Validation of a technique to assess radial torsion in the presence of procurvatum and valgus deformity using computed tomography: a cadaveric study.
OBJECTIVE
To validate a technique to assess radial torsion with and without procurvatum and valgus deformity using computed tomography (CT).


METHODS
Anatomic study.


METHODS
Radii (n=3) from normal dogs.


METHODS
Three cadaveric radii were scanned using CT (3 mm slices). Transverse image sections were assessed at the distal and proximal physeal scar parallel to the joint surface in both sagittal and dorsal planes. Anatomic landmarks of the radius were identified and torsion was measured. A hinged Ilizarov circular external skeletal fixator was constructed to create known procurvatum, valgus, and torsional deformities.


RESULTS
Between observers results were highly correlated for calculation of torsion (r=0.972, r(2)=0.9448, P<.00001). Mean baseline torsion of the radius in the construct was 4.88 degrees . At 20 degrees procurvatum and valgus, mean calculated torsion was 5.07 degrees (confidence interval [CI]=4.6-5.6 degrees ). At 20 degrees procurvatum and valgus with 22.5 degrees -induced torsion, mean measured torsion was 25.4 degrees (expected=27.38 degrees ; CI=22.7-28.1 degrees ). At 40 degrees procurvatum and valgus and 45 degrees -induced torsion, mean measured torsion was 51.1 degrees (expected=49.88 degrees ; CI=-49.2 to 53.0 degrees ).


CONCLUSIONS
Assessment of radial torsion by CT is reproducible and accurate in the presence of procurvatum and valgus antebrachial angular limb deformities in the dog.


CONCLUSIONS
Despite complex presurgical planning, current measurements only allow for measurement of valgus and procurvatum deformities in the sagittal and dorsal planes, this method allows for more precise measurements of radial torsion in the transverse plane.
Meola
Stacy D
SD
Wheat Ridge Veterinary Specialists, Wheat Ridge, CO, USA. smeola@wrah.com
Wheeler
Jason L
JL
Rist
Cassidy L
CL
D000818:Animals; D002102:Cadaver; D004285:Dogs; D011859:Radiography; D011884:Radius / Q000002:abnormalities / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D015898:Tomography Scanners, X-Ray Computed / Q000592:standards / Q000662:veterinary*; D014102:Torsion Abnormality / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000662:veterinary*