title: The effect of anterior cruciate ligament injury on bone curvature: exploratory analysis in the KANON trial.
abstract: OBJECTIVE
  Investigate the 5-year longitudinal changes in bone curvature after acute anterior cruciate ligament (ACL) injury, and identify predictors of such changes.
  
  
  METHODS
  In the KANON-trial (ISRCTN 84752559), 111/121 young active adults with an acute ACL tear to a previously un-injured knee had serial 1.5 T MR images from baseline (within 5 weeks from injury) to 5 years after injury. Of these, 86 had ACL reconstruction (ACLR) performed early or delayed, 25 were treated with rehabilitation alone. Measures of articulating bone curvature were obtained from computer-assisted segmentation of MR images. Curvature (mm(-1)) was determined for femur, tibia, medial/lateral femur, trochlea, medial/lateral tibia. Age, sex, treatment, BMI, meniscal injury, osteochondral fracture on baseline MR images were tested for association.
  
  
  RESULTS
  Over 5 years, curvature decreased in each region (P < 0.001) suggesting flattening of convex shapes and increased concavity of concave shapes. A higher BMI was associated with flattening of the femur (P = 0.03), trochlea (P = 0.007) and increasing concavity of the lateral tibia (LT) (P = 0.011). ACLR, compared to rehabilitation alone, was associated with flatter curvature in the femur (P < 0.001), medial femoral condyle (P = 0.006) and trochlea (P = 0.003). Any meniscal injury at baseline was associated with a more flattened curvature in the femur (P = 0.038), trochlea (P = 0.039), lateral femoral condyle (P = 0.034) and increasing concavity of the LT (P = 0.048).
  
  
  CONCLUSIONS
  ACL injury is associated with significant changes in articulating bone curvature over a 5 year period. Higher BMI, baseline meniscal injury and undergoing ACL reconstruction (as distinct from undergoing rehabilitation alone) are all associated with flattening of the articulating bone.
authors.affiliation: Rheumatology Department, Royal North Shore Hospital and Kolling Institute, University of Sydney, Sydney, NSW, Australia. Electronic address: David.Hunter@sydney.edu.au.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hunter
authors.affiliation: Department of Orthopedics, Clinical Sciences Lund, Lund University, Lund, Sweden; Research Unit for Musculoskeletal Function and Physiotherapy and Department of Orthopaedics and Traumatology, University of Southern Denmark, Odense, Denmark.
authors.forename: L S
authors.initials: LS
authors.lastname: Lohmander
authors.affiliation: Rheumatology Department, Royal North Shore Hospital and Kolling Institute, University of Sydney, Sydney, NSW, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Makovey
authors.affiliation: Escuela de Medicina, Tecnológico de Monterrey, Monterrey, NL, México; Qmetrics Technologies, Rochester, NY, USA.
authors.forename: J
authors.initials: J
authors.lastname: Tamez-Peña
authors.affiliation: Qmetrics Technologies, Rochester, NY, USA.
authors.forename: S
authors.initials: S
authors.lastname: Totterman
authors.affiliation: Qmetrics Technologies, Rochester, NY, USA.
authors.forename: E
authors.initials: E
authors.lastname: Schreyer
authors.affiliation: Department of Orthopedics, Clinical Sciences Lund, Lund University, Lund, Sweden.
authors.forename: R B
authors.initials: RB
authors.lastname: Frobell
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000473:pathology; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D015992:Body Mass Index; D005260:Female; D005269:Femur / Q000473:pathology*; D006801:Humans; D007718:Knee Injuries / Q000150:complications* / Q000473:pathology / Q000628:therapy*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D026741:Physical Therapy Modalities; D013977:Tibia / Q000473:pathology*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: Anterior cruciate ligament tear; Bone curvature; MRI