Abstract
There is a renewed debate regarding the relative importance of (primarily varus-valgus) stability versus alignment in TKA. Some surgeons have posited that stability is of greater importance. Perhaps this is because unstable knees fail immediately whereas mal-aligned knees generally suffer late failure from wear, osteolysis and loosening. Or perhaps some surgeons find soft tissue techniques challenging. Clearly alignment and stability are both necessary for immediate function and long-term durability.
Ligament tensioners are as old as condylar knee arthroplasties. They first appeared when surgeons moved beyond hinged arthroplasties with a goal of melding anatomy and biomechanics- to re-establish stability and correct pathologic deformity. Early techniques stipulated that ligament releases should be performed first, before any bone cuts thus correcting deformity and restoring stability. Crude mechanical instruments were replaced by mechanical devices.
Acknowledging more exacting standards, our ability to hit the target of desired alignment and stability is limited unassisted. As more sophisticated devices have been introduced to help surgeons correct alignment we have not yet discovered the perfect mechanical, electronic, navigated or laser guided “tensioner”. We still struggle to divine the “best” alignment. The principle however endures, that integrating stability and alignment, if with nothing more than a “cognitive tensioner” is essential to optimal short and long-term arthroplasty function.
