88 adult patients (<35 years of age) who had sustained a primary anterior glenohumeral dislocation were randomized to undergo either an arthroscopic examination and joint lavage alone or together with an anatomic repair of the antero-inferior aspect of the labrum (Bankart lesion). This study aimed to compare rates of future redislocations and shoulder function between techniques. At 2 years, the group treated by an anatomic arthroscopic repair was observed to have a significantly reduced risk of recurrent instability compared with those who had an arthroscopic examination and lavage alone. However, the primary repair did not provide additional functional benefit to patients at 2 years after dislocation.