Component In Total Hip Replacement Research Articles

Comparison of Intra-Articular and Intravenous Tranexamic Acid for Loss of Blood in Patients Undergoing Total Hip Replacement

Background: Tranexamic acid (TXA) is widely used in orthopedic surgeries to minimize blood loss, traditionally administered intravenously. Recent studies have explored intra-articular (IA) administration as a potentially more effective method due to its localized application and reduced systemic absorption. Objective: To compare the effectiveness of IA and IV TXA in reducing blood loss in patients undergoing total hip replacement (THR). Methods: This randomized controlled trial was conducted at Jinnah Hospital, Lahore, from August 30, 2019, to February 29, 2020, with approval from the Ethical Review Board. Seventy patients undergoing THR were enrolled and divided into two groups using a lottery system. Group A (n=35) received 1500 mg of IA TXA diluted in 100 ml of saline after implantation of THR components, while Group B (n=35) received 15 mg/kg of IV TXA five minutes before incision. Both groups were operated on using a lateral approach by the same surgeon. Postoperative blood loss was measured, and data were analyzed using SPSS version 20, with a p-value of <0.05 considered significant. Results: The mean total blood loss in Group A was significantly lower at 446.23 ± 33.81 ml compared to Group B, which had a mean of 928.23 ± 43.93 ml (p-value = 0.0001). The results highlighted a marked reduction in blood loss with IA administration compared to IV. Conclusion: IA administration of TXA during THR is more effective than IV administration in reducing total blood loss. This study supports the use of IA TXA as a safer, more efficient method for managing blood loss during hip replacement surgeries.

EXPERIMENTAL AND COMPUTATIONAL MODELLING ASSESSMENT OF EDGE-LOADED TOTAL HIP ARTHROPLASTY POLYETHYLENE LINERS

Non-optimal clinical alignment of components in total hip replacements (THRs) may lead to edge loading of the acetabular cup liner. This has the potential to cause changes to the liner rim not accounted for in standard wear models. A greater understanding of the material behaviours could be beneficial to design and surgical guidance for THR devices. The aim of this research was to combine finite element (FE) modelling and experimental simulation with microstructural assessment to examine material behaviour changes during edge loading.A dynamic deformable FE model, matching the experimental conditions, was created to simulate the stress strain environment within liners. Five liners were tested for 4Mc (million cycles) of standard loading (ISO14242:1) followed by 3Mc of edge loading with dynamic separation (ISO14242:4) in a hip simulator. Microstructural measurements by Raman spectroscopy were taken at unloaded and highly loaded rim locations informed by FE results. Gravimetric and geometric measurements were taken every 1Mc cycles.Under edge loading, peak Mises stress and plastic deformation occur below the surface of the rim during heel strike. After 7Mc, microstructural analysis determined edge loaded regions had an increased crystalline mass fraction compared to unloaded regions (p<0.05). Gravimetric wear rates of 12.5mm3/Mc and 22.3mm3/Mc were measured for standard and edge loading respectively. A liner penetration of 0.37mm was measured after 7Mc.Edge loading led to an increase in gravimetric wear rate indicating a different wear mechanism is occurring. FE and Raman results suggest that changes to material behaviour at the rim could be possible. These methods will now be used to assess more liners and over a larger number of cycles. They have potential to explore the impact of edge loading on different surgical and patient variables.

Study of proximal femoral geometry for standardizing femoral component in total hip replacement

Background and aims - Total Hip Replacement (THR) is the most common, permanent and effective surgical procedure available for the treatment of Osteoarthritis of the hip joint. In case of THR, it is mandatory that the design and dimensions of the femoral component, match (best-fit) the anatomy of the femur more so in cement-less variety. Significant variations are noted in the proximal femoral geometry of different races and ethnic groups Studies show that genetic and environmental factors including lifestyle determine the geometry of the proximal femur. The study is aimed to provide guidelines for future design of the femoral stem for Indian population. Materials & Methods - The present study was conducted on 202 adult human femora available in Anatomy, Orthopaedic & FMT departments of V.S.S Medical College, Burla, Odisha. The head vertical diameter (HVD), head transverse diameter (HTD), and circumference of femoral head (HC) were measured at the upper end of femur. The results were analyzed using statistical package SPSS 17.0 version. Results & Conclusion- - The average HVD was 41.24 ± 3.41 mm. whereas the average HTD was nearly similar with HVD averaging 41.21± 3.44mm.

Development and Validation of a Finite Element Model of Wear in UHMWPE Liner Using Experimental Data From Hip Simulator Studies.

The wear of acetabular liner is one of the key factors determining osseointegration and long-term performance of total hip joint replacement implants. The experimental measurements of wear in total hip replacement components are time and cost-intensive. While addressing this aspect, a finite element model of a hip joint bearing consisting of zirconia-toughened alumina femoral head and ultrahigh molecular weight polyethylene liner was developed to predict the dynamic wear response of the liner. The Archard-Lancaster equation, consisting of surface contact pressure, wear rate, and sliding distance, was employed to predict the wear of the acetabular liner. The contact pressure and wear at the articulating surface were found to decrease over time. A new computational method involving three-dimensional point clouds from the finite element analyzed results were used to construct wear maps. The model was able to predict the linear wear, over 2 × 106 cycles with relative errors ranging from 9% to 36% when compared to the published results. The increasing error percentage occurring primarily from the use of a constant wear rate was reduced to a maximum of 17% by introducing a correction factor. The volumetric rate was predicted with a maximum relative error of 7% with the implementation of the correction factor. When the model was implemented to study acetabular liners of diameters ranging from 28 to 36 mm, the linear wear was seen to decrease with an increase in femoral head diameter, which is in agreement with the clinical data. This study emphasizes the need to develop more such FEA-based computational studies to reliably predict and correlate with experimentally measured temporal evolution of wear of load-bearing articulating joints.

A new method for intraoperative assessment of leg length, sizing and placement of the components in total hip replacement.

Intraoperative radiograph of the pelvis is a well-established way to avoid misplacement/undersizing of the components and leg length discrepancy (LLD) in total hip replacement (THR). We describe a method for the obtainment and the evaluation of intraoperative radiographs with a sophisticated wireless radiographic system and a computerized digital tool originally used for preoperative templating. In this retrospective case-control study, 60 patients with unilateral hip osteoarthritis who underwent THR with intraoperative radiographic check with the conventional method (n = 30, control group) or the new method (AGFA flat panel DR14eG™/Orthosize™, n = 30, case group) were evaluated and compared for operation time, intraoperative changes in size/placement of the components and final radiological outcome (LLD, acetabular inclination and femoral offset) based on postoperative radiographs of the pelvis. Mean operation time was lower in case group (85.3min vs. 103.3min, p value < 0.005), as well as mean absolute LLD (1.93mm vs. 2.94mm, p value = 0.242). There was a higher percentage of intraoperative changes in the offset of the prostheses' head (70% vs. 40%, p value = 0.018) and a significantly lower percentage of patients with LLD > 5mm in the case group (0% vs. 27%, p value = 0.002). This new method for the obtainment and assessment of intraoperative radiographs proved to be fast and assuring for keeping LLD below 5mm in all patients.

Development of a Novel in Silico Model to Investigate the Influence of Radial Clearance on the Acetabular Cup Contact Pressure in Hip Implants.

A hip joint replacement is considered one of the most successful orthopedic surgical procedures although it involves challenges that must be overcome. The patient group undergoing total hip arthroplasty now includes younger and more active patients who require a broad range of motion and a longer service lifetime of the implant. The current replacement joint results are not fully satisfactory for these patients’ demands. As particle release is one of the main issues, pre-clinical experimental wear testing of total hip replacement components is an invaluable tool for evaluating new implant designs and materials. The aim of the study was to investigate the cup tensional state by varying the clearance between head and cup. For doing this we use a novel hard-on-soft finite element model with kinematic and dynamic conditions calculated from a musculoskeletal multibody model during the gait. Four different usual radial clearances were considered, ranging from 0 to 0.5 mm. The results showed that radial clearance plays a key role in acetabular cup stress-strain during the gait, showing from the 0 value to the highest, 0.5, a difference of 44% and 35% in terms of maximum pressure and deformation, respectively. Moreover, the presented model could be usefully exploited for complete elastohydrodynamic synovial lubrication modelling of the joint, with the aim of moving towards an increasingly realistic total hip arthroplasty in silico wear assessment accounting for differences in radial clearances.

Technical Note:Is Corrosion a Threat to the Strength of the Taper Connection in Femoral Components of Total Hip Replacements?

Taper corrosion has been suggested as a possible contributor to in vivo disassociation of modular connections in total hip arthroplasty (THA) systems, but this relationship has not been explored ex...

The orientation of acetabular component in total hip replacement using transverse acetabular ligament as a guide

Introduction: Acetabular component placement is a crucial determinant in outcomes following total hip arthroplasty. Malalignment predisposes to impingement, increased rate of dislocation, wear of the bearing, osteolysis, and revision after THA. The study aimed to determine how reliably the transverse acetabular ligament could be identified during primary THA and its validity as a guide for acetabular component placement within the safe zone in THA. Materials and Methods: In this prospective study, 52 patients undergoing total hip replacement during the period from August 2014 to January 2017 in Bowring and Lady Curzon Hospital and Victoria Hospital, Bangalore were included; in whom the acetabular component positioning was done using transverse acetabular ligament as a guide. 22 cases were done via modified lateral approach, while 30 cases were done via posterolateral approach. Acetabular reaming was done by placing the reamer parallel to TAL, starting with a reamer the diameter of the native femoral head. Following serial reaming, the final component is placed such that TAL should embrace it. The anteversion and inclination/abduction of the acetabular component was measured post-operatively by anteroposterior radiographs. Results: TAL was identified in all cases, irrespective of the surgical approach used. The mean planar anteversion was 19.84° (± 3.8°), and the radiological inclination was 43.65° (± 3.2°). Anteversion was within the safe zone in 96.15% (n=50) of the cases, while inclination was within the safe zone in 84.6% (n=44) of the cases. Conclusion: Transverse acetabular ligament can be reliably used as a guide in achieving patient-specific anteversion of the acetabular component within safe zone. A simple, reproducible technique, devoid of complex instrumentation. However, as inclination is influenced by factors in addition to TAL, TAL alone cannot be used for determining inclination of acetabular component positioning.

Mechanical Behavior of Bone Cement under Dynamic Loading

In orthopedic surgery and particularly in total hip arthroplasty, The fixation of the implant is generally made by the surgical cement, constituted essentially by polymer (PMMA), It is necessary to know the strengths applied to the prosthetic articulation during the current activities exercised by the patient in their life, to know the distribution of the constraints in the system (bone - cement - implant).This study aims to analyze numerically using the finite element method, the effect of activities (dynamic loads) of the patient on the level and distribution of stresses generated in the components of total hip prosthesis. Five activities, the most frequently performed by the patient such as normal walking, the up and down stairs, sitting and up from chair, were selected for this study. For this purpose, a three-dimensional model of the total hip prosthesis has been developed. The results obtained from this model show that the total hip replacement components and especially the bone cement are more highly stressed during the process of climbing stairs. These excessively high loads can lead to damage of the cement and thus the loosening of the prosthesis.

Long-term results with the Atlas IIIp elastic cementless acetabular component in total hip replacement.

Modular cementless elastic acetabular systems have advantages over cemented and hard shell cementless acetabular systems. There are few reports on the medium-term and long-term follow up of this particular type of implant. This study describes our experience with the Atlas IIIp modular acetabular system, which is a thin shell cementless elastic acetabular implant for total hip replacement commercialized under this name in many countries. We prospectively followed 244 patients treated with Atlas IIIp acetabular system between 2001 and 2004. Minimum ten year follow up was available for 148 hips (139 patients) from the original cohort of 263 hips (244 patients). One hundred five patients had died from unrelated causes and were excluded from the results. Post-operative and follow up radiographs of patients were assessed; and Harris hip scores were used as clinical outcome. Revision for any reason was defined as the end point for survivorship analysis. The mean pre-operative Harris hip score was 48 (S.D. 16) and the average post-operative score was 82 (S.D. 12). The mean follow up in our series was 11.5years, ranging from ten to 13.5years. Thirteen hips required further surgery in our cohort; of which ten cases required cup revision. The 13-years cumulative implant survival was 91.2% and the risk of implant revision was 8.8% at 13years in 148 hips (139 patients). Kaplan-Meier analysis showed the implant survival rate of 95.2% at tenyears for revision for any reason and 99.4% for aseptic loosening. Our clinical experience with this acetabular cup suggests good long-term survival rates that are similar to other cups on the market. The clinical experience in this study shows long-term survival rates that are consistent, acceptable and good results achieved with a low revision rate. Therapeutic III; therapeutic study.

A novel analytical approach for determining the frictional moments and torques acting on modular femoral components in total hip replacements

A three dimensional analytical approach was developed to determine the frictional moment vector generated by the relative sliding of the head-cup bearing couple of a total hip replacement. The frictional moment projection onto the femoral neck was also determined over the loading cycle. Predicted frictional moments for nine combinations of bearing materials and diameters were in close agreement with existing in vitro data. The analytical method was then applied to simplified gait (lubrication conditions of dry and serum), ISO standard gait and physiological level gait loading cycles. ISO standard gait had a total contact force of about two fold of physiological level gait and there was a corresponding increase in the maximum frictional torque on neck from 0.66×BW%m to 0.88×BW%m. For the ISO standard gait, the maximum frictional torque occurred at the same instance of maximum frictional moment and the maximum contact force. In contrast, for the physiological level gait, the frictional torque did not occur at the same instance as the peak load. This suggests that the neck frictional torque is a function of other parameters, such as angle between neck axis and frictional moment vector, as well as the magnitude of the contact force and frictional moment. The developed methodology was able to predict the maximum magnitude and change of directions of moments and the variation of torque at the head neck interface. The data will be useful for experimental studies assessing the fretting behaviour of the head neck junction, by providing appropriate loading data.

Study of results of total hip replacement with indigenous ceramic components in combination

Background: Total hip replacement (THR) arthroplasty at present it is the most commonly performed adult re-constructive hip procedure. Aims: To assess the clinical and functional outcome of the cementless ceramic THR. Materials and Methods: This pilot study was conducted in a tertiary care hospital of eastern India after taking institutional clearance and informed consent of the subjects. THR components were made from aluminum oxide from Central Glass and Ceramic Research Institute, Kolkata. During each visit, medical history was taken and physical examination was done. The deformity and range of motion (ROM) were measured with a goniometer. The clinical and functional outcomes were evaluated by modified Harris hip score. Results: 16 (80%) THR were on left and 4 (20%) were on left and age ranging from 34 to 66 years with a mean age of 52.2 years at the time of surgery. 14 (70%) were males and 6 (30%) females. At 2 years follow-up, the mean modified Harris hip score was 89.·With regards to the different parameters in the scoring system that is, pain, gait, functional activity, and ROM, there was significant improvement as per history. The results showed a significant improvement, wherein 33.33% had an excellent score and 50% showed good, and 16.7% had fair results. No patient had a poor score. Conclusion: Our study suggests that the current generation implants without cement can provide satisfactory clinical and radiographic outcomes after an intermediate duration of follow-up. Though the study was not free of complications, the overall functional and clinical outcome showed good results.

The impact of surgeon handedness in total hip replacement.

Total hip replacement (THR) is successful and performed commonly. Component placement is a determinant of outcome. Influence of surgeon handedness on component placement has not been considered previously. This study was a radiographic assessment of component positioning with respect to handedness. Early data from 160 patients are reported. Overall, 160 primary THRs for osteoarthritis were included. Equal numbers of left and right THRs were performed by four surgeons, two right-handed and two left-handed. Postoperative radiography was assessed for THR component position by measurement of leg length inequality, acetabular inclination and centre of rotation. Surgeons' handedness was assessed using the Edinburgh inventory. For leg length inequality, no significant interaction was seen between hip side and surgeon handedness. Acetabular inclination angles showed a statistically significant difference, however, depending on hand dominance, with higher inclination angles recorded when operating on the dominant side. There was a trend towards greater medialisation of the centre of rotation on the non-dominant side although this did not reach statistical significance. Surgeon handedness appears to influence acetabular component position during THR but it is one factor of many that interact to achieve a successful outcome.

The use of the transverse acetabular ligament in total hip replacement

It has recently been reported that the transverse acetabular ligament (TAL) is helpful in determining the position of the acetabular component in total hip replacement (THR). In this study we used a computer-assisted navigation system to determine whether the TAL is useful as a landmark in THR. The study was carried out in 121 consecutive patients undergoing primary THR (134 hips), including 67 dysplastic hips (50%). There were 26 men (29 hips) and 95 women (105 hips) with a mean age of 60.2 years (17 to 82) at the time of operation. After identification of the TAL, its anteversion was measured intra-operatively by aligning the inferomedial rim of the trial acetabular component with the TAL using computer-assisted navigation. The TAL was identified in 112 hips (83.6%). Intra-observer reproducibility in the measurement of anteversion of the TAL was high, but inter-observer reproducibility was moderate.Each surgeon was able to align the trial component according to the target value of the angle of anteversion of the TAL, but it was clear that methods may differ among surgeons. Of the measurements of the angle of anteversion of the TAL, 5.4% (6 of 112 hips) were outliers from the safe zone.In summary, we found that the TAL is useful as a landmark when implanting the acetabular component within the safe zone in almost all hips, and to prevent it being implanted in retroversion in all hips, including dysplastic hips. However, as anteversion of the TAL may be excessive in a few hips, it is advisable to pay attention to individual variations, particularly in those with severe posterior pelvic tilt.Cite this article: Bone Joint J 2014;96-B:306–11.

The use of the transverse acetabular ligament for determining the orientation of the components in total hip replacement

The orientation of the acetabular component can influence both the short- and long-term outcomes of total hip replacement (THR). We performed a prospective, randomised, controlled trial of two groups, comprising of 40 patients each, in order to compare freehand introduction of the component with introduction using the transverse acetabular ligament (TAL) as a reference for anteversion. Anteversion and inclination were measured on pelvic radiographs. With respect to anteversion, in the freehand group 22.5% of the components were outside the safe zone versus 0% in the transverse acetabular ligament group (p = 0.002). The mean angle of anteversion in the freehand group was 21° (2° to 35°) which was significantly higher compared with 17° (2° to 25°) in the TAL group (p = 0.004). There was a significant difference comparing the variations of both groups (p = 0.008). With respect to inclination, in the freehand group 37.5% of the components were outside the safe zone versus 20% in the TAL group (p = 0.14). There was no significant difference regarding the accuracy or variation of the angle of inclination when comparing the two groups. The transverse acetabular ligament may be used to obtain the appropriate anteversion when introducing the acetabular component during THR, but not acetabular component inclination.

Recurrent catastrophic ceramic femoral head failure in total hip arthroplasty.

Fracture of a modern ceramic head component in total hip replacement is an uncommon but catastrophic complication. Hence, the occurrence of a second ceramic head fracture in the same hip replacement of an individual represents a perishingly rare event. We present the case as a means of highlighting potential risk factors for ceramic head fracture and suggest possible management strategies in such cases.

The Warwick Hip Trauma Evaluation Two – an abridged protocol for the WHiTE Two Study

Fractures of the proximal femur are one of the greatest challenges facing the medical community, constituting a heavy socioeconomic burden worldwide. Controversy exists regarding the optimal treatment for independent patients with displaced intracapsular fractures of the proximal femur. The recognised alternatives are hemiarthroplasty and total hip replacement. At present there is no established standard of care, with both types of arthroplasty being used in many centres. The principal advantages of total hip replacement are a functional benefit over hemiarthroplasty and a reduced risk of revision surgery. The principal criticism is the increased risk of dislocation. We believe that an alternative acetabular component may reduce the risk of dislocation but still provide the functional benefit of total hip replacement in these patients. We therefore propose to investigate the dislocation risk of a dual-mobility acetabular component compared with standard polyethylene component in total hip replacement for independent patients with displaced intracapsular fractures of the proximal femur within the framework of the larger WHiTE (Warwick Hip Trauma Evaluation) Comprehensive Cohort Study.Cite this article: Bone Joint Res 2013;2:210–13.

Fracture of a ceramic component in total hip replacement

Fracture of a ceramic component in total hip replacement is a rare but potentially catastrophic complication. The incidence is likely to increase as the use of ceramics becomes more widespread. We describe such a case, which illustrates how inadequate initial management will lead to further morbidity and require additional surgery. We present the case as a warning that fracture of a ceramic component should be revised to another ceramic-on-ceramic articulation in order to minimise the risk of further catastrophic wear.

In vitro studies on the effect of particle size on macrophage responses to nanodiamond wear debris

Nanostructured diamond coatings improve the smoothness and wear characteristics of the metallic component of total hip replacements and increase the longevity of these implants, but the effect of nanodiamond wear debris on macrophages needs to be determined to estimate the long-term inflammatory effects of wear debris. The objective was to investigate the effect of the size of synthetic nanodiamond particles on macrophage proliferation (BrdU incorporation), apoptosis (Annexin-V flow cytometry), metabolic activity (WST-1 assay) and inflammatory cytokine production (qPCR). RAW 264.7 macrophages were exposed to varying sizes (6, 60, 100, 250 and 500nm) and concentrations (0, 10, 50, 100 and 200μgml−1) of synthetic nanodiamonds. We observed that cell proliferation but not metabolic activity was decreased with nanoparticle sizes of 6–100nm at lower concentrations (50μgml−1), and both cell proliferation and metabolic activity were significantly reduced with nanodiamond concentrations of 200μgml−1. Flow cytometry indicated a significant reduction in cell viability due to necrosis irrespective of particle size. Nanodiamond exposure significantly reduced gene expression of tumor necrosis factor-α, interleukin-1β, chemokine Ccl2 and platelet-derived growth factor compared to serum-only controls or titanium oxide (anatase 8nm) nanoparticles, with variable effects on chemokine Cxcl2 and vascular endothelial growth factor. In general, our study demonstrates a size and concentration dependence of macrophage responses in vitro to nanodiamond particles as possible wear debris from diamond-coated orthopedic joint implants.

Ceramic Versus Metal Femoral Heads in Combination With Polyethylene Cups: Long-Term Wear Analysis at 20 Years

Bearing surfaces are an important implant-related factor in the process of wear and resulting osteolysis. Especially, polyethylene (PE) wear is known to be a major reason for aseptic loosening of the acetabular and femoral components in total hip replacement (THR). In the past, several studies showed the advantages of ceramic femoral ball heads compared with metal ball heads with respect to the resulting PE wear. In this framework, we posed the question whether ceramic and metal ball heads still resulted in similar clinical outcome regarding PE wear after 20-year follow-up. Additionally, we investigated whether wear and osteolysis were correlated within these groups and compared our findings with results from appropriate publications. In this prospective study, 93 nonselected, consecutive uncemented hip arthroplasties were performed in 80 patients with use of the titanium-coated Robert Mathys (RM) cup and the cementless Spotorno stem. Eighty ceramic and 13 metal femoral heads with a diameter of 32 mm were used. The mean age of the patients was 52 years. The average follow-up was 19.3 years. No patient was lost for follow-up. The metal group showed a mean wear rate of 0.190 mm/year, whereas the ceramic group had 0.107 mm/year ( P = 0.025). The rate of revision cases was clearly higher within the CoCrMo group showing 6 revisions in 13 cases (46.2%) compared with 11 in 80 cases (13.8%) within the ceramic group. Wear rates were positively correlated to femoral head material ( P = 0.025), stem osteolysis ( P = 0.003), cup osteolysis ( P = 0.011), cup revision ( P = 0.041), and cup inclination ( P = 0.012). This long-term study shows that during a period of 20 years, ceramic ball heads generate less linear PE wear compared with metal ball heads, thus causing significantly less osteolysis and revisions of either component.