抄録
Bankart lesion is well known as being an essential lesion of recurrent anterior dislocation of the shoulder. However, anterior dislocation can also occur by capsular laxity, a midsubstance tear of the glenohumeral ligament(GHL), or a lateral capsular tear(LCT)of the GHL at the humeral origin.
The purpose of this study was to clarify the characteristic clinical, imaging, and arthroscopic findings in 6 patients(7 joints)with a recurrent anterior dislocation caused by LCT. LCT was present in six(7 joints)(2.3%)of 300 patients with a recurrent anterior dislocation or subluxation of the shoulder who had undergone arthoscopy. They consisted of four men and two women with a mean age of 23.4 years(11-35years)at the time of arthroscopy.
LCT was found at the initial operation in 4 cases, but was not seen in three patients who had poor results from their initial operation(modified Caspari's Bankart repair)or had undergone a second operation because of a postoperative recurrence. The traumatic history, physical findings, and presence of a Hill-Sachs lesion or Bankart lesion of these 7 joints were studied.
(1)Traumatic history: All the 7 patients had a history of trauma(sudden onset). (2)Physical findings: All the patients had a positive anterior apprehension sign. In two cases, the apprehension sigh was significantly positive even with external rotation in the 45 degree abduction position. And 4 patients had an apprehension in the forced flexion position. (3)CT arthrography: A LCT was found in only one case. The Hill-Sachs lesions were very shallow and small, and no Bankart lesions were seen. (4) MR arthrography: A LCT could be detected only in two cases. An avulsion fracture of the lesser tuberosity with bone and GHL(“bony HAGL”)was present in one. (5)Arthroscopic findings: Five cases showed LCT with a well-defined torn stump and subscapurlar muscle fibers. A small and shallow Hill-Sachs lesion was present in four. Three patients had no Bankart lesions and three had an immobile Bankant lesion. (6)The operative method: The GHL was repaired openly by suturing to the stump directly or insertion into the lesser tuberosity of the humerus using suture anchors.
Imaging findings were slight compared with the degree of instability seen clinically. In the diagnosis and treatment of recurrent anterior dislocation and subluxation of the shoulder, not only Bankart lesions but also the possibility of a LCT should be taken into consideration. Special caution is required when no Bankart lesion, or an immobile Bankart lesion is seen at arthroscopy. At present, there are no appropriate preoperative diagnostic methods, so careful arthrosopic diagnosis must be performed in accordance with the clinical findings.
In conclusion, the assessment of ligament disruption, glenoid-ligament attachment avulsion or humeral side avulsion is crucial for the treatment of a recurrent dislocation or subluxation of the shoulder.
