Ceramic Femoral Component Research Articles

No patella resurfacing total knee arthroplasty leads to reduction in the thickness of patellar cartilage to less than half within 5\u2009years: a quantitative longitudinal evaluation using MRI

PurposePatellar resurfacing in total knee arthroplasty (TKA) remains controversial as recent meta-analyses have not shown its clear superiority; however, most authors recommend it because it is associated with less frequent anterior knee pain and need for reoperation. We aimed to clarify the changes in patellar cartilage thickness in no patellar resurfacing TKA using a ceramic femoral component on magnetic resonance imaging (MRI).MethodsBetween 2009 and 2014, 40 consecutive patients (59 knees) were included in this study. All patients underwent TKA using zirconia ceramic femoral implants without patellar resurfacing. Indications for no patellar resurfacing TKA were absence of anterior knee pain, patellar compression pain, and osteoarthritic changes in the patellofemoral joint on plain radiography. The mean postoperative follow-up duration was 81.5 months (range, 25–131 months). Clinical and radiological evaluations were performed preoperatively and 5 years after TKA. Patellar cartilage thickness was evaluated preoperatively and every year for 5 years after TKA using MRI T2-weighted imaging. The patellar cartilage was divided into three regions of interest: medial, central, and lateral. To standardise the variation in patellar thickness among patients, the percent cartilage thickness was calculated.ResultsThe implant’s position was appropriate in all cases. Compared to preoperative scores, 5 years postoperatively, the Japanese Orthopedic Association score and Oxford knee score significantly improved from 52.1 to 84.7; mean tilting angle and congruence angle did not change significantly; mean lateral shift ratio significantly increased from 7.1% to 14.6%; cartilage thickness significantly decreased (P < 0.05); and the percentage cartilage thickness of the central, medial, and lateral cartilage zones gradually thinned to less than half. Four patients underwent conversion to patellar resurfacing due to anterior knee pain, without loosening the femoral and tibial implants.ConclusionThe patellar cartilage thickness decreased to less than half its preoperative level within 5 years after no patellar resurfacing TKA; this would led to clinical problems and conversion to patellar resurfacing.Level of evidenceLevel III.

Mechanical and numerical characterization of ceramic femoral components for hip resurfacing arthroplasty.

Hip resurfacing arthroplasty may have distinct advantages for young and active patients, but large metal-on-metal bearings can be associated with increased wear, adverse tissue reactions and higher rate of implant loosening. Ceramic wear couples are a commonly used alternative to metals and therefore might be an alternative for hip resurfacing arthroplastys. The aim of this study was to evaluate the mechanical strength of femoral components made of an alumina-toughened zirconia composite by means of experimental testing and finite element analysis. For the mechanical characterization, ceramic femoral components (Ø: 48 mm) were tested under compression loading experimentally until fracture occurred or a maximum load of 85 kN was obtained. The femoral components were either loaded against a ceramic cup or a copper ring (outer diameter Ø: 7.0 mm). In addition, the complex geometry of the ceramic femoral component was simplified, and only the stem was loaded in a cantilever test until fracture. In addition, the fracture tests were numerically simulated to investigate the influence of additional loading conditions and geometric parameters, which were not experimentally tested. The experimental data were used for validation of the finite element analysis. None of the tested ceramic femoral components fractured at a compression load of 85 kN when they were loaded against a ceramic cup at an inclination angle of 45°. When the femoral components were loaded against a copper ring, the femoral components fractured at 29.9 kN at a testing angle of 45°. The fracture load was reduced when an angle of 30° and increased when an angle of 60° was simulated. Using an experimental cantilever test, the stem of the femoral component fractured at 1124.0 N. When the stem length was increased or the diameter was reduced by 10% in the finite element analysis, the fracture load was reduced. Decreasing the length or increasing the diameter led to an increase of the fracture load. The strongest influence was found for the reduction of the transition radius of the stem, with a decrease of the fracture load up to 27.2%. The analyzed femoral components made of alumina-toughened zirconia (ATZ) showed sufficient mechanical capability to withstand high loadings during unfavorable loading conditions. However, further biomechanical and tribological investigations are required before clinical application.

Two-Year Results of a Posterior-Stabilized Total Knee Prosthesis Using Zirconia Ceramic Femoral Component Designed for Japanese Comparing with Another Posterior-Stabilized Model

Two-Year Results of a Posterior-Stabilized Total Knee Prosthesis Using Zirconia Ceramic Femoral Component Designed for Japanese Comparing with Another Posterior-Stabilized Model

Prospective comparative clinical study of ceramic and metallic femoral components for total knee arthroplasty over a five-year follow-up period

BackgroundThe aim of this prospective comparative study was to evaluate the clinical and radiological outcomes of a TKA system, comparing a ceramic (BIOLOX® delta) and metallic (Co28Cr6Mo) femoral component over a five-year follow-up period. MethodsForty-three TKA patients (17 metallic and 26 ceramic femoral components) were enrolled in the study. Clinical and radiological evaluations were performed preoperatively and at three, 12, 24 and 60months postoperatively, using the HSS-, WOMAC- and SF36-Scores, in addition to standardized X-rays. ResultsThe HSS-Score improved significantly from 58.7±12.7 points preoperatively to 88.5±12.3 points at five-years postoperative in the ceramic group, and 60.8±7.7 to 86.2±9.4 points in the metallic group. WOMAC- and SF-36-Scores showed significant improvement over time in both groups. There were no significant differences between groups for HSS-, WOMAC- and SF-36-Scores, nor for range of motion (p≤0.897) at any follow-up evaluation. Furthermore, radiological evaluation showed no implant loosening or migration in either group. ConclusionsMid-term outcomes for the ceramic femoral components demonstrated good clinical and radiological results, as well as comparable survivorship to the metallic femoral component of the same total knee system, and to other commonly used metallic total knee systems. Therefore, ceramic knee implants may be a promising solution for the population of patients with osteoarthritis and metal sensitivity. Long-term studies are required in order to confirm the positive mid-term clinical results, and to follow the implant survival rate in regard to the enhanced wear resistance of ceramic implants.

Prospective multi-centre study on a composite ceramic femoral component in total knee arthroplasty: Five-year clinical and radiological outcomes

BackgroundEnhanced wear resistance of ceramics in general and improved mechanical characteristics of composite ceramics in terms of strength and resistance meet the demands for application in TKA.The aim of this prospective international multi-centre study was to evaluate the 5-year clinical and radiological outcomes of an unconstrained TKA with a composite ceramic femoral component. MethodsA total of 107 patients (109 knees) underwent TKA with the MULTIGEN-PLUS Ceramic Knee at seven centres in three European countries. Clinical and radiological assessments were performed preoperatively and postoperatively at 3, 12, 24 and 60months, using HSS, WOMAC, SF-36 and standardised radiographs. ResultsMean HSS and WOMAC increased significantly from 55.1±11.5 (21–83) and 48.1±16.6 (3–90) preoperatively to 85.6±9.6 (49–98) and 73.3±20.4 (17–100) at 60months. Mean SF-36 showed significant improvements in patients' quality of life (49.1±17.6 (12–96) preoperatively versus 67.7±23.1 (12–100) at 60months). Non-progressive radiolucent lines (<1mm) were observed around the femoral component in four cases. Neither implant migration nor loosening were registered. Kaplan–Meier survivorship was 96.0% at 60months (92.1–100%, CI 95%). ConclusionsFive-year implant survival rate of the ceramic knee is comparable to other metallic and ceramic unconstrained TKA systems. Although the assessment of long-term implant survivorship is still pending, the ceramic implants represent a promising solution for patients with allergies against metallic components and furthermore for the general osteoarthritis population due to enhanced wear resistance.

Total Knee Replacement System with a Ceramic Femoral Component versus Two Traditional Metallic Designs: A Prospective Short-Term Study

To compare the short-term outcome of the Multigen Plus system using a symmetric ceramic femoral component with that of 2 metallic total knee replacement (TKR) systems. 60 patients (62 knees) with osteoarthritis or rheumatoid arthritis underwent primary TKR using the Genia system (n=20), the Multigen Plus system (n=17), and the Multigen Plus system with a ceramic femoral component (n=25). Outcome was evaluated pre- and post-operatively (at 3, 12, and 24 months) using the Hospital for Special Surgery (HSS) score, the Western Ontario and McMaster Universities (WOMAC) score, and the Short-Form 36 (SF-36) score. The 3 groups did not differ significantly at all 4 time points in terms of the HSS score, WOMAC score, and SF-36 score. The range of motion was significantly less in patients treated with the Genia system. Postoperatively, the HSS and WOMAC scores improved significantly in all 3 groups, whereas the SF-36 score improved significantly (at 12 and 24 months) only in patients treated with the Multigen Plus system with a ceramic femoral component. The implant position in most patients was optimal. All radiolucent lines were within 1 mm and did not progress. The short-term outcome of the 3 TKR systems was comparable. Ceramic femoral components performed comparably to traditional metallic designs.

Ceramic Femoral Component Fracture in Total Knee Arthroplasty: An Analysis Using Fractography, Fourier-Transform Infrared Microscopy, Contact Radiography and Histology

Ceramic components in total knee arthroplasty (TKA) are evolving. We analyze the first case of BIOLOX delta ceramic femoral component fracture. A longitudinal midline fracture in the patellar groove was present, with an intact cement mantle and no bony defects. Fractographic analysis with laser scanning microscopy and white light interferometry showed no evidence of arrest lines, hackles, wake hackles, material flaws, fatigue or crack propagation. Analysis of periprosthetic tissues with Fourier-transform infrared (FT-IR) microscopy, contact radiography, histology, and subsequent digestion and high-speed centrifugation did not show ceramic debris. A macrophage-dominated response was present around polyethylene debris. We conclude that ceramic femoral component failure in this case was related to a traumatic event. Further research is needed to determine the suitability of ceramic components in TKA.

Evaluating Frictional Temperature Rise in Sliding Surface of Artificial Hip Joint Materials with Different Loading Conditions

Friction between articulating surfaces cause temperature rise in acetabular cup and femoral head. This heating may in uence the rate of wear, fatigue, creep, oxidative degradation of bearing materials and may terminate surrounding tissue. The objective of this study is to determine temperature rise with di erent applied load for the articulating surfaces of conventional ultra high molecular weight polyethylene (UHMWPE) and vitamin E blended ultra high molecular weight polyethylene (VE-UHMWPE) acetabular components paired with a ceramic femoral component in bovine calf serum lubrication condition. Additionally frictional torque between the bearing surfaces was measured and friction coe cient was calculated. Frictional measurements of the joints were carried out on a custom made hip joint friction simulator. Various levels of static loads were applied on 28 mm diameter prostheses. In exion-extension plane, a simple harmonic oscillatory motion between ±24◦ was applied to the UHMWPE acetabular component. The period of motion was 1 Hz and the tests were run up to 12,000 cycles. Temperature rise in acetabular and femoral component was recorded with embedded thermocouples. The results were compared in terms of UHMWPE and vitamin E blended UHMWPE.

Influence of the distal femoral resection angle on the principal stresses in ceramic total knee components

PurposeA certain failure mode using a newly developed cemented ceramic femoral component in total knee replacement was observed in clinical application, i.e. fracture of the femoral component during intraoperative impaction. This may be caused by unintentional deflection of the saw blades during cutting with consecutive higher resection angle of the distal femur than desired, leading to bending of the femoral component during implantation. A finite-element-analysis was carried out to simulate implantation of the femoral component and to evaluate the influence of distal femur preparation on implant stress. ScopeWe developed and validated a numerical model of the ceramic femoral component including a contact formulation which allowed calculating the principal stresses of the implant during implantation onto the resected femur. The analysis considered different anterior and posterior resection angles with a total of 17 variations. By increasing the femoral resection angle in the finite-element-model it could be shown that a deviation of three degrees from the intended resection angle can cause critical stress amounts during implantation. ConclusionsWhen implanting the ceramic component in total knee arthroplasty, the femoral resection angles should be prepared very precisely, in particular anterior saw blade deflection has to be avoided. The implant manufacturer increased implant safety through an additional resection template. Moreover, the impaction of the ceramic femoral component during cementing was not further recommended by using a hammer.

Ceramic Femoral Components in Total Knee Arthroplasty - Two Year Follow-Up Results of an International Prospective Multi-Centre Study

Background: Total knee arthroplasty can be considered as a reliable surgical procedure with a good long-term clinical result. However, implant failure due to particle induced aseptic loosening as well as the aspect of hypersensitivity to metal ions still remains an emerging issue.Methods: The purpose of this prospective international multi-centre study was to evaluate the clinical and radiological outcomes and the reliability of the unconstrained Multigen Plus Total Knee System with a new BIOLOX® delta ceramic femoral component. Cemented total knee arthroplasty was performed on 108 patients (110 knees) at seven hospitals in three countries. Clinical and radiological evaluations were performed preoperatively, and after 3, 12 and 24 months postoperatively using the HSS-, WOMAC-, SF-36-score and standardised X-rays.Results: The mean preoperative HSS-Score amounted to 55.5 ± 11.5 points and improved significantly in all postoperative evaluations (85.7 ± 11.7 points at 24 months). Furthermore, improvements in WOMAC- and SF-36-score were evaluated as significant at all points of evaluation. Radiolucent lines around the femoral ceramic component at 24 months were found in four cases. Progression of radiolucent lines was not seen and no implant loosening was observed. During the 24 month follow-up eight patients underwent subsequent surgery due to reasons unrelated to the implant material.Conclusions: The observed clinical and radiological results are encouraging for a long-term survival of the ceramic femoral component. Therefore, ceramic implants could be a promising solution not only for patients with allergies against metallic implant materials, but also for the osteoarthritic knee joint. Long-term follow-up is necessary to draw conclusions regarding the superiority of the ceramic knee implants concerning in vivo wear and long-term survivorship.

Tribological conditions in mobile bearing total knee prostheses

This paper describes the in-vivo contact conditions that occur in total knee prostheses, with focus on mobile bearing designs. As background, typical loading and kinematic conditions occurring in the human knee joint are briefly reviewed, for normal walking as well as for other activities including running/jogging. The loads and relative motions are then used, along with typical properties of knee joint's synovial fluid, in a transient elastohydrodynamic analysis of the fluid film lubrication conditions at the articulating tibio-femoral interface of mobile bearing total knee prostheses. Most of the analyses in this paper are for the most common material combination used in total knee prostheses, cobalt–chrome–molybdenum femoral component in contact with ultra-high molecular weight polyethylene (UHMWPE) tibial bearing. The transient fluid film thickness and the pressure within the contact area on the implanted knee prostheses are determined during typical walking and jogging cycles. It is found that the lubricating film is so thin that the contact is within the mixed lubrication condition much of the time, and at times descends into the boundary lubrication zone. Therefore, wear of the contacting materials, particularly the UHMWPE, is expected to occur nearly continuously. Examination of retrieved mobile tibial bearings confirmed that wear of the articular bearing surfaces is consistent with predicted contact conditions; wear is most severe where contact pressure is highest and lubricant film thickness is lowest. The effects of different prosthesis materials (e.g., ceramic femoral component) on the resulting minimum film thickness and pressure are determined and the implications for implant wear are discussed.

Composite Ceramics in Total Knee Arthroplasty: Two-Year Experience in Clinical Application

Total knee arthroplasty (TKA) has been developed into a safe and reliable procedure in orthopedic surgery. Nevertheless, in some cases, wear particles trigger the well-known cascade of osteolysis-inducing aseptic implant loosening. Furthermore, hypersensitivity to allergens such as chromium, cobalt, and nickel can lead to implant failure. These facts have led to a rising interest in research for solutions of alternative implant materials in TKA. The use of ceramics in total hip arthroplasty is based on excellent wear resistance and corrosion durability. These advantages have led to the development of a TKA system with a Biolox delta composite ceramic femoral component. In the present article, the clinical experience and radiological results of a 2-year follow-up in some standard and specific indications are presented. Furthermore, special features on intraoperative handling, advantages, as well as limitations in clinical application are demonstrated.

Metal hypersensitivity in total knee arthroplasty: Revision surgery using a ceramic femoral component — A case report

We present a case involving the revision of a total knee arthroplasty with a metal femoral component using a ceramic implant due to metal hypersensitivity. A 58-year-old female patient underwent total knee arthroplasty (TKA) with a standard metal bicondylar knee system. She suffered from persistent pain and strong limitations in her range of motion (ROM) associated with flexion during the early postoperative period. Arthroscopic arthrolysis of the knee joint and intensive active and passive physical treatment, in combination with a cortisone regime, temporarily increased the ROM and reduced pain. No signs of low grade infection or other causes of implant failure were evident. Histology of synovial tissue revealed lymphoplasmacellular fibrinous tissue, consistent with a type IV allergic reaction. Allergometry (skin reaction) revealed type IV hypersensitivity against nickel-II-sulfate and palladium chloride.Revision surgery of the metal components was performed with a cemented ceramic femoral component (same bicondylar design) and a cemented titanium alloy tibial component. Postoperative evaluations were performed 10days, and 3 and 12months after the revision surgery. There was an increased ROM in flexion to 90° at the 12month follow-up. No swelling or effusion was observed at all clinical examinations after the revision surgery. No pain at rest and moderate walking pain were evident.The presented case demonstrates that ceramic implants are a promising solution for patients suffering from hypersensitivity to metal ions in total knee arthroplasty.

Intraoperative impaction of total knee replacements: An explicit finite-element-analysis of principal stresses in ceramic vs. cobalt–chromium femoral components

Background In connection with technological advances in the manufacturing of medical ceramics, a newly developed ceramic femoral component was introduced in total knee arthroplasty. We generated an explicit finite-element-model to calculate the stresses developed under the highly dynamic intraoperative impaction with regard to cobalt–chromium and ceramic implant material as well as application of a silicone cover in order to reduce stress. Methods The impaction was calculated with the hammer hitting the backside of the impactor at previously measured initial velocities. Subsequently the impactor, consisting of a steel handhold and a polyoxymethylene head, hit the femoral component. Instead of modelling femoral bone, the implant was mounted on four spring elements with spring constants previously determined in an experimental impaction model. The maximum principal stresses in the implants were evaluated at 8000 increments during the first 4 ms of impact. Findings The ceramic implant showed principal stresses 10% to 48% higher than the cobalt chromium femoral component. The simulation of a 5 mm thick silicone layer between the impactor and the femoral component showed a strong decrease of vibration resulting in a reduction of 54% to 68% of the maximum stress amounts. The calculated amounts of principal stress were beneath the ultimate bending strengths of each material. Interpretation Based on the results, intraoperative fracture of femoral components in total knee replacement may not be caused solely by impaction, but also by contributing geometrical factors such as inadequate preparation of the distal femur. In order to minimize the influence of impaction related stress peaks we recommend limiting the velocity as well as the weight of the impaction hammer when inserting femoral components. The silicone cover seems to deliver a strong decrease of implant stress and should be considered in surgery technique in the future.

Primary TKA With a Zirconia Ceramic Femoral Component

This article presents the 2-year clinical results of primary total knee arthroplasty (TKA) performed with a zirconia ceramic femoral component. A posterior-stabilized TKA was performed for degenerative arthritis in 36 patients (39 knees). The components included a zirconia femoral component, a cobalt-chrome alloy tibial baseplate, and a polyethylene patella; all were implanted with bone cement. The ultra-high molecular-weight polyethylene-bearing insert had a deep-dish, ultra-congruent design. At the 2-year interval, mean Western Ontario and McMaster Universities (WOMAC) osteoarthritis indices improved from 41 to 86, and mean Knee Society Scores improved from 40 to 92. Revision to constrained implants was necessary in one patient for persistent knee instability after trauma. These early results are encouraging, but more data are needed to determine whether ceramics are a suitable alternative to metal countersurfaces in TKAs.

Ceramic Versus Cobalt-Chrome Femoral Components; Wear of Polyethylene Insert in Total Knee Prosthesis

The present study aimed to determine the effect of femoral component materials and sterilization methods on wear properties of total knee prostheses by using a knee simulator test and retrieval analysis. The simulator test revealed that ultrahigh molecular weight polyethylene (UHMWPE) inserts had remarkably lower wear against the ceramic femoral component than against the Co-Cr femoral component. However, the retrieval study revealed no significant difference in the linear wear between the former and the latter. The alumina ceramic/UHMWPE insert combination showed a mild wear. However, whether cross-linking by gamma-ray sterilization reduces wear remained unconfirmed. In contrast, oxidative degradation and/or delamination was confirmed. Thus, we conclude that alumina ceramic/ethylene oxide gas–sterilized UHMWPE insert in a total knee prosthesis might exhibit a good wear resistance.

Alternative Werkstoffe und Lösungen in der Knieendoprothetik für Patienten mit Metallallergie

The annual number of total knee replacement implantations is rising continuously. A progressive cutaneous hypersensitivity rate against metallic materials in the population has been registered which can lead to an increase of allergy-induced reactions associated with implant loosening in the future although the correlation with an allergic cutaneous sensitisation has not been proven in all cases. On apparent allergy against metallic implant components different alternative solutions to standard endoprostheses should be taken into account for primary implantation or revision of total knee replacement, for example the application of implant components without metallic elements (e.g. ceramics), the use of non-allergic metallic implants, such as titanium or ZrNb alloys, or potential allergy-inducing metallic materials after masking the implant surface using a suitable coating. In the case of primary or revision surgery most patients with metal allergy are treated with a Ti(Nb)N-coated knee implant made of cobalt-chrome or titanium alloys in our hospital. Within an international multi-centre study we are currently implanting a newly developed knee endoprosthesis system with a ceramic femoral component as an alternative.

Patients’ perspective on controversial issues in total knee arthroplasty

We investigated the level of patient knowledge and preferences over the currently controversial issues in TKA. One hundred patients who had decided to undergo TKA for advanced osteoarthritis were asked to complete a questionnaire inquiring their knowledge and preferences over three controversial issues: (1) computer assisted surgery (CAS), (2) minimal invasive surgery (MIS), and (3) ceramic femoral component. The patient preferences over the three issues were questioned again after they had been informed of advantages and disadvantages of each option using an explanatory document. Most (more than 75%) of the patients did not have sufficient knowledge and their knowledge was based on non-professional sources (more than 85%). Before the information was given, most (more than 80%) of the patients preferred a new option. After the information was provided, more patients preferred a standard option in the issues of CAS (60%) and MIS (88%). This study prompts health care providers to become more active in providing accurate information and to consider patients perspective in making decisions which will influence the benefits and risk of the patients.

Finite-Elemente-Analyse einer zementierten, keramischen Femurkomponente unter Berücksichtigung der Einbausituation bei künstlichem Kniegelenkersatz / Finite element analysis of a cemented ceramic femoral component for the assembly situation in total knee arthroplasty

The femoral components of the total knee replacements are generally made of metal. In contrast, ceramic femoral components promise improved tribological and allergological properties. However, ceramic components present a risk of failure as a result of stress peaks. Stress peaks can be minimised through adequate implant design, proper material composition and optimum force transmission between bone and implant. Thus, the quality of the implant fixation is a crucial factor. The objective of the present study was to analyse the influence of the cement layer thickness on stress states in the ceramic femoral component and in the femur. Two- and three- dimensional finite element analyses of an artificial knee joint with cement layers of different thickness and with an unbalanced cement layer thickness between the ceramic femoral component and the femur were performed. Higher stress regions occurred in the area of force transmission and in the median plane. The maximum calculated stresses were below the accepted tensile strength. Stresses were found to be lower for cement layer thickness of <2.0 mm.

Patient Perspectives on Currently Controversial Issues in Total Knee Arthroplasty

Purpose : To examined the level of patient knowledge and their perspectives about the controversial issues in total knee arthroplasty (TKA), and to evaluate the effect of a relevant explanation about the issues on the patient preferences for their particular option. Materials and Methods : One hundred patients who visited our clinic and decided to undergo TKA were asked to complete a questionnaire asking about their knowledge and preference for 4 controversial issues: 1) surgical timing of the bilateral TKAs, 2) use of computer assisted surgery, 3) use of minimal invasive surgery, and 4) use of ceramic femoral component. The patients completed the same questionnaire after the advantages and disadvantages of each option had been explained using an explanatory document designed based upon what was documented in the literature. Results : The patients were not well-informed about the issues and received their information through a non-professional source. The patients tended to prefer new options with claimed promises before an explanation. The patients preferred the options with safety, accuracy, and proven evidence after an explanation. Male patients tended to prefer simultaneous TKAs more than female patients. Younger patients preferred ceramic femoral component claimed to have better longevity more than older patients did. Conclusion : This study demonstrates that patients’ knowledge of the current controversial issues is very limited, and that patient preferences would be significantly changed if they were given an explanation from a physician. Balanced information should be given to patients in order for them to reach a fair decision.