Macro- and Microscale Analysis of Bearing Surface Damage on Total Shoulder Replacements

2013 ◽  
Author(s):  
Farzana Ansari ◽  
Jeff Koller ◽  
Amelia Swan ◽  
Sunny Kung ◽  
Stephen B. Gunther ◽  
...  
Keyword(s):  
Surface Damage ◽  
Bearing Surface ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Total Knee Replacements ◽  
Uhmwpe Wear ◽  
Hip Replacements ◽  
Clinical Consequences ◽  
Bearing Damage

Damage to bearing surfaces of total joint replacements (TJR) can have clinical consequences: wear debris generated from ultra-high molecular weight polyethylene (UHMWPE) surfaces can cause osteolysis and subsequent implant loosening [1]. Counterbearing metallic damage may significantly increase UHMWPE wear [2]. Documenting the morphology, frequency and location of bearing surface damage may provide insight into wear initiation and prevention. While scoring methodologies have been available and validated for total hip replacements (THR) and total knee replacements (TKR) [3–4], there is a paucity of validated scoring protocols for total shoulder replacements (TSR) [5]. Our previous work presented a damage scoring methodology to evaluate the severity and coverage of six damage modes on retrieved cobalt chrome (CoCr) humeral heads [6]. In this study, we adapt that protocol to include bearing surface damage on the counter-bearings (UHMWPE glenoid components). Additionally, we incorporate the results of 3D profilometry analysis of scratches in the Co-Cr humeral heads [6]. Ultimately, this macroscale and microscale analysis, combined with clinical data, for coupled TSR retrievals will provide insight on the origin, evolution and consequences of bearing damage in vivo.

Profilometry Analysis and Improvements of a Novel Damage Scoring Method for Metal Bearing Surfaces of Shoulder Replacements

2012 ◽  
Author(s):  
Farzana Ansari ◽  
Eli W. Patten ◽  
Cynthia Cruz ◽  
Erin Beitel ◽  
Amelia Swan ◽  
...  
Keyword(s):  
Surface Damage ◽  
Implant Loosening ◽  
Scoring Method ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Uhmwpe Wear ◽  
Ultra High Molecular Weight ◽  
Cobalt Chrome

Characterizing the type and extent of in vivo damage to total joint replacements (TJR) is important for improving the success of arthroplasty outcomes, modeling damage modalities, and validating simulator studies. A method for quantifying the damage present on Cobalt Chrome (CoCr) humeral heads was developed in our lab to fulfill a much-needed gap in clinical knowledge regarding total shoulder replacements as well as metallic bearing surfaces [1,2]. A lack of inter-observer consistency with regard to severity classifications from our initial protocol [1] prompted several modifications to the method, which are tested and described here in this study. Also, since sub-micron scale ultra-high molecular weight polyethylene (UHMWPE) wear debris is linked to osteolysis and implant loosening, additional analysis with high magnification 3D optical profilometry was performed on a subset of damage modes with a long-term goal of correlating surface damage with propensity for osteolysis in TJR [3,4].

Designing for Crosslinked UHMWPE Implants: Clinical Consequences of Stress Concentrations

2013 ◽  
Author(s):  
Farzana Ansari ◽  
Eli Patten ◽  
Jennifer Chang ◽  
Suzanne Chou ◽  
Amir Mehdizadeh ◽  
...  
Keyword(s):  
Ultrahigh Molecular Weight Polyethylene ◽  
Joint Space ◽  
Stress Concentrations ◽  
Total Joint Replacements ◽  
Uhmwpe Wear ◽  
Clinical Consequences ◽  
Radiation Processes ◽  
The Cost ◽  
Term Performance

Ultrahigh molecular weight polyethylene (UHMWPE) remains the polymer bearing of choice for total joint replacements (TJR) [1]. However, the long-term performance of this polymer has been limited by in vivo wear: UHMWPE wear debris generated in the joint space can travel into the periprosthetic bone, initiating osteolysis and implant loosening [2]. Crosslinked UHMWPE (through ionizing radiation) has demonstrated increased wear resistance [3], but at the cost of reduced fatigue crack propagation and fracture resistance [4]. Additionally, radiation processes can release free radicals which, when not eliminated through thermal treatment, can increase UHMWPE susceptibility to oxidation and mechanical embrittlement [5]. Such tradeoffs present clinical concerns when implant designs incorporate stress concentrations that experience elevated stresses under loading. These compromises are evaluated through the failure analysis of several crosslinked UHMWPE retrievals that fractured in vivo.

The size and shape of particulate polyethylene wear debris in total joint replacements

1997 ◽  
Vol 211 (1) ◽  
pp. 11-15 ◽  
Author(s):  
A Kobayashi ◽  
W Bonfield ◽  
Y Kadoya ◽  
T Yamac ◽  
M A R Freeman ◽  
...  
Keyword(s):  
High Performance ◽  
Polyethylene Wear ◽  
Exact Nature ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Total Knee Replacements ◽  
Knee Replacements ◽  
Hip Replacements ◽  
Total Knee

Osteolysis induced by wear particles has been recognized as one of the major causes of long-term failure in total joint replacements. However, little is currently known about the exact nature of particles, as the particles are too small to be characterized by light microscopy. In this study, ultra-high molecular weight polyethylene (UHMWPE) particles retrieved from ten cases (six cemented and four uncemented) for Freeman type conforming tibiofemoral total knee replacements (TKRs), three Charnley total hip replacements (THRs) and five Imperial College/London Hospital double cup surface hip replacements for aseptic loosening were extracted using a high-performance method with ultracentrifugation and characterized by scanning electron microscopy. The equivalent circle diameter (ECD) of all 18 cases ranged from 0.40 to 1.15 μm (Mean ± SE = 0.70 ± 0.05 μm, median = 0.67 μm). The aspect ratio was 1.50 to 2.04 (Mean ± SE = 1.75 ± 0.04, median = 1.73), and roundness was 1.24 to 2.34 (Mean ± SE = 1.61 ± 0.07, median = 1.65). The numbers of particles were 5.2 × 108 to 9.17 × 1010/g tissue (Mean ± SE = 1.42 × 1010 ± 5.41 × 109/g tissue, median = 7.04 × 109). The number of polyethylene (PE) particles/g tissue in TKRs was significantly larger than that in THRs (1.04 × 1010/g tissue and 2.16 × 109/g tissue respectively, median. p = 0.03, Mann-Whitney U test). Unstable fixation of the tibial PE component might account for the accumulation of a large number of PE particles in the interface tissue.

Load Scenarios Influence Fluid Absorption of Polyethylene

2005 ◽  
Author(s):  
T. Schwenke ◽  
C. Rieker ◽  
M. A. Wimmer
Keyword(s):  
Wear Testing ◽  
Fluid Absorption ◽  
Joint Replacements ◽  
Wear Rates ◽  
Total Joint Replacements ◽  
Fluid Uptake ◽  
Dynamically Loaded ◽  
Low Wear ◽  
Lubrication Conditions

Wear of total joint replacements is determined gravimetrically in simulator studies. A mix of bovine serum, distilled water, and additives is intended to replicate the lubrication conditions in-vivo. Weight gain due to fluid absorption during testing of UHMWPE components is corrected using a load soak station. In this study six sets of UHMWPE pins were tested for their fluid soak behavior. The samples were subjected to three different loading scenarios while being submersed in two types of commonly used lubricants. After two million cycles or 23.1 days, respectively, the different fluids lead to significantly different soaking results. Test groups that were dynamically loaded gained more weight than unloaded or statically loaded samples. The results suggest that dynamically loaded soak control stations are required during wear testing of UHMWPE components. Otherwise the fluid uptake masks the wear measurement, especially for new polyethylene materials with low wear rates. Furthermore, an agreement on detailed lubricant specifications is desirable.

Influence of Cross-linking and Oxidation on the Microstructural Mechanical Properties of UHMWPE

2005 ◽  
Vol 874 ◽  
Author(s):  
Marcel E. Roy
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Cross Linking ◽  
Bearing Surface ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Reduced Modulus ◽  
Tibial Insert ◽  
Future Work ◽  
Ultra High Molecular Weight

AbstractUltra-high molecular weight polyethylene (UHMWPE) is commonly used as a bearing surface in total joint replacements. This study examined the effects of cross-linking and oxidation on the mechanical properties of UHMWPE at the microstructural level, rather than at the bulk level. Nanoindentation tests were performed on the articulating surfaces of two freshly machined UHMWPE acetabular inserts, one of which was cross-linked, and also performed along a freshly cut cross-section of a UHMWPE tibial insert that had been sealed in its original packaging and shelf-aged for at least five years. The reduced modulus of cross-linked UHMWPE was significantly lower than native UHMWPE. Tests on the cross-section of the shelf-aged specimen revealed a reduced modulus profile with a subsurface peak that was similar to the oxidation profiles of aged UHMWPE observed by others. Future work should examine the microstructural mechanical properties of UHMWPE using methods that more accurately account for its viscoelastic nature, and should directly correlate microstructural properties with oxidation.

Bone-Bonding Ability of Ce-TZP/Al2O3 Nanocomposite with a Microporous Surface and Calcium Phosphate Coating

2005 ◽  
Vol 284-286 ◽  
pp. 987-990 ◽  
Author(s):  
Mitsuru Takemoto ◽  
Shunsuke Fujibayashi ◽  
J. Suzuki ◽  
Tadashi Kokubo ◽  
Takashi Nakamura
Keyword(s):  
Calcium Phosphate ◽  
Tetragonal Zirconia ◽  
Calcium Phosphate Coating ◽  
Control Group ◽  
Phosphate Coating ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Al2o3 Composite ◽  
High Bone

The nano-composite of a ceria-stabilized tetragonal zirconia polycrystals (Ce-TZP) and alumina (Al2O3) polycrystals (Ce-TZP/Al2O3) is attractive as a load-bearing bone substitute because of its mechanical properties and phase stability. We have developed a new method of hydrofluoric acid and heat treatment (HFT) to give a microporous structure to the surface of this Ce-TZP/Al2O3 nanocomposite ceramic. Bone-bonding ability of a microporous surface and calcium phosphate coating on Ce-TZP/Al2O3 composite has been investigated through in vivo detaching model. Thin calcium phosphate coating layer was added by alternate soaking process, and thick CaP layer was produced by soaking in simulated body fluid for 5 days. HFT treated Ce-TZP/Al2O3 composite showed high bone-bonding ability compared with the control group. Thick and thin CaP coating accelerated bone-bonding ability in early post-implantation period. The submicron microporous surface was beneficial for achieving mechanical interlocking between the ceramic and surrounding bone. These results suggest the possibility of using a Ce-TZP/Al2O3 nanocomposite ceramic with microporous surface and calcium phosphate coating as the bearing material for uncemented total joint replacements.

scholarly journals An Antibiotic-Releasing Bone Void Filling (ABVF) Putty for the Treatment of Osteomyelitis

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5080
Author(s):  
Raquib Hasan ◽  
Abbey Wohlers ◽  
Jacob Shreffler ◽  
Pranothi Mulinti ◽  
Hunter Ostlie ◽  
...  
Keyword(s):  
Bone Growth ◽  
Release Kinetics ◽  
Control Group ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Press Fitting ◽  
Antibiotic Release ◽  
Bone Void

The number of total joint replacements (TJR) is on the rise with a corresponding increase in the number of infected TJR, which necessitates revision surgeries. Current treatments with either non-biodegradable, antibiotic-releasing polymethylmethacrylate (PMMA) based bone cement, or systemic antibiotic after surgical debridement do not provide effective treatment due to fluctuating antibiotic levels at the site of infection. Here, we report a biodegradable, easy-to-use “press-fitting” antibiotic-releasing bone void filling (ABVF) putty that not only provides efficient antibiotic release kinetics at the site of infection but also allows efficient osseointegration. The ABVF formulation was prepared using poly (D,L-lactide-co-glycolide) (PLGA), polyethylene glycol (PEG), and polycaprolactone (PCL) as the polymer matrix, antibiotic vancomycin, and osseointegrating synthetic bone PRO OSTEON for bone-growth support. ABVF was homogenous, had a porous structure, was moldable, and showed putty-like mechanical properties. The ABVF putty released vancomycin for 6 weeks at therapeutic level. Furthermore, the released vancomycin showed in vitro antibacterial activity against Staphylococcus aureus for 6 weeks. Vancomycin was not toxic to osteoblasts. Finally, ABVF was biodegradable in vivo and showed an effective infection control with the treatment group showing significantly higher bone growth (p < 0.001) compared to the control group. The potential of infection treatment and osseointegration makes the ABVF putty a promising treatment option for osteomyelitis after TJR.

Simulation of Fretting Wear at Orthopaedic Implant Interfaces

2005 ◽  
Vol 127 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Edward Ebramzadeh ◽  
Fabrizio Billi ◽  
Sophia N. Sangiorgio ◽  
Sarah Mattes ◽  
Werner Schmoelz ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Wear Debris ◽  
Fretting Wear ◽  
Orthopaedic Implant ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Wear Simulator ◽  
Plasma Sprayed ◽  
Fiber Mesh

Osteolysis due to wear debris is a primary cause of failure of total joint replacements. Although debris produced by the joint articulating surfaces has been studied and simulated extensively, fretting wear debris, produced at nonarticulating surfaces, has not received adequate attention. We developed a three-station fretting wear simulator to reproduce in vivo motion and stresses at the interfaces of total joint replacements. The simulator is based on the beam bending theory and is capable of producing cyclic displacement from 3to1000microns, under varying magnitudes of contact stresses. The simulator offers three potential advantages over previous studies: The ability to control the displacement by load, the ability to produce very small displacements, and dynamic normal loads as opposed to static. A pilot study was designed to test the functionality of the simulator, and verify that calculated displacements and loads produced the predicted differences between two commonly used porous ingrowth titanium alloy surfaces fretting against cortical bone. After 1.5 million cycles, the simulator functioned as designed, producing greater wear of bone against the rougher plasma-sprayed surface compared to the fiber-mesh surface, as predicted. A novel pin-on-disk apparatus for simulating fretting wear at orthopaedic implant interfaces due to micromotion is introduced. The test parameters measured with the fretting wear simulator were as predicted by design calculations, and were sufficient to measure differences in the height and weight of cortical bone pins rubbing against two porous ingrowth surfaces, plasma-sprayed titanium and titanium fiber mesh.

scholarly journals Improvement in the assessment of wear of total knee replacements using coordinate-measuring machine techniques

2008 ◽  
Vol 222 (3) ◽  
pp. 309-318 ◽  
Author(s):  
L A Blunt ◽  
P J Bills ◽  
X-Q Jiang ◽  
G Chakrabarty
Keyword(s):  
Total Joint Replacement ◽  
Coordinate Measuring Machine ◽  
Activity Levels ◽  
Material Loss ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Total Knee Replacements ◽  
Elective Surgical Procedures ◽  
Important Means ◽  
Measuring Machine

Total joint replacement is one of the most common elective surgical procedures performed worldwide, with an estimate of 1.5×106 operations performed annually. Currently joint replacements are expected to function for 10–15 years; however, with an increase in life expectancy, and a greater call for knee replacement due to increased activity levels, there is a requirement to improve their function to offer longer-term improved quality of life for patients. Wear analysis of total joint replacements has long been an important means in determining failure mechanisms and improving longevity of these devices. The effectiveness of the coordinate-measuring machine (CMM) technique for assessing volumetric material loss during simulated life testing of a replacement knee joint has been proved previously by the present authors. The purpose of the current work is to present an improvement to this method for situations where no pre-wear data are available. To validate the method, simulator tests were run and gravimetric measurements taken throughout the test, such that the components measured had a known wear value. The implications of the results are then discussed in terms of assessment of joint functionality and development of standardized CMM-based product standards. The method was then expanded to allow assessment of clinically retrieved bearings so as to ascertain a measure of true clinical wear.

An automated method for assessing routine radiographs of patients with total hip replacements

1997 ◽  
Vol 211 (2) ◽  
pp. 145-154 ◽  
Author(s):  
A L Redhead ◽  
A C W Kotcheff ◽  
C J Taylor ◽  
M L Porter ◽  
D W L Hukins
Keyword(s):  
Reference Points ◽  
Hip Prostheses ◽  
Joint Replacements ◽  
Total Joint Replacements ◽  
Total Hip ◽  
Mean Error ◽  
Automated Method ◽  
Total Hip Replacements ◽  
Unseen Data ◽  
Hip Replacements

This paper describes a new, fully automated method of locating objects on radiographs of patients with total joint replacements (TJRs). A statistical computer model, known as an active shape model, was trained to identify the position of the femur, pelvis, stem and cup marker wire on radiographs of patients with Charnley total hip prostheses. Once trained, the model was able to locate these objects through a process of automatic image searching, despite their appearance depending on the orientation and anatomy of the patient. Experiments were carried out to test the accuracy with which the model was able to fit to previously unseen data and with which reference points could be calculated from the model points. The model was able to locate the femur and stem with a mean error of approximately 0.8 mm and a 95 per cent confidence limit of 1.7 mm. Once the model had successfully located these objects, the midpoint of the stem head could be calculated with a mean error of approximately 0.2 mm. Although the model has been trained on Charnley total hip replacements, the method is generic and so can be applied to radiographs of patients with any TJR. This paper shows that computer models can form the basis of a quick, automatic method of taking measurements from standard clinical radiographs.

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