Clinical outcomes of ceramicized ball heads in total hip replacement bearings: a literature review

Metal-Driven Autoantifriction Function of Artificial Hip Joint

The service life of an artificial hip joint is limited to 10-15 years, which is not ideal for young patients. To extend the lifespan of these prostheses, the coefficient of friction and wear resistance of metallic femoral heads must be improved. In this study, a Cu-doped titanium nitride (TiNX -Cu) film with "autoantifriction" properties is deposited on a CoCrMo alloy via magnetron sputtering. When delivered in a protein-containing lubricating medium, the Cu in TiNX -Cu quickly and consistently binds to the protein molecules in the microenvironment, resulting in the formation of a stable protein layer. The proteins adsorbed on the TiNX -Cu surface decompose into hydrocarbon fragments owing to the shear stress between the Al2 O3 /TiNX -Cu tribopair. The synergistic effect of the catalysis of Cu and shear stress between the Al2 O3 /TiNX -Cu tribopair transforms these fragments into graphite-like carbon tribofilms with an antifriction property. These tribofilms can simultaneously reduce the friction coefficient of the Al2 O3 /TiNX -Cu tribopair and enhance the wear resistance of the TiNX -Cu film. Based on these findings, it is believed that the autoantifriction film can drive the generation of antifriction tribofilms for lubricating and increasing the wear resistance of prosthetic devices, thereby prolonging their lifespan.

Evaluation of Corrosion Inhibition of Plasma Sprayed FsHA/YSZ Coating on β-Titanium (Ti-13Nb-13Zr) Alloy Using Electrochemical Techniques

α + β titanium alloys especially Ti-6Al-4V alloy have dominated implant industry over the years due to their high corrosion resistance, strength, and flexibility. However, their high modulus (110GPa) compared to the human bone (18-30GPa) results in aseptic loosening of implants. Hydroxyapatite (HA) coating on Ti-6Al-4V alloys has been used to mitigate these demerits, nevertheless, more still need to be done. Hence, the present study aims at developing a natural and economical bioceramic coating on low modulus Ti-13Nb-13Zr alloy substrates using plasma spraying technique for biomedical applications. The bioceramic used was natural HA derived from fish scales (FsHA) and FsHA doped yttria stabilized zirconia at (10-20 wt.%). FsHA/YSZ powders and the coated samples were examined by XRD and SEM/EDX and the surface roughness, microhardness and corrosion resistance of the uncoated substrate and coated samples determined. The XRD pattern showed good crystalline FsHA/YSZ powders for all the compositions while the microstructure of the coatings revealed a fine splat lamellar morphology with partially melted and non-melted FsHA particles along with evenly dispersed Zr particles within the coating matrix for the FsHA/YSZ coatings. The maximum surface roughness (4.215 µm) was found with the FsHA coating while FsHA/YSZ coatings presented the highest hardness values (492.5-536.9 Hv) compared to the FsHA coating (467.8 Hv) and the uncoated substrate (385.9 Hv). Similarly, the corrosion resistance of the Ti-13Nb-13Zr alloy was significantly improved with the deposition of FsHA/YSZ bioceramic coatings.

Observation of Anesthetic Effect of Dexmedetomidine Combined With Intraspinal Anesthesia in Hip Arthroplasty and its Effect on Postoperative Delirium and Stress Response

Objective

To observe the anesthetic effect of dexmedetomidine combined with spinal anesthesia in hip arthroplasty, and to analyze the effects of dexmedetomidine on postoperative stress response, incidence of delirium, immune function and inflammatory indicators.

Methods

A total of 42 patients who underwent hip replacement in our hospital from March 2020 to June 2021 were selected as the research subjects and randomly divided into the control group and the observation group, 21 cases in each group. The control group was given intraspinal anesthesia, and the observation group was given dexmedetomidine on this basis. The onset time and maintenance time of sensory and motor nerve block were recorded. Stress response indexes [cortisol (Cor), blood glucose (Glu), adrenaline (E), noadrenaline (NE)], T lymphocyte subsets (CD3+, CD4+, CD8+, CD4+/CD8+), inflammatory indexes [tumor necrosis factor -α (TNF-α) and interleukin-6 (IL-6)] were detected before and after operation, and the incidence of postoperative delirium in both groups was recorded.

Results

The onset time of sensory nerve block and motor block in the observation group were lower than those in the control group, and the retention time of sensory nerve block and motor nerve block were higher than those in the control group (P < 0.05). After surgery, the levels of Cor, Glu, E and NE in the observation group were lower than those in the control group (P < 0.05). After surgery, the incidence of postoperative delirium in the observation group (4.79%) was lower than that in the control group (28.57%) (P < 0.05). After surgery, the levels of CD3+, CD4+, CD8+, and CD4+/CD8+ in the observation group were higher than those in the control group (P < 0.05). After surgery, the levels of TNF-α and IL-6 in the observation group were lower than those in the control group (P < 0.05).

Conclusion

The combined use of dexmedetomidine and intraspinal anesthesia has good anesthesia effect in hip joint replacement, which can greatly reduce the stress response of patients, reduce the incidence of postoperative delirium, and effectively restore the immune function of patients, reduce the level of inflammatory response, and has high clinical application value.

Ceramic-on-ceramic versus ceramic-on-polyethylene in total hip arthroplasty: a comparative study at a minimum of 13 years follow-up

BACKGROUND

Nowadays hip replacement is one of the most successful surgery in terms of clinical outcome and patient's satisfaction. Therefore, the choice of biomaterials in hip replacement is increasingly important with the aim of obtaining a long-term satisfaction of patient and a greater survivorship of the implants. Ceramic-on-polyethylene (COP) and ceramic-on-ceramic (CoC) bearings are two common coupling used in total hip arthroplasty. The aim of this retrospective study was to compare clinical and radiological outcomes between patients treated using CoC and CoP THA at a mean follow-up of 15 years.

METHODS

86 patients, average age 65.6, were included in the study: 43 in group A bearing CoC and 43 in group B bearing CoP. Minimum follow-up was 13 years. Primary outcome was a clinical evaluation assessed by HOOS and SF-12 questionnaires. Secondary outcome was a radiological evaluation on a A-P pelvis x-ray calculating acetabular cup inclination and anteversion and detecting osteolysis.

RESULT

After a multivariate analysis was performed, our results show clinical outcomes in group B significantly better than in group A: statistically significant value (p < 0,05) was found in the mean HOOS-symptoms subscale (83.0 ± 15.4 in Group A vs 90.3 ± 12.2 in group B) in the SF-12 physical component score (39.7 ± 11.0 in Group A vs 48.1 ± 10.1 in group B) and in HOOS (79.0 ± 16 in Group A vs 87.0 ± 16 in group B). 3 squeaking was found in group A. The calculated mean acetabular cup inclination value was 44,87 in group A and 44,5 in group B and the mean socket version was 17,54 in group A and 15,10 in group B. No significant statistically relationship between radiographic parameters analyzed and clinical outcomes was noted.

CONCLUSION

The current results provide us important information about the THA long-term outcome. CoP offered significantly better results compared with CoC at long-term follow up, and thus it should be considered in the choose of bearing in THA.

Bone Response to Conventional Titanium Implants and New Zirconia Implants Produced by Additive Manufacturing

The aim of the present study was to evaluate the in vivo bone response to an additively manufactured zirconia surface compared to osseointegration into titanium (Ti) surfaces. Scanning electron microscopy, confocal laser scanning microscopy, and electron spectroscopy for chemical analysis were performed to assess the surface characteristics of implant specimens. For the in vivo evaluation, eight Ti implants and eight 3D-printed zirconia implants were used. The surface of four Ti implants was sandblasted, large-grit, and acid-etched (Ti-SLA group), while those of the other four Ti implants were left untreated (Ti-turned group). The zirconia implants had no further surface modification. Implants were placed into the tibiae of four rabbits; two received the Ti-SLA and zirconia implants and the other two received Ti-turned and zirconia implants. The experimental animals were sacrificed after four weeks of surgery, and the undecalcified microscopic slides were prepared. The bone–implant interface was analyzed by histomorphometry to evaluate the bone response. The degree of surface roughness showed that Ti-SLA was the highest, followed by zirconia and Ti-turned surfaces. The 3D-printed zirconia surface showed similar bone-to-implant contact to the Ti-turned surface, and Ti-SLA had the most bone-to-implant contact. The additively manufactured zirconia implant surface is biocompatible with respect to osseointegration compared to the commercially pure Ti surface.

Hip and knee replacement in patients with ochronosis: Clinical experience and literature review

Patients with alkaptonuria can present ochronotic degenerative arthropathy due to the accumulation of pigments in the cartilages. Ochronotic arthropathy initially affects the spine, then there is the involvement of the other large joints, with greater frequency of the knees. In this article we will present two patients with alkaptonuria who have been effectively treated with knee and hip replacement, comparing our experience with what is available in the literature.

Ability of adhesion and biofilm formation of pathogens of periprosthetic joint infections on titanium-niobium nitride (TiNbN) ceramic coatings

BACKGROUND

Orthopedic metal implants are notoriously associated with release of metallic ions able to cause biological adverse reactions which might lead to implant loosening and failure. To limit any possible adverse reactions, ceramic coatings for orthopedic metal implants have been introduced. However, information regarding the interaction of these coatings with microbes responsible for periprosthetic joint infections (PJIs) is lacking. Hence, the aim of the present in vitro study is to assess the microbial affinity to a titanium-niobium nitride (TiNbN) coating.

METHODS

Adhesion and biofilm formation of clinical isolates of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Cutibacterium acnes were assessed on TiNbN-coated titanium discs in comparison with uncoated titanium and cobalt-chrome alloys discs, with either smooth or rough surfaces. Bacterial adhesion was performed by counting adhered bacteria in the first hours of incubation, and the biofilm formation was performed by means of a spectrophotometric assay and by confocal laser scan microscopy after 72 hours of incubation.

RESULTS

Overall, Staphylococcus aureus and Staphylococcus epidermidis, among the most common bacteria responsible for PJIs, displayed a significantly decreased attachment in the first hours of contact and, when cultured in presence of TiNbN coating, in comparison with CoCrMo. Biofilm formation of the four tested strains was comparable on all alloys.

CONCLUSIONS

Although the onset of a PJI is more complex than in an in vitro scenario, these findings suggest that TiNbN-coated orthopedic implants do not increase PJIs risk while ameliorating tribological and surface properties could represent a valid choice to limit possible complications such as metal hypersensitivity.

The Effect of Coating Density on Functional Properties of SiNx Coated Implants

Ceramic coatings may be applied onto metallic components of joint replacements for improved wear and corrosion resistance as well as enhanced biocompatibility, especially for metal-sensitive patients. Silicon nitride (SiNx) coatings have recently been developed for this purpose. To achieve a high coating density, necessary to secure a long-term performance, is however challenging, especially for sputter deposited SiNx coatings, since these coatings are insulating. This study investigates the time-dependent performance of sputter-deposited SiNx based coatings for joint applications. SiNx coatings with a thickness in the range of 4.3-6.0 µm were deposited by reactive high power impulse magnetron sputtering onto flat discs as well as hip heads made of CoCrMo. SiNx compositional analysis by X-ray photoelectron spectroscopy showed N/Si ratios between 0.8 and 1.0. Immersion of the flat disks in fetal bovine serum solution over time as well as short-term wear tests against ultra-high molecular weight polyethylene (UHMWPE) discs showed that a high coating density is required to inhibit tribocorrosion. Coatings that performed best in terms of chemical stability were deposited using a higher target power and process heating.

New alternate bearing surfaces in total hip arthroplasty: A review of the current literature

As indications for total hip arthroplasty (THA) have expanded, the incidence of THA has increased among younger patients, who live longer and tend to place more strain on implants via higher activity levels. This demographical shift accentuates the importance of advancing innovation to ensure implant longevity for younger and more active patients. Future innovation, as it pertains to THA components, is likely to focus on modifying implant designs and tribology in conjunction with identification and application of newer biomaterials. By reviewing the literature for development status of various materials and novel design advancements in THA component outside of the standard highly cross-linked polyethylene, this investigation provided an update on the current and future status of design initiatives as they pertain to THA. Though the highlighted alternative bearing surfaces have shown promising in vitro and limited, yet encouraging clinical data, they lack larger and longer-term clinical trial results. Further research and innovation is warranted to identify the optimal bearing surface to most effectively accommodate for the trend of younger and more active patients undergoing THA. Implant longevity is crucial if the clinical success of THA is to be maintained.