Abstract
Introduction and Aims: Complications after total knee arthroplasty (TKA) have been attributed to soft-tissue imbalance. The current approach to soft-tissue balance is static measurements in extension and 90 degrees flexion. Dynamic balancing during the entire range of flexion may be more valuable.
Method: Complications after total knee arthroplasty (TKA) have been attributed to soft-tissue imbalance. The current approach to soft-tissue balance is static measurements in extension and 90 degrees flexion. Dynamic balancing during the entire range of flexion may be more valuable.
Results: All knees (in vitro and in vivo) initially recorded imbalance in the tibial forces: mean 18N (6–72) in the mediolateral and 26N (13–108) in the anteroposterior direction. After soft-tissue balancing, the mean imbalance reduced by 87%. Even when knees appeared well balanced at zero and 90-degree flexion, there was imbalance [mean 22N (2–34)] at flexion angles between zero and 90 degrees. The 2mm thicker insert increased forces by a mean of 89% (22–180%).
Conclusion: Soft-tissue balance in TKA remains a complex concept. The routine instruments used for soft-tissue balance only detect mediolateral imbalance. Even when accurate static balancing was achieved, dynamic measurements revealed imbalance in mid-flexion. These results explain some of the variability in knee kinematics after TKA and the incidence of mid-flexion instability.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
