Department of Orthopedics, Sundsvall Hospital, 85186 Sundsvall, Sweden.
Foot Ankle Int. 2011 Sep;32(9):861-6. doi: 10.3113/FAI.2011.0861.
The management of intra-articular calcaneal fractures is difficult. One aspect for successful management is the use of a reliable and reproducible fracture classification system (FCS). The purpose of this study was to evaluate the interobserver reliability and intraobserver reproducibility of Letournel, Sanders, and Zwipp classification systems on CT scan and the Bohler's angle measurement on plain X-ray. Furthermore, we studied if the addition of a CT scan to the plain X-ray influenced the evaluation of fracture extension to the calcaneocuboid joint.
The CT scan and plain X-ray images of 51 intra-articular calcaneal fractures were evaluated two times by three observers (two radiologists and one orthopedic surgeon) within a 5-month interval. The interobserver reliability was measured using the Fleiss kappa while the intraobserver reproducibility was measured using the Cohen's kappa.
The mean kappa values for the interobserver reliability and intraobserver reproducibility of the Sanders classification were 0.25 and 0.39, respectively, of Zwipp classification were 0.24 and 0.16, respectively, while those of the Letournel classification were 0.50 and 0.42, respectively. For the Böhler's angle, the mean kappa values for the interobserver reliability and intraobserver reproducibility were 0.34 and 0.32, respectively. The addition of CT scan images to plain X-ray found a higher incidence of calcaneocuboid joint involvement.
Clinicians should be aware of the limitation regarding the interobserver reliability and intraobserver reproducibility of the Letournel, Sanders and Zwipp classification systems for calcaneal fractures. Future studies should attempt to improve the present classification systems.
关节内跟骨骨折的治疗颇具难度。成功治疗的关键之一是使用可靠且可重复的骨折分型系统（FCS）。本研究旨在评估 CT 扫描下的 Letournel、Sanders 和 Zwipp 分型系统以及平片上的 Bohler 角测量的观察者间可靠性和观察者内可重复性。此外，我们还研究了平片加 CT 扫描是否会影响对跟骰关节受累的骨折延伸的评估。
在 5 个月的时间间隔内，3 名观察者（2 名放射科医生和 1 名骨科医生）两次评估了 51 例关节内跟骨骨折的 CT 扫描和平片图像。使用 Fleiss kappa 测量观察者间可靠性，使用 Cohen's kappa 测量观察者内可重复性。
Sanders 分型的观察者间可靠性和观察者内可重复性的平均kappa 值分别为 0.25 和 0.39，Zwipp 分型分别为 0.24 和 0.16，而 Letournel 分型分别为 0.50 和 0.42。Böhler 角的观察者间可靠性和观察者内可重复性的平均 kappa 值分别为 0.34 和 0.32。与平片相比，加扫 CT 发现跟骰关节受累的发生率更高。
临床医生应注意 Letournel、Sanders 和 Zwipp 分型系统用于跟骨骨折的观察者间可靠性和观察者内可重复性的局限性。未来的研究应尝试改进现有的分型系统。
