Conclusions. In patients with adolescent idiopathic scbliosis who undergo surgery with Harrington instrumentation, the overall long-term clinical outcome does not correlate with the radiologic outcome. However, a significant inverse correlation was found between the magnitude of the primary thoracic curve at follow-up assessment and the scores for questions on cosmetic matters in the Scoliosis Research Society questionnaire. Spine mobility is diminished as a result of spondylodesis, but the patients perform, on the average, as well as the normal population in nondynamometric trunk strength measurements.