The Function of Bipolar Hip Prostheses—A Laboratory Study Using Cadaveric Acetabula

1992 ◽  
Vol 206 (1) ◽  
pp. 37-42 ◽  
Author(s):  
R G Wetherell ◽  
A Unsworth ◽  
A A Amis
Keyword(s):  
Femoral Head ◽  
Laboratory Study ◽  
Hip Prosthesis ◽  
Weight Bearing ◽  
The Self ◽  
Head Size ◽  
Separate Study ◽  
Hip Prostheses ◽  
Hip Simulator

Cadaveric acetabula were mounted in a hip simulator and the friction developed in each during articulation with a series of metal femoral head prostheses of differing sizes was measured. In a separate study, assembled Hastings bipolar hip prostheses were subjected to weight-bearing forces in the same acetabula and their self-righting mechanism was observed. The self-righting mechanism was found to function efficiently, in most cases overcoming the combined friction of the inner and outer articulations of the Hastings hip. However, during motion in the hip simulator a wide variation of friction was observed between different acetabula and within the same acetabulum with differing head size. In several cases this acetabular friction was found to be less than the friction in the inner articulation of the Hastings bipolar hip prosthesis, and this may explain some cases of reported failure of biarticular function.

scholarly journals Spontaneous Early Intraprosthetic Dislocation of 22 mm Skirted Femoral Head in Dual Mobility Hip Prosthesis: A Case Report

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Gur Aziz Singh Sidhu ◽  
Amit Kotecha ◽  
Sanjay Mulay ◽  
Neil Ashwood
Keyword(s):  
Case Report ◽  
Femoral Head ◽  
Revision Surgery ◽  
Hip Prosthesis ◽  
Weight Bearing ◽  
Femoral Stem ◽  
Acetabular Cup ◽  
Dual Mobility ◽  
Metal Head ◽  
Intraprosthetic Dislocation

Introduction: There is a trend for increasing use of dual mobility hip designs for both primary and revision hip arthroplasty settings. It provides dual articular surfaces along with increased jump distance to increase the stability of construct. However, this design has some unique complications of its own which surgeons should be aware of especially intraprosthetic dislocation (IPD). Case Report: A 76-year-old lady presented to clinic with painful hip hemiarthroplasty after fracture neck of femur. She underwent revision surgery with dual mobility uncemented acetabular cup and femoral stem was retained as it was well fixed. She was mobilizing well and around 5 weeks post her surgery, developed pain in hip region and difficulty in weight-bearing. Radiographs showed eccentric position of femoral neck in the socket. A diagnosis of IPD was established and revision surgery was planned. Intraoperatively, metal head had dislocated from the polyethylene head and both components were resting in the acetabular socket. No macroscopic erosion of acetabulum was noticed. The polyethylene component and femoral head were retrieved. With previous failed dual mobility, decision was made to achieve stability with larger head size and lipped liner posteriorly. Conclusion: IPD is a rare occurrence and unique complication to dual mobility implants. This report highlights that patients can have IPD without fall or trauma. Keywords: Intraprosthetic dislocation, dual mobility cup, dislocation, total hip replacement.

Hip simulator evaluation of the effect of femoral head size on sequentially cross-linked acetabular liners

Wear ◽  
2007 ◽  
Vol 263 (7-12) ◽  
pp. 1034-1037 ◽  
Author(s):  
Lizeth Herrera ◽  
Reginald Lee ◽  
Jason Longaray ◽  
Aaron Essner ◽  
Aiguo Wang
Keyword(s):  
Femoral Head ◽  
Head Size ◽  
Femoral Head Size ◽  
Hip Simulator

Research Report 7: A Laboratory Experiment on Total Hip Prosthesis

1966 ◽  
Vol 181 (10) ◽  
pp. 140-141 ◽  
Author(s):  
A. Poli
Keyword(s):  
Stainless Steel ◽  
Femoral Head ◽  
Laboratory Experiment ◽  
Hip Prosthesis ◽  
Weight Bearing ◽  
Research Report ◽  
Mechanical Device ◽  
Total Hip Prosthesis ◽  
Total Hip ◽  
Femoral Heads

A simple mechanical device for testing weight-bearing resistance of total hip prosthesis has been developed. Head and cotyle are submitted to movement very close to that of natural hips of a man walking at 6 km/h. Stainless steel femoral heads have been tested against artificial cotyles made of three different materials: Nylonplast A, Teflon and Delrin. Among the three, Delrin proved the most resistant and safest material for building the cotyle when a steel femoral head is used.

Modularity of total hip prosthesis and its tribological implications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liliana-Laura Badita ◽  
Virgil Florescu ◽  
Constantin Tiganesteanu ◽  
Lucian Capitanu
Keyword(s):  
Femoral Head ◽  
Hip Prosthesis ◽  
Femoral Stem ◽  
Fretting Wear ◽  
Fretting Corrosion ◽  
Content Type ◽  
Hip Prostheses ◽  
Total Hip ◽  
Starting Point ◽  
Modular Prostheses

Purpose The study aims to analyze the fretting phenomenon, manifested at the taper junctions of modular total hip prostheses (THP). Modularity of prostheses implies the micro-movement occurrence. Fractures can arise as a result of the fretting cracking of the prostheses components, affecting durability of modular THPs. Fretting corrosion is associated with the decrease in the clinical acceptance of hip modular implants. Design/methodology/approach Starting from the fretting phenomenon influence on modularity, monoblock THPs and prostheses with modular femoral head recovered from some review surgeries were investigated. Modular prostheses have a taper junction femoral head – femoral stem neck. Investigation consisted in the analysis of fretting wear and fretting corrosion, of the femoral heads’ taper and of the femoral stems’ trunnions. Findings The main result was that the micro-movement that provokes the fretting of the femoral head-femoral stem taper junction analyzed does not have the same direction. It is manifesting in the direction of the axis of the femoral head taper, around this axis or as a composed movement. The authors suspect that this is due to the different design of the taper. In this way, the inclination of the stem’s trunnion into the head hole has a different angular misalignment and may cause greater damages of the taper. Originality/value This result can be a starting point from the improvement of the future taper junctions design that will improve the quality, durability and modularity of THPs.

scholarly journals A Computational Analysis of Squeaking Hip Prostheses

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Ehsan Askari ◽  
Paulo Flores ◽  
Danè Dabirrahmani ◽  
Richard Appleyard
Keyword(s):  
Femoral Head ◽  
Hip Prosthesis ◽  
Angular Speed ◽  
Initial Position ◽  
Force Model ◽  
Stick Slip ◽  
Hip Prostheses ◽  
Continuous Contact ◽  
Joint Friction ◽  
Implant Size

A ceramic-on-ceramic (CoC) hip prosthesis with clearance is modeled as a multibody dynamics system for the purpose of studying hip squeaking. A continuous contact force model provides the intrajoint forces developed at the hip joint. Friction effects due to the relative motion are also considered. A FFT analysis of the audible sounds from CoC hip acceleration is carried out to analyze hip squeaking. The effects of friction, hip implant size, and the head initial position on hip squeaking and the trajectory of femoral head are analyzed and discussed. It was shown that the causes of hip squeaking are stick/slip, friction-induced vibration, and the femoral head angular speed and force changes.

Our Experience with Alumina on Alumina Weight Bearing in Everyday Orthopedic Practice

2014 ◽  
Vol 614 ◽  
pp. 212-217
Author(s):  
Dan Grecu ◽  
Dan Tarnita ◽  
Daniela Tarniţă ◽  
D.R. Nita
Keyword(s):  
Femoral Head ◽  
Hip Prosthesis ◽  
Weight Bearing ◽  
Lateral Wall ◽  
Acetabular Cup ◽  
Ceramic Bearing ◽  
The Mean ◽  
Almost All ◽  
Mid Term Results

The research for an ideal hip prosthesis has led to the development of several durable materials that have been tested very intensly during the past decades, both clinically and mechanically. Alumina on alumina bearing has proven to be a very reliable bearing and is used more and more often. Nevertheless, because of the lack of ductility of alumina ceramic, concerns have been raised regarding its risk of fracture. The purpose of our study is to evaluate the mid-term results (78 months follow-up) of alumina on alumina prosthesis and the complications that have appeared regarding to the properties of the implant. We have reviewed retrospectively 89 THA performed in our clinic during October 2005 – October 2013 on a follow-up period of maximum 78 months. The mean age of the patients included was 49,60 years for men and 48,44 years for women. It was used a single kind of implant with same type of alumina parts, applied only on a postero-lateral surgical approach. The survival rate of ceramic-on-ceramic bearing surface by itself was 98.87% (88 out of 89). The most frequent complication was the dislocation of the prosthesis that happened in 7 cases, mainly due to a malposition of the acetabular cup, without any damage done to the ceramic bearing surfaces. In the failed case we have encountered a cracked femoral head that has been previously resterilized by steam. We could conclude that the alumina on alumina prosthesis is a very reliable prosthesis regarding its durability and strength. It requires a very precise surgical technique when implanted, since almost all the complications were due to a malposition of the acetabular component. A postero-lateral wall of the liner might decrease the rate of dislocations and ceramic wear. Also, we might debate that the steam sterilization is not suitable for alumina implants, since the fractured femoral head was resterilized.

scholarly journals Reducing Contact Stress of the Surface by Modifying Different Hardness of Femoral Head and Cup in Hip Prosthesis

2021 ◽  
Vol 7 ◽  
Author(s):  
Eko Saputra ◽  
Iwan Budiwan Anwar ◽  
J. Jamari ◽  
Emile van der Heide
Keyword(s):  
Femoral Head ◽  
Contact Stress ◽  
Hip Prosthesis ◽  
Hip Prostheses ◽  
Wear Process ◽  
Element Simulation ◽  
Static Contact ◽  
Surface Contact ◽  
The Difference ◽  
Wear Law

The wear of hip prosthesis due to applied load and sliding distance during the patient's daily activity cannot be avoided. Wear causes osteolysis or metallosis due to the wear debris produced by the wear process. Several methods were used to reduce wear in metal-on-metal hip prostheses. One of the efforts performed to reduce wear was the differential-hardness concept. Based on the literature, the fine surface roughness of the femoral head are the reason why the hip prosthesis with differential-hardness reduces wear. Besides, the differential-hardness will contribute to the difference of modulus elasticity then influenced the contact stress on the surface contact. According to Archard's wear law, wear on the material pair is affected by contact stress. Therefore, the analysis of contact stress on the hip prosthesis with differential-hardness is important to investigate. The investigation performed by the static contact of two-dimensional axisymmetric with frictionless by using finite element simulation. The simulated models are the alumina vs. alumina, alumina vs. SS316L, CoCr vs. CoCr, CoCr vs. SS316L, and SS316L vs. UHMWPE. The purpose of this study is to determine the contact stress on the surface contact due to differential-hardness of the femoral head and cup. The results of simulations show that the differential-hardness marked by differences in the modulus of elasticity can reduce the contact stress on the surface contact if compare with the similar hardness.

scholarly journals Does the Femoral Head Size in Hip Arthroplasty Influence Lower Body Movements during Squats, Gait and Stair Walking? A Clinical Pilot Study Based on Wearable Motion Sensors

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3240 ◽  
Author(s):  
Helena Grip ◽  
Kjell G Nilsson ◽  
Charlotte K Häger ◽  
Ronnie Lundström ◽  
Fredrik Öhberg
Keyword(s):  
Femoral Head ◽  
Hip Arthroplasty ◽  
Hip Prosthesis ◽  
Normal Function ◽  
Head Size ◽  
Motion Sensors ◽  
Lower Body ◽  
Femoral Head Size ◽  
Large Femoral Head ◽  
Stair Walking

A hip prosthesis design with larger femoral head size may improve functional outcomes compared to the conventional total hip arthroplasty (THA) design. Our aim was to compare the range of motion (RoM) in lower body joints during squats, gait and stair walking using a wearable movement analysis system based on inertial measurement units (IMUs) in three age-matched male groups: 6 males with a conventional THA (THAC), 9 with a large femoral head (LFH) design, and 8 hip- and knee-asymptomatic controls (CTRL). We hypothesized that the LFH design would allow a greater hip RoM, providing movement patterns more like CTRL, and a larger side difference in hip RoM in THAC when compared to LFH and controls. IMUs were attached to the pelvis, thighs and shanks during five trials of squats, gait, and stair ascending/descending performed at self-selected speed. THAC and LFH participants completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS). The results showed a larger hip RoM during squats in LFH compared to THAC. Side differences in LFH and THAC groups (operated vs. non-operated side) indicated that movement function was not fully recovered in either group, further corroborated by non-maximal mean HOOS scores (LFH: 83 ± 13, THAC: 84 ± 19 groups, vs. normal function 100). The IMU system may have the potential to enhance clinical movement evaluations as an adjunct to clinical scales.

Novel methods for demonstrating osseointegration of hydroxylapatite-coated titanium hip prostheses

1991 ◽  
Vol 49 ◽  
pp. 34-35 ◽  
Author(s):  
P. Frayssinet ◽  
J. Hanker ◽  
D. Hardy ◽  
B. Giammara
Keyword(s):  
Hip Prosthesis ◽  
Ethanol Concentration ◽  
Bone Matrix ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Hip Prostheses ◽  
Cellular Inclusions ◽  
Microscopic Studies ◽  
Diamond Saw ◽  
Plasma Sprayed

Prostheses implanted in hard tissues cannot be processed for electron microscopic examination or microanalysis in the same way as those in other tissues. For these reasons, we have developed methods allowing light and electron microscopic studies as well as microanalysis of the interface between bone and a metal biomaterial coated by plasma-sprayed hydroxylapatite(HA) ceramic.An HA-coated titanium hip prosthesis (Corail, Landos, France), which had been implanted for two years, was removed after death (unrelated to the orthopaedic problem). After fixation it was dehydrated in solutions of increasing ethanol concentration prior to embedment in polymethylmethacrylate(PMMA). Transverse femur sections were obtained with a diamond saw and the sections then carefully ground to a thickness of 200 microns. Plastic-embedded sections were stained for calcium with a silver methenamine modification of the von Kossa method for calcium staining and coated by carbon. They have been examined by back-scatter SEM on an ISI-SS60 operated at 25 KV. EDAX has been done on cellular inclusions and extracellular bone matrix.

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