caa a22 4500 605457719 CHVBK 20210128100224.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00167-014-3296-7 doi (NATIONALLICENCE)springer-10.1007/s00167-014-3296-7 Unicompartmental knee arthroplasty cannot restore the functional flexion axis of a living knee to normal [Elektronische Daten] [Tomoharu Mochizuki, Takashi Sato, Osamu Tanifuji, Koichi Kobayashi, Hiroshi Yamagiwa, Satoshi Watanabe, Yoshio Koga, Go Omori, Naoto Endo] Purpose: The purpose of this study was to investigate the hypothesis that a medial unicompartmental knee arthroplasty might restore the functional flexion axis of a knee to normal. The flexion axis can be indirectly identified by tracking the vertical translation of anatomic landmarks that basically move around the flexion axis during a knee motion. If a unicompartmental knee could help restore the normal flexion axis, the anatomic landmarks after the arthroplasty would show the vertical translation similar to those of normal knees during a knee flexion. Methods: While performing a squatting motion, the kinematics of 17 knees were determined before and after a medial unicompartmental arthroplasty to calculate the vertical translation of a clinical epicondylar axis, using a three- to two-dimensional registration technique through a single-plane fluoroscopic system incorporating a biplanar static radiography. The results were compared with a normal data, and a statistical analysis including a two-way repeated-measured analysis of variance was performed. Results: For the medial end, from 10° to 100° knee flexion, normal, osteoarthritic, and unicompartmental knees had the average superior vertical translation of 7.3±4.2, 4.3±7.2, and 2.4±3.1mm, respectively, with statistical significance between normal and unicompartmental knees (p<0.001). The vertical translation did not return to normal post-implantation. Conclusions: A unicompartmental knee could not reproduce the normal flexion axis. As for clinical relevance, the changes of the implant design and surgical procedure may be necessary to obtain the normal flexion axis reproducing a normal motion. Level of evidence: IV. European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA), 2014 Functional flexion axis nationallicence Unicompartmental knee arthroplasty nationallicence Osteoarthritis and normal knees nationallicence 3D to 2D registration nationallicence Clinical epicondylar axis nationallicence Vertical translation nationallicence Mochizuki Tomoharu Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut Sato Takashi Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut Tanifuji Osamu Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan aut Kobayashi Koichi Department of Health Sciences, Niigata University School of Medicine, Niigata City, Niigata, Japan aut Yamagiwa Hiroshi Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan aut Watanabe Satoshi Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut Koga Yoshio Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut Omori Go Department of Health and Sports, Niigata University of Health and Welfare, Niigata City, Niigata, Japan aut Endo Naoto Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan aut Knee Surgery, Sports Traumatology, Arthroscopy Springer Berlin Heidelberg 23/12(2015-12-01), 3736-3742 0942-2056 23:12<3736 2015 23 167 https://doi.org/10.1007/s00167-014-3296-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00167-014-3296-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mochizuki Tomoharu Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Sato Takashi Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Tanifuji Osamu Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Kobayashi Koichi Department of Health Sciences, Niigata University School of Medicine, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Yamagiwa Hiroshi Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Watanabe Satoshi Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Koga Yoshio Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Omori Go Department of Health and Sports, Niigata University of Health and Welfare, Niigata City, Niigata, Japan aut NATIONALLICENCE 700 1- Endo Naoto Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan aut NATIONALLICENCE 773 0- Knee Surgery, Sports Traumatology, Arthroscopy Springer Berlin Heidelberg 23/12(2015-12-01), 3736-3742 0942-2056 23:12<3736 2015 23 167