Tomoharu Mochizuki1,2,3, Takashi Sato4, Osamu Tanifuji5, Koichi Kobayashi6, Hiroshi Yamagiwa5, Satoshi Watanabe4, Yoshio Koga4, Go Omori7, Naoto Endo5. 1. Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan. tommochi121710@gmail.com. 2. Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan. tommochi121710@gmail.com. 3. Department of Orthopaedic Surgery, Niigata Prefectural Central Hospital, Joetsu City, Niigata, Japan. tommochi121710@gmail.com. 4. Department of Orthopaedic Surgery, Niigata Medical Center, Niigata City, Niigata, Japan. 5. Department of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Science, Niigata City, Niigata, Japan. 6. Department of Health Sciences, Niigata University School of Medicine, Niigata City, Niigata, Japan. 7. Department of Health and Sports, Niigata University of Health and Welfare, Niigata City, Niigata, Japan.
Abstract
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 ± 3.1 mm, 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.
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 ± 3.1 mm, 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.
Keywords:
3D to 2D registration; Clinical epicondylar axis; Functional flexion axis; Osteoarthritis and normal knees; Unicompartmental knee arthroplasty; Vertical translation
Authors: Donald G Eckhoff; Joel M Bach; Victor M Spitzer; Karl D Reinig; Michelle M Bagur; Todd H Baldini; Nicolas M P Flannery Journal: J Bone Joint Surg Am Date: 2005 Impact factor: 5.284
Authors: Roland Becker; Christian Mauer; Christian Stärke; Mathias Brosz; Thore Zantop; Christoph H Lohmann; Martin Schulze Journal: Knee Surg Sports Traumatol Arthrosc Date: 2012-08-07 Impact factor: 4.342
Authors: R A Berger; D D Nedeff; R M Barden; M M Sheinkop; J J Jacobs; A G Rosenberg; J O Galante Journal: Clin Orthop Relat Res Date: 1999-10 Impact factor: 4.176
Authors: Shaw Akizuki; John K P Mueller; Hiroshi Horiuchi; Daigo Matsunaga; Atsuyuki Shibakawa; Richard D Komistek Journal: J Arthroplasty Date: 2008-08-12 Impact factor: 4.757
Authors: Michael D Kurdziel; Meagan Salisbury; Lige Kaplan; Tristan Maerz; Kevin C Baker Journal: J Mater Sci Mater Med Date: 2017-05-22 Impact factor: 3.896