The Effect of Crosslinking UHMWPE on In Vitro Wear Rates of Fixed and Mobile Bearing Knees

2008 ◽  
pp. 73-73-13
Author(s):  
DE McNulty ◽  
SW Swope ◽  
DD Auger ◽  
T Smith
Keyword(s):  
Mobile Bearing ◽  
Wear Rates

scholarly journals Knee Wear Assessment: 3D Scanners Used as a Consolidated Procedure

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2349 ◽  
Author(s):  
Saverio Affatato ◽  
Maria Cristina Valigi ◽  
Silvia Logozzo
Keyword(s):  
Clinical Performance ◽  
Wear Behavior ◽  
Wear Test ◽  
Mobile Bearing ◽  
Clinical Problem ◽  
Material Loss ◽  
Optical Scanners ◽  
Wear Rates ◽  
3D Scanners

It is well known that wear occurring in polyethylene menisci is a significant clinical problem. At this regard, wear tests on biomaterials medical devices are performed in order to assess their pre-clinical performance in terms of wear, durability, resistance to fatigue, etc. The objective of this study was to assess the wear of mobile total knee polyethylene inserts after an in vitro wear test. In particular, the wear behavior of mobile bearing polyethylene knee configurations was investigated using a knee joint wear simulator. After the completion of the wear test, the polyethylene mobile menisci were analyzed through a consolidated procedure by using 3D optical scanners, in order to evaluate the 3D wear distribution on the prosthesis surface, wear depths, wear rates, amount of material loss and contact areas. The results in terms of wear rates and wear volumes were compared with results of gravimetric tests, finding equivalent achievements.

Wear of a Mobile Bearing Uni-Compartmental Knee Replacement Prosthesis: A Comparison of In Vitro and In Vivo Wear Rates

2011 ◽  
Vol 8 (2) ◽  
pp. 103328 ◽  
Author(s):  
P. J. Ellison ◽  
A. Traynor ◽  
B. P. Casey ◽  
S. N. Collins ◽  
K. Trier ◽  
...  
Keyword(s):  
Knee Replacement ◽  
Mobile Bearing ◽  
Wear Rates ◽  
Replacement Prosthesis

Balancing mobile-bearing unicondylar knee arthroplasty in vitro

2016 ◽  
Vol 25 (12) ◽  
pp. 3733-3740 ◽  
Author(s):  
Thomas J. Heyse ◽  
Joshua Slane ◽  
Geert Peersman ◽  
Philipp Dworschak ◽  
Susanne Fuchs-Winkelmann ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Mobile Bearing ◽  
Unicondylar Knee Arthroplasty

Wear and deformation of ceramic-on-polyethylene total hip replacements with joint laxity and swing phase microseparation

2003 ◽  
Vol 217 (2) ◽  
pp. 147-153 ◽  
Author(s):  
S Williams ◽  
M Butterfield ◽  
T Stewart ◽  
E Ingham ◽  
M Stone ◽  
...  
Keyword(s):  
Volume Change ◽  
Swing Phase ◽  
Joint Laxity ◽  
Acetabular Cup ◽  
Hip Joints ◽  
Wear Rates ◽  
Ceramic Femoral Head ◽  
Artificial Hip ◽  
Artificial Hip Joints

Wear of polyethylene and the resulting wear debris-induced osteolysis remains a major cause of long-term failure in artificial hip joints. There is interest in understanding engineering and clinical conditions that influence wear rates. Fluoroscopic studies have shown separation of the head and the cup during the swing phase of walking due to joint laxity. In ceramic-on-ceramic hips, joint laxity and microseparation, which leads to contact of the head on the superior rim of the cup, has led to localized damage and increased wear in vivo and in vitro. The aim of this study was to investigate the influence of joint laxity and microseparation on the wear of ceramic on polyethylene artificial hip joints in an in vitro simulator. Microseparation during the swing phase of the walking cycle produced contact of the ceramic head on the rim of the polyethylene acetabular cup that deformed the softer polyethylene cup. No damage to the alumina ceramic femoral head was found. Under standard simulator conditions the volume change of the moderately crosslinked polyethylene cups was 25.6 ± 5.3 mm3/million cycles and this reduced to 5.6 ± 4.2 mm3/million cycles under microseparation conditions. Testing under microseparation conditions caused the rim of the polyethylene cup to deform locally, possibly due to creep, and the volume change of the polyethylene cup when the head relocated was substantially reduced, possibly due to improved lubrication. Joint laxity may be caused by poor soft tissue tension or migration and subsidence of components. In ceramic-on-polyethylene acetabular cups wear was decreased with a small degree of joint laxity, while in contrast in hard-on-hard alumina bearings, microseparation accelerated wear. These findings may have significant implications for the choice of fixation systems to be used for different types of bearing couples.

scholarly journals The Effect of Glaze Coating on Wear Resistance of Some Acrylic Denture Teeth: An In Vitro Study

2021 ◽  
Vol 13 (2) ◽  
pp. 47-51
Author(s):  
Samaneh Abbasi ◽  
Soodabe Ebrahimi ◽  
Arash Shisheian ◽  
Maryam Farhadian
Keyword(s):  
Wear Resistance ◽  
In Vitro Study ◽  
Resistance Rate ◽  
Vitro Study ◽  
Wear Rates ◽  
Denture Teeth ◽  
Significant Difference ◽  
The Mean ◽  
Post Hoc

Background: Acrylic resin teeth wear resistance has an important role in the denture longevity. This study aimed to clarify the effect of glaze coating on wear resistance of three types of artificial acrylic teeth. Methods: In this in vitro study, the wear resistance rate of three of acrylic denture teeth (GENIUS, STON and CLASSIC) was compared with Ivoclar teeth (n=25/group). The wear resistance was measured by estimating the weight loss in pre and post removing glaze coating, following 5000 cycles in the chewing simulator device. Data analysis was made using paired t test, one-way ANOVA and Tukey’s post hoc test. Results: ANOVA test showed that there was no significant difference between the mean amount of wear of GENIUS, CLASSIC, STON and IVOCLAR teeth in the first stage (P <0.061), but this difference was significant (P <0.001) in the second stage. The result of Tukey post hoc test showed that wear rates of GENIUS were significantly lower than other groups (P<0.001). Comparison between the mean wear rates of each dental group at the first and second stages showed a significant difference between average teeth wear resistance of CLASSIC, STON and IVOCLAR in the first and second stages (P <0.001). Conclusions: In conclusion, the teeth wear resistance of STON and CLASSIC were similar to IVOCLAR. Also, after removing the glaze coating, the teeth wear resistance decreased in all groups but was not statistically significant for group GENIUS.

scholarly journals Mobile bearing leads to less proximal medial tibial strain following UKA in comparison with fixed bearing in a cadaver setup

2020 ◽  
Vol 8 (5_suppl4) ◽  
pp. 2325967120S0029
Author(s):  
Thomas J. Heyse ◽  
Orcun Taylan ◽  
Joshua Slane ◽  
Harry van Lenthe ◽  
Geert Peersman ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Proximal Tibia ◽  
Infrared Camera ◽  
Mobile Bearing ◽  
Bone Strain ◽  
Fixed Bearing ◽  
Camera System ◽  
Tibial Bone ◽  
Fresh Frozen

Aims and Objectives: Inexplicable pain to the medial proximal tibia is a frequent finding leading to revision after unicondylar knee arthroplasty (UKA). This study is an effort to find out, if there are any differences between mobile (MB) and fixed bearing (FB) UKA designs in terms of resulting strain in the medial proximal tibia as measured in an in vitro cadaver setup. It was hypothesized that MB UKA would result in lower bone strain. Materials and Methods: Five pairs of fresh-frozen full leg cadaver specimens were mounted in a kinematic rig that applied a dynamic squatting motion knee flexion after prior 3D CT. The rig allowed for 6 degrees-of-freedom at the knee while forces were applied to the quadriceps and hamstrings. During testing, an infrared camera system tracked the location of reflective markers attached to the tibia and femur with bicortical bone pins. Tibial cortical bone strain was measured with stacked strain gauge rosettes attached at predefined anterior and posterior positions on the medial cortex. Sensor outputs were recorded at 2000 Hz and synchronized with kinematic data prior and after pairwise implantation of MB and FB UKA directly comparing those between left and right knees from the same donor. Results: Bone strain values consistently increased with increasing flexion angle. FB UKA significantly increased strain in the anterior region of the medial tibial bone, while MB closely replicated strain values of the native knee. Conclusion: Proximal tibial bone strain seems to be lesser following MB UKA in comparison with FB UKA. Clinical studies will have to show, if this translates into a higher rate of pain problems with FB UKA.

In Vitro Knee Wear, Kinematics, and Particle Morphology Among Different Bearing Geometries in a Mobile Bearing Knee System

2011 ◽  
Vol 8 (5) ◽  
pp. 103304 ◽  
Author(s):  
T. M. Grupp ◽  
R. K. Miehlke ◽  
M. Hintner ◽  
J. Schwiesau ◽  
C. Kaddick ◽  
...  
Keyword(s):  
Mobile Bearing ◽  
Particle Morphology

In Vitro Study of Backside Wear Mechanisms on Mobile Knee-Bearing Components

2005 ◽  
Vol 128 (2) ◽  
pp. 275-281 ◽  
Author(s):  
S. A. Atwood ◽  
F. E. Kennedy ◽  
J. H. Currier ◽  
D. W. Van Citters ◽  
J. P. Collier
Keyword(s):  
In Vitro Study ◽  
Mobile Bearing ◽  
Porous Coating ◽  
Third Body ◽  
Rotating Platform ◽  
Wear Performance ◽  
Tibial Tray ◽  
Inferior Surface ◽  
Pmma Bone Cement

The long-term success of a total knee replacement depends on the wear performance of a polyethylene bearing that separates a metal femoral component from a metal tibial tray. Although fixed bearing designs secure the polyethylene bearing to the tibial tray, mobile bearing knees allow the polyethylene to move relative to the tibial tray. This study has evaluated the wear performance of an intended articulation on the inferior surface of the LCS®-Rotating Platform mobile bearing by conducting clinically relevant tribological testing and comparing results to retrieved knee bearings. A retrieval analysis leads to the conclusion that third-body particles in the contact produce curvilinear scratches longer than the expected rotation of the knee on both the polyethylene bearing and the CoCr tibial tray. Tribological testing shows that polymethylmethacrylate (PMMA) bone cement particles produce worn surfaces most similar to retrievals. Porous-coating beads and bone debris also have the ability to damage both surfaces. Worn polyethylene surfaces from pin-on-flat tests show scratches longer than the excursion length, and “skipping marks”—pits spaced at smaller rotation intervals along a scratch—as observed in retrievals. These wear features suggest that a ratcheting mechanism, which moves the third-body particles further along the scratch with each cycle, may be responsible for the observed wear.

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