2006 - UZ Leuven

earing posterior-stabilised. To do this we used a three-dimensional totwo-dimensional model registration technique. Both the fixed- andmobile-bearing posterior-stabilised configurations used the samefemoral component. We found that fixed-bearing posterior stabilisedand mobile-bearing posterior-stabilised knee replacementsdemonstrated similar kinematic patterns, with consistent femoral rollbackduring flexion. Mobile-bearing posterior-stabilised kneereplacements demonstrated greater and more natural internal rotationof the tibia during flexion than fixed-bearing posterior-stabiliseddesigns. Such rotation occurred at the interface between the insertand tibial tray for mobile-bearing posterior-stabilised designs.However, for fixed-bearing posterior-stabilised designs, rotationoccurred at the proximal surface of the bearing. Posterior cruciateligament-retaining knee replacements demonstrated paradoxicalsliding forward of the femur. We conclude that mobile-bearingposterior-stabilised knee replacements reproduce internal rotation ofthe tibia more closely during flexion than fixed-bearing posteriorstabiliseddesigns. Furthermore, mobile-bearing posterior-stabilisedknee replacements demonstrate a unidirectional movement whichoccurs at the upper and lower sides of the mobile insert. The femurmoves in an anteroposterior direction on the upper surface of theinsert, whereas the movement at the lower surface is pure rotation.Such unidirectional movement may lead to less wear when comparedwith the multidirectional movement seen in fixed-bearing posteriorstabilisedknee replacements, and should be associated with moreevenly applied cam-post stresses.DESCHAMPS K., CALLEWAERT B., BIRCH I., MC INNES J.,DESLOOVERE K., MATRICALI G.: What is the inter- and intra-observerreliability of landmark placement (in a hallux valgus group) withinplantar pressure measurements. Gait and Posture 24S, 2006: S98-S289.Using a method based upon 2D coordinates calculations made itpossible to estimate the inter- and intra-observer reliability of landmarkplacements within plantar pressure measurements. Results of thisinvestigation showed that landmark placement (of small size) is not areliable method to analyze plantar pressures in the forefoot. Resultsagreed well with other reliability studies: the intra-observer reliabilitycan be considered as sufficient, but the inter-observer reliability ispoor.54