J Korean Orthop Assoc.  2001 Jun;36(3):259-264.

An analysis of adolescent idiopathic scoliosis according to Coonrad classification

  • 1Department of Orthopaedic Surgery, College of Medicine, Pusan National University, Pusan, Korea.


To establish the interobserver and intraobserver reliability of the Coonrad classification for an idiopathic coronal curve pattern.
Radiographs of 257 idiopathic scoliosis patients that had a rib humping of more than 1 cm and a Cobb angle of more than 10 were reviewed. The interobserver and intraobserver reliability was assessed by a comparison of the classification of the curves between four observers.
In the Coonrad classification, a 1A type-curve occurred in 37 cases, the 1B type-curve occurred in 27 cases, the 2A type-curve occurred in 70 cases, a 2B type-curve occurred in 22 cases, a 3 type-curve occurred in 44 cases, a 4 type-curve occurred in 6 cases, a 5 type-curve occurred in 15 cases, a 6 type-curve occurred in 22 cases, a 7 type-curve occurred in 13 cases and a 8 type curve occurre in 1 case. The interobserver reliability for the Coonrad classification was 0.60 and the intraobserver reliability was 0.71.
The Coonrad classification proved to be relatively reliable, but revealed some confusion, particularly between type 2A and type 3. Also, there seemed to be no advantage in using this method of determining the treatment modality compared with the conventional scoliosis classification system.


Idiopathic scoliosis; Coonrad classification; Interobserver reliability; intraobserver reliability
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