Assessment of Head Displacement and Disassembly Force With Increasing Assembly Load at the Head/Trunnion Junction of a Total Hip Arthroplasty Prosthesis

Ramoutar, Darryl; Crosnier, Emilie; Shivji, Faiz; Miles, A W; Gill, H. S.

doi:10.1016/j.arth.2016.11.054

Cited by 13 publications

(14 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During femoral head and trunnion assembly, care should be taken to make certain the trunnion is dry and void of any debris before assembly. While many manufacturers do not offer optimal assembly technique guides [43] it has been determined that an axially directed force of over 2.5kN should be utilized to optimize the modular connection between the head and trunnion of the stem [44]. When dealing with a revision scenario for a corroded trunnion, it has been shown that cleaning the trunnion and placing a new femoral head (CoCr or Ceramic) has no difference in stability of the head trunnion junction compared to pristine new tapers [45].…”

Section: Trunnion Corrosionmentioning

confidence: 99%

Trunnion Corrosion in Total Hip Arthroplasty—Basic Concepts

Urish

Giori

Lemons

et al. 2019

Orthopedic Clinics of North America

View full text Add to dashboard Cite

There has been an increased interest in the role of corrosion in total hip arthroplasty. This is based on reports of early implant failures and adverse local tissue reaction resulting from excessive corrosion at the modular interfaces of some implant designs. Orthopedic alloys are not selected based solely on their mechanical properties of strength, but rather because they possess the best balance between material properties of corrosion resistance and mechanical properties of strength. The passive layer of a metal oxide that develops on a surface of a metal serves a critical role in preventing corrosion. However, this protective layer is a dynamic structure. Aggressive corrosion occurs on implants when the kinetics of this oxide layer's destruction dominates over its generation. There is a spectrum of different types of corrosion defined by the environment and stability of the passive layer. Pitting is the localized dissolution of this protective metal oxide film. Crevice corrosion occurs with a similar mechanism but in an isolated environment that promotes corrosion. Fretting corrosion or mechanically assisted crevice corrosion (MACC) occurs with the addition of mechanical oscillating loads at the modular junction that disrupts this protective layer. Understanding this process is important to improve implant designs, surgical technique, and assessment of patients.

show abstract

Section: Trunnion Corrosionmentioning

confidence: 99%

Trunnion Corrosion in Total Hip Arthroplasty—Basic Concepts

Urish

Giori

Lemons

et al. 2019

Orthopedic Clinics of North America

View full text Add to dashboard Cite

show abstract

“…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%

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

Rieker

Wahl

2020

Materials

View full text Add to dashboard Cite

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.

show abstract

“…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. Nevertheless, the study shows that the assembly forces can vary greatly between surgeons and that this in uences the strength of a Morse taper junction [14,15]. The aim of this study was to investigate the assembly forces of different surgeons under in situ conditions.…”

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

View full text Add to dashboard Cite

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.

show abstract

Assessment of Head Displacement and Disassembly Force With Increasing Assembly Load at the Head/Trunnion Junction of a Total Hip Arthroplasty Prosthesis

Abstract: An assembly force of 2 kN may be too low to overcome the frictional forces needed to engage the head and achieve maximum displacement on the trunnion and thus an assembly load of greater than 2.5 kN is recommended.

Cited by 13 publications

References 20 publications

Trunnion Corrosion in Total Hip Arthroplasty—Basic Concepts

Trunnion Corrosion in Total Hip Arthroplasty—Basic Concepts

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

Contact Info

Product

Resources

About