Basic Concepts of TKA — Hip & Knee Book | 合法醫療器材資訊網

2017年2月28日—TKAaimstorecreatethemechanicalaxisofthenativeleg,however,itdoesnotrecreatethesameangleofjointline.Explainthedifferencesin ...

One goal of TKA is to achieve balanced tension within the knee throughout range of motion.  This balanced tension is important for implant stability and longevity .

A balanced knee has rectangular Flexion and Extension gaps - the rectangle demonstrates that the medial and lateral compartment share equal tension.  A trapezoid means that one side is looser (aka "opening up") and therefore, this side will experience less tension and this may cause an unstable TKA and/or asymmetric wear and early failure. 

The angle of bone cuts and the surrounding soft tissue tension can both affect the balance of the flexion gap (90°) and extension gap (0°). 

The balance of a gap is measured with a spacer block.  

A balanced knee has equal sized Flexion and Extension gaps.  A balanced knee has rectangular Flexion and Extension gaps.