Alignment and articular orientation of lower limbs: manual vs computer-aided measurements on digital radiograms.
OBJECTIVE
To compare the manual measurements of lower limbs on digital images with those obtained with dedicated software.


METHODS
Forty patients with a clinical suspicion of lower limb deformity were enrolled. Eighty digital radiographs were produced with a remote-controlled radiography system (Philips Omnidiagnost). The measurements were taken separately by an Orthopaedic Surgeon and by a Radiologist, by hand and with the aid of software, respectively. Five parameters were assessed: femoral length, tibial length, distal-medial femoral angle, proximal-medial tibial angle and tibial-femoral angle. The statistical analysis of the comparison was based on Student's t-test. The inter-observer variability of the methods, manual and computer-aided, was evaluated with Fisher's F-test on a sample of measurements (20 lower limbs), taken by 5 different Orthopaedic Surgeons and Radiologists, respectively.


RESULTS
There were no statistically significant differences between the measurements taken with the manual and computer-aided methods (p<0.05). The overall reproducibility of both methods was similar; conversely, the separate evaluation of angles and lengths showed that the computer-aided method was less variable in the measurement of angles and a little more variable in the measurement of lengths than the manual method.


CONCLUSIONS
The computer-aided evaluation of the alignment and articular orientation parameters of lower limbs is as accurate and reliable as the traditional manual method, but is faster and allows better-quality images.
Rozzanigo
Umberto
U
Dipartimento di Diagnostica per Immagini, Azienda Ospedaliera Carlo Poma, Mantova.
Pizzoli
Andrea
A
Minari
Chiara
C
Caudana
Roberto
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001837:Body Weights and Measures; D002648:Child; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D035002:Lower Extremity / Q000000981:diagnostic imaging*; D038061:Lower Extremity Deformities, Congenital / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012984:Software; D013977:Tibia / Q000000981:diagnostic imaging