Technical feasibility of personalized articulating knee joint distraction for treatment of tibiofemoral osteoarthritis

Abstract Background Knee osteoarthritis is a highly prevalent degenerative joint disorder characterized by joint tissue damage and pain. Knee joint distraction has been introduced as a joint preserving surgical procedure to postpone knee arthroplasty. An often used standard externally fixation device for distraction poses a burden to patients due to the absence of joint flexion during the 6 weeks treatment. Therefore, a personalized articulating distraction device was developed. The aim of this study was to test technical feasibility of this device. Methods Based on an often applied rigid device, using equal bone pin positions and connectors, a hinge mechanism was developed consisting of a cam-following system for reproducing the complex joint-specific knee kinematics. In support, a device was developed for capturing the joint-specific sagittal plane articulation. The obtained kinematic data were translated into joint-specific cam shapes that were installed bilaterally in the hinge mechanism of the distraction device, as such providing personalized knee motion. Distraction of 5 mm was performed within a range of motion of 30 deg. joint flexion. Pre-clinical evaluation of the working principle was performed on human cadaveric legs and system stiffness characteristics were biomechanically evaluated. Findings The desired range of motion was obtained and distraction was maintained under physiologically representative loading. Moreover, the joint-specific approach demonstrated tolerance of deviations from anatomical and alignment origin during initial placement of the developed distraction device. Interpretation Articulation during knee distraction is considered technically feasible and has potential to decrease burden and improve acceptance of distraction therapy. Testing of clinical feasibility is warranted.