See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/282574167 Quadriceps Efficiency Following Total Knee Arthroplasty with a Medial-Pivot System is Similar to Control Conference Paper · October 2015 CITATIONS READS 204 authors, including: John D Blaha Charles Lowry Barnes University of Michigan University of Arkansas for Medical Sciences 89 PUBLICATIONS 3,071 CITATIONS 157 PUBLICATIONS 2,538 CITATIONS SEE PROFILE All content following this page was uploaded by David A Fitch on 05 October 2015 The user has requested enhancement of the downloaded file SEE PROFILE Quadriceps Efficiency Following Total Knee Arthroplasty with a Medial-Pivot System is Similar to Control David Kent DeBoer1, J David Blaha2, C Lowry Barnes3, David Fitch4, Richard Obert4, Michael Carroll4 Southern Joint Replacement Institute, Nashville, TN; University of Michigan Orthopaedics, Ann Arbor, MI; University of Arkansas for Medical Sciences, Little Rock, AR; MicroPort Orthopedics, Arlington, TN Does a medial pivot TKA design affect quadriceps efficiency following TKA compared to a non-implanted control? •• Quadriceps Closed Chain efficiency Quadriceps restoration Efficiency following Experiment TKA is critical to promote improved and patient satisfaction1 • cadaveric legfunction specimens •• • Quad rehab quality &heel-up speed affected by AP stability to Loaded to simulate squat from full extension inherent in implant design deep flexion and back to full extension Medial pivot asymmetrical design = more normal knee joint • kinematics3,4 Higher QLF = reduced quadriceps (QE) motion • • IE rotation similar to normal knee and efficiency lack of anterior 5,6 improve quad efficiency from symmetrical designs • should Specimens implanted with EVOLUTION® Medial Pivot CS implants by board certified surgeon than ã EVOLUTIONđ Medial Pivot orthopaedic less quad activation NexGen PSactivity for same activities following TKR6 • Loading repeated Pritchett, J et al JBJS Br 2004, 86(7): p.979-982 Lam, MH et al BMC Sports Science Medicine & Rehabilitation 2009, 1:20.3 Blaha, JD JOA 2012; 27(8):1460-1468 Schmidt, R et al CORR 2003 May; (410), 139-147 Komistek, RD et al CORR 2003 May; (410), 66-81 LaMontaigne, M et al 2014 Flexion to Extension Quadriceps Load Factor 12 Quadriceps Load Factor Control (Pre-Implantation) 10 Medial-Pivot TKA (Post-Implantation) As EVOLUTION® a whole, quadriceps Medial Pivot least CS had efficient slightly during higher peak quad flexion efficiency than (80-115° control when during FQ peak flexion highest No significant difference throughout ROM -2 115 105 95 85 75 65 55 45 Degrees of Flexion 35 25 15 View publication stats Conclusions Quadriceps Efficiency Role in rehabilitation Return to daily living activities • Anterior knee pain Patient fatigue Similar QE in pre- and post- implantation • Could be result of medial pivot design seeks to mimic normal knee kinematics • Nearly-linear change in FQ through 75º likely due to • Combination of medial spherical radius and conformity of medial tibial insert socket • Provides constant moment arm on which extensor mechanism can act