More than 1 million patients undergo total knee replacement surgery in the US alone each year. Unfortunately, 20 – 25% of these patients have a poor outcome due to persistent pain, instability, stiffness, and/or implant failure. These poor clinical outcomes can be traced to the conventional method of 'mechanical alignment', or aligning the implants on the bones. Mechanical alignment is a one size fits all approach where the surgical alignment goal is a ‘straight’ lower limb, which means that the knee is centered along a line connecting the hip and ankle joints. However, 98% of the population are knock-kneed or bow-legged and not straight. To make these patients ‘straight’, perfectly healthy ligaments must be cut in most patients. This cutting often leads to poor outcomes.
To improve outcomes, beginning in 2006 and working at the University of California Davis, we pioneered a new personalized method for aligning implants termed 'kinematic alignment'. In contrast to mechanical alignment, the personalized surgical goal is to restore the alignments of the bones to pre-arthritic (i.e. healthy) knee without ligament release. Hence, if a patient was knock-kneed or bow-legged when healthy, then they would be knock-kneed or bow-legged post surgery.
After performing the surgery on more than 6,000 patients, patients have statistically significant better outcomes with kinematic alignment rather than those treated with mechanical alignment. KinAlign Orthopaedics Inc. has evolved from a 17-year effort at UC Davis. Our research and development goal is to motivate a complete transition to an different clinical practice paradigm of personalized versus non-personalized alignment in total knee arthroplasty to the benefit of all patients having knee replacement surgery.