scholarly journals Valgus subsidence of the tibial component in cementless Oxford unicompartmental knee replacement

2014 ◽  
Vol 96-B (3) ◽  
pp. 345-349 ◽  
Author(s):  
A. D. Liddle ◽  
H. G. Pandit ◽  
C. Jenkins ◽  
P. Lobenhoffer ◽  
W. F. M. Jackson ◽  
...  
The Knee ◽  
2009 ◽  
Vol 16 (5) ◽  
pp. 310-313 ◽  
Author(s):  
R. Chau ◽  
A. Gulati ◽  
H. Pandit ◽  
D.J. Beard ◽  
A.J. Price ◽  
...  

2012 ◽  
Vol 94-B (10) ◽  
pp. 1356-1361 ◽  
Author(s):  
M. R. Streit ◽  
T. Walker ◽  
T. Bruckner ◽  
C. Merle ◽  
J. P. Kretzer ◽  
...  

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3345
Author(s):  
Yong-Gon Koh ◽  
Hyoung-Taek Hong ◽  
Kyoung-Tak Kang

The current study aims to analyze the biomechanical effects of ultra-high molecular weight polyethylene (UHMWPE) and carbon-fiber-reinforced polyetheretherketone (CFR-PEEK) inserts, in varus/valgus alignment, for a tibial component, from 9° varus to 9° valgus, in unicompartmental knee replacement (UKR). The effects on bone stress, collateral ligament force, and contact stress on other compartments were evaluated under gait cycle conditions, by using a validated finite element model. In the UHMWPE model, the von Mises’ stress on the cortical bone region significantly increased as the tibial tray was in valgus >6°, which might increase the risk of residual pain, and when in valgus >3° for CFR-PEEK. The contact stress on other UHMWPE compartments decreased in valgus and increased in varus, as compared to the neutral position. In CFR-PEEK, it increased in valgus and decreased in varus. The forces on medial collateral ligaments increased in valgus, when compared to the neutral position in UHMWPE and CFR-PEEK. The results indicate that UKR with UHMWPE showed positive biomechanical outputs under neutral and 3° varus conditions. UKR with CFR-PEEK showed positive biomechanical outputs for up to 6° varus alignments. The valgus alignment should be avoided.


2016 ◽  
Vol 136 (9) ◽  
pp. 1303-1307 ◽  
Author(s):  
Nael Hawi ◽  
Jochen Plutat ◽  
Daniel Kendoff ◽  
Eduardo M. Suero ◽  
Michael B. Cross ◽  
...  

2018 ◽  
Vol 7 (3) ◽  
pp. 226-231 ◽  
Author(s):  
S. Campi ◽  
S. J. Mellon ◽  
D. Ridley ◽  
B. Foulke ◽  
C. A. F. Dodd ◽  
...  

Objectives The primary stability of the cementless Oxford Unicompartmental Knee Replacement (OUKR) relies on interference fit (or press fit). Insufficient interference may cause implant loosening, whilst excessive interference could cause bone damage and fracture. The aim of this study was to identify the optimal interference fit by measuring the force required to seat the tibial component of the cementless OUKR (push-in force) and the force required to remove the component (pull-out force). Materials and Methods Six cementless OUKR tibial components were implanted in 12 new slots prepared on blocks of solid polyurethane foam (20 pounds per cubic foot (PCF), Sawbones, Malmo, Sweden) with a range of interference of 0.1 mm to 1.9 mm using a Dartec materials testing machine HC10 (Zwick Ltd, Herefordshire, United Kingdom) . The experiment was repeated with cellular polyurethane foam (15 PCF), which is a more porous analogue for trabecular bone. Results The push-in force progressively increased with increasing interference. The pull-out force was related in a non-linear fashion to interference, decreasing with higher interference. Compared with the current nominal interference, a lower interference would reduce the push-in forces by up to 45% (p < 0.001 One way ANOVA) ensuring comparable (or improved) pull-out forces (p > 0.05 Bonferroni post hoc test). With the more porous bone analogue, although the forces were lower, the relationship between interference and push-in and pull-out force were similar. Conclusions This study suggests that decreasing the interference fit of the tibial component of the cementless OUKR reduces the push-in force and can increase the pull-out force. An optimal interference fit may both improve primary fixation and decrease the risk of fracture. Cite this article: S. Campi, S. J. Mellon, D. Ridley, B. Foulke, C. A. F. Dodd, H. G. Pandit, D. W. Murray. Optimal interference of the tibial component of the cementless Oxford Unicompartmental Knee Replacement. Bone Joint Res 2018;7:226–231. DOI: 10.1302/2046-3758.73.BJR-2017-0193.R1.


2013 ◽  
Vol 21 (1) ◽  
pp. 81-85 ◽  
Author(s):  
Eduardo M. Suero ◽  
Mustafa Citak ◽  
Innocent U. Njoku ◽  
Andrew D. Pearle

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