C. Stanciu et al., THE VALUE OF COMPUTED-TOMOGRAPHY FOR THE DIAGNOSIS OF RECURRENT PATELLAR SUBLUXATION IN ADOLESCENTS, CAN J SURG, 37(4), 1994, pp. 319-323
Objective: To determine if computed tomography of the patellofemoral j
oint has any advantage over standard radiologic techniques in the eval
uation of recurrent patellar subluxation. Design: A case series. Setti
ng: A tertiary children's hospital out-patient clinic. Participants: F
orty consecutive adolescents with a clinical diagnosis of recurrent pa
tellar subluxation (study group) and 14 volunteers with normal knees (
control group). Interventions: A standardized radiologic protocol, inc
luding axial views of the patella at 30-degrees of knee flexion, with
and without external torsion of the tibia, and computed tomography (CT
) of the patella at 15-degrees of knee flexion. Main Outcome Measures:
The lateral patellofemoral angle on the axial views and on the CT sca
n and patellar centralization on the CT scan. Results: In the control
group, no radiologic evidence of recurrent patellar subluxation was fo
und. In the study group, an abnormal lateral patellofemoral angle was
found in 25% of axial views; this rate increased to 42% with external
rotation and 86% on the CT scan. Patellar centralization was abnormal
in 79% of cases. Conclusions: CT of the patellofemoral joint is more s
ensitive than standard radiographs for the diagnosis of recurrent pate
llar subluxation. The use of CT is recommended when standard radiograp
hs appear normal.