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KEN OKAZAKI
Department School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine Position Professor and Division head |
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| Article types | Original article |
| Language | English |
| Peer review | Peer reviewed |
| Title | Semi-constrained posterior stabilized total knee arthroplasty reproduces natural deep knee bending kinematics. |
| Journal | Formal name：BMC musculoskeletal disorders Abbreviation：BMC Musculoskelet Disord ISSN code：14712474/14712474 |
| Domestic / Foregin | Foregin |
| Volume, Issue, Page | 21(1),pp.107 |
| Author and coauthor | Sumino Takanobu, Tomita Tetsuya, Sugamoto Kazuomi, Yamazaki Takaharu, Okazaki Ken |
| Publication date | 2020/02 |
| Summary | BACKGROUND:The Flexible Nichidai Knee Posterior Stabilized (FNK-PS) system was designed to provide relatively high varus-valgus stabilities without the stem extensions to patients with severe knee joint disorders. This is a combination of a large tibial post and high femoral cam adapted to a PS system. The aim of our study was to analyze the in vivo two-dimensional/three-dimensional registration kinematics of the FNK PS-total knee arthroplasty (TKA) system during deep knee bending.METHODS:Nineteen knees from 15 total knee arthroplasty (TKA) patients who were able to squat with enough knee flexion were selected. During deep knee bending under weight bearing (WB) and non-weight bearing (NWB) conditions, we quantified range of motion, axial rotation, femoral anteroposterior translation, and post-cam engagement angle.RESULTS:The maximum-flexion was significantly different between the two conditions. The mean axial femoral external rotation was 4.8° and 6.2° under WB and NWB conditions, respectively, at 120° flexion. Anteroposterior translation based on bicondylar posterior roll-back patterns was noted with increasing knee flexion. Both the medial and lateral femoral aspects were significantly more posterior during early to mid-flexion. Initial post-cam engagement occurred significantly earlier during flexion under NWB than under WB conditions. Under WB, the timing of the post-cam engagement correlated with the maximum flexion .CONCLUSIONS:The kinematics of the semi-constrained PS system reproducibly exhibited a mild external rotation with smooth posterior roll-back. This was assisted by the engagement of the large tibial post and high femoral cam during the early phase of flexion. |
| DOI | 10.1186/s12891-020-3059-1 |
| PMID | 32066423 |