Stainless steel femoral heads reduce rate of revision when compared to ion implanted chromium-cobalt heads with the Exeter V40 stem: An analysis of 40 468 total hip replacements from the AOANJRR

Ceramic-on-ceramic bearings for total hip replacement are considered the best choice to avoid problems such as osteolysis and wear, mainly related to soft bearings. The aim of this work was to investigate in a comparative way different kinds of ceramic femoral heads for total hip replacements from a biotribological point of view, discussing the results obtained in terms of topographies, presence of metal transfer (MT) phenomena, and wettability on their worn surfaces in a tribological framework. Different ceramic femoral heads derived from in vitro wear tests, retrieved form patients, and brand new total hip replacements were investigated. The patients group had an average age of 60 years (ranging from 27 to 83). In most cases, the cause of failure was aseptic loosening of the acetabular component. Roughness analyses were performed to measure the tribological surface evolution of the material; an SEM and EDS investigation on the explanted heads proves and quantified MT, while the wettability was measured through a novel optical laboratory set-up with the aim to furnish useful data in the framework of synovial lubrication phenomena acting in the tribosystem. For the average roughness measurements on explanted specimens were considered three parameters (Ra = the average area between the roughness profile and its mean line; Rt = the vertical distance from the deepest valley to the highest peak of the roughness profile; and Rsk = it is the skewness and it is a measure of the asymmetry of the amplitude distribution function. In other words, the skewness indicates whether a surface is dominated by peaks or by valleys) and their values were: Ra 0.22 ± 0.12 μm, Rt 34.5 ± 13.5 μm and Rsk −0.01 ± 11.3; on the new specimens we measured Ra 0.01 ± 0.001 μm, Rt 0.12 ± 0.09 μm, and Rsk = 5.67 ± 8.7; for the in vitro specimens they were Ra 0.05 ± 0.12 μm, Rt 0.71 ± 1.4 μm and Rsk 7.73 ± 20.6. The wettability angle measurements showed hydrophilic surfaces for all femoral heads considered in this study with small differences between the three investigated categories, allowing to discuss their effects on the biobearings’ lubrication phenomena.

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An Experimental Study of Metallic Transfer on Ceramic Femoral Heads

ASME 2009 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2009-206351 ◽

2009 ◽

Author(s):

Douglas M. Doud ◽

Preston R. Beck ◽

Donald R. Petersen ◽

Jack E. Lemons ◽

Alan W. Eberhardt

Keyword(s):

Experimental Study ◽

Femoral Head ◽

Life Expectancy ◽

Metal Transfer ◽

Acetabular Cup ◽

Total Hip ◽

Total Hip Replacements ◽

Femoral Heads ◽

Hip Replacements ◽

Postoperative Dislocation

Postoperative dislocation of total hip replacements has been documented to occur at a rate of approximately 2.4–3.9% [1–3]. Such events may result in the transfer of titanium from the acetabular cup to the femoral head, both during the dislocation and surgical reduction of the dislocated joint [3,4]. If the head is reduced with this transfer present, the joint life expectancy, which depends on articulating surfaces remaining smooth, is reduced [4]. Although the presence of metal transfer on retrieved femoral heads after dislocation is documented, no previous studies have attempted to quantify the forces or contact stresses at which metal transfer occurs.

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Assessment of Titanium Alloy on Polyethylene Bearing Surfaces in Retrieved Uncemented Total Hip Replacements

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/pime_proc_1994_208_270_02 ◽

1994 ◽

Vol 208 (2) ◽

pp. 91-95 ◽

Cited By ~ 4

Author(s):

K J Drabu ◽

R J Michaud ◽

P J J McCullagh ◽

K Brummitt ◽

R A Smith

Keyword(s):

Titanium Alloy ◽

Hip Arthroplasty ◽

Surface Finish ◽

Revision Surgery ◽

Articular Surface ◽

Total Hip ◽

Total Hip Replacements ◽

Femoral Heads ◽

Hip Replacements ◽

Bone Particles

Changes to the bearing surfaces of eighteen uncemented total hip replacements retrieved at revision surgery were assessed by three-dimensional binocular microscopy, Rank Taylor Hobson talysurf measurements, scanning electron microscopy, and X-ray dispersive analysis. Abrasions on the non-articular surface of the polyethylene cups were present. Bone particles were found in tracks in the bearing surfaces of both the titanium femoral heads and the polyethylene cups and were responsible for wear of these surfaces. Although the wear of the femoral heads appeared substantial to naked eye examination, the surface finish of these surfaces remained within the British ISO standards for titanium alloy when assessed by the methods used above. This study concluded that direct contact between polyethylene and bone should be avoided in total hip arthroplasty and that ‘third body’ wear from bone particles occurred in these uncemented prostheses. Both components of this type of implant should be replaced at revision surgery and titanium should be avoided as a bearing surface in hip arthroplasty. Present methods of assessing the surface finish of titanium should be re-evaluated and more reliable ones considered.

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An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

Applied Sciences ◽

10.3390/app11062852 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2852

Author(s):

Maeruan Kebbach ◽

Christian Schulze ◽

Christian Meyenburg ◽

Daniel Kluess ◽

Mevluet Sungu ◽

...

Keyword(s):

Range Of Motion ◽

Internal Rotation ◽

Computer Aided Design ◽

External Rotation ◽

Patient Specific ◽

Computational Framework ◽

Total Hip ◽

Total Hip Replacements ◽

Significant Difference ◽

Hip Replacements

The calculation of range of motion (ROM) is a key factor during preoperative planning of total hip replacements (THR), to reduce the risk of impingement and dislocation of the artificial hip joint. To support the preoperative assessment of THR, a magnetic resonance imaging (MRI)-based computational framework was generated; this enabled the estimation of patient-specific ROM and type of impingement (bone-to-bone, implant-to-bone, and implant-to-implant) postoperatively, using a three-dimensional computer-aided design (CAD) to visualize typical clinical joint movements. Hence, patient-specific CAD models from 19 patients were generated from MRI scans and a conventional total hip system (Bicontact® hip stem and Plasmacup® SC acetabular cup with a ceramic-on-ceramic bearing) was implanted virtually. As a verification of the framework, the ROM was compared between preoperatively planned and the postoperatively reconstructed situations; this was derived based on postoperative radiographs (n = 6 patients) during different clinically relevant movements. The data analysis revealed there was no significant difference between preoperatively planned and postoperatively reconstructed ROM (∆ROM) of maximum flexion (∆ROM = 0°, p = 0.854) and internal rotation (∆ROM = 1.8°, p = 0.917). Contrarily, minor differences were observed for the ROM during maximum external rotation (∆ROM = 9°, p = 0.046). Impingement, of all three types, was in good agreement with the preoperatively planned and postoperatively reconstructed scenarios during all movements. The calculated ROM reached physiological levels during flexion and internal rotation movement; however, it exceeded physiological levels during external rotation. Patients, where implant-to-implant impingement was detected, reached higher ROMs than patients with bone-to-bone impingement. The proposed framework provides the capability to predict postoperative ROM of THRs.

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