Effect of trunnion roughness and length on the modular taper junction strength under typical intraoperative assembly forces

Jauch-Matt, Sabrina; Miles, A W; Gill, H. S.

doi:10.1016/j.medengphy.2016.11.001

Cited by 22 publications

(19 citation statements)

References 63 publications

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“…When the relation of the pull-off force to the dynamic load of 3 kN was compared, it was nearly the same as in the static group, with a mean relation of 53% (intact: 50%, scratched: 59%, and truncated: 50%). This is in line with previous studies, which showed a linear relationship between assembly and pull-off force [4,18,31,37]. In further investigations, an assembly load above the maximum load during dynamic testing has to be analysed in order to determine whether the dynamic load has an influence on the fixation strength of the taper connection.…”

Section: Discussionsupporting

confidence: 78%

Influence of Different Damage Patterns of the Stem Taper on Fixation and Fracture Strength of Ceramic Ball Heads for Total Hip Replacement

Vogel

Hembus

Jackszis

et al. 2020

BioMed Research International

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Background. Modularity finds frequent application in total hip replacement, allowing a preferable individual configuration and a simplified revision by retaining the femoral stem and replacing the prosthetic head. However, micromotions within the interface between the head and the stem taper can arise, resulting in the release of wear debris and corrosion products. The aim of our experimental study was to evaluate the influence of different taper damages on the fixation and fracture stability of ceramic femoral heads, after static and dynamic implant loading. Methods. Ceramic ball heads (36 mm diameter) and 12/14 stem tapers made of titanium with various mild damage patterns (intact, scratched, and truncated) were tested. The heads were assembled on the taper with a quasistatic load of 2 kN and separated into a static and a dynamic group afterwards. The dynamic group (n=18) was loaded over 1.5 million gait cycles in a hip wear simulator (ISO 14242-1). In contrast, the static group (n=18) was not mechanically loaded after assembly. To determine the taper stability, all heads of the dynamic and static groups were either pulled off (ASTM 2009) or turned off (ISO 7206-16). A head fracture test (ISO 7206-10) was also performed. Subsequent to the fixation stability tests, the taper surface was visually evaluated in terms of any signs of wear or corrosion after the dynamic loading. Results. In 10 of the 18 cases, discoloration of the taper was determined after the dynamic loading and subsequent cleaning, indicating the first signs of corrosion. Pull-off forces as well as turn-off moments were increased between 23% and 54% after the dynamic loading compared to the unloaded tapers. No significant influence of taper damage was determined in terms of taper fixation strength. However, the taper damage led to a decrease in fracture strength by approximately 20% (scratched) and 40% (truncated), respectively. Conclusion. The results suggest that careful handling and accurate manufacturing of the stem taper are crucial for the ceramic head fracture strength, even though a mild damage showed no significant influence on taper stability. Moreover, our data indicate that a further seating of the prosthetic head may occur during daily activities, when the resulting hip force increases the assembly load.

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Section: Discussionsupporting

confidence: 78%

Influence of Different Damage Patterns of the Stem Taper on Fixation and Fracture Strength of Ceramic Ball Heads for Total Hip Replacement

Vogel

Hembus

Jackszis

et al. 2020

BioMed Research International

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“…When all other parameters are equal, MacLeod's model estimates a higher fixation force than Fessler's model by about a third ( Figure 2). However, when considering the technical aspects of the different experimental setups, nearly all fixation force values described in the literature correspond to the values estimated by Fessler's formula, ranging 40% to 55% of the impaction force [6,21,44,[47][48][49][50][51][52]. Surprisingly, the values measured by MacLeod et al do not correspond to those estimated by their own model [43].…”

Section: Technical Aspects Of Taper Connections In Hip Arthroplastymentioning

confidence: 70%

“…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%

“…Interestingly, the influence of the head size is not always seen on retrievals [62]. In addition, and perhaps somewhat counterintuitively, the length of the trunnion does not appear to have a significant impact on micromotion or fixation force [47,64]. Increased trunnionosis has also been linked with low flexural rigidity necks (i.e., those with increased elasticity) [65] and small taper Symptomatic trunnionosis appears to be associated with increased head offsets and longer neck lever arms [21,22,56,57].…”

Section: Technical Aspects Of Taper Connections In Hip Arthroplastymentioning

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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“…Machined profiles on trunnions used with ceramic heads were introduced to reduce tensile stresses at the taper interface, but trunnions with threaded stems are now commonly mated with either ceramic or metal head tapers . In addition surgical factors such as low impaction force (<4 kN), off‐axis impaction and taper contamination coupled with an increase in trunnion flexibility, due to the use of lower elastic modulus alloys, have all been reported to facilitate crevice corrosion . Taper geometry itself has evolved, including a reduction in both taper diameter and trunnion length .…”

Section: Introductionmentioning

confidence: 99%

Prediction of taper performance using quasi static FE models: The influence of loading, taper clearance and trunnion length

Raji

Shelton

2018

J Biomed Mater Res

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The head-neck taper junction has been widely reported to corrode leading to adverse tissue reactions. Taper corrosion is a poorly understood phenomenon but has been associated with oxide layer damage and ingress of corrosive physiological fluids. Micromotion may damage the oxide layer; although little is understood about the prevailing stresses which cause this. The ingress of fluid around the joint space into the taper will depend on the taper contact position and the separation of the interfaces during loading. The current work reports on the effect of taper clearances and trunnion length on the taper surface stresses and the taper gap opening. These were determined for CoCr/Ti taper interfaces using FE under loading conditions including walking and stair climb as well as hip simulator load profiles. Shorter trunnions and stair climb loading were shown to generate the greatest taper gaps (82 µm) and also the largest surface stresses (1200 MPa) on the head taper. The largest taper gaps were associated with smaller taper contact areas. Clearances within ±0.1° had no effect on the taper gaps generated, as the tapers engaged over comparable lengths; the taper gap opening was dependent upon the taper engagement length rather than location (proximal or distal) of contact. The walking profile or variants applied by hip simulators, was insufficient to differentiate between taper designs and evaluate differences in the magnitudes of taper gaps. The use of more demanding activity such as stair climb during in vitro evaluations could provide better predictions of taper performance in vivo. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018.

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Effect of trunnion roughness and length on the modular taper junction strength under typical intraoperative assembly forces

Cited by 22 publications

References 63 publications

Influence of Different Damage Patterns of the Stem Taper on Fixation and Fracture Strength of Ceramic Ball Heads for Total Hip Replacement

Influence of Different Damage Patterns of the Stem Taper on Fixation and Fracture Strength of Ceramic Ball Heads for Total Hip Replacement

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

Prediction of taper performance using quasi static FE models: The influence of loading, taper clearance and trunnion length

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