title: Contact pressure at osteochondral donor sites in the patellofemoral joint.
abstract: BACKGROUND
  The lowest contact pressure point is presumed to be the best site to harvest an osteochondral plug and minimize morbidity.
  
  
  OBJECTIVE
  Patellofemoral contact pressures are not uniform and are lowest along the medial patellofemoral articulation.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Seven cadaveric knees were tested with an electroresistive, dynamic pressure sensor placed onto the femoral side of the patellofemoral joint. The extensor mechanism was loaded with 89.1 N and 178.2 N, and the knee was manually cycled 3 times (0 degrees -105 degrees ) per load. Mean trochlear pressures were calculated.
  
  
  RESULTS
  Mean contact pressures were greatest in the central trochlea (5.80 kgf/cm(2)), followed by the lateral (2.56 kgf/cm(2)) and medial trochlea (1.60 kgf/cm(2)) at 89.1 N (P <.05). At 178.2 N, pressures increased to 9.47, 5.81, and 2.75 kgf/cm(2), respectively (P <.05). Lateral trochlear pressures decreased moving distally from 1.25 to 0.50 kgf/cm(2) at 89.1 N and 4.57 to 1.29 kgf/cm(2) at 178.2 N.
  
  
  CONCLUSIONS
  Contact pressures are lowest along the medial trochlea and decrease distally along the lateral trochlea.
  
  
  CONCLUSIONS
  Osteochondral plugs from the medial femoral trochlea may be desirable if trochlear size permits. If harvesting from the lateral femoral trochlea, consider harvesting distally near the sulcus terminalis.
authors.affiliation: Department of Orthopedic Surgery, University of Pennsylvania Hospitals, Philadelphia, PA, USA.
authors.forename: Ralph B
authors.initials: RB
authors.lastname: Garretson
authors.forename: Leonid I
authors.initials: LI
authors.lastname: Katolik
authors.forename: Nikhil
authors.initials: N
authors.lastname: Verma
authors.forename: Paul R
authors.initials: PR
authors.lastname: Beck
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bach
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cole
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D016025:Bone Transplantation / Q000379:methods; D002356:Cartilage / Q000637:transplantation*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008875:Middle Aged; D011312:Pressure; D020858:Tissue and Organ Harvesting; D014182:Transplantation, Autologous