[Diagnostic value of MR analysis of cartilaginous lesions compared with intraoperative arthroscopy in calcaneal fractures].
OBJECTIVE
To determine the diagnostic value of MRI in preoperative analysis and classification of cartilaginous lesions - especially of the posterior facet - in traumatic calcaneal fractures compared with intraoperative arthroscopy.


METHODS
Twenty-four consecutive patients with traumatic calcaneal fractures underwent prospective MRI of the subtalar joint surface using T1- and T2-weighted spin echo sequences and fat suppressed 3D gradient echo sequences in semicoronal slice orientation (1.5 T MRI). After randomization, the images were analyzed by two blinded and independent readers experienced in MRI. The results were compared with the intraoperative arthroscopic findings as to location and depth of the defects using the Outerbridge classification.


RESULTS
We examined 12 calcaneal fractures of type 2, 8 of type 3 and 4 of type 4 according to the Sanders classification. With respect to principal detection and exact classification, 67 of 96 (69.8 %) of all arthroscopic verified cartilaginous defects were diagnosed correctly by MRI. Disregarding the degree of the defects, 38 of 44 (86.4 %) chondral lesions were detected (sensitivity: 86.4 %, specificity: 86.5 %, diagnostic accuracy: 86.5 %). Considering the chondral lesions of degrees 3 and 4 together, the sensitivity was 86.0 %, the specificity 86.8 %, and the diagnostic accuracy 86.5 % . Assessing these degrees separately, the sensitivity was only 33.3 % for degree 3 and 58.1 % for degree 4, whereas the specificity was definitely higher with 82.1 % for degree 3 and 89.2 % for degree 4.


CONCLUSIONS
The MR detection of cartilaginous defects in calcaneal fractures has a sufficient diagnostic accuracy for planning the surgical intervention and assessing the long-term postsurgical prognosis.
Schröder
R J
RJ
Klinik für Strahlenheilkunde, Campus Virchow-Klinikum, Charité, Universitätsmedizin Berlin. ralf.schroeder@charite.de
Boack
D H
DH
Nekwasil
S J
SJ
Martus
P
P
Haas
N P
NP
Felix
R
R
Hidajat
N
N
D000328:Adult; D001182:Arthroscopy; D002111:Calcaneus / Q000293:injuries*; D002356:Cartilage / Q000473:pathology*; D003627:Data Interpretation, Statistical; D005260:Female; D050723:Fractures, Bone / Q000145:classification / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity