title: Evaluation of the isometry of different points of the patella and femur for medial patellofemoral ligament reconstruction.
abstract: The location of patellar and femoral fixation of the graft in medial patellofemoral ligament reconstructions has been widely discussed. This study aimed to assess the distances between different patellar and femoral fixation points to identify the least anisometric pairs of points.
  
  
  
  Ten cadaver knees were attached to an apparatus that simulated an active range of motion of 120°, with three metallic markers fixed onto the medial side of the patella, and seven markings onto the medial epicondyle. The examined points included the proximal patella pole (1), the patellar center (3), the midpoint between points 1 and 3 (2), a point directly on the epicondyle (6), points 5mm anterior (5) and posterior (7) to the epicondyle, points 5mm anterior to point 5 (4) and 5mm posterior to point 7 (8), and points 5mm proximal (9) and distal (10) to the epicondyle. The distances between patella and femur points were measured by a photogrammetry system at 15° intervals.
  
  
  
  The pair of points that exhibited the lowest average variability in distance, and hence was the most isometric, was the patella center combined with the anterior to the medial femoral epicondyle. The pairs of points that exhibited the highest average variability in distance, and hence were the least isometric, were the ones located distal or posterior to the medial femoral epicondyle, with less influence by the patellar location.
  
  
  
  Surgeons should avoid positioning the graft distally or posterior to the epicondyle due to the increase in anisometry.
authors: Hospital das Clínicas da Universidade de São Paulo, SP, Brazil. Electronic address: gobbiortopedia@gmail.com.
authors: Riccardo Gomes
authors: RG
authors: Gobbi
authors: Hospital das Clínicas da Universidade de São Paulo, SP, Brazil.
authors: César Augusto Martins
authors: CA
authors: Pereira
authors: Clínica ortopédica e Traumatológica, COT-Martagão, BA, Brazil.
authors: David
authors: D
authors: Sadigursky
authors: Hospital das Clínicas da Universidade de São Paulo, SP, Brazil.
authors: Marco Kawamura
authors: MK
authors: Demange
authors: Hospital das Clínicas da Universidade de São Paulo, SP, Brazil.
authors: Luis Eduardo Passarelli
authors: LE
authors: Tírico
authors: Hospital das Clínicas da Universidade de São Paulo, SP, Brazil.
authors: José Ricardo
authors: JR
authors: Pécora
authors: Hospital das Clínicas da Universidade de São Paulo, SP, Brazil.
authors: Gilberto Luis
authors: GL
authors: Camanho
mesh_terms: D002102:Cadaver; D005269:Femur / Q000601:surgery*; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D009983:Orthopedic Equipment; D010329:Patella / Q000601:surgery*; D017847:Patellar Ligament / Q000601:surgery*; D056888:Patient Positioning; D010780:Photogrammetry; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures
keywords: Articular; Biomechanical phenomena; Knee; Patellar dislocation; Patellofemoral joint; Range of motion