Validation of a New Technique for the Evaluation of the Patello-femoral Joint Kinematics

In total knee replacement with patellar resurfacing, the patellar bone preparation and relevant component positioning, including relevant motion assessments, are still not navigated, and only femoral/tibial component positioning is supported by computer-assistance. After surgery, anterior knee pain is generally reported and this may due to prosthesis component mal-positioning, including the patella, and, ultimately, this may result in revision arthroplasty. Within computer-assisted surgery, surgical navigated system have been introduced to monitor femur and tibia prosthesis implantation and to assess tibio-femoral joint kinematics. In this context, the patella is still disregarded or limitedly considered, whereas it is still debated if the patella should be resurfaced in total knee replacement. Recently, new navigation-based procedures have been tested to allow the intra-operative monitoring of patellar-based data for more proper patellar resurfacing; at follow-up under active conditions, video-fluoroscopy, so far used to assess general tibio-femoral kinematics, offers the potentials for patellar motion tracking.

The possibility in vivo to perform intra-operative evaluations of the patello-femoral joint data, i.e. including patellar bone morphology and motion, via computer assisted procedures during surgery would allow the surgeon to have a more complete comprehension of the knee functioning in patients undergoing total knee replacement; these procedures, along with derived data, can act as a support in for the most critical surgical actions in terms of femoral/tibial prosthesis component implantation and related patellar resurfacing. Furthermore, at post-operative follow-ups via fluoroscopic acquisitions and gait analysis, it is possible to evaluate how the implant is able to recover, or not, the normative physiological motion at both tibio-femoral and patello-femoral joint.

The goal of this study is to validate a new technique for intra-operative quantification of the patello-femoral joint kinematics in patients undergoing total knee replacement, and for postoperative quantification of implanted knee and general lower limb activity, along with relevant muscle dynamics.

Inclusion criteria

• Patients with unilateral primary knee arthrosis indicated for total knee replacement.
• Patients able to understand the protocol and to sign the informed consent.

Exclusion criteria

• Patients with indications for revision surgery.
• Patients with patellectomy.
• Child-bearing female.