 12 patients reported a good-excellent outcome of the operation with complete recovery of shoulder function and return to previously performed sporting activities. In conclusion, this technique is shown to have a good medium-term outcome. Although there have been no complications in our series, a longer follow-up to evaluate possible complications would be advisable.