Abstract
In a cadaveric study, the anterior shoulder capsule indicated the presence of the middle (MGHL) and inferior (IGHL) glenohumeral ligament by displaying folds. These folds became more prominent in adduction (AD) and internal rotation (IR), whereas they were smoothed out upon abduction (AB) and external rotation (ER).
The present study was set up to determine whether this folding-unfolding mechanism (FUM) is influenced by the type of shoulder pathology.
300 consecutive shoulder arthroscopies were evaluated. 68 were done for instability, 21 for frozen shoulder and 221 for various pathologies in stable shoulders of which 100 for rotator cuff tears.
Stable shoulders: The anterior band (AB) of the IGHL was marked by a prominent fold in IR and 30°AD. In full ER and 45°AB the fold was completely smoothed out. The MGHL was smooth in full ER and 15°AB.
Frozen shoulders: The anterior capsule was smooth without visible folds in any degree of rotation, limited by the adhesive capsulitis. Releasing the capsule from the glenoid rim did not change this appearance.
Unstable shoulders: In 17 shoulders with anterosuperior instability (SLAP and RCI lesions), the FUM of the anterior capsule had the same appearance as in stable shoulders. In 51 shoulders with anteroinferior instability, the MGHL and ABIGHL still formed prominent folds in IR. Full ER, increased up to 90° in some patients, did not result in smoothing of the folds, not even with up to 90°AB. After repair of the labroligamentous lesion and associated capsular shift, the FUM reappeared at 45°AB and ER that was reduced to 45°.
These observations suggest that smoothing of the anteroinferior capsule at a maximum of 45°ER and 45°AB could be used as an indication of normal tension in the MGHL and IGHL. When the FUM does not occur within this range, these ligaments are probably insufficient, be it torn or stretched. During capsular shift, esp electrothermal, a reappearing FUM could be used to evaluate achievement of adequate capsular tension. When no folds at all are visible, even with full IR, this indicates a very tight capsule and likely a frozen shoulder, esp when rotation is decreased.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
