Prosthesis simulator

It has also been shown by various testing laboratories that the in-vivo failures can be simulated using in-vitro simulators without the presence of a corrosive medium and provided that a torsional component of load is applied to the prosthesis. 

Experiments were carried out in the simulator on an early form of Freeman-Swanson Knee Joint and on a Leeds Knee Joint. Distilled water was allowed to drip onto the prosthesis to wet the interface, the flow rate being adjusted to maintain temperature of the tlbial component at 37 C. Contour diagrams based upon holography are recorded for the initial and worn tlbial components of each joint in Figures 3 and 4 and schematic representations of the wear scars are shown in Figures 5 and 6. 

Figure 4a. Contours of Leeds Knee Prosthesis Tibial Component prior to test in knee joint simulator (Ah = 1.75 /im).

Mohammadi H, Boughner D, Millon LE, Wan WK (2009) Design and simulation of a poly (vinyl alcohol)-bacterial cellulose nanocomposite mechanical aortic heart valve prosthesis. Proc Inst Mech Eng H 223 697-711... 

Clarke, I.C. (1982) Wear-screening and joint simulation studies vs. materials selection and prosthesis design. CRC Crit. Rev. in Biomed. Eng., 8, 29-91. 

Romaquera C, Grimalt F, Vilaplana J (1985) Methyl methacrylate prosthesis dermatitis. Contact Dermatitis 12 172 Shelley ED, Shelley WB (1984) Chronic dermatitis simulating small-plaque parapsoriasis due to cyanoacrylate adhesive used on finger nails. JAMA 252 2455 Tomb RR, Lepoittevin J-P, Durepaire F, et al. (1993) Ectopic contact dermatitis from ethyl-cyanoacrylate instant adhesives. Contact Dermatitis 28 206... 

C. R. Gentle, The role of simulation studies in cardiac valve prosthesis design, Eng1 in Med., 7 101 (1978). 

Kaufmann T, Linde T, Cuenca-Navalon E, Schmitz C, Hormes M, Schmitz-Rode T, et al. Transient, three-dimensional flow field simulation through a mechanical, trileaflet heart valve prosthesis. ASAIO J 2011 57(4) 278-82. 

In the present study, a knee joint simulator is used to simulate the tibial axis load and flexion-extension motion under walking condition. The lubrication condition or fluid film formation in knee prosthesis models is evaluated by measuring the electric contact resistance between the femoral metallic component and tibial conductive polymeric or elastomeric component under the constant applied voltage in a knee joint simulator. 

In another study, to simulate the swing phase of gait a 5kg mass was applied to the foot of the prosthesis, and an x-ray was taken with the prosthesis suspended at a knee flexion angle of 30° [7]. 

Affatato S, Leardini A, Leardini W, Giannini S, Viceconti M. Meniscal wear at a three-component total anMe prosthesis by a knee joint simulator. J Biomech 2007 40(8) 1871-6. 

Clarke IC, McKellop HA, Okuda R, McGuire P, Young R, Hull D. Materials and prosthesis design criteria—hip simulator studies. Trans Orthop Res Soc 1982. 

A minimum of three 28 mm prosthesis pairs of each UHMWPE material were studied under standard simulation conditions in a 10-station Leeds ProSim hip joint simulator for 5 million cycles [64]. The cups were positioned superiorly and inclined at 35 degrees to the horizontal plane in an anatomical configuration. The simulator applied two independently controlled motions. The head underwent flexion extension (+30 degrees and —15 degrees), and the acetabular insert underwent 10 degrees rotation. A twin peak time-dependent loading curve was applied with a peak load of 3 kN at heel strike and toe off, and a swing phase load of 50N was also applied. 

It is clear from this Figure that most metal-on-metal total replacement hip joints operate with mean theoretical film thicknesses of the order of nanometres or a few tens of nanometres. Furthermore, there is a fair correlation between wear rate and film thickness, irrespective of the type of prosthesis and the form of simulator and test conditions selected. 

Scott, R.A. and Schroeder, D.W. The effect of radial mismatch on the wear of metal on metal hip prosthesis a hip simulator study. Proc. 43 Ann. Meeting of the Orthopaedic Research Society, 1997, 764. 

SiUcones on the other hand, are both soft and flexible and keep body temperature. Hair and skin features can be easily simulated and the edges can be thirmed as to become imperceptible. This enhances camouflage of the finishing border between the prosthesis and the surrounding skin. By using the modern polydimethylsiloxane (PDMS) elastomers, it is possible to fabricate facial prostheses of outstanding aesthetic quality [1,47,48]. 

A prosthesis material using calcium phosphates-poly(ether etherketone)thermoplastic nano composite was developed. The nanosized calcium phosphates were synthesized by sol-gel technique. The biocompatibility test was carried out by SBF-conditioned study using freshly prepared simulated body fluid (SBF) at a temperature of 25-40°C and pH of 6.5-7.7. XRD was used to see the crystallinity and composition. The morphology and component distribution were performed by OM, SEM, AFM, etc. The functional groups present in composite materials were evaluated by FTIR. The growth study of SBF crystal was carried out by OM and XRD. The porous microsphere of HAp-PEEK composite was observed in SEM. 

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