Knee Joint Analysis: A Review of Existing Research Studies

This report provides a comprehensive overview of existing research on the human knee joint, focusing on its biomechanics, function, and common issues such as injury and mechanical wear. It explores the use of finite element analysis (FEA) as a computational method for analyzing the knee joint's behavior under various loads and conditions, highlighting its advantages in terms of cost, time efficiency, and accuracy. The report delves into total knee replacement (TKR) surgeries, discussing the evolution of implant designs, materials, and the challenges of implant failure due to mechanical wear and the body's immune response. It examines the historical development of knee prosthetics, from early designs to modern modular implants, and reviews studies on different implant types, including dual articulating total knee prostheses, and their impact on joint stability, range of motion, and stress distribution. The report emphasizes the importance of balancing model complexity with computational efficiency in FEA and its role in providing valuable biomechanical information for clinical evaluation.

1-3-Existing Research
The joint of the knee is considered one of the most essential and critical joints of the human
anatomy. The knee joint is additionally known as the ‘hinge joint’. The hinge joint performs several
activities that include standing, sitting, flexion, extension, bending, or walking. In all the
aforementioned activities, the extent of load acting on the knee joint varies (Machado et al. 2010).
The human knee joint primarily comprises of three main components: the tibia, the femur, and the
patellar component along with a deformed body. The people who suffer from the pain of the knee
or trauma to the knee joint, risk of injury to the knee, and individuals involved in activities of sports
that result in mechanical wear and tear of the knee joint. Improper functioning or dysfunction of the
knee joint occurs due to defects in the knee. Such defects of the knee that cause failure of activity
often lead to operative solutions. The operative solution involves knee prosthesis or the surgical
removal of various defective components of the joint followed by the replacement of the
component with an artificial implant. The defect of the knee is primarily carried out by methods such
as X-ray, CT-scan procedure, or MRI imaging techniques. Most often, the knee replacement surgery
is performed by making a small incision of about 3 or 4 inches (Hernandez-Vaqueroet al. 2010).
According to a study, Peña et al.study (2006), several models of computation are an effective
alternative method to the analysis of several biomechanical quantities. These methods may be
employed for the reduction of cost, time, and efficiency of machinery. Particularly, the method of
finite element or FE can be used to provide results of high medical accuracy and relevance (Peña et
al. 2006). In a study by Herrera et al., (2012), the technique of FE simulation usually allows for the
calculation of the variations in the special and temporal values of stress, strain, and areas and forces
of contact that are present in different situations that are easy to reproduce, with high precision
(Herrera et al. 2012).
A study by Kiapouret al., (2014), focused on the reliability and precision of results of the model of FE.
The study concentrated on three primary factors that determine the accuracy of the FE model. The
factors were found to be the complexity in the geometrical configuration, the interaction that occurs
between the various parts of the model, and defining the material properties that represent the
correct mechanical behaviour of the structure that has to be modelled (Kiapouret al. 2014).
Thus, the study suggested that the application of the method of FE analysis on complex structures
presents several challenges caused by the various distinctive features of the model. However, in the
method of FE modelling, the maintenance of a stringent balance between the complexity of the
model and the efficiency of computation is absolutely essential. Upon the successful achievement of
such a balance, the method of FE analysis has been proven as a powerful tool for the provision of
biomechanical information that is of extreme use in the context of clinical evaluation (Xieet al.
2009). A study by Adouni, M et al, (2012) focused on the investigation of the computational models
of FE. The analysis of the knee by the FE model was analysed in this study, and the diverse
parameters were considered that included the degree of complexity, the variables of the study, the
models of material definitions, and cases of loading of the knee joint that results in the simulation.
The parameters chosen for the study define the analysis and the nature of assessment. The nature
of analysis may vary as being static or quasi-static (Xieet al. 2009), or dynamic states (Adouni et al.
2009).
1 | P a g e

The analysis of stress is a major discipline under engineering science. It is essential an efficacious
method for the determination of the values of stress and strain that act upon different materials.
These materials are typically subjected to particular values of load and forces applied in different
directions. The analysis of stress is used for the maintenance of specific structures in specific
functional states. The study involves the investigation of various causes that may eventually lead to
the damage and subsequent failure of the structure (Maas et al. 2012).
A study conducted by Shih et al, (2012), assessed the conditions of defect and failure of procedures
of partial or total knee replacement surgeries. These different aspects were investigated for duration
of 3 to 5 years. In the surgery involving the total replacement of the knee joint with a large artificial
implant is inserted in the place of the joint of the knee. This replacement procedure is favourable for
the biocompatibility of the implant along with the durability of the artificial joint. Despite the
excellent condition of working and the result of frequent failure of the implant in about a time
period of 4 or 5 years. The frequent failure occurs due to chronic inflammation of the particles
generated from mechanical wear. This results in the failure of the implant which leads to defective
outcomes of the surgery. Those particles of mechanical wear typically interact with the immune
system. This results in toxicity effects inside the body (in-vivo) following the transplant.
The first procedure of the total knee replacement (TKR) was found by Prof. Themistocles Gluck in the
year 1891. The first implant was constructed from a material of ivory originally. These are cemented
in place with cement which is made from a mixture of colophony pumice and gypsum cement. Most
principles and theories which have been applied to the modern day designs of prosthetics have been
accredited to Prof. Gluck. These include the different designs that have been used in the recent
times have been discovered including the fixation of the artificial joint of a stable condition (Claes et
al. 2000). The construction of artificial joint is modular (Kenneth et al. 2005), the choice of the
material that matches the different properties of the bone (Kalpana et al. 2004), various allografts
(David et al. 2005), various methods of fixation that are present in the tracts of the bone marrow
(Viceconti et al. 2006), and the properties of material biocompatibility (Grill et al. 2003).The Wallidus
design was developed 60 years following the Gluck Ivory design in the year 1951. The design
primarily comprised of a hinge of cobalt chrome in the joint which cemented the stems of femur and
tibia. This design has comprehended and reproduced the movement of the knee joint. It additionally
utilised several hard materials (Walldius et al. 1957). The pre-modern procedures of TKR have had
exceptionally high rates of failure, much unlike the hip replacement surgeries. Miller et al., (2006),
notes that the rotation of the knee occurs in multiple directions as compared to the hip bone joint.
Thus, the artificial implant is required have a more complex design. The study also observed that
since the time of the first knee replacement surgery in the 1960’s, there has a concurrent
redesigning procedure that imitates the natural joint. Thus, the modern day TKR procedure has
similar rates of success as the hip joint.
The initial hindrances in the replacement occurred due to the manufacture of the bearing surfaces
out of metal. This caused an action of rubbing that ultimately lead to the formation of debris of the
mechanical wear. Additionally, the forces of the muscles and ligaments underwent loosening during
physical movement. Such problems result in high rates of failure and clinical challenges that include
aseptic loosening or similar mechanisms of implant failure.
2 | P a g e

A study by Carother et al, (2011), manufactured an implant procedure that involved the
implementation of the dual articulating total knee prosthesis. It comprises of a component of femur,
a tibial tray, and a plate which is movable in nature. The condyle of the femur consists of a lateral
and medial condyle. It is present in proximity to a mechanical curvature present at the surface of
articulation. A prosthesis of this type leads to the provision of flexion and extension of complete
extent. Additionally, dislocation of inserts does not occur and there is the occurrence of a near-
articulating motion of the rear physiological type. In this motion, the concentration of the stress at
the surface of articulation is negligible. The occurrence of the articulation primarily happens in at the
surfaces of inserts of the femur and tibia. The concentration of stress is mainly calculated at the
region of insert of the knee prosthesis. The aforesaid value of stress undergoes a gradual reduction
ultimately resulting in a lower extent of prosthesis loosening. There is a gradual increase in the
durability of the implant which is fixed to the knee joint. A larger area of contact present throughout
the range of motion of the knee joint results in an ultimate reduction of the concentration of the
total stress and the extent of mechanical wear of the components of implant. The cruciate ligament
allows for a higher range of motion as compared to the conventional method of prosthesis in TKR.
The number of implants designed was of the range of 140 implants on a gross average. The
relationship between the surfaces which are concave or convex which are present at the lower
surface are, in fact, of congruence with the surface of articulation and the tibial tray convex of a
fixed bearing and the articulating upper convex surface. The aforementioned numerous interfaces
present between the surfaces which are convex or concave make the implant less viable of loosening
along with reducing the possibility of mechanical wear effect. It further provides additional stability
to the knee joint at the times of flexion or extension movements of the knee joint consisting of the
artificial implant. Additionally, it provides for an appropriate motion of the rotator (Carothers et al.
2011).
3 | P a g e