title: Early patellofemoral osteoarthritis caused by an osteochondral defect after retrograde solid nailing of the femur in sheep.
abstract: BACKGROUND
  Retrograde femoral nailing (RFN) is an increasingly used technique for internal fixation of femoral fractures. Geometrically and empirically, the nail entry zone is close to the center of the femoral groove, causing concern about the development of patellofemoral osteoarthritis.
  
  
  METHODS
  We studied the effect of opening the distal femur through the femoral groove on the development of osteoarthritis in sheep after retrograde reamed insertion of a solid titanium nail into the femoral canal. Knees were radiographically and macroscopically studied for the presence of osteophytes and signs of cartilage degeneration. Controls underwent the same procedure without opening the femoral groove.
  
  
  RESULTS
  The study group showed time-dependent macroscopic and radiographic signs of osteoarthritis with predominant involvement of the patellofemoral joint.
  
  
  CONCLUSIONS
  RFN can cause patellofemoral osteoarthritis. Care should be exercised to use RFN in isolated supracondylar or shaft fractures of the femur in healthy young adults.
authors.affiliation: Department of Orthopedics, Essen University Medical School, Essen, Germany. a.pingsmann@biberburg.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Pingsmann
authors.forename: Maximilian
authors.initials: M
authors.lastname: Lederer
authors.forename: Claudia
authors.initials: C
authors.lastname: Wüllenweber
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Lichtinger
mesh_terms: D000818:Animals; D001858:Bone Nails / Q000009:adverse effects*; D004195:Disease Models, Animal; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D010007:Osteochondritis / Q000150:complications*; D010329:Patella / Q000000981:diagnostic imaging / Q000503:physiopathology; D011859:Radiography; D012016:Reference Values; D012756:Sheep