title: Dynamic lower extremity alignment in children with achondroplasia.
abstract: The purpose of this study is to analyze lower extremity dynamic malalignment during gait using a 3-dimensional kinematics and kinetics in 13 children (3-17 years old) with achondroplasia and to compare measurements of alignment and malrotation between gait, radiographic, and clinical measures. Gait analysis in the coronal plane showed a varus malalignment of the knee (19 +/- 13 degrees) and variable tibial torsion abnormalities (13 [internal] +/- 15.7 degrees). Radiographs also showed knee varus malalignment (16 +/- 9 degrees); however, there was poor correlation with gait analysis measures (P > 0.05). In the sagittal plane, radiographs showed genu recurvatum deformity (23.5 +/- 13.2 degrees), although the sagittal plane knee kinematics were normal. Kinetic analyses of the knee showed high internal knee valgus moments (external varus moments, 0.48 +/- 0.25 N m/kg), which were significantly different from the normal population (P < 0.05). In conclusion, there is a 3-dimensional, complex, dynamic deformity of the lower extremity present in children with achondroplasia. We recommend a very careful assessment of the limb focusing on both the static and dynamic varus deformity and tibial torsion using a combination of radiographic, clinical, and gait analysis.
authors.affiliation: Orthopeadic Department, Inonu University Medical Faculty, Malatya, Turkey.
authors.forename: Muharrem
authors.initials: M
authors.lastname: Inan
authors.forename: Mihir
authors.initials: M
authors.lastname: Thacker
authors.forename: Chris
authors.initials: C
authors.lastname: Church
authors.forename: Freeman
authors.initials: F
authors.lastname: Miller
authors.forename: William G
authors.initials: WG
authors.lastname: Mackenzie
authors.forename: Dolores
authors.initials: D
authors.lastname: Conklin
mesh_terms: D000130:Achondroplasia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D011379:Prognosis; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013977:Tibia / Q000000981:diagnostic imaging