Biomechanics and Motion Analysis

Prospective, Randomized, Controlled, Blinded Study Comparing Functional Outcomes of Two Contemporary Surgical Approaches in Total Knee Arthroplasty

Principal Investigator: Mark W. Pagnano, M.D.
Project Coordinator: Christine Huyber — huyber.christine@mayo.edu

The American Academy of Orthopaedic Surgeons reports that 300,000 people undergo total knee arthroplasty (TKA) every year for severe degenerative disease, and nearly 1,000 of those procedures are performed by the Mayo Clinic Orthopedic Surgery Department. Recently, surgeons are turning towards using a minimally invasive surgery (MIS) for joint replacements with conventional TKA implant to minimize surgical trauma. Although differences in surgery recovery time and pain have been studied between MIS TKA and the standard parapatellar approach, functional measures such as gait and strength correlated with patient satisfaction have never been compared between the two approaches.

To fully investigate the TKA procedure, we developed a randomized, controlled trial with blinded outcome measurements.  Patients are randomized into either the MIS TKA or the standard parapatellar procedure group.  Patient measures are collected preoperatively and postoperatively at 2 months and 1 year.  At each visit patients complete a lower extremity gait analysis, thigh strength testing, and a self-assessment questionnaire regarding functional outcomes.  During the gait analysis, lower extremity function is captured using a computerized realtime video motion analysis system and instrumented forceplates embedded in stairs and a level surface.  Joint kinematics (motion) and kinetics (moments and powers) are calculated for the hip, knee and ankle along with temporal distance parameters such as velocity, cadence, single and double limb support time, step and stride length.  The combination of objective and subjective measures will provide a clear picture of the relative benefits of the two TKA approaches.  We hypothesize that the MIS TKA approach will result in superior functional outcome results when compared to the standard approach.