Cobb angle measurement of scoliosis using computer measurement of digitally acquired radiographs-intraobserver and interobserver variability.
METHODS
We evaluated computer assisted digital measurement of radiographic parameters in patients with idiopathic scoliosis.


OBJECTIVE
To assess the reliability of digital measurements.


BACKGROUND
Various authors analyzed scoliotic deformities by conventional radiographs, but very few studies have addressed the reliability of digital radiographic measurement using computer software.


METHODS
Three independent, blinded observers measured 318 whole spine pre-operative antero-posterior radiograms of children with varying degrees of idiopathic scoliosis. Only one curve per radiograph was measured. Each observer measured the Cobb angle three times with a 1-week gap between each measurement. The computer system, picture archiving and communication system (PACS, PiViewSTAR version 5) was used in all cases. The end vertebrae were pre-selected to avoid this as a potential source of error. The results were statistically analyzed for intraobserver and interobserver reliability and variability.


RESULTS
The 95% confidence intervals for intraobserver and interobserver variability were +/-1.30 and +/-1.260, respectively. There was better reliability in larger curves.


CONCLUSIONS
Measurement using a digitized system may help to minimize measurement discrepancies by eliminating an intrinsic cause of error.
Srinivasalu
S
S
Department of Orthpedic Surgery, Scoliosis Research Institute, Korea University Guro Hospital, Seoul, Korea.
Modi
Hitesh N
HN
Smehta
Satyen
S
Suh
Seung-Woo
SW
Chen
Ting
T
Murun
Temuujin
T
J Spinal Disord. 1990 Dec;3(4):387-91
2134454
Spine (Phila Pa 1976). 2005 Feb 15;30(4):444-54
15706343
Spine (Phila Pa 1976). 2007 Jan 1;32(1):98-105
17202899
Spine (Phila Pa 1976). 2005 May 1;30(9):1064-9
15864160
Spine (Phila Pa 1976). 2006 May 15;31(11):1240-6
16688038
Eur Spine J. 2002 Dec;11(6):535-42
12522710
Spine (Phila Pa 1976). 1998 Mar 1;23(5):551-5
9530786
J Bone Joint Surg Am. 1990 Mar;72(3):320-7
2312527
J Spinal Disord Tech. 2005 Apr;18(2):152-9
15800433
Control Clin Trials. 1991 Aug;12(4 Suppl):142S-158S
1663851
Biometrics. 1977 Mar;33(1):159-74
843571
J Bone Joint Surg Am. 1990 Mar;72(3):328-33
2312528