A simple technique to aid intraoperative identification of the tibial mechanical axis during total knee replacement

BACKGROUND Successful total knee replacement (TKR) requires accurate component placement and coronal plane malalignment of greater than 3o varus/valgus from the mechanical axis has been shown to predispose to early failure.1–3 An extramedullary alignment jig is most commonly used to identify the mechanical axis. The distal end of the jig should be centred over the ankle mortise, which can be difficult to assess when the leg is covered by surgical drapes, particularly in obese patients.