Die Bedeutung der Setzkraft für die Sicherheit einer Konuskopplung von Hüftstiel und keramischem Prothesenkopf / Relevance of the insertion force for the taper lock reliability of a hip stem and a ceramic femoral head

Nassutt, R.; Mollenhauer, I.; Klingbeil, K.; Henning, Oliver; Gründei, H.

doi:10.1515/bmt.2006.018

Cited by 45 publications

(27 citation statements)

References 5 publications

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“…In both models, the fixation force correlates linearly with the force applied to impact the taper. The fixation force, therefore, has a major effect on the stability of the taper connection [6,[44][45][46][47][48][49][50][51][52]. Because the taper angle α is determined by the chosen prosthesis design (typically between 5 • 30 and 6 • [36]), this parameter has to be considered as fixed.…”

Section: Technical Aspects Of Taper Connections In Hip Arthroplastymentioning

confidence: 99%

“…Impaction with at least 4000 N is recommended. An adequate impaction force can be reached with a strong blow from a 500 g hammer [46,50]. Surgeons should become familiar and proficient with force-measuring instruments, especially those surgeons with low levels of experience in arthroplasty, to avoid the application of insufficient or off-axis impaction force [46].…”

Section: Surgeon-related Factors Determining Taper Fixationmentioning

confidence: 99%

“…An adequate impaction force can be reached with a strong blow from a 500 g hammer [46,50]. Surgeons should become familiar and proficient with force-measuring instruments, especially those surgeons with low levels of experience in arthroplasty, to avoid the application of insufficient or off-axis impaction force [46]. The settings of the instrumentation should be checked carefully to ensure that the force measured corresponds to the potential assembly force, and not the force applied with the hammer.…”

Section: Surgeon-related Factors Determining Taper Fixationmentioning

confidence: 99%

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What the Surgeon Can Do to Reduce the Risk of Trunnionosis in Hip Arthroplasty: Recommendations from the Literature

Rieker

Wahl

2020

Materials

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Trunnionosis, defined as wear and corrosion at the head-neck taper connection, is a cause of failure in hip arthroplasty. Trunnionosis is linked to a synergistic combination of factors related to the prosthesis, the patient, and the surgeon. This review presents analytical models that allow for the quantification of the impact of these factors, with the aim of providing practical recommendations to help surgeons minimize the occurrence of this failure mode. A tighter fit reduces micromotion and, consequently, fretting of the taper connection. The paramount parameters controlling the fixation force are the coefficient of friction and the impaction force. The influence of the head diameter, as well as of the diameter and angle of the taper, is comparatively small, but varus alignment of the taper and heads with longer necks are unfavourable under physiologic loads. The trunnion should be rinsed, cleaned, and dried carefully, while avoiding any contamination of the bore-the female counterpart within the head-prior to assembly. Biological debris, and even residual water, might critically reduce the fixation of the taper connection between the head and the neck. The impaction force applied to the components should correspond to at least two strong blows with a 500 g hammer, striking the head with an ad hoc impactor aligned with the axis of the taper. These strong blows should correspond to a minimum impaction force of 4000 N.

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Section: Technical Aspects Of Taper Connections In Hip Arthroplastymentioning

confidence: 99%

Section: Surgeon-related Factors Determining Taper Fixationmentioning

confidence: 99%

Section: Surgeon-related Factors Determining Taper Fixationmentioning

confidence: 99%

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What the Surgeon Can Do to Reduce the Risk of Trunnionosis in Hip Arthroplasty: Recommendations from the Literature

Rieker

Wahl

2020

Materials

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“…However, it must be assumed that such a hammer blow is performed very individually by the surgeon and is therefore not reproducible. This is illustrated by Nasutt et al [16] who compared the assembly forces resulting from hammer blows of 39 surgeons. It was shown that the force varies between 0.27 kN and 7.85 kN [16].…”

Section: Introductionmentioning

confidence: 99%

“…This is illustrated by Nasutt et al [16] who compared the assembly forces resulting from hammer blows of 39 surgeons. It was shown that the force varies between 0.27 kN and 7.85 kN [16]. However, these were only trials on a test rig, so it must be assumed that the absolute values in surgery are different due to soft tissue damping.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Assembly Forces During Creation of Head-Neck Taper Junction Following Total Hip Arthroplasty: A Biomechanical Study

Wendler

Prietzel

Möbius

et al. 2020

Preprint

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BackgroundAll current total hip arthroplasty (THA) systems are modular in design. Only during the operation femoral head and stem get connected by a Morse taper junction. The junction is realized by hammer blows from the surgeon. Decisive for the junction strength is the maximum force acting once in direction of the neck axis, which depends both on the applied impulse and the damping of human soft tissues. This leads to large differences in assembly forces between the surgeons. The investigation of assembly forces of different surgeons under influence of soft tissue damping is subject of this study.MethodsFirst, a measuring system, consisting of a prosthesis and a hammer, was developed. Both components are equipped with a piezoelectric force sensor. Initially, in situ experiments on human cadavers were carried out using this system in order to determine the actual assembly forces and to characterize the damping properties of human soft tissue. In addition to these experiments, an in vitro model in form of an artificial femur (Sawbones Europe AB, Malmo, Sweden) with implanted measuring stem embedded in gelatine was developed. The gelatine mixture was chosen in such a way that damping properties of the model correspond to those in situ. A study with 31 surgeons was carried out on the in vitro model mentioned above, in which the assembly forces were determined.ResultsA model has been developed, that represents the physiological damping behaviour of human soft tissue. The assembly forces measured on in vitro model were on average 2037.2 N ± 724.9 N and ranged from 822.5 N to 3835.2 N. The comparison of the surgeons showed no significant differences regarding sex (p=0.09), work experience (p=0.71) and number of THAs per year (p=0.69).ConclusionsAll measured assembly forces were below 4 kN, which is recommended in the literature. This could lead to increased corrosion following fretting in the head-neck interface. In addition, there was a very wide range of assembly forces among the surgeons, although other influencing factors such as different implant sizes or materials were not taken into account. To ensure optimal assembly force, the impaction should be standardized, e.g. by an appropriate surgical instrument.

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Effect of impact assembly on the interface deformation and fretting corrosion of modular hip tapers: An in vitro study

Panagiotidou

Cobb

Meswania

et al. 2017

Journal Orthopaedic Research

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Wear and corrosion at the modular head-neck junction has been recognised to be a potential clinical concern, with multiple reports on adverse local tissue reactions and subsequent early failure of metal-on-metal hip replacements. Furthermore, reports on head-neck taper corrosion are also being described with conventional metal-on-polyethylene bearings. Manufacturing tolerances, surgical technique, non-axial alignment, material combination, high frictional torque and high bending moment have all been implicated in the failure process. There is limited guidance on the force of impaction with which surgeons should assemble modular hip prostheses. This study aims to investigate the effect of impaction force on the deformation and corrosion of modular tapers. Short neck tapers with high surface roughness (average R = 16.58 μm, R = 4.14μm) and long neck tapers with low surface roughness (average R = 3.82 μm, R = 0.81μm), were assembled with CoCrMo alloy heads (smooth finish) under controlled conditions with 2, 4 or 8 kN of impaction force. Material combinations tested included CoCrMo-head/CoCrMo-neck and CoCrMo-head/Ti-6Al-4V-neck. Assessment of surface deformation before and after impaction was made using surface profilometry. Measurement of fretting current during sinusoidal cyclic loading evaluated mechanically assisted corrosion for each assembly load during short-term cyclic loading (1000-cycles) and long-term cyclic loading (5 million-cycles). Deformation on head and neck tapers increased with assembly load. Fretting currents during short term simulation testing showed significantly lower currents (p < 0.05), in 8 kN assemblies when compared to 2 and 4 kN, especially for the short-rough tapers. Long-term simulator testing demonstrated a progressive reduction in fretting corrosion for samples impacted with 4 and 8 kN; however, this reduction was greater for samples impacted at 8 kN even at the start of testing. Based on our results, surgeons could minimise mechanically assisted crevice corrosion by using higher impact loads when assembling the head to the stem in total hip arthroplasty. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:405-416, 2018.

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Die Bedeutung der Setzkraft für die Sicherheit einer Konuskopplung von Hüftstiel und keramischem Prothesenkopf / Relevance of the insertion force for the taper lock reliability of a hip stem and a ceramic femoral head

Cited by 45 publications

References 5 publications

What the Surgeon Can Do to Reduce the Risk of Trunnionosis in Hip Arthroplasty: Recommendations from the Literature

What the Surgeon Can Do to Reduce the Risk of Trunnionosis in Hip Arthroplasty: Recommendations from the Literature

Investigation of Assembly Forces During Creation of Head-Neck Taper Junction Following Total Hip Arthroplasty: A Biomechanical Study

Effect of impact assembly on the interface deformation and fretting corrosion of modular hip tapers: An in vitro study

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