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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5881_Библиотеки_им_академика_М_И_Перельмана.pdf
13 Wear andFriction Mechanism Study inKnee andHip Rehabilitation
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CoM) hip prostheses were less than 50nm, exhibiting round and irregular morphologies. Notably, needle-shaped particles (40–120nm) containing both Co and
Cr were identied in the periprosthetic tissue of MoM bearings [206]. Concentrations
of wear debris from CoC hip joints invivo were signicantly lower than those from
MoP and CoP joints. Studies on CoC and CoP hip prostheses found no signicant
differences in the average size among different particle types [207]. Regarding
ceramic wear particles, initially reported to range from 5 to 90nm by TEM [208],
subsequent SEM examinations revealed sizes ranging from 0.05 to 3.2 mm.
Importantly, during the micro-separation of CoC joint prosthesis components, very
small alumina wear debris (2–27.5 nm) was observed [209]. This compilation
underscores the diversity in wear debris characteristics across various bearing materials and provides valuable insights into the intricate world of joint prosthetic wear
phenomena [36].
The particles isolated from both joint simulators and periprosthetic tissues
exhibit predominantly submicron sizes [214] and display a range of both regular
and irregular shapes, as illustrated in Figs.13.13 and 13.14. These shapes, depicted
in Fig. 13.13, include various morphologies such as cylindrical, radial broken,
blocky/slice, bril and twig for materials like Carbon/Carbon composites and CrCo
alloy [210, 211]. Figure 13.14 further illustrates typical morphologies of wear
debris from periprosthetic tissue, showing shapes like spherical, sheet/ake type,
and bril for materials such as UHMWPE and Alumina [191, 208, 212, 215, 216].
Common shapes of particles retrieved from joint prosthetics include spherical,
ake, and bril [212], as shown in Fig.13.14. In contrast, joint simulators generate
particles with various shapes, including cylindrical, radial broken, blocky, bril/
twig, spherical sheet, and ake [34, 110], as depicted in Fig.13.13. Differences in
particle sizes between invivo and invitro environments were observed in studies
involving UHMWPE and CoCr alloy friction pairs. Hongtao etal. [212] reported
that UHMWPE particles from joint simulators were larger (average diameter of
6.89μm) compared to those isolated from periprosthetic tissues (average diameter
of 1.33μm). Buscher etal. [79] found that a majority of invitro CoCr wear particles
were globular with a diameter <100nm, while invivo particles had a mean diameter
of <80nm, with a minority exhibiting needle-shaped morphology.
In Fig.13.13i, j, scanning electron micrographs depict UHMWPE wear debris
collected from a serum solution [213]. Two distinct types of UHMWPE particles are
identied: one exhibiting a spherical or rounded morphology, with most particles
being less than 0.3μm in diameter, and another displaying an elongated or brous
shape, with lengths primarily ranging from 1 to 2μm and widths less than 0.5μm.
The size distributions (length and width) of approximately 150 randomly selected
particles, measured on a 10,000× magnication micrograph, are presented in
Fig.13.11i, j. Notably, most wear particles are submicron-sized, with an average
length of 0.53μm and an average width of only 0.19μm. Visual and SEM examina-
tions of the CoCr femoral head post-simulator test under serum lubrication reveal
no signs of transfer lm formation. The corresponding UHMWPE cup surface
appears glossy and shiny, consistent with previous reports on both retrieved and hip
simulator-tested cups by Hongtao etal. [212]. In the context of hip and knee joint
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Fig. 13.13 Typical morphologies of debris from joint simulator [36]; (a) Carbon/Carbon compos-
ites [210]; and (b) Cobalt-Chrome alloy [211]; (c) Cylindrical (C/C composites) [210]; (d) Radial
broken (C/C composites) [210]; (e) Blocky/Slice (C/C composites) [210]; (f) Fibril and Twig
(UHMWPE) [212]; (g) Spherical (UHMWPE) [212] (h) Sheet/ake type (UHMWPE) [212]; (i)
polyethylene (UHMWPE) wear debris recovered from serum 10,000× [213] and (j) 40,000× resolution [36, 213]
13 Wear andFriction Mechanism Study inKnee andHip Rehabilitation
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Fig. 13.14 Common wear debris morphologies found in periprosthetic tissue include (a)
UHMWPE [215], (b) Alumina [208], (c) Spherical (UHMWPE) [212], (d) Sheet/Flake type
(UHMWPE) [191], and (e) Fibril (UHMWPE) [195]; (f–h) The AFM morphology of UHMWPE
wear debris [217] this includes (f) a two-dimensional projection of AFM data showcasing debris
particles in the 0.2–0.8μm fraction on a lter, with six larger particles and three pores identied;
(g) three-dimensional projections of AFM data for the six indicated particles, with dimensions in
nanometers; and (h) examples of length (L), width (W), and height (H) measurements conducted
on two representative UHMWPE particles [36]
wear debris, the visual representation in Fig.13.13 underscores the diverse morphologies that can arise from different materials and conditions. Understanding
these variations is crucial for assessing the potential biological responses and longterm performance of joint implants [197]. The observed differences between invivo
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and invitro wear debris characteristics emphasize the importance of rening simulation methodologies to better replicate the complexities of the invivo environment.
While the in vivo and in vitro analyses demonstrate variations in the sizes and
shapes of wear debris, the justication for evaluating invitro tribological studies
lies in their ability to reproduce invivo results. However, uncertainties persist, as
observed by Catelas etal. [211], who noted that CoCr particles retrieved from a
metal-on-metal (MoM) joint simulator closely resembled those retrieved from
MoM joints of patients. Figure13.14f–h pertains to the quantication of the size
and shape of UHMWPE wear debris in all three spatial dimensions. Complemented
by ultra-precision contour-graphy, the AFM technique was employed for this investigation, providing a comprehensive analysis of the wear debris morphology. The
resulting data allowed for precise measurements of the length (L), width (W), and
height (H) of UHMWPE wear debris, presenting a valuable dimensionality overview by Gladkis etal. [217]. This approach represents a methodological compromise aligning practical considerations of AFM with the accurate determination of
particle dimensions in three dimensions. Another recent work [217] has introduced
a three-dimensional characterization of the size and shape of UHMWPE wear
debris. This builds upon earlier efforts by Scott etal. [214], who employed Atomic
Force Microscopy (AFM) to enhance the estimation of UHMWPE volumetric wear
rate invitro. The investigation utilized a MiaoXAM2.5X-50X ultra-precision contour graph to delve into the three-dimensional morphology and thickness of the
wear debris [212].
Wear debris in joint prosthetics has garnered signicant attention due to its
implications for cellular responses, implant longevity, and patient outcomes.
Figure 13.15a presents crucial insights into the cellular interactions with wear
debris. The TEM images illustrate MG63 cells exposed to Al2O3 nanoparticles,
revealing the dynamic process of internalization and actin rearrangement near the
plasma membrane [218]. Simultaneously, the SEM image (Fig.13.15b) displays
primary human dermal broblasts exposed to CoCr alloy nanoparticles, offering a
visual representation of cellular responses to metallic wear debris [219]. It portrays
live primary human dermal broblasts exposed to CoCr alloy nanoparticles for
24hours, both outside and inside the cell. This provides a visual understanding of
how cells respond to metallic wear debris [36].
Figure 13.15c further enriches our understanding by presenting Saos-2 cells
challenged with FeAlCr alloys. The short-term response after 24hours and mineral
formation after 21days offer a glimpse into the complex interplay between alloy
compositions and cellular reactions [220]. This information is critical for assessing
potential osteolytic risks associated with specic alloy wear particles. The
Fig.13.15a–e collectively contribute to our understanding of wear debris-induced
biological responses in joint implants. They underscore the importance of considering particle characteristics such as size, shape, and composition in evaluating cellular viability, proliferation, and inammatory reactions. This information is crucial
for improving the design and longevity of prosthetic devices. Figure13.15e could
serve as a valuable addition to this exploration. It could potentially offer a more indepth analysis of the intricate relationship between wear particle characteristics and
13 Wear andFriction Mechanism Study inKnee andHip Rehabilitation
411
Fig. 13.15 Depicts (a) Transmission Electron Microscopy (TEM) images capturing MG63 cells
at 37 °C after 6-hour incubation with Al2O3 NPs. Arrows indicate the internalization process,
showcasing actin rearrangement near the plasma membrane and extension into the extracellular
space [218]. Additionally, (b) a Scanning Electron Microscopy (SEM) image illustrates live primary human dermal broblasts exposed to CoCr alloy nanoparticles for 24hours, both outside and
inside the cell [219]; (c) Saos-2 cells subjected to a 24-hour challenge with 0.5mg/mL of FeAlCr
alloys (average diameter 3.7±0.4) and (d) mineral formation observed after 21days by Saos-2
cells supplemented with 1mg/mL of FeAlCr alloys [220]; (e) biological response to wear particles
varies based on particle size [36]
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their impact on cellular responses. This gure considers the critical particle size
range reported in previous studies [36, 221–223], exploring the stimulation of cell
response and potential inammatory effects [36]. Understanding wear debris at the
cellular and molecular levels is paramount for improving the design and longevity
of prosthetic devices. Additionally, considerations of the impact of wear debris on
the host tissues, immune responses, and potential long-term effects on implant stability are crucial for optimizing patient outcomes [224]. Further research, potentially represented in the presumed Fig. 13.15e, can guide the development of
prosthetic materials that minimize adverse cellular reactions.
A. Choudhari et al.
13.10 Future Directions andEmerging Technologies
Several emerging technologies hold promise for advancing wear and friction
studies.
13.10.1 Additive Manufacturing forCustom Implants
Additive Manufacturing (AM), colloquially known as 3D printing, represents a
paradigm shift in the realm of orthopedic implantology, particularly in the development of custom implants for hip and knee joints. This transformative technology
leverages layer-by-layer deposition of materials, enabling the fabrication of intricate structures with unprecedented precision. The customization aspect is particularly advantageous in addressing the inherent anatomical variations among
individuals, as AM allows for the creation of bespoke implants tailored to the unique
geometry of a patient’s hip or knee [225]. The material selection in additive manufacturing plays a pivotal role in ensuring the biomechanical compatibility of custom
implants. Titanium alloys, renowned for their biocompatibility and robust mechanical properties, are frequently employed in this context. Additionally, biocompatible
polymers are gaining prominence for their versatility and capacity to mimic natural
tissue characteristics. The use of such advanced materials ensures that the custom
implants exhibit optimal strength, durability, and compatibility with the host biological environment [226].
One of the distinguishing features of AM in orthopedics is the ability to introduce controlled porosity in the implant structure. Porosity can be strategically
designed to facilitate osseointegration, the process by which the implant fuses with
the surrounding bone tissue. This enhances the overall stability of the implant and
mitigates issues such as loosening or implant-related complications. The precise
control over porosity is a testament to the nesse achievable through additive manufacturing techniques. Furthermore, the iterative and rapid prototyping capabilities
of AM signicantly expedite the design and development phases of custom implants.
This agility enables clinicians and researchers to ne-tune implant designs based on
13 Wear andFriction Mechanism Study inKnee andHip Rehabilitation
413
patient-specic feedback and evolving medical insights. The dynamic nature of this
iterative process contributes to continuous improvements in implant design, fostering a trajectory toward enhanced patient outcomes and long-term implant success [227].
Therefore, the amalgamation of additive manufacturing with orthopedic implantology for custom hip and knee implants marks a pioneering advancement. This
approach not only caters to the individualized needs of patients but also exemplies
the intersection of precision engineering, biomaterials science, and medical innovation in the pursuit of optimal musculoskeletal healthcare. As research and development in this domain persist, the scientic community anticipates a transformative
impact on the landscape of orthopedic interventions, ushering in an era of unparalleled customization and efcacy [228–232].
13.10.1.1 Tailored Geometries
The pursuit of Tailored Geometries in the realm of hip and knee orthopedic implants
represents a paramount endeavor in addressing the unique anatomical variations
among individuals. Tailoring the geometries of these implants involves meticulously considering the patient’s specic anatomy, ensuring a precise t and optimal
biomechanical alignment [233]. This approach acknowledges the inherent diversity
in hip and knee joint structures, advocating for a departure from the one-size-ts-all
paradigm. Tailored geometries are achieved through advanced imaging techniques,
such as computed tomography (CT) scans, which provide detailed three- dimensional
representations of the patient’s joint anatomy. The signicance of tailored geometries is underscored by their direct impact on implant performance and patient outcomes. A bespoke implant design, conforming to the individual’s anatomy, mitigates
the risk of malalignment, reduces stress concentrations, and minimizes the potential
for implant-related complications. The integration of patient-specic data into the
design process ensures that the implant not only addresses the immediate surgical
requirements but also aligns with the broader biomechanical dynamics of the musculoskeletal system [233, 234]. Tailored geometries are particularly pertinent in
optimizing the longevity and functionality of hip and knee implants. The intricacies
of joint motion, load distribution, and contact stresses necessitate a nuanced
approach to implant design [235]. By tailoring the geometries to each patient’s
unique joint morphology, orthopedic surgeons can achieve a harmonious interface
between the implant and the natural tissues, thereby enhancing the implant’s stability and longevity. This tailored approach also contributes to a reduction in postoperative complications, such as instability, wear, and discomfort. Hence, the
integration of Tailored Geometries in hip and knee orthopedic implants epitomizes
a personalized and precision-oriented paradigm in musculoskeletal healthcare.
Through a synthesis of advanced imaging technologies, biomechanical principles,
and engineering expertise, tailored geometries stand at the forefront of optimizing
implant performance. As research in this domain continues to evolve, the scientic
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community anticipates a transformative impact on the standard of care for individuals undergoing hip and knee implantation, ushering in an era where customization
is paramount for achieving optimal clinical outcomes [236].
13.10.1.2 Improved Wear Characteristics
3D printing technology enables the fabrication of implants with intricate surface
features and optimized material properties, contributing to improved wear characteristics. The customization afforded by additive manufacturing allows for the
incorporation of advanced biomaterials and novel surface textures that enhance the
implant’s resistance to wear and friction. The result is a bespoke implant designed
to withstand the specic mechanical demands of the joint, potentially extending the
functional life of the prosthetic and reducing the likelihood of wear-related issues
over time.
13.10.1.3 Accelerated Innovation
Additive manufacturing accelerates the pace of innovation in implant design. This
technology empowers researchers and engineers to explore novel structures, materials, and surface treatments, pushing the boundaries of what is achievable with traditional manufacturing methods. The rapid prototyping capabilities of 3D printing
facilitate iterative design processes, allowing for the renement of implants based
on real-world performance data and clinical feedback. This iterative approach holds
the potential to continually improve wear resistance and overall implant performance. Therefore, additive manufacturing is a transformative force in the realm of
hip and knee replacement prosthetics. The ability to create custom implants with
tailored geometries and optimized wear characteristics represents a leap forward in
personalized medicine, offering patients the prospect of more durable and functionally superior joint replacements. As this technology continues to evolve, its impact
on the eld is likely to shape a future where implants are not just replacements but
tailored solutions for individual patients [237].
13.10.2 Smart Implants forReal-Time Monitoring
A transformative era in hip and knee replacement prosthetics is unfolding with the
advent of smart implants, incorporating sensors for real-time monitoring. This innovative technology holds great promise in revolutionizing patient care by providing
continuous insights into wear, function, and implant status, ushering in a new frontier of proactive healthcare management.
13 Wear andFriction Mechanism Study inKnee andHip Rehabilitation
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13.10.2.1 Real-Time Wear Monitoring
Smart implants equipped with sensors offer real-time wear-monitoring capabilities.
These embedded sensors can detect and quantify subtle changes in the wear patterns
of the implant components during joint articulation. This real-time wear data provides valuable insights into the progression of joint deterioration, allowing healthcare professionals to intervene promptly when necessary. Such early detection has
the potential to minimize wear-related complications and extend the longevity of
the implant [238].
13.10.2.2 Functionality Assessment
The integration of sensors in smart implants enables continuous functionality
assessment. These sensors can measure joint forces, range of motion, and overall
implant performance during daily activities. By providing a comprehensive understanding of how the implant functions in real-world scenarios, healthcare providers
can tailor rehabilitation programs and post-operative care plans to the specic needs
of each patient. This personalized approach enhances overall patient outcomes and
satisfaction [239, 240].
13.10.2.3 Implant Status Monitoring
Smart implants go beyond wear and functionality monitoring by providing realtime data on the overall status of the implant. This includes information on factors
such as stability, alignment, and potential signs of complications. The continuous
monitoring of implant status enables timely interventions and adjustments, addressing issues before they escalate and ensuring the sustained success of hip and knee
replacements [241, 242].
13.10.2.4 Patient-Centric Healthcare
The implementation of smart implants fosters a patient-centric approach to healthcare. Smart implants facilitate informed decision-making and proactive management of orthopedic conditions by empowering patients and healthcare providers
with real-time data. Patients can actively participate in their care, and healthcare
professionals can make timely adjustments to treatment plans, contributing to
improved overall patient outcomes and quality of life. Hence, the integration of sensors in hip and knee implants marks a transformative shift towards smart implants
capable of real-time monitoring. This innovation not only enhances our understanding of implant performance but also opens avenues for personalized and proactive
healthcare strategies. Smart implants represent a dynamic step forward in the
evolution of orthopedic care, promising a future where implants actively contribute
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to the well-being and longevity of patients undergoing joint replacement procedures [243].
A. Choudhari et al.
13.10.3 Biomaterial Innovations forEnhanced
Wear Resistance
The evolution of hip and knee replacement prosthetics is poised for a signicant
leap forward through ongoing biomaterial innovations. The integration of novel biomaterials, advanced coatings, and surface modications presents a compelling avenue for achieving unprecedented levels of wear resistance, setting the stage for
enhanced durability and performance in orthopedic implants [244–249].
13.10.3.1 Advanced Biomaterials
The exploration of advanced biomaterials holds immense potential for revolutionizing wear resistance in hip and knee implants. Researchers are delving into the
development of biocompatible materials with superior mechanical properties, aiming to create implants that closely mimic the natural biomechanics of joints.
Innovations in this realm include biodegradable polymers, bioactive ceramics, and
nanocomposites, each offering distinct advantages in terms of strength, exibility,
and wear resilience [250].
13.10.3.2 Coatings withEnhanced Properties
The continual renement of coatings for orthopedic implants contributes to heightened wear resistance. Cutting-edge developments involve the application of selfrenewing coatings designed to repair surface damage over time. Additionally,
bioactive coatings, inspired by natural bone composition, further enhance osseointegration and reduce friction, promoting a seamless interaction between the implant
and the surrounding tissues. These coating innovations represent a proactive
approach towards not only addressing wear challenges but also fortifying the overall
performance of the implant [160, 251].
13.10.3.3 Surface Modications
Surface modications at the nanoscale level are emerging as a key strategy for
achieving enhanced wear resistance in hip and knee replacements. Nanotexturing
and other surface engineering techniques are being explored to create surfaces with