The characteristic features of traumatic anterior shoulder instability due to an event of minor trauma

There are some patients who have traumatic anterior shoulder instability due to minor injuries like overhead activities. The purpose of this study was to clarify characteristic features of traumatic anterior shoulder instability due to minor injuries. According to the mechanism of injury in an initial dislocation, 83 shoulders that underwent the stabilizing surgery for traumatic anterior shoulder instability were divided into two groups. Traumatic group included patients who suffered from a fall or a direct injury. Minor injury group included patients who suffered from the other injury like overhead activity. General joint laxity, range of motion and laxity under anesthesia, and intraarticular findings were compared between two groups. The morphology of superior and middle glenohumeral ligaments, Bankart lesion, Hill-Sachs lesion, and partial articular surface tendon avulsion lesion were observed in arthroscopy. Minor injury group consisted of 19 shoulders with 8 males, 11 females and the mean age of 22.5 years. Traumatic group consisted of 64 shoulders with 52 males, 7 females and the mean age of 24.3 years. Female in minor injury group was significantly more than that in traumatic group. There was no difference in general joint laxity and intraarticular findings between two groups. Range of external rotation in injured side in minor injury group was significantly more than that in traumatic group. Inferior laxity in both sides in minor injury group was more than that in traumatic group. In conclusion, the traumatic anterior shoulder instability due to minor injuries might incline to occur the shoulder in female and with inferior laxity of shoulder.