title: Reliability of lower-limb alignment measurements in patients with multiple epiphyseal dysplasia.
abstract: BACKGROUND
  Although radiographic measurements are used in multiple epiphyseal dysplasia (MED) during correction of lower-limb alignment, the reliabilities of the measurements are unclear.
  
  
  OBJECTIVE
  We determined interobserver and intraobserver reliabilities of the measurement methods used in evaluation of lower-limb alignment in MED.
  
  
  METHODS
  After consensus building, we included 10 radiographic measurement methods widely used to evaluate lower-limb alignment: mechanical tibiofemoral angle, anatomic tibiofemoral angle, mechanical axis deviation, joint line convergence angle, mechanical lateral distal femoral angle, anatomic lateral distal femoral angle, mechanical medial proximal tibial angle, anatomic medial proximal tibial angle, epimetaphyseal angle, and tibial metadiaphyseal angle. A study group consisting of 30 patients with MED was compared with a control group consisting of 30 sex- and age-matched patients with genu varum and genu valgum. Mean age in both groups was 11 years (study group: SD, 2 years; range, 6-16 years; control group: SD, 2 years; range, 6-15 years). Interobserver and intraobserver reliabilities of all radiographic measurement methods were obtained and expressed by intraclass correlation coefficients (ICCs).
  
  
  RESULTS
  Mechanical tibiofemoral angle, anatomic tibiofemoral angle, and mechanical axis deviation were associated with high interobserver reliability (ICCs, 0.987, 0.985 and 0.982, respectively). Epimetaphyseal angle had the lowest reliability (ICC, 0.280). Intraobserver reliability exhibited similar trends, with mechanical axis deviation and mechanical tibiofemoral angle having the highest ICCs and epimetaphyseal angle the lowest.
  
  
  CONCLUSIONS
  Mechanical tibiofemoral angle, anatomic tibiofemoral angle, and mechanical axis deviation are reasonably reliable measures of alignment in MED. The lateral distal femoral angle and medial proximal tibial angle (mechanical and anatomic) can be used as complementary measurement methods.
  
  
  METHODS
  Level II, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, 300 Gumi-Dong, Bundang-Gu, Sungnam, Kyungki 463-707, Korea.
authors.forename: Bekhzad
authors.initials: B
authors.lastname: Akhmedov
authors.forename: Ki Hyuk
authors.initials: KH
authors.lastname: Sung
authors.forename: Chin Youb
authors.initials: CY
authors.lastname: Chung
authors.forename: Kyoung Min
authors.initials: KM
authors.lastname: Lee
authors.forename: Moon Seok
authors.initials: MS
authors.lastname: Park
mesh_terms: D000293:Adolescent; D001696:Biomechanical Phenomena; D002648:Child; D005260:Female; D005269:Femur / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000503:physiopathology; D056304:Genu Valgum / Q000000981:diagnostic imaging / Q000503:physiopathology; D056305:Genu Varum / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D015588:Observer Variation; D010009:Osteochondrodysplasias / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011859:Radiography; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013977:Tibia / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000503:physiopathology