Consequences of capsular plications on translations of the glenohumeral joint
Authors: A Gerber, C Werner
References: SECEC 2005, Rome
Idiopathic or surgical tightening of the glenohumeral joint capsule may cause displacement of the humeral head relative to the glenoid fossa and favour the development of instability and/or osteoarthritis.
Obligate translations of the glenohumeral joint were determined before and after selective capsular plication in cadaveric shoulders to study the effects of selective capsular plications on shoulder kinematics.
While the capsule was in its unaltered state, translation of the humeral head was 3.8 mm superiorly in abduction, 7.3 mm antero-superiorly in flexion. In internal rotation in 0°, 45° and 90° of abduction the head moved 6.1, 8.0 and 120 mm antero-inferiorly. In external rotation at 0° of abduction the translation was 0.9 mm antero-inferiorly, at 45° and 90° of abduction it was 4.3 and 5.6 mm postero-inferiorly, respectively. Plications of the anterior part of the capsule reproducibly and significantly either increased or decreased translations during flexion (up to 5.9 mm anteriorly and up to 3.8 mm inferiorly), external rotation (up to 2.9 mm posteriorly and 1 mm inferiorly) and internal rotation (from 5.5 mm posteriorly to 2 mm anteriorly and up to 2.2 mm superiorly). Posterior plications had only little effect on translations.
The ‘obligate’ glenohumeral translations, which occur towards the end of passive shoulder movements, are altered in a reproducible fashion by tightening specific parts of the glenohumeral joint capsule, as often carried out in treatment of shoulder instability. These alterations of the kinematics of the glenohumeral joint may be relevant for the development of static subluxation and osteoarthritis as seen after too tight plication in the treatment of instability.