Effects of Suture and Tourniquet on Intraoperative Kinematics in Navigated Total Knee Arthroplasty

To investigate the effects of suture (soft tissue closure) and air tourniquet use on intraoperative kinematics in navigated total knee arthroplasty.

The study included 20 patients with varus-type knee osteoarthritis who underwent primary posterior-stabilized total knee arthroplasty using computed tomography (CT)–based navigation. Intraoperative tibiofemoral kinematics from maximum extension to maximum flexion were measured using the computed tomography–based navigation. The measurements were performed 3 times as follows: measurement 1: before suture (tourniquet on), measurement 2: after suture (tourniquet on), and measurement 3: after tourniquet removal. Details of kinematics including knee joint gap, tibiofemoral rotational angles, and anteroposterior (AP) distance between the femur and tibia were compared among the 3 measurements and statistically evaluated.

On the medial side, there was no significant difference among the 3 measurements in the extension gap, but measurement 1 showed a significantly larger flexion gap compared with the other 2 measurements. On the lateral side, there was no significant difference between the extension and flexion gaps in all measurements. The anteroposterior distance in measurement 1 showed that the femur was positioned significantly more anterior to the tibia at 10° and 20° of flexion compared with the other 2 measurements after suture. There was no significant difference among the 3 measurements in the tibiofemoral rotation angles.

These results found that the effect of suture and tourniquet was minimal, and that intraoperative kinematics can effectively evaluate postoperative passive kinematic conditions.