Smart collateral ligament balancer for intra- and postoperative mediolateral balance

International audienceThe poor ligament balance performed at the time of total knee arthroplasty (TKA) can cause postoperative instability and consequently early loosening of the prosthetic knee. The improper intraoperative assessment of ligamentous balance is due to the use of an inaccurate surgical instrument which tenses the medial and lateral collateral ligaments in uncontrolled way. A smart ligament balancer is proposed in this paper to assess and perform ligament balancing intra- and postoperatively. A detailed three-dimensional model of the prototype is developed using CAD software in order to discuss the operation of this device. The intraoperative use of this balancer could allow to accurately reestablish a rectangular tibiofemoral gap with symmetric mediolateral load distribution across the whole range of knee flexion. On the other hand, the implanted balancer could be used postoperatively to assess ligamentous balance and to correct it when needed