NEUTRAL MECHANICAL ALIGNMENT: STICKIN' WITH THE ONE THAT BRUNG YA – AFFIRMS

Abstract Restoring the overall mechanical alignment to neutral has been the gold standard in total knee arthroplasty since the 1970s. Recently, there has been renewed interest in alternative alignment goals that place implants in a more “physiologic” position with the hope of improving clinical outcomes. However, placing components outside of the classic “safe zone” of ± 3° is controversial, as studies have shown increased risk of mechanical failure, especially in obese patient populations. This paper will outline mechanical and kinematic alignment and present the evidence for why mechanical alignment is still the gold standard in total knee arthroplasty.

[1]  Robert B. Bourne,et al.  AT THE ANNUAL MEETINGS OF THE KNEE SOCIETY Patient Satisfaction after Total Knee Arthroplasty Who is Satisfied and Who is Not ? , 2009 .

[2]  Daniel J Berry,et al.  Effect of postoperative mechanical axis alignment on the fifteen-year survival of modern, cemented total knee replacements. , 2010, The Journal of bone and joint surgery. American volume.

[3]  Masao Akagi,et al.  The functional flexion-extension axis of the knee corresponds to the surgical epicondylar axis: in vivo analysis using a biplanar image-matching technique. , 2005, The Journal of arthroplasty.

[4]  Gerard A Engh,et al.  Factors associated with the loss of thickness of polyethylene tibial bearings after knee arthroplasty. , 2007, The Journal of bone and joint surgery. American volume.

[5]  P. Lotke,et al.  Influence of positioning of prosthesis in total knee replacement. , 1977, The Journal of bone and joint surgery. American volume.

[6]  B. Espehaug,et al.  Survival rates and causes of revision in cemented primary total knee replacement: a report from the Norwegian Arthroplasty Register 1994-2009. , 2013, The bone & joint journal.

[7]  Joel Bach,et al.  AN ABJS BEST PAPER: Difference Between the Epicondylar and Cylindrical Axis of the Knee , 2007, Clinical orthopaedics and related research.

[8]  R. Barrack,et al.  No impact of under-correction and joint line obliquity on clinical outcomes of total knee arthroplasty for the varus knee , 2018, Knee Surgery, Sports Traumatology, Arthroscopy.

[9]  Darryl D D'Lima,et al.  Effect of tibial component varus on wear in total knee arthroplasty. , 2012, The Knee.

[10]  J. Victor,et al.  Rotational alignment of the distal femur: a literature review. , 2009, Orthopaedics & traumatology, surgery & research : OTSR.

[11]  W Waugh,et al.  Tibiofemoral alignment and the results of knee replacement. , 1985, The Journal of bone and joint surgery. British volume.

[12]  P. Shang,et al.  Shorter survival rate in varus-aligned knees after total knee arthroplasty , 2016, Knee Surgery, Sports Traumatology, Arthroscopy.

[13]  M. Ritter,et al.  Malalignment: forewarned is forearmed. , 2009, Orthopedics.

[14]  Frederick W Werner,et al.  The effect of valgus/varus malalignment on load distribution in total knee replacements. , 2005, Journal of biomechanics.

[15]  L. Arendt-Nielsen,et al.  Chronic Postoperative Pain After Primary and Revision Total Knee Arthroplasty , 2015, The Clinical journal of pain.

[16]  Marco Viceconti,et al.  Polyethylene damage and deformation on fixed-bearing, non-conforming unicondylar knee replacements corresponding to progressive changes in alignment and fixation. , 2010, Clinical biomechanics.

[17]  Richard R Glisson,et al.  The effects of varus tibial alignment on proximal tibial surface strain in total knee arthroplasty: The posteromedial hot spot. , 2002, The Journal of arthroplasty.

[18]  J. Bellemans,et al.  The Chitranjan Ranawat Award: Is Neutral Mechanical Alignment Normal for All Patients?: The Concept of Constitutional Varus , 2012, Clinical orthopaedics and related research.

[19]  H. Dossett,et al.  A randomised controlled trial of kinematically and mechanically aligned total knee replacements: two-year clinical results. , 2014, The bone & joint journal.

[20]  J. Bellemans,et al.  Slight undercorrection following total knee arthroplasty results in superior clinical outcomes in varus knees , 2013, Knee Surgery, Sports Traumatology, Arthroscopy.

[21]  V. Spitzer,et al.  Three-Dimensional Morphology and Kinematics of the Distal Part of the Femur Viewed in Virtual Reality: Part II , 2003, The Journal of bone and joint surgery. American volume.

[22]  J. Bellemans,et al.  Current opinions about coronal plane alignment in total knee arthroplasty: A survey article. , 2015, Acta orthopaedica Belgica.

[23]  A. Saxena,et al.  Intermediate and long-term quality of life after total knee replacement: a systematic review and meta-analysis. , 2015, The Journal of bone and joint surgery. American volume.

[24]  J. Insall,et al.  Total knee arthroplasty , 2015 .

[25]  K. Kuehn,et al.  Acrylic bone cements: mechanical and physical properties. , 2005, The Orthopedic clinics of North America.

[26]  Thomas Lind,et al.  Analgesic Effect of Perioperative Escitalopram in High Pain Catastrophizing Patients after Total Knee Arthroplasty: A Randomized, Double-blind, Placebo-controlled Trial , 2015, Anesthesiology.

[27]  R. Barrack,et al.  Relationship of the posterior femoral axis of the "kinematically aligned" total knee arthroplasty to the posterior condylar, transepicondylar, and anteroposterior femoral axes. , 2014, The Knee.

[28]  F. Catani,et al.  Deviations From Optimal Alignment in TKA: Is There a Biomechanical Difference Between Femoral or Tibial Component Alignment? , 2014, Journal of Arthroplasty.

[29]  V. Spitzer,et al.  Three-dimensional mechanics, kinematics, and morphology of the knee viewed in virtual reality. , 2005, The Journal of bone and joint surgery. American volume.

[30]  R. Barrack,et al.  Patient dissatisfaction following total knee replacement: a growing concern? , 2014, The bone & joint journal.

[31]  D S Barrett,et al.  The importance of tibial alignment: finite element analysis of tibial malalignment. , 2000, The Journal of arthroplasty.

[32]  Bradley S Davidson,et al.  Cylindrical Axis, Not Epicondyles, Approximates Perpendicular to Knee Axes , 2013, Clinical orthopaedics and related research.

[33]  N. Clement,et al.  The early outcome of kinematic versus mechanical alignment in total knee arthroplasty: a prospective randomised control trial. , 2016, The bone & joint journal.

[34]  H. Kehlet,et al.  Persistent postsurgical pain: risk factors and prevention , 2006, The Lancet.

[35]  Jang-Won Park,et al.  The relationship between the survival of total knee arthroplasty and postoperative coronal, sagittal and rotational alignment of knee prosthesis , 2014, International Orthopaedics.

[36]  R. Buzzi,et al.  Posteriorly stabilised total-condylar knee replacement. Three to eight years' follow-up of 85 knees. , 1988, The Journal of bone and joint surgery. British volume.

[37]  M. Ritter,et al.  Postoperative alignment of total knee replacement. Its effect on survival. , 1994, Clinical orthopaedics and related research.

[38]  C. D. Bryce,et al.  Total knee replacement in young, active patients: long-term follow-up and functional outcome: a concise follow-up of a previous report. , 2014, The Journal of bone and joint surgery. American volume.

[39]  M A Freeman,et al.  Alignment in total knee arthroplasty. Correlated biomechanical and clinical observations. , 1983, Clinical orthopaedics and related research.

[40]  M. Ritter,et al.  Tibial Component Failure Mechanisms in Total Knee Arthroplasty , 2004, Clinical orthopaedics and related research.

[41]  S. Howell,et al.  Alignment options for total knee arthroplasty: A systematic review. , 2017, Orthopaedics & traumatology, surgery & research : OTSR.