We assessed the Japanese specific bone age standard with Tanner-Whitehouse 2 (TW2) method for the evaluation of skeletal maturity in adolescent scoliosis.

TW2 bone age was investigated by the left hand-wrist X-rays of 120 girls with adolescent scoliosis. Their chronological age ranged from 10.2 to 19.0 years. Because Risser’s sign is uncertain between Risser IV and V, for comparison of TW2 bone age with Risser’s sign, we classified apophyses that with an apparent narrowing of cartilage and that with a partial fusion as the later of Risser IV. In addition, clinical courses of the skeletal matured cases (adult bones) in 6 months before investigation were reviewed retrospectively. Even or less than 5 degrees change of Cobb’s angle was evaluated as unchanged. Furthermore, bone age distribution of immature cases was also reviewed for comparision of the unchanged group with the progressive group.

None was evaluated as adult bone in the stage from Risser 0 to III. The rate of adult bone which was shown in Risser IV was 43.5%, but 88.9% was in the later of IV. 95.8% of Risser V was already adult bone. Moreover, 93.1% of adult bone was unchanged in their clinical courses. Remaining 4 cases (6.9%) was progressive, but had not progressed in the following 6 months. Bone ages of the progressive immature group distributed in the range from 11.7 to 13.9 years. Those of the unchanged immature group distributed mainly over 13.1 years.

Although it is necessary to follow the immature longitudinally, adult bone appeared almost in the later of Risser IV, and appeared earlier than Risser V. And Cobb’s angle may become unchanged before adult bone. At least adult bone would be an indicator between Risser IV and V.