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Introduction: Patients with Haemophilia (PWH) need orthopaedic treatments and often they undergo surgery. Classically, PWH with inhibitors have to face such procedures earlier than other patients. Major orthopaedic surgery is not easy and complications are frequent. Emicizumab is the first monoclonal antibody introduced for haematological prophylaxis for PWH with inhibitors, achieving an efficacious haemostasis also in patients with severe haemophilia A with inhibitors, later demonstrated for PWH without inhibitors. A few years ago, emicizumab was also proposed for PWH undergoing surgery, as it supports excellent bleeding control. The literature on orthopaedic surgery using an emicizumab protocol is scarce: only isolated case reports with short-term follow-ups are available. Aim: The purpose of this study is the assessment of the mid-term outcomes of major orthopaedic surgery performed in a population of patients with and without inhibitors and an emicizumab regimen. Methods: We reviewed the records of 13 PWH (eight with high-titre inhibitors, five without) with a mean age of 54.6 years, undergoing 15 orthopaedic surgical procedures between 2017 and 2022: primary knee and hip arthroplasty, revision, pseudotumor excision, or amputation. Their prophylaxis consisted of the combination of emicizumab and boluses of rFVIIa (PWH with inhibitors) or rFVIII (PWH without inhibitors). The clinical parameters of evaluation were: VAS, Haemophilic Joint Health Score (HJHS), and standard radiologic studies. Follow-up was conducted at 1, 3, 6 months, and then yearly. The survival rate of all implants was also assessed. Results: The mean follow-up was 38.8 months (range: 12–65). All patients were successfully treated without complications during surgery. During the postoperative period, a patient affected by a septic complication two months after his pseudotumor excision underwent an above-the-knee amputation. All patients were regularly discharged to the rehabilitative ward, reporting satisfaction for pain reduction and improved joint and global function at the VAS and HJHS scores. No revisions or implant failures were recorded. Conclusions: A prophylaxis regimen with emicizumab and factor replacement in PWH with or without inhibitors undergoing major orthopaedic surgery ensures effective bleeding control and good postoperative clinical outcomes at mid-term follow-up, and may be routinely adopted in dedicated high-volume hospitals. This series is the most consistent to date reported at a single Haemophilia centre. [ABSTRACT FROM AUTHOR]

(1) Background: Unicompartmental knee arthroplasty (UKA) provides a viable alternative to total knee arthroplasty (TKA) in patients with isolated medial osteoarthritis (OA). From 2007 to 2021, 23% of all primary knee arthroplasties in Italy were UKAs. We retrospectively evaluated clinical outcomes and satisfaction in patients implanted with a new oxinium metal-backed fixed-bearing medial unicompartmental prosthesis at a 24-month follow-up. (2) Methods: From December 2020 to December 2021, 145 patients were treated by a single surgeon at a single institution using the hypoallergenic Journey II prosthesis. Clinical outcome measures included the Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), Oxford Knee Society (OKS) score, University of California Los Angeles Activity Score (UCLA), the Physical Component Summary (PCS), and the Mental Component Summary (MCS), and were calculated preoperatively and at 12 and 24 months. The Forgotten Joint Score-12 (FJS-12) was calculated at 12 and 24 months. Patient satisfaction was collected at 24 months. The scores were compared using the Friedman test. (3) Results: All clinical scores improved significantly from baseline to 24 months (p < 0.0001), except for the FJS-12, which from 12 to 24 months did not improve significantly (p = 0.041). Patient satisfaction was 9.32 ± 0.74 out of 10. No patient experienced complications or required revision surgery. (4) Conclusions: The Journey II unicompartmental prosthesis is a valuable treatment option for end-stage medial OA, improving knee function, providing pain relief, and ensuring high patient satisfaction at 24 months. [ABSTRACT FROM AUTHOR]

(1) Background: Total Knee Arthroplasty (TKA) in patient with haemophilia (PWH) has usually been performed with the use of cobalt-chrome femoral and titanium tibial components, coupled with standard polyethylene (PE) inserts. The aim of this retrospective study was to evaluate the long-term outcomes and survival rates of TKA in a series of consecutive PWH affected by severe knee arthropathy at a single institution. (2) Methods: We followed 65 patients undergoing 91 TKA, implanted using the same implant, characterized by an oxidized zirconium femoral component, coupled with a titanium tibial component, and a highly crosslinked PE. At 1, 6, and 12 months; then every year for 5 years; and finally, every other 3 years, all patients were scored for pain (VAS), function (HJHS; KSS), ROM, and radiographic changes. Kaplan–Meier survivorship curves were used to calculate the implant survival rates. (3) Results: The mean follow-up was 12.3 years (4.2–20.6). All clinical and functional scores improved significantly from preoperatively to the latest follow-up (VAS: from 6.9 to 1.3; HJHS: from 13.4 to 1.9; KSS: from 19.4 to 79; ROM: from 42.4° to 83.6°). The overall survivorship of the implants was 97.5% at the latest follow-up. (4) Conclusions: The present series showed a high survival rate of specific implants potentially linked to the choice of an oxidized zirconium coupled with a highly crosslinked PE. We promote the use of modern implants in these patients in order to ensure long-lasting positive outcomes. [ABSTRACT FROM AUTHOR]

The International Classification of Diseases-10 Procedure Code System (ICD-10-PCS) introduced oxidized zirconium (OxZi) and niobium procedural codes to the types of femoral head bearing surfaces in 2017. These codes aimed to increase procedural specificity in coding and improve data collection through administrative claims databases. This study aimed to assess the accuracy of ICD-10-PCS coding for femoral head bearing surfaces (cobalt chrome/metal, ceramic, and OxZi) in hip procedures. A retrospective analysis of 6,204 procedures utilizing femoral heads performed between October 1, 2017 and August 26, 2021 at a large, urban academic hospital was conducted. Operative reports and implant logs were queried to determine the femoral head bearing surface, which was used during the total hip arthroplasty. These results were then compared to the ICD-10-PCS codes in the billing records. Coding accuracy was subsequently determined and statistical differences between the three groups were evaluated. The ICD-10-PCS coding was accurate for 90.8% (5,634/6,204) of cases. Coding accuracy for ceramic femoral heads (95.4%, 4,171/4,371) was significantly greater than that of both cobalt chrome/metal (73.7%, 606/822; P <.001) and OxZi (84.8%, 857/1,011; P <.001) femoral heads. While coding for ceramic femoral heads was very accurate, OxZi and cobalt chrome/metal femoral heads were miscoded at a rate of approximately 20%. These inaccuracies call for further evaluation of the ICD-10-PCS coding process to ensure that conclusions drawn from clinical research performed through administrative claims databases are not subject to error. [ABSTRACT FROM AUTHOR]

The use of inert head materials such as ceramic heads has been proposed as a method of reducing wear and corrosion products from the articulating surfaces in total hip arthroplasty, as well as from the stem‐head taper connection. The aim of the present study was to compare the blood metal ion levels in patients with Oxinium and CoCrMo modular femoral heads, as well as monoblock stainless steel Charnley prostheses at 10 years postoperatively. The 150 patients with osteoarthritis of the hip joint included in a randomized clinical trial were grouped according to femoral head material. One group (n = 30) had received the Charnley monoblock stainless steel stem (DePuy, UK). The other patients (n = 120) received a Spectron EF CoCrMo stem with either a 28 mm CoCrMo or Oxinium modular head (Smith & Nephew, USA). After 10 years, 38 patients had withdrawn, 19 deceased, 7 revised due to aseptic loosening and 5 revised due to infection. The 81 patients with median age of 79 years (70–91) were available for whole blood metal ion analysis. The levels of Co, Cr, Ni and Zr in the blood were generally low with all the head materials (medians <0.3 micrograms/L) and no statistical difference between the groups were found (p =.2–.8). Based on the low blood metal ion values in our study groups, no indication of severe trunnion corrosion in patients with CoCrMo heads was observed, neither was there any beneficial reduction in metal ion exposure with the Oxinium femoral heads. [ABSTRACT FROM AUTHOR]

Oxidized zirconium was first introduced in total hip arthroplasty procedures to merge the strengths of metal and ceramic into one prosthetic. The subsequent adoption of oxidized zirconium (oxinium) for total knee arthroplasty is attributed to the theory of causing less wear on the tibial components compared to the alternative, cobalt chromium. However, the superficial layer of the femoral component is occasionally breached, exposing the softer zirconium substrate. Multiple mechanisms leading to zirconium substrate exposure have been explained, including collateral ligament instability and polyethylene wear. Such a failure may lead to damage to the periprosthetic tissues and often requires a revision procedure. In the current case report, we present a case of bilateral total knee arthroplasty with oxidized zirconium components that resulted in catastrophic failure and subsequent revision with hinged knee prostheses.

Background: Oxidized zirconium (OxZi) femoral heads combine the decreased abrasive properties of ceramics with the toughness of metal alloys to lower wear and increase the durability of total hip arthroplasty. The purpose of this study was to compare the 10-year polyethylene wear rates between OxZi/XLPE and cobalt chrome (CoCr)/XLPE articulations.Methods: A radiostereometric analysis (RSA) was performed on two cohorts of 23 patients who underwent total hip arthroplasty using either OxZi/XLPE or CoCr/XLPE at a minimum of 10-year follow-up. Cohorts were matched for age, gender, body mass index (BMI), and diagnosis. Polyethylene wear was measured using RSA to determine total and steady-state wear rates for both cohorts. Preoperative and postoperative patient-reported outcome measures (SF12, HHS, and Western Ontario and McMaster Universities Arthritis Index scores) were compared.Results: The mean total head penetration rate was found to be statistically different between the entire cohorts (OxZi 0.048 ± 0.021 mm/y, CoCr 0.035 ± 0.017 mm/y, P = .02) but not when 28-mm heads only (OxZi 0.045 ± 0.016 mm/y, CoCr 0.034 ± 0.017 mm/y, P = .066) were directly compared. The mean steady-state wear rate was not significantly different between the entire cohorts (OxZi 0.031 ± 0.021 mm/y, CoCr 0.024 ± 0.019 mm/y, P = .24) or 28-mm head cohorts (OxZi 0.028 ± 0.019 mm/y, CoCr 0.024 ± 0.019 mm/y, P = .574). Outcome measures showed no statistical difference except for the Harris Hip Score where the OxZi cohort demonstrated higher median scores.Conclusion: Using RSA to evaluate the 10-year in-vivo head penetration, there was no statistically significant difference in steady-state wear rates between OxZi and CoCr articulations. Both bearing combinations demonstrated wear rates well below the threshold for osteolysis. [ABSTRACT FROM AUTHOR]

We present a case of a 72-year-old male with a history of a late 1980s metal-on-polyethylene total hip arthroplasty who presented with unilateral leg vascular compromise, joint pain, and stiffness and subsequently underwent revision for adverse local tissue reaction secondary to mechanically assisted crevice corrosion. His stable and extensively porous coated femoral implant had a legacy taper with no currently manufactured option for a non–Co-alloy femoral head. After shared decision-making with the patient, we opted to use an oxidized zirconium femoral head from another manufacturer with a similar taper during his revision surgery and documented that his vascular compromise resolved and his serum Co was undetectable 3 years after the revision.

Oxinium implants are composed of a zirconium alloy with a hard ceramic surface formed by oxidization of the outer layer. This material has been shown to be an effective bearing surface for total joint arthroplasty and an alternative material for use in patients with metal hypersensitivity. Reports exist of metallosis due to unintended wear of Oxinium components from multiple mechanisms including polyethylene liner dissociation and joint instability. This metallosis creates a distinct appearance on radiographic imaging similar to that of an arthrogram. We report 2 cases of metallosis and describe the characteristic radiographic appearance of failed oxidized zirconium implants.

Oxidized zirconium was introduced as an alternative bearing surface to decrease polyethylene wear and reduce aseptic mechanical failure of hip and knee arthroplasties. Oxidized zirconium combines the strength of a metal with wear properties of ceramic, proposing increased survivorship of implant components, and possible decreased rate of revision. Despite a harder surface than cobalt-chromium, the substrate of zirconium is a softer metal. Although uncommon, prior reports have described accelerated wear and severe metallosis after femoral head dislocation in oxidized zirconium total hip arthroplasty; however, this has not been described in total knee arthroplasty. We report a case of an oxidized zirconium total knee arthroplasty failure in a patient with knee instability. This is the first report of catastrophic failure of an oxidized zirconium total knee arthroplasty implant.

Oxidized zirconium alloys can appear as black, white and all gray shades depending on the heat treatment process. The black color results from a high amount of oxygen vacancies in non-stoichiometric zirconia (ZrO2−x) that effectively reduces the band gap of the material. In this work we compare the surface properties of black and white zirconia on ZrNb7 substrate. An oxidation in air at 600 °C for 1 h results in a dark-gray oxide with only a few micro cracks. Oxidation at low oxygen partial pressure at 600 °C for 8 h (pO2 = 10–19 Pa) generates a dense, totally black oxide scale. A three step heat treatment process, that was introduced for better coating adhesion, results in a white oxide layer with many micro cracks parallel to the surface. From the results of various microscopy and spectroscopy techniques, we derive a model of the layer formation of zirconia on ZrNb7 and give reason why black zirconia, and therefore the oxidation at low oxygen partial pressure, is favorable for tribological applications (e.g., artificial joint replacements). [ABSTRACT FROM AUTHOR]

Background: Oxidized zirconium (OxZr) offers theoretical advantages in total hip and knee arthroplasty (THA and TKA, respectively) relative to other biomaterials by combining the tribological benefits of ceramics with the fracture toughness of metals. Yet, some studies have found that OxZr does not improve outcomes or wear rates relative to traditional bearing materials such as cobalt-chromium (CoCr). Separately, effacement of the thin ceramic surface layer has been reported for OxZr components, though the prevalence and sequelae are unclear.Methods: To elucidate the in vivo behavior of OxZr implants, the articular surfaces of 94 retrieved THA and TKA femoral components (43 OxZr TKA, 21 OxZr THA, 30 CoCr THA) were analyzed using optical microscopy, non-contact profilometry, and scanning electron microscopy.Results: We found that OxZr components maintain a smooth articular surface except following hip dislocation. Three of four OxZr femoral heads revised following dislocation exhibited severe damage to the articular surface, including macroscopic regions of ceramic-layer effacement and exposure of the underlying metal substrate; these components were 23-32 times rougher than pristine OxZr controls. When revised for dislocation, OxZr femoral heads were substantially rougher than CoCr femoral heads (median Sa = 0.431 v. 0.020 μm, P = .03). In contrast, CoCr femoral heads exhibited low overall roughness values regardless of whether they dislocated (median Sa = 0.020 v. 0.008 μm, P = .09, CoCr dislocators v. non-dislocators).Conclusions: Effacement of the ceramic surface layer and substantial articular surface roughening is not atypical following dislocation of OxZr femoral heads, making OxZr much less tolerant than CoCr to hip dislocation. [ABSTRACT FROM AUTHOR]

Introduction: The association between haemophilia and the so‐called 'inhibitors', alloantibodies against the infused factor able to neutralize its clotting activity, is a very rare condition. Those sporadic patients suffer of an even more severe arthropathy and performing primary or revision arthroplasty become truly challenging. Literature about this topic is scarce, consisting in small case series, high rates of complications and mid‐term follow‐ups. Aim: The purpose of this study is the assessment of the long‐term outcomes of primary and revision arthroplasty performed in a population of patients with inhibitors, the more consistent to date reported at a single haemophilia centre. Methods: We reviewed the records of 18 patients with inhibitors (26 procedures) between 1999 and 2017, divided in two groups. Group A [primary total Knee‐Hip arthroplasty (TKA‐THA)]: 13 patients underwent 19TKA and 2THA; and B (revision): 5 subjects underwent 3rTKA and 2rTHA. All patients received the same haematological prophylaxis (rFVIIa). Haemophilic Joint Health score and VAS, and X‐rays were recorded pre‐ and postoperatively. The survival rate of all primary implants was assessed. Results: The median follow‐up was 12.2 years (3‐21) for group A, 8.6 years (4‐12) for B. Few complications have been reported; the overall survival rate was 94.7% at 15 years. All patients reported satisfaction, pain reduction and improved functional ability. Conclusion: Primary and revision TKA/THA in haemophilic subjects and inhibitors may be nowadays considered safe and effective if performed in dedicated multidisciplinary centres. The use of continuous infusion of rFVIIa showed an adequate haemostatic effect and low rate of complications. As expected, revisions are more prone to complications compared to primary arthroplasty. [ABSTRACT FROM AUTHOR]

Background: Oxidized zirconium (OxZi) is a relatively new type of material that combines the strength of a metal with the surface/wears properties of a ceramic. Our aim was to investigate whether OxZi femoral heads lead to lower polyethylene wear, higher survival rate, and better clinical outcomes than the other bearing types in patients treated with total hip arthroplasty (THA).Methods: Two reviewers independently conducted a systematic search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses using the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews. These databases were queried with the terms: a. "oxidized" AND "zirconium" AND "total" AND "hip" AND "arthroplasty"; b. "oxinium" AND "total" AND "hip" AND "arthroplasty". The primary outcome measures were the survival rate of the bearing surfaces as well as the polyethylene wear.Results: The vast majority (85.7%) of the studies, which reported the mean polyethylene wear rate, showed that there was not any significant difference between OxZi and cobalt-chrome (CoCr) femoral heads (rate ratio: 0.836; 95% confidence interval: 0.362-1.928; P = .674). All studies comparing the survival rate of OxZi and CoCr femoral heads illustrated almost excellent survivorship with both implants.Conclusion: OxZi femoral heads did not lead to lower polyethylene wear rate or higher survival rate, when compared with CoCr femoral heads in patients treated with THA. On the basis of these results and taking into account the higher cost of these implants, we would not recommend the routine use of OxZi femoral heads in primary THAs.Level Of Evidence: Systematic review and meta-analysis of therapeutic studies I-III. [ABSTRACT FROM AUTHOR]

Introduction: Polyethylene wear and subsequent osteolysis remain obstacles to the long-term survivorship of total hip arthroplasty (THA). Highly cross-linked polyethylene (XLPE) with radical quenching represents a massive leap forward with dramatically improved wear rates compared to ultra-high molecular weight polyethylene (UHMWPE). In this study we evaluate the wear of UHMWPE and XLPE coupled with oxidized zirconium (OxZr) femoral heads. Methods: A longitudinal, retrospective analysis was performed identifying consecutive patients who received a 28-mm OxZr-on-polyethylene primary THA from 2003 to 2004 by a single, high-volume arthroplasty surgeon. Patients were divided into two groups: those that received (1) UHMWPE liner and (2) a highly XLPE liner. Patients were included if clinical follow-up was complete to 2014 or later. Radiographic analysis was performed by two blinded observers. Measures included cup position, annual linear wear rate, and presence of osteolysis. Pairwise comparisons, correlations, and inter-rater reliability were calculated. Results: Eighty patients were in the UHMWPE group with an average follow-up of 10 ± 1.23 years and 88 patients in the XLPE group with an average of 10 ± 1.03-year follow-up. Average age (68) was similar between groups (p = 0.288). Observer reliability was excellent for cup abduction (ICC = 0.940), anteversion (ICC = 0.942), and detection of osteolysis (ICC = 0.811). Annual linear wear rates were significantly higher (p = 1 × 10−19) with UHMWPE (0.21 ± 0.12 mm/year) compared to XLPE (0.05 ± 0.03 mm/year). Linear wear rate was significantly correlated to decreasing acetabular abduction (p = 0.035). Osteolysis was noted only in the UHMWPE group, with 17 patients (21.2%) exhibiting acetabular osteolysis and 37 (46.3%) patients exhibiting femoral osteolysis. Conclusions: OxZr coupled with XLPE showed minimal wear and no osteolysis at 10-year follow up. The yearly linear penetration rate is similar to that seen in other studies of XLPE THA. A careful longitudinal follow-up will be required to determine if advanced bearings such as OxZr or ceramic can show improved performance in the second decade of implantation.

The objective of this study was to develop an advanced-bearing couple for TKA that optimizes the balance between wear resistance and mechanical properties. The mechanical and structural properties of virgin and highly crosslinked, re-melted UHMWPE were evaluated, and tibial inserts manufactured from these UHMWPE materials were tested against either oxidized zirconium (OxZr) or CoCr femoral components on a knee simulator. This study confirmed that the wear resistance of crosslinked UHMWPE improves with increasing radiation dose but is accompanied by a concomitant reduction in mechanical properties. Compared to CoCr, the ceramic surface of OxZr allows the use of a lower irradiation dose to achieve equivalent reductions in wear rates. As a result, a given wear rate can be achieved without sacrificing the mechanical properties to the same extent that is necessary with a CoCr femoral component. The advantage of ceramic counter bearing surfaces extends to both pristine and microabrasive conditions.

Patients with THA using a ceramic head and using an OxZr head were each matched to patients with a CoCr head. Mean implantation time was 5 years. There was no difference in steady state wear rate between the ceramic (0.066 ± 0.050 mm/year) and CoCr match groups (0.052 ± 0.041 mm/year), or between the OxZr (0.022 ± 0.029 mm/year) and CoCr match groups (0.048 ± 0.071 mm/year). Follow-up into the second decade will be necessary before any changes in THA wear rate from using ceramic or OxZr bearings may be appreciated clinically with available imaging techniques. [ABSTRACT FROM AUTHOR]

ZrNb7 was exposed to a very specific three step heat treatment. The alloy is first oxidized in ambient air. The second step is a solid state reduction in vacuum, during which the oxide scale is dissolved and the oxygen diffuses into the substrate. Within a third step, the alloy is oxidized again to generate the desired ceramic coating on the outside followed by an oxygen hardened diffusion zone, that gradually reduces the hardness of the material from the outer surface to the inside. The high oxygen solubility of up to 29 at.% is distinctive in zirconium. Only titanium and hafnium show similar properties. Therefore, this rare phenomenon is further investigated with the main focus on the oxygen diffusion mechanisms through the oxide scale and the substrate. The reaction kinetics are evaluated and activation energies, parabolic oxidation constants and diffusion coefficients are determined for the two diffusion controlled processes: the oxidation and deoxidation of zirconium. This article reveals why the diffusion hardened zone does not appear in the desired thickness within a simple oxidation step and ideal process parameters are given concerning oxide thickness, cracks in the oxide scale and oxygen diffusion depth. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Oxidized zirconium (OxZr) is produced by thermally driven oxidization creating an oxidized surface with the properties of a ceramic at the top of the Zr metal substrate. OxZr is much harder and has a lower coefficient of friction than cobalt-chrome (CoCr), both leading to better wear characteristics. We evaluated and compared damage to the cartilage of porcine patella plugs, articulating against OxZr vs CoCr. Our hypothesis was that, owing to its better wear properties, OxZr would damage cartilage less than CoCr. If this is true, OxZr might be a better material for the femoral component during total knee arthroplasty if the patella is not resurfaced.Methods: Twenty-one plugs from porcine patellae were prepared and tested in a reciprocating pin-on-disk machine while lubricated with bovine serum and under a constant load. Three different configurations were tested: cartilage-cartilage as the control group, cartilage-OxZr, and cartilage-CoCr. Macroscopic appearance, cartilage thickness, and the modified Mankin score were evaluated after 400,000 wear cycles.Results: The control group showed statistically significant less damage than plugs articulating against both other materials. Cartilage plugs articulating against OxZr were statistically significantly less damaged than those articulating against CoCr.Conclusion: Although replacing cartilage by an implant always leads to deterioration of the cartilage counterface, OxZr results in less damage than CoCr. The use of OxZr might thus be preferable to CoCr in case of total knee arthroplasty without patella resurfacing. [ABSTRACT FROM AUTHOR]

This study examines the damage and wear on the polyethylene (PE) inserts from 52 retrieved Genesis II total knee replacements to identify differences in tribological performance between matched pairs of cobalt-chromium (CoCr) and oxidized zirconium (OxZr) femoral components. Observer damage scoring and microcomputed tomography were used to quantify PE damage and wear, respectively. No significant differences were found between CoCr and OxZr groups in terms of PE insert damage, surface penetration, or wear. No severe damage such as cracking or delamination was noted on any of the 52 PE inserts. Observer damage scoring did not correlate with penetrative or volumetric PE wear. The more costly OxZr femoral component does not demonstrate clear tribological benefit over the standard CoCr component in the short term with this total knee replacement design. [ABSTRACT FROM AUTHOR]

Oxidized zirconium (Oxinium) implants has been claimed as the best material in terms of wear reduction. However, longevity of an all polyethylene uni knee arthroplasty (UKA) has been a long debate. We reported a rare case of 74 year old female who was performed all polyethylene UKA 6 years prior and fell 3 months prior. After the incident, patient was wheel-chair ridden afterwards. There was no evidence of fracture upon conventional radiography examination. Conversion of UKA to total knee replacement (TKA) was performed and patient was able to walk with aid after the surgery. The failed Oxinium all polyethylene UKA failure in this case is suspected due osteoarthritis progression. • Oxinium is claimed as the best material for its low wear and durability rate. • Outcome of an all polyethylene uni knee arthroplasty (UKA) has been a debate. • We report a rare case of an Oxinium all-polyethylene UKA failure. • Patient was treated well with total knee arthroplasty (TKA) conversion. • The correlation between osteoarthritis progression and UKA materials is yet to be explained. [ABSTRACT FROM AUTHOR]

Background: Oxidized zirconium (OxZr) femoral component for total knee arthroplasty (TKA) have been introduced in an attempt to reduce polyethylene wear and secondary osteolysis and improve longevity of implants. Questions/Purposes: We reviewed clinical studies in literature evaluating OxZr femoral component for TKA. The aim of this review was to evaluate the clinical outcome and survival rate of TKA with an OxZr femoral component. Methods: A review of the existing literature was undertaken to collect data on the OxZr femoral component in order to provide a better understanding of its performance. Of 34 studies published in the literature, 8 met the eligibility criteria and were included in the final analysis. Results: Findings indicated that the mean Knee Society knee score improved in all series from preoperative to postoperative evaluation. The postoperative Knee Society knee score reported range from 84 to 95 and mean postoperative Knee Society functional score range from 74 to 90. The revision rate with this implant is low with up to 12.6 years of follow-up, with three revisions in total. The survival rate ranged from 100-98.7% at 5-7 years to 97.8% at 10 years. Conclusions: Excellent clinical outcome and high survival rate has been demonstrated for OxZr femoral component in TKA. No adverse reaction has been described for this new material. [ABSTRACT FROM AUTHOR]

The purpose of the investigation was to assess the clinical and radiographic outcomes in four bearing surfaces. Eighty patients (91 hips) undergoing total hip arthroplasty between 2004 and 2007 were randomized to one of four bearing surfaces: (1) cobalt-chrome (CoCr) and ultra-high molecular weight polyethylene (UHMWPE); (2) CoCr and XLPE; (3) Oxinium and UHMWPE; and (4) Oxinium and XLPE. The mean follow-up for this study was 6.8 years. There were no significant differences in clinical outcomes. The linear wear rates for the four groups were 0.241 mm/year, 0.076 mm/year, 0.238 mm/year and 0.061 mm/year respectively. HXLPE results in significantly less wear than UHMWPE. However, we found no significant reduction in wear rate by using Oxinium in place of CoCr femoral heads at early follow-up. [ABSTRACT FROM AUTHOR]

Background: New bearing surfaces for total knee replacement have been described in an attempt to reduce polyethylene wear and secondary osteolysis and improve longevity of implants. Oxidized zirconium is a new material that combines the strength of a metal with the wear properties of a ceramic. However, there are no reports as to who documents the long term results. We report a 10 year follow-up note of a selected series of TKAs with an oxidized zirconium femoral component. Methods: We prospectively follow 98 TKAs performed in 94 patients with an oxidized zirconium femoral component. Five patients (5 knees) had died and 6 (6 knees) were lost to follow-up at a minimum of 2 years (mean, 6.3 years; range, 2-9 years) after the operation. For the remaining 83 patients (87 knees), the minimum follow-up was 10 years (mean, 11.3 years; range, 10.0-12.6 years). In 51 cases (58.6%), a cruciate-retaining implant with a deep-dished, more conforming PE was used, and in 36 cases (41.4%), a posterior-stabilized design was used. The patellae were resurfaced in 32 cases (36.7%) and in 55 cases (63.3%) were left unresurfaced. Results: Survivorship was 97.8% at 10 years postoperatively. Two knees were revised for aseptic loosening of the femoral component. No major complication was observed clinically or radiologically. Mean Knee Society score improved from 36 to 84 and functional score from 37 to 83. Conclusions: Oxidized zirconium femoral component in TKA performs well over the first 10 years following implantation, with excellent survival rates and good clinical and radiological outcomes. Level of evidence: Level IV, therapeutic study. [ABSTRACT FROM AUTHOR]

Purpose: Polyethylene wear particle generation is one of the most important factors affecting mid- to long-term results of total knee arthroplasties. Oxidized zirconium was introduced as a material for femoral components to reduce polyethylene wear generation. However, an in vivo advantage of oxidized zirconium on polyethylene wear particle generation is still controversial. The purpose of this study was to compare in vivo polyethylene wear particles between oxidized zirconium total knee prosthesis and conventional cobalt-chromium (Co-Cr) total knee prosthesis. Methods: Synovial fluid was obtained from the knees of 6 patients with oxidized zirconium total knee prosthesis and from 6 patients with conventional cobalt-chromium (Co-Cr) total knee prosthesis 12 months after the operation. Polyethylene particles were isolated and examined using a scanning electron microscope and image analyser. Results: Total number of particles in each knee was 3.3 ± 1.3 × 10 in the case of oxidized zirconium (mean ± SD) and 3.4 ± 1.2 × 10 in that of Co-Cr (n.s.). The particle size (equivalent circle diameter) was 0.8 ± 0.3 μm in the case of oxidized zirconium and 0.6 ± 0.1 μm in that of Co-Cr (n.s.). The particle shape (aspect ratio) was 1.4 ± 0.0 in the case of oxidized zirconium and 1.4 ± 0.0 in that of metal Co-Cr (n.s). Conclusions: Although newly introduced oxidized zirconium femoral component did not reduce the in vivo polyethylene wear particles in early clinical stage, there was no adverse effect of newly introduced material. At this moment, there is no need to abandon oxidized zirconium femoral component. However, further follow-up of polyethylene wear particle generation should be performed to confirm the advantage of the oxidized zirconium femoral component. Level of evidence: Therapeutic study, Level III. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this article is to provide an up-to-date overview of zirconia-toughened alumina (ZTA) components used in total hip arthroplasties. The structure, mechanical properties, and available data regarding the clinical performance of ZTA are summarized. The advancements that have been made in understanding the in vivo performance of ZTA are investigated. This article concludes with a discussion of gaps in the literature related to ceramic biomaterials and avenues for future research. [Copyright &y& Elsevier]

Background: The surface characteristics of the femoral component affect polyethylene wear in modular total knee replacements. In the present retrieval study, the surface characteristics of cobalt-chromium (CoCr) alloy and oxidized zirconium (OxZr) femoral components were assessed and compared. Methods: Twenty-six retrieved CoCr alloy femoral components were matched with twenty-six retrieved OxZr femoral components for implantation period, body-mass index, patient gender, implant type, and polyethylene insert thickness. The surface damage on the retrieved femoral components was evaluated using a semi-quantitative assessment method, scanning electron microscopy, and contact profilometry. Results: The retrieved CoCr alloy femoral components showed less posterior surface gouging than OxZr femoral components; however, at a higher magnification, the grooving damage features on the retrieved CoCr alloy femoral components confirmed an abrasive wear mechanism. The surface roughness values Rp, Rpm, and Rpk for the retrieved CoCr alloy femoral components were found to be significantly higher than those of the retrieved OxZr femoral components (p≤0.031). The surface roughness values were higher on the medial condyles than on the lateral condyles of the retrieved CoCr alloy femoral components; such a difference was not observed on the retrieved OxZr femoral components. Conclusions: The surface roughness of CoCr alloy femoral components increased while the surface roughness of the OxZr femoral components remained unchanged after in vivo service. Therefore, the OxZr femoral components' resistance to abrasive wear may enable lower polyethylene wear and ensure long-term durability in vivo. Level of Evidence: Level IV [ABSTRACT FROM AUTHOR]

Aims: This study reports the ten-year wear rates, incidence of osteolysis, clinical outcomes, and complications of a multicentre randomized controlled trial comparing oxidized zirconium (OxZr) versus cobalt-chrome (CoCr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) and highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA)., Methods: Patients undergoing primary THA were recruited from four institutions and prospectively allocated to the following treatment groups: Group A, CoCr femoral head with XLPE liner; Group B, OxZr femoral head with XLPE liner; and Group C, OxZr femoral head with UHMWPE liner. All study patients and assessors recording outcomes were blinded to the treatment groups. The outcomes of 262 study patients were analyzed at ten years' follow-up., Results: Patients in Group C were associated with increased mean liner wear rates compared to patients in Group A (0.133 mm/yr (SD 0.21) vs 0.031 mm/yr (SD 0.07), respectively; p < 0.001) and Group B (0.133 mm/yr (SD 0.21) vs 0.022 mm/yr (SD 0.05), respectively; p < 0.001) at ten years' follow-up. Patients in Group C were also associated with increased risk of osteolysis and aseptic loosening requiring revision surgery, compared with patients in Group A (7/133 vs 0/133, respectively; p = 0.007) and Group B (7/133 vs 0/135, respectively; p = 0.007). There was a non-statistically significant trend towards increased mean liner wear rates in Group A compared with Group B (0.031 mm/yr (SD 0.07) vs 0.022 mm/yr (SD 0.05), respectively; p = 0.128). All three groups were statistically comparable preoperatively and at ten years' follow-up when measuring normalized Western Ontario and McMaster Universities Osteoarthritis Index (p = 0.410), 36-Item Short Form Health Survey (p = 0.465 mental, p = 0.713 physical), and pain scale scores (p = 0.451)., Conclusion: The use of UHMWPE was associated with progressively increased annual liner wear rates after THA compared to XLPE. At ten years' follow-up, the group receiving UHMWPE demonstrated an increased incidence of osteolysis and aseptic loosening requiring revision surgery compared to XLPE. Femoral heads composed of OxZr were associated with trend towards reduced wear rates compared to CoCr, but this did not reach statistical significance and did not translate to any differences in osteolysis, functional outcomes, or revision surgery between the two femoral head components. Cite this article: Bone Joint J  2022;104-B(7):833-843.

Polyethylene wear is a key contributor to long-term failure in total knee arthroplasty. Oxidized zirconium alloy was created as a bearing surface for total joint arthroplasty in an attempt to address this concern. Oxidized zirconium has shown considerable improvements over existing materials in several key areas related to component longevity, including resistance to roughening, wear reduction, frictional behavior and biocompatibility. This review aims to summarize the current use of oxidized zirconium alloy in knee arthroplasty, as well as the possible advantages and downsides of this material. INSET: Key issues. [ABSTRACT FROM AUTHOR]

Abstract: Metallic femoral components with ceramic articulating surfaces can substantially lower polyethylene (PE) wear during walking activities under conditions of normal knee alignment. It is unknown whether these types of components can maintain low wear rates under conditions of knee malalignment and the harsher kinematics associated with younger, athletically active patients. Wear was measured in non–cross-linked, ethylene oxide–sterilized PE inserts against oxidized zirconium or cobalt-chrome femoral components in a knee wear simulator. The vertical load was modified to replicate knee varus malalignment of 3°, and the range of tibial rotation was increased to 20°. Mean gravimetric and volumetric wear rate over 5 million cycles was 55% lower in the oxidized zirconium group. An oxidized zirconium femoral component can significantly reduce PE wear under simulated conditions of athletically active patients with modestly malaligned total knee arthroplasty prostheses. [Copyright &y& Elsevier]

Abstract: Oxidized zirconium (OxZr) was introduced to serve as a ceramic surface for femoral components in TKA. The aim of this study was to compare retrieved OxZr components and corresponding PE inserts in matched comparison with conventional cobalt/chrome/molybdenum alloy (CoCrMo). Eleven retrieved posterior stabilized TKA with an OxZr femoral component were included. This included 6 implants from an earlier preliminary study. From a cohort of 56 retrieved TKA with conventional CoCrMo femoral components, pairs were matched according to duration of implantation, patient age, reason for revision, and BMI. Polyethylene inlays and femoral components were optically scored for in vivo damage. The average damage score of the tibial PE inserts was significantly lower with OxZr components (p=0.01). Mainly burnishing and scratches were found. The average wear score in the visual analysis of the femoral components was significantly lower for the OxZr as well (p=0.005). Femoral components made of OxZr were less sensitive to in vivo damage and corresponding PE inlays also showed less damage than CoCrMo components. [Copyright &y& Elsevier]

Abstract: Safety of oxidized zirconium (OxZr) in total knee arthroplasty (TKA) has been supported by biomechanical, clinical, and radiologic data. Retrieved OxZr femoral components and corresponding polyethylene (PE) inserts were examined to rule out patterns leading to early failure. Sixteen retrieved TKA with an OxZr femoral component were included. The PE inlays were analyzed applying an established scoring system for wear and surface damage. Femoral components were screened for scratching, pitting, delamination, and striations. The prostheses were in situ for 16.4 ± 11.9 months. The average wear and damage score for the tibial PE inserts was 36.0 ± 12.7. The average score in the visual analysis of the OxZr femoral components was 1.3 ± 1.3. The data presented in this study did not show major wear of the PE in TKA using OxZr components. In this cohort, there were no failures directly related to this implant. [Copyright &y& Elsevier]

The classical wear mechanisms abrasion, fatigue, and adhesion are the most frequent causes of surface changes of ultra high molecular weight polyethylene (UHMWPE) in artificial joints. The counterpart material has a strong influence on the wear and friction behavior of artificial joints due to its abrasive properties and adhesive interaction with UHMWPE. The formation of a transfer layer on the counterpart in UHMWPE bearing systems is often described as being a clear indication of strong adhesive forces. The influence of using a cobalt‐chromium‐molybdenum (CoCrMo) alloy, a titanium nitride plasma coating or an oxidized zirconium alloy on adhesive wear was studied. The surface free energy and the bonding forces of these counterpart materials to UHMWPE were investigated. Catalytic effects on the degradation behavior of polyethylene, the micro friction behavior, and the build‐up and constitution of a transfer layer deposited under loads, and relative velocities that are relevant in knee joints were analyzed. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [ABSTRACT FROM AUTHOR]

Summary: Objective: The purpose of the current study was to investigate the feasibility of applying defect-size femoral implants for the treatment of localized cartilage defects in a 1-year follow-up model. Methods: In 13 goats, a medial femoral condyle defect was created in both knees. Defects were randomly treated by immediate placement of an oxidized zirconium (OxZr) (n =9) or cobalt–chromium (CoCr) implant (n =9) or left untreated (n =8). Six un-operated knee joints served as a control. Animals were sacrificed at 52 weeks. Joints were evaluated macroscopically. Cartilage quality was analyzed macroscopically and microscopically and cartilage repair of untreated defects was scored microscopically. Glycosaminoglycan (GAG) content, release and synthesis were measured in tissue and medium. Implant osseointegration was measured by automated histomorphometry. Results: Cartilage repair score of the defects was 13.3±3.0 out of 24 points (0=no repair, 24=maximal repair). Articular evaluation scores decreased (indicative of degeneration) in untreated defects and in defects treated with either implant (P <0.05). Macroscopical, microscopical and biochemical analysis showed that the presence of untreated defects and the implants caused considerable degeneration of medial tibial plateau, and to a lesser extent of the lateral compartment. Mean bone-implant contact was extensive and not different between materials (39.5±28.1% for OxZr and 42.3±31.5% for CoCr) (P =0.873). Conclusions: Considerable cartilage degeneration was induced in the articulating cartilage of the medial tibial plateau 1 year after creating an osteochondral defect in the medial femoral condyle. Treating this defect with a small metal implant, made of either OxZr or CoCr, could not prevent this degeneration. Further optimization of defect-size implants and their placement is required to make this the therapy of choice for the treatment of local cartilage defects. [Copyright &y& Elsevier]

Abstract: Oxidized Zr alloys have been shown to exhibit lower friction and superior wear properties, suggesting that they could be used in hip and knee implants. However, conventional oxidation of Zr alloys above 500°C, in dry air, for several hours has been shown to have detrimental effects on the substrate’s properties. In this work, we deposited pure Zr on Ti, then oxidized the coating using a continuous-wave Nd:YAG laser, which facilitated localized heating to elevated temperatures without affecting the substrate. Laser-assisted oxidation resulted in a 7μm thick fully dense ZrO2 layer on Zr in which an increase in oxidation kinetics was evident due to an increase in the laser power and/or the oxygen partial pressure. Due to its high surface energy and wettability, the wear rate of laser-oxidized Zr was two orders of magnitude less compared to that of as-deposited Zr. The oxidized coatings showed comparable in vitro biocompatibility to that of pure Ti and excellent in vitro cell–material interactions. This article reports the processing of Zr/ZrO2 coatings on Ti using lasers, and the influence of laser parameters and oxygen partial pressure on the coating’s mechanical, microstructural, wear and in vitro biological properties using human osteoblast cells. [Copyright &y& Elsevier]

Abstract: Increased femoral knee component surface roughness is clinically and experimentally correlated with increased ultra-high molecular weight polyethylene (UHMWPE) wear rates. Ceramic-surfaced femoral components have increased scratch resistant surfaces, which offer the potential to reduce UHMWPE wear rates. In this study, oxidized zirconium (OxZr) and cobalt chromium (CoCr) femoral components were first subjected to a standardized roughening protocol. An in vitro total knee replacement (TKR) wear study was then conducted using conventional UHMWPE to quantify the effect of femoral surface roughening on TKR kinematic, kinetic and wear performance over time. An Instron/Stanmore force-controlled knee simulator was used to conduct a 5 million cycle wear simulation using ISO-14243 walking cycles. During the pre-test roughening procedure, the OxZr component surfaces resisted third body scratching better than the CoCr component surfaces. During wear testing, the roughened OxZr femoral components generated 82% less wear when compared to the roughened CoCr femoral components. Significant reductions in TKR ranges of motion were found over time despite linear wear rates. This study demonstrates the potential of OxZr femoral knee components for reducing polyethylene wear in vivo when under potentially abrasive conditions and offers new insights into the effects of wear on TKR kinematics over time. [Copyright &y& Elsevier]

Objective: Currently, the surgical treatment of localized cartilage defects has limitations. Alternatively, localized cartilage defects may be treated with small biocompatible metal cartilage tacks. Our purpose was to investigate the applicability of defect-size femoral implants. Different bearing materials, cobalt-chromium (CoCr) and oxidized zirconium (OxZr), were tested to evaluate the effect on opposing cartilage quality and osseointegration at different insertion depths.Methods: In 18 adult female New Zealand White rabbits, a medial femoral condyle defect was filled with either an OxZr or a CoCr implant (Ø articulating surface 3.5 mm; fixating pin of 9.1 mm length), placed flush, 1mm deep or 1mm protruding with respect to the level of the surrounding cartilage. Animals were sacrificed after 4 weeks. Tibial cartilage quality was scored microscopically and osseointegration measured by automated histomorphometry.Results: Considerable articulating cartilage erosion was found in all conditions. Tibial cartilage quality was least compromised when both implants were placed flush compared to deep (P=0.01) or protruding position (P=0.004) and was better for OxZr compared to CoCr (P=0.011) when left protruding, while no differences were found when placed deep of flush. Most bone formation around the fixating pin was observed in a protruding position (P=0.01). In deep position, more bone-implant contact was observed with CoCr compared to OxZr (P=0.02).Conclusions: OxZr and CoCr implants showed good osseointegration when used as a localized cartilage defect treatment in the rabbit knee; however, opposite cartilage damage was observed in all cases. Placement flush to the surrounding cartilage seems essential and when left protruding OxZr may be less erosive. In conclusion, caution is warranted using small metal implants for the treatment of localized cartilage in the human patient. [ABSTRACT FROM AUTHOR]

Because it is difficult to adapt ceramic technology to prevent ceramic fractures, attention has been directed at the development of a new metal alloy, the surface of which can be treated to be made more scratch-resistant than cobalt chromium alloy. A niobium (Nb) alloy of zirconium (Zr–2.5Nb) has recently been introduced as a bearing surface for the femoral component in hip arthroplasty. The advantage is that the surface of the metal can be transformed into a relatively thick (micrometers) zirconium oxide (i.e., zirconia) ceramic-like material, thus combining the benefits of ceramic and metal in one component. The oxide layer is not a coating but rather the surface zone of the metal alloy. The oxide/metal interface is continuous, without pores or voids which might be detrimental to oxide adhesion. The ceramic like zirconia surface layer is highly adherent to the metal alloy and further supported the use of this novel alloy as a scratch-resistant counterface for total joint replacement prostheses. Laboratory studies have demonstrated the superior wear performance of oxidized zirconium against polyethylene in comparison with cobalt–chromium alloy. This paper comments the advantage of this new bearing surface for hip replacement. [ABSTRACT FROM AUTHOR]

In vivo roughening of cobalt chrome bearing surfaces, which can increase ultra-high molecular weight polyethylene wear, may occur in total hip and knee arthroplasty. Ceramic surfaces are more scratch-resistant than metal and less susceptible to in vivo roughening. Oxidized zirconium implants consist of a zirconium-2.5% niobium (Zr-2.5NB) alloy substrate with a relatively thick ceramic oxide surface. Multiple in vitro wear studies have consistently demonstrated lower wear rates with oxidized zirconium compared with cobalt chrome under clean and abrasive conditions and early clinical studies demonstrate favorable results with oxidized zirconium, suggesting that this material may improve the durability of total hip and knee arthroplasty. [ABSTRACT FROM AUTHOR]