Evaluation of intra- and interobserver variability and repeatability of tibial plateau angle measurements with digital radiography using a novel digital radiographic program.
OBJECTIVE
To compare the intra- and interobserver variability occurring when observers with differing experience levels measure tibial plateau angles (TPAs) with a novel digital radiographic projection program (tibial plateau leveling osteotomy [TPLO] planning program), the Kodak Picture Archiving and Communications System (PACS), and standard sized printed films (SF).


METHODS
Cross-sectional study.


METHODS
Dogs (n=36) with cranial cruciate ligament (CCL) rupture that had a TPLO.


METHODS
Six observers, divided into 3 equal groups based on experience level, measured TPA on 36 digitally captured radiographic images of tibiae of dogs clinically affected with CCL rupture. Each observer used 3 methods of measuring TPA and repeated the measurements 3 times with each method. The intra- and interobserver variability was compared using the coefficient of variation.


RESULTS
Averaged over all replications and images, there was no significant difference (P>.05) in the average variability occurring with each method for all but 1 observer. There was no effect of experience level on measurement variability; however, interobserver variability was significantly less with measurements made with the PACS and TPLO planning program compared with measurements made from SF (P<.05).


CONCLUSIONS
Repeated measurements of TPA made using digital images and computer-based measurement programs were significantly less variable between observers than those made from images printed on standard radiographic films.


CONCLUSIONS
Digital radiography and computer-based measurement programs are effective for determining the TPA, allowing less variability in measurements compared with SF. The ability to manipulate the image may allow better identification of anatomic landmarks.
Unis
Marcos D
MD
Small Animal Surgery Department, University of Illinois College of Veterinary Medicine, Urbana, IL, USA. munis@vet.k-state.edu
Johnson
Ann L
AL
Griffon
Dominique J
DJ
Schaeffer
David J
DJ
Ragetly
Guillaume R
GR
Hoffer
Melissa J
MJ
Ragetly
Chantal A
CA
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging; D000070598:Anterior Cruciate Ligament Injuries; D004283:Dog Diseases / Q000000981:diagnostic imaging; D004285:Dogs; D005260:Female; D008297:Male; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000592:standards; D012421:Rupture / Q000000981:diagnostic imaging / Q000662:veterinary; D013264:Stifle / Q000000981:diagnostic imaging; D013977:Tibia / Q000000981:diagnostic imaging*