Current concepts for aligning knee implants: Patient-specific or systematic?

Abstract

▪ Mechanical or anatomical alignment techniques create a supposedly 'biomechanically friendly' but often functionally limited prosthetic knee. ▪ Alternative techniques for alignment in total knee arthroplasty (TKA) aim at being more anatomical and patientspecific, aiming to improve functional outcomes after TKA. ▪ The kinematic alignment (KA) technique for TKA has shown good early clinical outcomes. Its role in extreme anatomical variation remains to be defined. ▪ The restricted KA technique for TKA might be a reasonable option for patients with extreme anatomical variation. ▪ While unicompartmental knee arthroplasty (UKA) has many advantages over TKA, the revision rate remains higher compared with TKA. One major explanation is the relative ease with which a UKA can be converted to a TKA, compared with revising a TKA. This can be considered as an additional advantage of UKA. Another reason is that surgeons favour revising a UKA to a TKA in cases of degeneration of the other femorotibial compartment rather than performing a relatively simple re-operation of the knee by doing an additional UKA (staged bi-UKA).