title: MR imaging of the hip and knee before and after marathon running.
abstract: BACKGROUND
  Despite its obvious benefits regarding aerobic fitness, the possible deleterious effects of long-distance running remain controversial. The repetitive loading associated with this activity could potentially predispose to the subsequent development of osteoarthritis. Lower extremity malalignment can also result in abnormal joint loading and is another possible contributing factor for premature articular cartilage degeneration. The purpose of this study is to investigate whether external impact loading in marathon runners creates internal stresses on bone and cartilage that are demonstrable on MR images. Participants were separately assessed for static lower extremity alignment, using standard radiographs.
  
  
  METHODS
  Six recreational and two semi-professional runners underwent magnetic resonance (MR) imaging of the hip and knee before and after a marathon run using coronal T1-weighted and coronal STIR sequences.
  
  
  RESULTS
  The pre-run and post-run scans failed to demonstrate marrow oedema, periosteal stress reactions, or joint effusions in seven runners. One patient who underwent a reconstruction of his anterior cruciate ligament 18 months ago demonstrated a small effusion in the reconstructed knee before and after the race.
  
  
  CONCLUSIONS
  Our results suggest that the high impact forces in long-distance running are well tolerated and subsequently do not demonstrate changes on MR images.
authors.affiliation: Department of Orthopaedic Sports Medicine, University of Munich, Germany, and the Department of Radiology, Klinikum re. der Isar, University of Munich, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: Hohmann
authors.forename: Klaus
authors.initials: K
authors.lastname: Wörtler
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Imhoff
mesh_terms: D001696:Biomechanical Phenomena; D025981:Hip Injuries / Q000175:diagnosis* / Q000473:pathology; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000473:pathology; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D012420:Running; D012775:Shoes