Reliability evaluation of inter-eminence line, Akagi and Dalury lines for intraoperative tibial rotation: An osteology-based study.

Background: This large osteology study examined the reliability, reproducibility and correlation between previously described tibial tray rotation alignment lines (including Akagi and Dalury lines). In addition, it described a novel inter-eminence line utilising the tibial plateau intercondylar eminences as a landmark. Methods: A total of 214 post-medieval (18-19th centuries) skeletal tibia were examined. The inter/intra-observer variation and correlation between reference lines were measured. Results: Inter-observer reproducibility was excellent and there were no differences between Akagi, Dalury, and inter-eminence lines. Similarly, intra-observer reliability was excellent for Akagi, Dalury, and inter-eminence lines. Qualitative review of tibial inter-condylar eminences suggested that these could be easily identifiable. When taking the medial angle from a medial-lateral reference line, the Akagi line showed a mean of 96.90 degrees (+/- 10.27), inter-eminence line 94.52 degrees (+/- 12.84), and Dalury line 88.06 degrees (+/- 11.75). The angle produced by the Dalury line was significantly different from both the Akagi and inter-eminence lines (P <= 0.001). The Akagi line and inter-eminence line showed a strong correlation (r = 0.74). The Dalury line showed a weaker correlation with both the Akagi line (r = 0.69) and inter-eminence line (r = 0.40). Conclusion: This study suggested that tibial rotation lines showed excellent intra/inter-observer reliability and reproducibility. The novel and easily drawn inter-eminence line showed strong correlation with the Akagi line and could be used for tibial tray rotational alignment in total knee arthroplasty. (C) 2018 Elsevier BM. All rights reserved.