Robotized distraction device for knee replacement surgery

To obtain a long life span of knee prosthesis, it is necessary to restore the alignment of the lower limb. Now, in some cases of severe arthrosis, the ligament envelope of the joint may be deformed, thus inducing an asymmetric laxity once the lower limb is realigned. Because there is not yet unanimity regarding how to optimally measure or implement soft tissue balance, we provide means to acquire a variety of measurements. In traditional surgery, the surgeon sometimes uses a "tensor," which is like a forceps. This system was redesigned, instrumented, actuated and integrated into a navigation system for orthopedic surgery. In improving the perception of the surgeon, it helps him to address this problem. The prototype has been tested on sawbones before having been validated in the course of an experiment on two cadavers. The surgeon was able to assess soft tissue balance but judged the device not powerful enough and led us to develop a new more powerful system. This toot is nowadays in an integration process. (C) 2004 Published by Elsevier B.V.