MRI differentiates femoral condylar ossification evolution from osteochondritis dissecans. A new sign.
OBJECTIVE
To determine if MRI (magnetic resonance imaging) of the femoral condyles in children can differentiate variations in ossification from osteochondritis dissecans (OCD).


METHODS
MRI studies of the knee of 315 patients demonstrated ossification defects of the femoral condyles involving the subchondral bone plate. MRI features categorized the defects as ossification variability (N = 150) or OCD (N = 165). Both groups were compared for age, residual physeal cartilage, site, configuration, 'lesion angle' and associated findings.


RESULTS
(a) Ossification variability did not occur in girls >10 year. and boys >13 year., OCD did not occur in children younger than 8 year. (b) Ossification variability was not seen in patients with 10% or less residual physeal cartilage, OCD was rare in patients with 30% or greater residual physeal cartilage. (c) Ossification variability was located in the posterior third of the femoral condyle, OCD occurred most commonly in the middle third. (d) Intracondylar extension was seen in OCD and not in ossification variability. (e) Perilesional oedema was very common with OCD and absent with ossification variability. (f) Lesion angle <105° was a feature of ossification variability.


CONCLUSIONS
MRI may help differentiate variations in ossification of the femoral condyles from OCD.
Department of Radiology and Medical Imaging, Ghent University Hospital, De Pintelaan 185, 9000, Ghent, Belgium. lennartjans@hotmail.com
Lennart B O
LB
Jans
Jacob L
JL
Jaremko
Michael
M
Ditchfield
Wouter C
WC
Huysse
Koenraad L
KL
Verstraete
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009999:Ossification, Heterotopic / Q000473:pathology*; D010008:Osteochondritis Dissecans / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
Radiology. 2008 Aug;248(2):571-8
18552309
Radiology. 2000 Mar;214(3):705-9
10715034
Am J Sports Med. 1989 Sep-Oct;17(5):601-5; discussion 605-6
2610273
J Bone Joint Surg Am. 2008 Dec;90(12):2655-64
19047711
Pediatr Radiol. 2005 Sep;35(9):880-6
15940391
Clin Sports Med. 2001 Apr;20(2):321-42
11398361
Acta Orthop Scand. 1976 Dec;47(6):664-7
1015263
Curr Opin Pediatr. 2003 Feb;15(1):38-44
12544270
Radiology. 2009 Jan;250(1):28-38
19092089
Eur Radiol. 1998;8(1):103-12
9442140
Am J Knee Surg. 1998 Fall;11(4):221-32
9854000
J Bone Joint Surg Am. 1984 Dec;66(9):1340-8
6501330
Pediatr Radiol. 1999 Oct;29(10):781-4
10525788
Clin Orthop Relat Res. 1977 Mar-Apr;(123):25-6
852179
Biometrics. 1977 Mar;33(1):159-74
843571