Radial head dislocation and subluxation in osteogenesis imperfecta.
BACKGROUND
Upper limb deformity in children with osteogenesis imperfecta may substantially impair function. The aims of this retrospective work were to study the prevalence of radial head malalignment (dislocation or subluxation) in different types of osteogenesis imperfecta and to identify factors linked to it.


METHODS
We assessed 489 upper limbs from 254 patients (with a mean age of 9.6 years and including 130 female patients) who had various types of osteogenesis imperfecta. Radiographs representing a single time-point for each patient were assessed for the presence and direction of radial head malalignment and associated abnormalities (dysplasia of the capitellum or of the radial head or neck, calcification of the interosseous membrane, or radioulnar synostosis). Deformations of the humerus, radius, and ulna were assessed with regard to location, direction, and magnitude. The forearm range of motion in pronation and supination and the hand grip force were measured in a subset of patients.


RESULTS
We observed radial head dislocation or subluxation in forty-four and thirty-nine upper extremities, respectively. The frequency of radial head malalignment was significantly higher in type-V osteogenesis imperfecta (86%) than in the other types (0% to 29%) (p < 0.001). Dysplasia of the humeral capitellum, radial head, or radial neck was associated with malalignment in all types of osteogenesis imperfecta, with the exception of capitellum dysplasia in type V. Malalignment in type V was associated with calcification of the interosseous membrane, an abnormality that was specific for type V. In the other osteogenesis imperfecta types, malalignment was commonly linked with radial and ulnar deformation and was associated with decreased forearm range of motion in supination and pronation and a lower grip force.


CONCLUSIONS
Radial head malalignment is common in osteogenesis imperfecta, especially in type V. Malalignment is associated with bowing characteristics and impaired function of the upper limb. These findings may provide support for surgical correction of radial and ulnar bowing in selected patients with osteogenesis imperfecta.
Pediatric Orthopaedics Clinical Fell, McGill University, 1529 Cedar Avenue, Montreal, QC H3G 1AG, Canada. amarcdargent@shriners.mcgill.ca
Alice Marcdargent
AM
Fassier
Frank
F
Rauch
Mehdi
M
Aarabi
Chantal
C
Janelle
François
F
Fassier
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D004204:Joint Dislocations / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology; D008297:Male; D010013:Osteogenesis Imperfecta / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D015995:Prevalence; D011859:Radiography; D011884:Radius / Q000000981:diagnostic imaging / Q000473:pathology*; D012189:Retrospective Studies