Radiographic assessment of bone formation in tibia during distraction osteogenesis

The radiologic appearance of bone formation during limb lengthening is used to judge the competence of the underlying biologic process and predict the likely time to healing. Interpretation is, however, based upon subjective parameters that have never been clearly defined. Thirty anteroposterior radiographs from pediatric tibial lengthenings were classified by four pairs of surgeons using a three-part system. Across the group, interobserver consistency showed considerable variation for all parameters tested. Pairwise analysis indicated that the surgeons directly involved in limb lengthening procedures agreed better than those whose practice was of a different nature. A second series of radiographs contained 12 radiographs with a satisfactory and 12 with a poor bone healing index (BHI). These radiographs were digitized, and an interobserver study showed significantly improved observer concordance if the images were enhanced. No feature was associated with a 100% chance of a satisfactory outcome, but certain appearances in the regenerate were associated with a better BHI than others.