Personalised alignment in total knee replacement: Restoring the individual knee

Total knee replacement (TKR) has traditionally relied on standardised alignment principles, with the aim of creating a mechanically aligned limb and a balanced knee. However, increasing recognition of individual anatomical variation has led to a shift towards personalised alignment, with the goal of reproducing the patient’s native knee anatomy and biomechanics as closely as possible.

Kinematic alignment (KA) is one approach to personalised TKR. Rather than routinely correcting every knee to a predefined neutral mechanical axis, KA aims to restore the patient’s pre-arthritic joint line and native femoral and tibial joint surfaces. The philosophy is simple: rather than making every knee conform to the implant philosophy, the implant is positioned to respect the patient’s individual anatomy.

I use kinematic alignment techniques with the Medacta GMK Sphere system, which is particularly suited to a personalised approach. The GMK Sphere’s design incorporates a medial pivot concept, aiming to reproduce the natural stability and kinematics of the native knee.

Combined with patient-specific assessment and careful soft-tissue management, this allows alignment and component positioning to be considered as part of an overall strategy rather than as isolated targets.

Personalised alignment does not mean simply accepting every pre-operative deformity. Instead, it requires understanding the individual knee, distinguishing between constitutional anatomy and disease-related changes, and making informed decisions about bone resection, component positioning and ligament balance.

The potential benefits of this approach include a more natural-feeling knee, preservation of the native joint line and reduced reliance on extensive soft-tissue releases. Ultimately, the objective is not simply to achieve a technically “correct” radiograph, but to create a knee that feels stable, moves naturally and functions well for the individual patient.

As our understanding of knee biomechanics continues to evolve, personalised alignment represents an important step towards patient-specific TKR, moving from a one-size-fits-all philosophy towards restoration of the individual knee.