Navigation as a Predictor of Soft Tissue Release During 90 Cases of Computer-assisted Total Knee Arthroplasty

摘要

Soft tissue balance during total knee arthroplasty (TKA) may be challenging for surgeons to achieve in knees with severe valgus or varus deformities. Traditionally, orthopedic surgeons have assessed ligament balance in 3 stages during surgery. Stage 1 assessment occurs when a patient is under anesthesia, before the leg is draped, which allows surgeons to check the reducibility of the deformity without referring to the lower leg mechanical axis. The evaluation at stage 1 assessment provides a general indication of the contracture rather than an exact measurement. Stage 2 assessment is made after the distal femur is resected. At this time, surgeons are able to use distracters, as well as alignment guides, to give an accurate indication of how much contracture remains and what soft tissue releases must be balanced. Stage 3 assessment is performed after the proximal tibia is resected, when all peripheral rim osteophytes have been removed. Subsequently, the kneeis re-extended, and the capsular sleeve is tensed with two laminar spreaders to manage residual imbalance.This traditional method of balancing ligaments varies slightly because it is based on the surgeon's intuition. Surgeons consider a well-balanced knee and a well-aligned lower leg impossible to obtain if no accurate reference to the mechanical axis is created during the operation. Computer-assisted TKA gives surgeons permanent access to a mechanical axis reference.The aim of this study was to evaluate the role of navigation using the OrthoPilot (B. Braun Aesculap, Tuttlingen, Germany) to predict soft tissue release during 90 computer assisted-total knee TKA procedures performed between December 2001 and December 2003.