Stress Concentration Regions in Ceramic Ball Heads for Total Hip Replacement Considering Trauma-Like Loading

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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Clinical Outcomes of Ceramicized Ball Heads in Total Hip Replacement Bearings: A Literature Review

Journal of Applied Biomaterials & Functional Materials ◽

10.5301/jabfm.5000330 ◽

2017 ◽

Vol 15 (1) ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Corrado Piconi ◽

Vincenzo De Santis ◽

Giulio Maccauro

Keyword(s):

Clinical Outcomes ◽

Total Hip Replacement ◽

Hip Replacement ◽

Pyrolytic Carbon ◽

Carbon Coatings ◽

Ceramic Ball ◽

Total Hip ◽

Head Surface ◽

Cocr Alloy ◽

Cobalt Chrome

Background Metallic ball heads for total hip replacement (THR) bearings with ceramicized surfaces were introduced in orthopedics during the second half of the 1980s, with the aim of decreasing the wear of polyethylene cups. Methods An analysis was made of the literature regarding outcomes for metallic ball heads with ceramicized surfaces now in clinical use (TiN, TiNbN, ZrN, monoclinic ZrO2), as well as carbon coatings (pyrolytic carbon, diamond-like carbon) and silicon nitride as coatings in ball heads for THR bearings. Results Notwithstanding the diffusion of ceramicized ball heads in THRs, there are few reports about their clinical outcomes in hip arthroplasty. In addition, several clinical studies and some registry data are putting under scrutiny the clinical advantages of ceramicized ball heads over cobalt chrome (CoCr) alloy and ceramic ball heads. Conclusions The wear of THR bearings with ceramicized ball heads looks like it depends more on the behavior of the polyethylene cups than on the treatment of the ball head surface. The risk of coating damage and of its consequences has to be taken into account in selecting this type of bearing.

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Postoperative functioning, age, obesity, and social support influence where patients go after total hip replacement

PsycEXTRA Dataset ◽

10.1037/e556262006-011 ◽

2005 ◽

Keyword(s):

Social Support ◽

Total Hip Replacement ◽

Hip Replacement ◽

Total Hip

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The Hemodynamic and Fibrinolytic Response to Low Dose Epinephrine and Phenylephrine Infusions During Total Hip Replacement Under Epidural Anesthesia

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646293 ◽

1992 ◽

Vol 68 (04) ◽

pp. 436-441 ◽

Cited By ~ 23

Author(s):

Nigel E Sharrock ◽

George Go ◽

Robert Mineo ◽

Peter C Harpel

Keyword(s):

Heart Rate ◽

Deep Vein Thrombosis ◽

Cardiac Index ◽

Total Hip Replacement ◽

Epidural Anesthesia ◽

Hip Replacement ◽

Low Dose ◽

Total Hip ◽

Vein Thrombosis ◽

Deep Vein

SummaryLower rates of deep vein thrombosis have been noted following total hip replacement under epidural anesthesia in patients receiving exogenous epinephrine throughout surgery. To determine whether this is due to enhanced fibrinolysis or to circulatory effects of epinephrine, 30 patients scheduled for primary total hip replacement under epidural anesthesia were randomly assigned to receive intravenous infusions of either low dose epinephrine or phenylephrine intraoperatively. All patients received lumbar epidural anesthesia with induced hypotension and were monitored with radial artery and pulmonary artery catheters.Patients receiving low dose epinephrine infusion had maintenance of heart rate and cardiac index whereas both heart rate and cardiac index declined significantly throughout surgery in patients receiving phenylephrine (p = 0.0001 and p = 0.0001, respectively). Tissue plasminogen activator (t-PA) activity increased significantly during surgery (p <0.0005) and declined below baseline postoperatively (p <0.005) in both groups. Low dose epinephrine was not associated with any additional augmentation of fibrinolytic activity perioperatively. There were no significant differences in changes in D-Dimer, t-PA antigen, α2-plasmin inhibitor-plasmin complexes or thrombin-antithrombin III complexes perioperatively between groups receiving low dose epinephrine or phenylephrine. The reduction in deep vein thrombosis rate with low dose epinephrine is more likely mediated by a circulatory mechanism than by augmentation of fibrinolysis.

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Effects on Coagulation and Fibrinolysis of Desmopressin in Patients Undergoing Total Hip Replacement

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646480 ◽

1991 ◽

Vol 66 (06) ◽

pp. 652-656 ◽

Cited By ~ 7

Author(s):

Per Anders Flordal ◽

Karl-Gösta Ljungström ◽

Jan Svensson ◽

Brenda Ekman ◽

Gustaf Neander

Keyword(s):

Total Hip Replacement ◽

Hip Replacement ◽

Bleeding Time ◽

Antithrombin Iii ◽

Postoperative Bleeding ◽

Double Blind ◽

Total Hip ◽

Von Willebrand ◽

Willebrand Factor ◽

Coagulation And Fibrinolysis

SummaryTwelve patients undergoing total hip replacement, with regional anaesthesia and with dextran infusion for plasma expansion and thromboprophylaxis, were given the vasopressin analogue desmopressin (DDAVP) or placebo in a randomized, double-blind prospective study. In controls (n = 6) we found a prolongation of the bleeding time, low factor VIII (FVIII) and von Willebrand factor (vWF) and a decrease in antithrombin III to levels known to be at risk for venous thrombosis. Desmopressin shortened postoperative bleeding time, gave an early FVIII/vWF complex increase, prevented antithrombin III from falling to critically low values and appeared to activate the fibrinolytic system, both by tPA increase and PAI-1 decrease.Thus in the controls we found changes in both coagulation and fibrinolysis indicating a haemorrhagic diathesis as well as a risk for thromboembolism. Desmopressin induced factor changes that possibly reduce both risks.

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Low-Dose Heparin and Deep-Vein Thrombosis after Total Hip Replacement

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648020 ◽

1976 ◽

Vol 36 (01) ◽

pp. 157-164 ◽

Cited By ~ 34

Author(s):

P. M Mannucci ◽

Luisa E. Citterio ◽

N Panajotopoulos

Keyword(s):

Deep Vein Thrombosis ◽

Total Hip Replacement ◽

Hip Replacement ◽

Low Dose ◽

Control Group ◽

Total Hip ◽

Vein Thrombosis ◽

Dose Heparin ◽

Deep Vein ◽

Low Dose Heparin

SummaryThe effect of subcutaneous low-dose heparin on postoperative deep-vein thrombosis (D. V. T.) (diagnosed by the 125I-labelled fibrinogen test) has been investigated in a trial of 143 patients undergoing the operation of total hip replacement. Two randomized studies were carried out: in one the scanning for D.V.T. was carried out daily for 7 days post operatively and in the other for 15 days. In both, the incidence of D.V.T. was significantly lower in the heparin-treated patients (P<0.005). Bilateral D.V.T. was also prevented (P<0.05), through the extension of D.V.T. to the distal veins of the thigh was not significantly reduced. Heparin treatment was, however, followed by a higher incidence of severe postoperative bleeding (P< 0.02) and wound haematoma formation (P< 0.005), and the postoperative haemoglobin was significantly lower than in the control group (P<0.005). A higher number of transfused blood units was also needed by the heparin treated patients (P<0.001).

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