The femoral trochlear anterior line is a better alternative intra-operative reference compared to femoral anterior tangent line for femoral rotation in both genders in total knee arthroplasty

Ji-Hoon Nam; Yong-Gon Koh; Paul Shinil Kim; Kiwon Kang; Kyoung-Tak Kang

doi:10.1186/s40634-020-00259-1

The femoral trochlear anterior line is a better alternative intra-operative reference compared to femoral anterior tangent line for femoral rotation in both genders in total knee arthroplasty

J Exp Orthop. 2020 Jun 8;7(1):43. doi: 10.1186/s40634-020-00259-1.

Authors

Ji-Hoon Nam¹, Yong-Gon Koh², Paul Shinil Kim³, Kiwon Kang⁴, Kyoung-Tak Kang⁵

Affiliations

¹ Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
² Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, 10 Hyoryeong-ro, Seocho-gu, Seoul, 06698, Republic of Korea.
³ Department of Orthopaedic Surgery, The bone hospital, 67, Dongjak-daero, Dongjak-gu, Seoul, Republic of Korea.
⁴ Orthopaedic Clinic, Gaja Yonsei Hospital, A-304,7, Janggogae-ro 337 beon-gil, Seo-gu, Incheon, Republic of Korea.
⁵ Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea. tagi1024@gmail.com.

Abstract

Purpose: To determine the most reliable reference axis for the femoral component rotation in TKA patients by comparing the trochlear anterior line (TAL) and the femoral anterior tangent line (FAT). To evaluate the variability of each anatomic parameter in a Korean population.

Methods: Magnetic resonance images (MRIs) were taken for 500 patients (400 females and 100 males) with knee joint osteoarthritis who had Kellgren and Lawrence grade 3 and 4 prior to TKA in our institution between February 2016 and September 2017. It was investigated that whether significant differences in variance and gender exist for TAL and FAT.

Results: TAL and the FAT were internally rotated by 5.1° ± 3.1° and 6.8° ± 6.1°, respectively, about the Transepicondylar axis (TEA). Although no gender-related differences were found for the TAL, they were found for the FAT. The variance of the TAL with respect to the TEA was significantly smaller compared with that for the FAT and thus exhibited a more consistent distribution. In addition, such a trend was found for both genders.

Conclusions: The results show that the TAL is a favorable index for appropriate rotational alignment of the femoral component in TKA.

Keywords: Korean patients; femoral rotation; Morphometry; Total knee replacement.