Emmanuel Thienpont1, Jess H Lonner2. 1. Department of Orthopaedic Surgery, University Hospital Saint Luc, Av. Hippocrate 10, 1200 Brussels, Belgium. Electronic address: emmanuel.thienpont@uclouvain.be. 2. Department of Orthopaedic Surgery, Rothman Institute, Thomas Jefferson University, 925 Chestnut St, Philadelphia, PA 19107, USA.
Abstract
BACKGROUND: Patellofemoral arthroplasty (PFA) can yield successful results in appropriately selected patients. The varus-valgus position or coronal alignment of the trochlear implant is determined by how its transitional edges articulate with the condylar cartilage. Whilst variation in condylar anatomy will not influence the axis of the lower limb in PFA, it can impact on the Q-angle of the PF joint. The aim of this study was to analyze how the coronal alignment can be influenced by the choice of anatomical landmarks. MATERIALS AND METHODS: Retrospective analysis of 57 PFAs with measurements of alignment from full leg radiographs. RESULTS: Coronal alignment following anterior condylar anatomy leads to a mean (SD) proximal valgus alignment of 100° (9°). Aligning the component with Whiteside's line gives a better alignment with less variance 89° (3°). DISCUSSION: A trochlear component with a higher Q-angle compensates for patellar maltracking if the condylar anatomy would tend to put the implant in a more proximal varus or neutral position. If the trochlear component is proximally aligned in valgus this may have the opposite effect. Aligning the trochlear component with the AP-axis in the coronal plane avoids maltracking and optimally utilizes the design features of the implant. LEVEL OF EVIDENCE: Level III.
BACKGROUND:Patellofemoral arthroplasty (PFA) can yield successful results in appropriately selected patients. The varus-valgus position or coronal alignment of the trochlear implant is determined by how its transitional edges articulate with the condylar cartilage. Whilst variation in condylar anatomy will not influence the axis of the lower limb in PFA, it can impact on the Q-angle of the PF joint. The aim of this study was to analyze how the coronal alignment can be influenced by the choice of anatomical landmarks. MATERIALS AND METHODS: Retrospective analysis of 57 PFAs with measurements of alignment from full leg radiographs. RESULTS: Coronal alignment following anterior condylar anatomy leads to a mean (SD) proximal valgus alignment of 100° (9°). Aligning the component with Whiteside's line gives a better alignment with less variance 89° (3°). DISCUSSION: A trochlear component with a higher Q-angle compensates for patellar maltracking if the condylar anatomy would tend to put the implant in a more proximal varus or neutral position. If the trochlear component is proximally aligned in valgus this may have the opposite effect. Aligning the trochlear component with the AP-axis in the coronal plane avoids maltracking and optimally utilizes the design features of the implant. LEVEL OF EVIDENCE: Level III.
Authors: Mo Saffarini; Jacobus H Müller; Giuseppe La Barbera; Gerjon Hannink; Kyung Jin Cho; Cécile Toanen; David Dejour Journal: Knee Surg Sports Traumatol Arthrosc Date: 2017-03-07 Impact factor: 4.342
Authors: Andreas B Imhoff; Eva Bartsch; Christoph Becher; Peter Behrens; Gerrit Bode; Matthias Cotic; Theresa Diermeier; Holger Falk; Matthias J Feucht; Ulrich Haupt; Stefan Hinterwimmer; Johannes Holz; René Hutter; René Kaiser; Tobias Knoblauch; Wolfgang Nebelung; Philipp Niemeyer; Turlough O'Donnel; Geert Pagenstert; Thilo Patzer; Tim Rose; Marco C Rupp; Thomas Tischer; Arne J Venjakob; Stephan Vogt; Jonas Pogorzelski Journal: Knee Surg Sports Traumatol Arthrosc Date: 2021-04-02 Impact factor: 4.342