Advertisement for orthosearch.org.uk
Orthopaedic Proceedings Logo

Receive monthly Table of Contents alerts from Orthopaedic Proceedings

Comprehensive article alerts can be set up and managed through your account settings

View my account settings

Visit Orthopaedic Proceedings at:

Loading...

Loading...

Full Access

COMPARISON OF MICROMOVEMENT OF PEGGED VERSUS KEELED GLENOID COMPONENTS USING RSA.



Abstract

To measure any observed differences in migration and rotation between keeled and pegged glenoid components using roentgen stereo-photogrammetric analysis.

Between 2000–2001 in a prospective randomised study, 20 patients with osteoarthritis had a TSR with roentgen stereo-photogrammetric analysis. Five tantalum markers were introduced into the scapula and acromion, spaced widely apart. Another 4 markers were placed in either a pegged or keeled glenoid component.

RSA radiographs were taken postoperatively, three, six, twelve and eighteen months. The radiographs were digitised and analysed using dedicated software (UmRSA). The relative movement of the glenoid with respect to the scapula was measured.

The largest translation for the keeled components was in the proximal/distal direction with a mean of 1.3mm, the pegged group mean was 0.27mm. This difference was significant, P = 0.001. Both other translation axes showed no significant difference between the two component types. Medial/lateral migration gave means of 0.38mm(keel) and 0.52mm(peg) and the anterior/ posterior translation with means of 0.54mm(keel) and 0.41mm(peg). Maximal total point motion mean values at 18 months were 2.6mm for keeled and 1.1mm for pegged glenoid components. This difference was also significant P=0.001

The largest rotation was anterior/posterior tilt with means of 3.5°(keel) and 1.1°(peg) this difference was significant p=0.005; varus/valgus tilt with a mean of 3.2°(keel) compared to 20(peg) was again, significant P = 0.002. and finally anteversion/retroversion means were 3.3°(keel) and 2.7°(peg). Multivariate analysis identified 2 principal components from the keeled data each accounting for 35% of the variation in the data. The first included transverse and saggital translation together with rotation about the longitudinal axis; the second component consisted of translation on the longitudinal axis with rotation about the transverse axis.

These abstracts were prepared by Mr Cormac Kelly. Correspondence should be addressed to him c/o British Orthopaedic Association, Royal College of Surgeons, 35-43 Lincoln’s Inn Fields, London WC2A 3PN.