Mako Robotic Arm-Assisted Unicompartmental Knee Arthroplasty

The Mako [Mako Surgical Corp. (Stryker), Fort Lauderdale, FL, USA] robotic arm-assisted (RA) unicompartmental knee arthroplasty (UKA) enables the surgeon to perform resurfacing partial knee replacement adapting implant placement to the patient’s anatomy before bone preparation with higher accuracy, reproducibility and survivorship than conventional UKA. This robotic system allows three UKA procedures: medial, lateral, and patello-femoral partial knee replacement. A three-dimensional reconstruction is processed from a lower limb CT scan of the patient and is used for preoperative and intraoperative planning. Using a navigation-based system established on infrared optical arrays, with stable sensors fixed to the patient’s femur and tibia, the surgeon is able to perform surgery with the assistance of a robotic arm that provides neurosensory haptic feedback for bone preparation. This system is based on the concept of patient-specific knee arthroplasty, based on the patient’s anatomy, allowing the surgeon to avoid overcorrection and components’ malalignment during implant placement. The sequence of five phases is the base of every Mako RA-UKA: system setting, preoperative planning and surgical setting, system registration, intraoperative planning and soft-tissue balancing, and finally haptically controlled bone preparation.