title: Regional bone geometry of the tibia in triathletes and stress reactions--an observational study.
abstract: OBJECTIVE
  The association between tibial morphology and tibial stress fractures or tibial stress syndrome was examined in triathletes with an unusually high incidence of these injuries.
  
  
  METHODS
  A cross-sectional study design examined associations between tibial geometry from MRI images and training and injury data between male and female triathletes and between stress fracture (SF) and non-stress fracture (NSF) groups.
  
  
  METHODS
  Fifteen athletes (7 females, 8 males) aged 17-23 years who were currently able to train and race were recruited from the New Zealand Triathlete Elite Development Squad. Geometric measurements were taken at 5 zones along the tibia using MRI and compared between symptomatic and asymptomatic tibiae subjects.
  
  
  RESULTS
  SF tibiae displayed either oedema within the cancellous bone and/or stress fracture on MRI. When collapsed across levels, symptomatic tibiae had thicker medial cortices (F1,140=9.285, p=0.003), thicker lateral cortices (F1,140=10.129, p=0.002) and thinner anterior cortices (F1,140=14.517, p=0.000) than NSF tibiae. Only medial cortex thickness in SF tibia was significantly different (F4,140=3.358, p=0.012) at different levels. Follow-up analysis showed that athletes showing oedema within the cancellous bone and/or stress fracture on MRI had, within 2 years of analysis, subsequently taken time off training and racing due a tibial stress fracture.
  
  
  CONCLUSIONS
  The thinner anterior cortex in SF tibiae is associated with a stress reaction in these triathletes.
authors.affiliation: Centre for Musculoskeletal Research, School of Physiotherapy and Exercise Science, Griffith Health Institute, Griffith University, Australia. Electronic address: r.newsham-west@griffith.edu.au.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Newsham-West
authors.affiliation: Horizon Radiology, New Zealand.
authors.forename: Brett
authors.initials: B
authors.lastname: Lyons
authors.affiliation: Centre for Musculoskeletal Research, School of Physiotherapy and Exercise Science, Griffith Health Institute, Griffith University, Australia.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Milburn
mesh_terms: D000293:Adolescent; D001642:Bicycling / Q000502:physiology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D012090:Cumulative Trauma Disorders / Q000209:etiology / Q000473:pathology; D004487:Edema / Q000175:diagnosis*; D005260:Female; D015775:Fractures, Stress / Q000209:etiology / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012420:Running / Q000502:physiology; D013550:Swimming / Q000502:physiology; D013977:Tibia / Q000033:anatomy & histology / Q000293:injuries* / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult
keywords: Athletic injury; Morphology; Overuse injury; Stress fracture; Tibia