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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]

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]

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]

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]

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]

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]

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]

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: 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]

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]

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]

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]