scholarly journals Effect of bearing friction torques on the primary stability of press-fit acetabular cups: A novel in vitro method

2018 ◽  
Vol 36 (10) ◽  
pp. 2745-2753 ◽  
Author(s):  
Alexander Jahnke ◽  
Stefan Schroeder ◽  
Carlos A. Fonseca Ulloa ◽  
Gafar A. Ahmed ◽  
Bernd A. Ishaque ◽  
...  
Keyword(s):  
Primary Stability ◽  
In Vitro Method ◽  
Press Fit ◽  
Bearing Friction

In vitro examination of the primary stability of three press-fit acetabular cups under consideration of two different bearing couples

2019 ◽  
Vol 67 ◽  
pp. 49-54 ◽  
Author(s):  
Alexander Jahnke ◽  
Catharina Chiara Bott ◽  
Carlos Alfonso Fonseca Ulloa ◽  
Gerhard Walter Jahnke ◽  
Markus Rickert ◽  
...  
Keyword(s):  
Primary Stability ◽  
Press Fit ◽  
In Vitro Examination

In Vitro Evaluation of the Acetabular Cup Primary Stability by Impact Analysis

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Adrien Michel ◽  
Romain Bosc ◽  
Romain Vayron ◽  
Guillaume Haiat
Keyword(s):  
Impact Analysis ◽  
Primary Stability ◽  
Bovine Bone ◽  
Acetabular Cup ◽  
Hip Prostheses ◽  
Press Fit ◽  
The Press ◽  
Force Signal ◽  
The Impact

The implant primary stability of the acetabular cup (AC) is an important parameter for the surgical success of press-fit procedures used for the insertion of cementless hip prostheses. In previous studies by our group (Mathieu, V., Michel, A., Lachaniette, C. H. F., Poignard, A., Hernigou, P., Allain, J., and Haiat, G., 2013, “Variation of the Impact Duration During the in vitro Insertion of Acetabular Cup Implants,” Med. Eng. Phys., 35(11), pp. 1558–1563) and (Michel, A., Bosc, R., Mathieu, V., Hernigou, P., and Haiat, G., 2014, “Monitoring the Press-Fit Insertion of an Acetabular Cup by Impact Measurements: Influence of Bone Abrasion,” Proc. Inst. Mech. Eng., Part H, 228(10), pp. 1027–1034), the impact momentum and duration were shown to carry information on the press-fit insertion of the AC within bone tissue. The aim of the present study is to relate the impact momentum recorded during the AC insertion to the AC biomechanical primary stability. The experimental protocol consisted in testing 13 bovine bone samples that underwent successively series of 15 reproducible mass falls impacts (5 kg, 5 cm) followed by tangential stability testing. Each bone sample was tested with different hole sizes in order to obtain different stability configurations. The impact momentum and the tangential primary stability reach a maximum value for an interference fit equal to around 1 mm. Moreover, a correlation between the impact momentum and the stability was obtained with all samples and all configuration (R2 = 0.65). The implant primary stability can be assessed through the measurement of the impact force signal analysis. This study opens new paths for the development of a medical device which could be used as a decision support system to assist the surgeon during the insertion of the AC implant.

A in Vivo Assay for Standardizing Heparin Preparations

1979 ◽  
Vol 41 (03) ◽  
pp. 576-582
Author(s):  
A R Pomeroy
Keyword(s):  
In Vitro Assays ◽  
British Pharmacopoeia ◽  
In Vitro Method ◽  
Standard Preparation ◽  
Reliable Estimation ◽  
Assay Procedure ◽  
Accuracy And Precision ◽  
Heparin Preparation

SummaryThe limitations of currently used in vitro assays of heparin have demonstrated the need for an in vivo method suitable for routine use.The in vivo method which is described in this paper uses, for each heparin preparation, four groups of five mice which are injected intravenously with heparin according to a “2 and 2 dose assay” procedure. The method is relatively rapid, requiring 3 to 4 hours to test five heparin preparations against a standard preparation of heparin. Levels of accuracy and precision acceptable for the requirements of the British Pharmacopoeia are obtained by combining the results of 3 to 4 assays of a heparin preparation.The similarity of results obtained the in vivo method and the in vitro method of the British Pharmacopoeia for heparin preparations of lung and mucosal origin validates this in vivo method and, conversely, demonstrates that the in vitro method of the British Pharmacopoeia gives a reliable estimation of the in vivo activity of heparin.

Influence of Bone Quality, Drilling Protocol, Implant Diameter/Length on Primary Stability: An In Vitro Comparative Study on Insertion Torque and Resonance Frequency Analysis

2020 ◽  
Vol 46 (3) ◽  
pp. 182-189 ◽  
Author(s):  
Davide Farronato ◽  
Mattia Manfredini ◽  
Michele Stocchero ◽  
Mattia Caccia ◽  
Lorenzo Azzi ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Bone Quality ◽  
Frequency Analysis ◽  
Primary Stability ◽  
Mean Difference ◽  
Insertion Torque ◽  
Resonance Frequency Analysis ◽  
Bone Response ◽  
Implant Length

The aim of this study was to evaluate the influence of bone quality, drilling technique, implant diameter, and implant length on insertion torque (IT) and resonance frequency analysis (RFA) of a prototype-tapered implant with knife-edge threads. The investigators hypothesized that IT would be affected by variations in bone quality and drilling protocol, whereas RFA would be less influenced by such variables. The investigators implemented an in vitro experiment in which a prototype implant was inserted with different testing conditions into rigid polyurethane foam blocks. The independent variables were: bone quality, drilling protocol, implant diameter, and implant length. Group A implants were inserted with a conventional drilling protocol, whereas Group B implants were inserted with an undersized drilling protocol. Values of IT and RFA were measured at implant installation. IT and RFA values were significantly correlated (Pearson correlation coefficient: 0.54). A multivariable analysis showed a strong model. Higher IT values were associated with drilling protocol B vs A (mean difference: 71.7 Ncm), implant length (3.6 Ncm increase per mm in length), and substrate density (0.199 Ncm increase per mg/cm3 in density). Higher RFA values were associated with drilling protocol B vs A (mean difference: 3.9), implant length (1.0 increase per mm in length), and substrate density (0.032 increase per mg/cm3 in density). Implant diameter was not associated with RFA or IT. Within the limitations of an in vitro study, the results of this study suggest that the studied implant can achieve good level of primary stability in terms of IT and RFA. A strong correlation was found between values of IT and RFA. Both parameters are influenced by the drilling protocol, implant length, and substrate density. Further studies are required to investigate the clinical response in primary stability and marginal bone response.

In vitro method for teaching percutaneous vascular catheterization.

1991 ◽  
Vol 157 (5) ◽  
pp. 1125-1125
Author(s):  
D J Eschelman ◽  
A J Greenfield ◽  
D T Gibbens
Keyword(s):  
In Vitro Method ◽  
Vascular Catheterization

scholarly journals Comparative In Vitro Evaluation of the Primary Stability in D3 Synthetic Bone of Two Different Shapes and Pitches of the Implant Threads

2021 ◽  
Vol 11 (12) ◽  
pp. 5612
Author(s):  
Stefano Fanali ◽  
Margherita Tumedei ◽  
Pamela Pignatelli ◽  
Alessandra Lucchese ◽  
Francesco Inchingolo ◽  
...  
Keyword(s):  
Surgical Techniques ◽  
Primary Stability ◽  
Implant Design ◽  
Insertion Torque ◽  
Synthetic Bone ◽  
One Stage ◽  
Prosthetic Joint ◽  
Joint Connection ◽  
The One

Background: Implant primary stability can be affected by several factors related to implant macrogeometry, local anatomy, and surgical techniques. The aim of this research was to study primary stability on polyurethane foam sheets of wide-threaded implant design compared to narrow-threaded implants. Materials and methods: Two different implant designs were positioned on D3 density polyurethane blocks in a standardized environment: the wide-threaded implant and the narrow-threaded implant, for a total of 160 specimens. Moreover, for each group, two different sizes were considered: 3.8mm × 12mm and 4.8mm × 12 mm. The insertion torque (IT) values, the removal strength (RT), and the Periotest analyses were evaluated. Results: A significantly higher IT and RT was reported for wide-threaded implants and two-stage implants (p < 0.01), compared to the narrow-threaded implants. The diameters seemed to provide a significant effect on the primary stability for both implants’ geometry (p < 0.01). A higher mean of the one-stage implant was evident in the Periotest measurements (p < 0.01). Conclusions: Both of the implants showed sufficient stability in polyurethane artificial simulation, while the wide-threaded implant design showed a higher primary stability on alveolar cancellous synthetic bone in vitro. Additionally, the prosthetic joint connection seemed to have a determinant effect on Periotest analysis, and the one-stage implants seemed to provide a high stability of the fixture when positioned in the osteotomy, which could be important for the immediate loading protocol.

An in Vitro Method for Measuring Ophthalmic Preservative Cytotoxicity

1986 ◽  
Vol 5 (4) ◽  
pp. 309-317 ◽  
Author(s):  
Paul S. Imperia ◽  
Hillard M. Lazarus ◽  
Roberte Botti ◽  
Jonathan H. Lass
Keyword(s):  
In Vitro Method

Primary Stability of Short Implants Inserted Using Piezoelectric or Drilling Systems: An In Vitro Comparison

2019 ◽  
Vol 45 (4) ◽  
pp. 259-266
Author(s):  
Claudio Stacchi ◽  
Matteo De Biasi ◽  
Lucio Torelli ◽  
Massimo Robiony ◽  
Roberto Di Lenarda ◽  
...  
Keyword(s):  
Cancellous Bone ◽  
Operative Time ◽  
Primary Stability ◽  
Site Preparation ◽  
Preparation Technique ◽  
Implant Stability ◽  
Implant Stability Quotient ◽  
Custom Made ◽  
Implant Site Preparation

The primary objective of the present in vitro study was to evaluate the influence of implant site preparation technique (drills vs ultrasonic instrumentation) on the primary stability of short dental implants with two different designs inserted in simulated low-quality cancellous bone. Eighty implant sites were prepared in custom-made solid rigid polyurethane blocks with two different low cancellous bone densities (5 or 15 pounds per cubic foot [PCF]), equally distributed between piezoelectric (Surgysonic Moto, Esacrom, Italy) and conventional drilling techniques. Two short implant systems (Prama and Syra, Sweden & Martina) were tested by inserting 40 fixtures of each system (both 6.0 mm length and 5.0 mm diameter), divided in the four subgroups (drills/5 PCF density; drills/15 PCF density; piezo/5 PCF density; piezo/15 PCF density). Insertion torque (Ncm), implant stability quotient values, removal torque (Ncm), and surgical time were recorded. Data were analyzed by 3-way ANOVA and Scheffé's test (α = 0.05). With slight variations among the considered dependent variables, overall high primary implant stability was observed across all subgroups. Piezoelectric instrumentation allowed for comparable or slightly superior primary stability in comparison with the drilling procedures in both implant systems. The Prama implants group showed the highest mean reverse torque and Syra implants the highest implant stability quotient values. Piezoelectric implant site preparation took prolonged operative time compared to conventional preparation with drills; among the drilling procedures, Syra system required fewer surgical steps and shorter operative time.

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