Paper #IV-3

COMPUTER ASSISTED GAP EQUALIZATION (CAGE) IN TOTAL KNEE ARTHROPLASTY

Darius G. Viskontas, MD¹,

London, ON

Co-Authors

TV Skrinskas¹

DG Chess¹

JA Johnson¹

GJ King¹

MJ Winemaker²

¹Hand and Upper Limb Clinic, St. Joseph's Health Centre, University of Western Ontario, London, Canada

²Hamilton Arthroplasty Group, Hamilton Health Sciences Centre - Henderson Site, McMaster University, Hamilton, Canada

Introduction

Computerized techniques of knee balancing during Total Knee Arthroplasty (TKA) may improve function and prolong prosthesis survival. The conventional 'Measured Resection' technique of knee balancing was compared to the new 'Computer Assisted Gap Equalization' (CAGE) technique.

Methods

TKA's were performed on eight pairs of cadaver knees. One side of each pair was randomly selected for the control (measured resection) group. The experimental technique using a computer-assisted ligament-tensioning device (CAGE) to equalize gap symmetry and load was used in the contralateral side. Post-operatively, a knee simulator and a tibial load transducer measured compartmental force at different flexion angles. Outcome assessment consisted of measuring gap loads and symmetry pre-component insertion and compartment force post-component insertion.

Results

Pre-component insertion, CAGE trended towards improved gap symmetry and significant equalization (p<0.05) of gap load.
Post-component insertion there was no significant difference in knee balance between the groups.

Discussion

CAGE improves balance pre-component insertion due to improved accuracy with computer-assistance. However, component design, posterior capsular tension and tibial rotation preclude sustaining the improved balance post-component insertion. Further work is needed to translate the improved surgical accuracy into improved balance following component insertion.