Knee Bending Research Articles

Ergonomic Evaluation of Maize Seeding using Conventional Method and Lightweight Motorized Maize Seeder

Manual activity in maize seeding shows an awkward posture due to repetitive movement on walking forward, body lowering, knee bending, squatting, digging, and seed sowing, which can cause body tiring. These are the symptom of human fatigue or the ergonomic hazard in an agricultural field, leading to Musculoskeletal Disorders (MSD) if done repeatedly and extended for a long time. The paper explained the ergonomic evaluation of seeding risk assessment using two methods; bare hand and lightweight motorized maize seeder. The evaluated maize seeder was designed with a minimum number of parts to make the assembly and maintenance requirements easy without affecting the functionality of the metering device. The maize seeder is easy to operate, light to carry, and convenient to use with a single-handed griper to improve ergonomics in the field. Using the concept of gravitational drop and the battery to power the motor, the farmer experiences a slightly bent body position with a relaxed posture that requires less stressful angles on seeding activity. Seeding postures on methods were evaluated using Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA) to determine the area of bodily discomfort. The RULA result shows that the ergonomic risk score on manual seeding activity was at score 7, which is high risk compared to seeding activity using the maize seeder, which results in a score of 4 that shows a low risk.In comparison, the REBA result shows a high risk on manual seeding with a score of 11 and a low risk on seeding with a seeder, which is in score 3—seeding by bare hand, adopting poor posture at the neck, trunk, and wrist twist. The work rate for seeding maize using the conventional method and seeder was 0.114 m/s and 0.167 m/s, respectively. The study concludes that using the lightweight motorized maize seeder can reduce the risks of MSDs due to working in an awkward posture in sowing maize on the field.

Effects of a Gluteus Squeeze with Real-time Visual Biofeedback on Hip Extensor Muscle EMG Activity during Small Knee Bending

Effects of a Gluteus Squeeze with Real-time Visual Biofeedback on Hip Extensor Muscle EMG Activity during Small Knee Bending

Stretchable array of CdSe/ZnS quantum-dot light emitting diodes for visual display of bio-signals

Display devices that can visually present various bio-signals are a core future technology required for skin attachable wearable electronics. Quantum dot light emitting diodes (QD-LEDs), which can be used as high performance display devices, exhibit many advantages such as a narrow bandwidth, high color purity, high environmental stability, easy and fast processing, and a high brightness at low voltage. In this study, we report on the fabrication of a stretchable QD-LED array for the visual display of body movement and skin temperature signals from skin-attached sensors. After forming an array of a rigid NOA63 islands, an array of CdSe/ZnS QD-LEDs is fabricated on top of that island array and electrically connected using liquid metal Galinstan interconnections. Finally, the array of QD-LEDs on the NOA63 islands is transferred onto a stretchable elastomer substrate of Ecoflex/PDMS. Of particular importance, for stable performance of the QD-LEDs under deformation, in replacement of the conventionally used ITO, a flexible and highly transparent electrode of Au grid/Ethylene glycol doped PEDOT:PSS is used. Such a design architecture can minimize the strain applied to the QD-LEDs by concentrating the strain onto the soft elastomer film substrate and the Galinstan interconnections. As a result, the fabricated QD-LED array exhibits stable operation under both 50% uniaxial and 30% biaxial strains. After attachment of the stretchable QD-LED array onto skin, the extent of knee bending, and changes in skin temperature are displayed as changes in the pattern of the QD-LED array. This work demonstrates the potential application of our stretchable array of QD-LEDs for easy and daily monitoring of health conditions through a visual display.

A Highly Stretchable and Sensitive Strain Sensor Based on Dopamine Modified Electrospun SEBS Fibers and MWCNTs with Carboxylation

AbstractWearable flexible electronic strain sensor devices have developed rapidly in recent years due to their potential capacity to detect human motion in various situations. However, it still remains still a big challenge to fabricate strain sensors with high sensitivity over a wide workable strain range. In order to meet this challenge, a new type of strain sensor based on elastomer/carbon nanotube composite fiber is reported in this work. Elastomer fibers are initially prepared via the electrospinning of styrene ethylene butene styrene block copolymer (SEBS). The resultant SEBS fibers are then functionalized by sequentially coating with dopamine (DA) coating and carboxyl group (‐COOH) grafted multi‐walled carbon nanotubes (MWCNTs) under vacuum filtration and ultrasonication. Scanning electron microscopy (SEM) and thermogravimetric analysis reveals that a large amount of MWCNTs is firmly bonded onto the SEBS fibers and evenly distributed. SEBS@PDA/MWCNTs composite fibers based strain sensors exhibit excellent performance, including a high gauge factor of 3717 and large workable strain range up to 530%. Furthermore, the developed sensors demonstrate excellent washing fastness and superior sensitivity in monitoring both small strains (e.g., pulse beats and vocal cord vibrations) and large strains (e.g., finger, elbow, and knee bending).

Kinematic comparison between asymmetrical and symmetrical polyethylene inserts during deep knee bend activity

BackgroundThe in vivo kinematic benefit of an asymmetrical polyethylene insert is still unknown in comparison with that of a symmetrical insert with the same femoral component design. The purpose of this study was to analyze the kinematic differences between symmetrical and asymmetrical polyethylene inserts and to detect the kinematic benefit in the asymmetrical polyethylene insert. The hypotheses are that greater axial rotation and more posterior rollback are observed in the asymmetrical polyethylene insert. MethodsThe patients were randomly allocated to the following two groups: total knee arthroplasty with a symmetrical insert and with an asymmetrical insert. In vivo knee kinematics was analyzed in asymmetrical (17 knees) and symmetrical (16 knees) inserts using an image matching technique. The symmetrical polyethylene insert had the same geometry on both sides, whereas the asymmetrical polyethylene insert had a flat surface on the postero-lateral side. The anterior/posterior position and axial rotation were compared between the two polyethylene inserts. ResultsThe femoral component was significantly positioned posteriorly at 70° (p = 0.016) and 80° (p = 0.040) of knee flexion and externally rotated at 80° of knee flexion (p = 0.040) in the asymmetrical polyethylene insert as compared to the position of the symmetrical polyethylene insert. Femoral rollback and axial rotation from full extension to maximum flexion were greater in the asymmetrical polyethylene insert, although the difference was not significant. ConclusionsIn the asymmetrical polyethylene insert, slight kinematic benefit with greater axial rotation and more posterior rollback was observed in comparison with the symmetrical polyethylene insert. Further research should be required whether the kinematic benefit of an asymmetrical polyethylene insert will lead to better patient satisfaction and function.

Facilely constructed randomly distributed surface microstructure for flexible strain sensor with high sensitivity and low detection limit

The epidermis and dermis of human skin have randomly distributed microstructures, so we can sense external stimuli with high sensitivity and a low detection limit. Herein, a biomimetic microstructure sensor was fabricated using sandpaper as a template. The finite element simulation results show that the strain sensing property of the sensor can be improved by introducing a biomimetic microstructure, which is consistent with the experimental results. The gauge factor of the microstructure sensor (20.64) is 4.81 times that of the planar structure sensor (4.29) in the linear strain range from 0.1% to 1.0%. The microstructure sensor has a very low detection limit (0.1% strain), fast response (53.6 ms), and good cycling durability (3000 cycles). In addition, the microstructure sensor can achieve real-time monitoring of human motion and physiological signals, such as finger bending, knee bending, and breathing frequency. The proposed microstructure sensor is expected to have broad application prospects in motion monitoring and health-care fields.

Computational method in database-assisted design for wind engineering with varying performance objectives

The concept of Performance objective assessment is extended to wind engineering. This approach applies using the Database-Assisted Design technique, relying on the aerodynamic database provided by the National Institute of Standards and Technology (NIST). A structural model of a low-rise building is analyzed to obtain influence coefficients for internal forces and displacements. Combining these coefficients with time histories of pressure coefficients on the envelope produces time histories of load effects on the structure, for example knee and ridge bending moments, and eave lateral drift. The peak values of such effects are represented by an extreme-value Type I Distribution, which allows the estimation of the gust wind speed leading to the mean hourly extreme loading that cause specific performance objective compromises. Firstly a fully correlated wind field over large tributary areas is assumed and then relaxed to utilize the denser pressure tap data available but with considerably more computational effort. The performance objectives are determined in accordance with the limit state load combinations given in the ASCE 7-16 provisions, particularly the Load and Resistance Factor Design (LRFD) method. The procedure is then repeated for several wind directions and different dominant opening scenarios to determine the cases that produce performance objective criteria. Comparisons with two approaches in ASCE 7 are made.

Kinematic differences between professionals and young players in the tennis serve

The aim of the present study was to measure and examine the differences in lower limb kinematics between the flat, slice and topspin serves, in the kinematic features of the lower limbs, at two different times of the service movement, maximum knee bending and point of contact of the racket with the ball, in 12 young tennis athletes, aged 12-16 years and in 12 professional players that they were playing on the main draw of Roland Garros. The results showed no significant differences in time between the three types of service in young athletes. Comparing the time of young athletes 34.56ms with the time of high level athletes with 30.67ms, the results showed that the professionals performed the service faster than the young athletes having a significant difference.

Voluntary control of pelvic frontal rotations in belly dance experts.

The present study investigated how belly dance experts perform the "hip shimmy", a complex rhythmic dance movement consisting in a voluntary oscillation of the pelvis exclusively in the frontal plane with maximised amplitude, with no movement of the upper trunk. The aims of this study were to 1) assess whether the amplitude and stability of the pelvic movement can be maximised in certain postural and frequency conditions; and 2) investigate in a 1 to 3Hz range whether it is indeed possible to oscillate the pelvis only in the frontal plane and to dissociate this one-axis pelvic rotation from potential spontaneous upper-trunk oscillations. Nineteen belly dance experts performed this task in three frequencies and three knee bending postures. Eight joint angles were calculated using the kinematic data of 20 markers over the entire body collected with a motion capture system. Mean amplitude, frequency, and spatial and temporal variability of frontal pelvic oscillations were analysed to characterise motor performance and movement stability. Five Continuous Relative Phases (CRP) were computed to identify the modes and stability of coordination patterns. The results showed that a low posture enhances amplitude performance and that the pelvic oscillation amplitude tended to decrease at 3Hz, although between-condition differences remained small. Temporal stability was highest at 2Hz and significant inter-individual differences emerged at 3Hz. CRP analysis revealed an unpreventable coupling between pelvis and upper-trunk oscillations in the frontal and transversal planes. A consistent antiphase coordination between transversal pelvis and upper-trunk may have been caused by anatomical and counter-balancing constraints. In the frontal plane, multiple stable pelvis-upper trunk patterns including inphase, out-of-phase and antiphase evolved to antiphase predominance and inphase disappearance upon reaching 3Hz. In sum, increasing frequency highlighted the concomitance of two control phenomena: the inter-individual differentiation in performance and standardisation of the possible pelvis-upper-trunk patterns.

Wearable Strain Sensors Based on a Porous Polydimethylsiloxane Hybrid with Carbon Nanotubes and Graphene.

High-performance flexible strain sensors are urgently needed with the rapid development of wearable intelligent electronics. Here, a bifiller of carbon nanotubes (CNTs) and graphene (GR) for filling flexible porous polydimethylsiloxane (CNT-GR/PDMS) nanocomposites is designed and prepared for strain-sensing applications. The typical microporous structure was successfully constructed using the Soxhlet extraction technique, and the connected CNTs and GR constructed a perfect three-dimensional conductive network in the porous skeleton. As a result, the stretchability and sensitivity of the CNT-GR/PDMS-based strain sensors were well regulated based on the porous structure and the typical synergistic conductive network. Based on the destruction effect of the brittle synergistic conductive network located in the outer and inner layers of the cell skeleton and the contact effect between adjacent cells in different strain ranges, the prepared CNTs-GR/PDMS-based strain sensor exhibited superior gauge factors of 182.5, 45.6, 70.2, and 186.5 in the 0-3, 3-57, 57-90, and 90-120% strain regions, respectively. In addition, this material also exhibited an ultralow detection limit (0.5% strain), a fast response time (60 ms), good stability and durability (10,000 cycles), and frequency-/strain-dependent sensing performances, making it active for the detection of various external environments. Finally, the prepared porous CNTs-GR/PDMS-based strain sensor was attached to the skin to detect various human motions, such as wrist bending, finger bending, elbow bending, and knee bending, thereby demonstrating wide application prospects in smart wearable devices.

A ball-in-ball type self-powered magnetoelectric inertial sensor for 3D multi-angle motion monitoring of humanoid robots

Abstract Motion monitoring stands as a powerful tool for humanoid robots to well adapt to nearby changing environment. However, despite the recent advance of inertial measuring units, both simplification of the sensors and free of power supply for 3D multi-angle monitoring remains elusive. Herein we demonstrate a facile & self-powered magnetoelectric inertial sensor for 3D multi-angle head motion monitoring of humanoid robots. A magnetic sphere could freely roll inside a smooth polymeric shell patterned with regionally distributed coils, allowing for monitoring the accelerations for 8 directions in the horizontal plane, the bowing angle for diverse directions in 3D space and rotations when tilting with multi-angle. It can detect an acceleration down to 0.06 m/s2 and a tilting angle of 2° in the vertical plane. Owing to these sensing capacities, the magnetoelectric inertial sensor can be placed inside a model head for detecting head bowing, head turning and even sudden strikes from diverse directions. Furthermore, when being placed in the humanoid robot’s head, it can monitor continuous motions like left-kicking, bending knees, standing on one leg and doing the splits. Such a single inertial sensor provides a building block for motion monitoring of humanoid robots and for future development of robotics.

In vivo kinematics and cruciate ligament forces in bicruciate-retaining total knee arthroplasty

We analyzed the effects of bicruciate-retaining total knee arthroplasty (BCR-TKA) on knee kinematics and cruciate ligament forces. Patients (N = 15) with osteoarthritis (OA) and an intact anterior cruciate ligament (ACL) underwent magnetic resonance imaging and single-plane fluoroscopy to measure tibiofemoral kinematics during two deep knee bend activities before and after BCR-TKA: (1) weight-bearing squat; (2) non-weight-bearing cross-legged sitting. Forces in ligament bundles were calculated using VivoSim. The dynamic range of varus-valgus angulation decreased from 3.9 ± 4.4° preoperatively to 2.2 ± 2.7° postoperatively. Preoperatively, the medial femoral condyle translated anteriorly from 10° to 50° of flexion, and posteriorly beyond 50° of flexion. Postoperatively, the medial and lateral femoral condyles translated posteriorly throughout flexion in a medial pivot pattern. ACL forces were high in extension and decreased with flexion pre- and postoperatively. PCL forces increased with flexion preoperatively and did not change significantly postoperatively. Preoperatively, ACL forces correlated with anteroposterior translation of the femoral condyles. Postoperatively, PCL forces correlated with anteroposterior translation of the lateral femoral condyle. BCR-TKA altered knee kinematics during high flexion activity which correlated significantly with changes in cruciate ligament forces.

Self-healing and toughness cellulose nanocrystals nanocomposite hydrogels for strain-sensitive wearable flexible sensor

Recently, self-healing and high mechanical strength hydrogels have aroused much research due to their potential future in strain-sensitive flexible sensors. In this manuscript, we successfully designed self-healing and toughness cellulose nanocrystals (CNCs) nanocomposite hydrogels by grafted polypyrrole (PPy) on the surface of CNCs to enhance electrical conductivity. The obtained nanocomposite hydrogels exhibit outstanding self-healing and mechanical behaviors, and the optimal mechanical strength, toughness and self-healing efficiency can be up to 5.7 MPa, 810% and 89.6%, respectively. Using these functional nanocomposite hydrogels, strain-sensitive wearable flexible sensors were designed to monitor finger joint motions, bending of knee, and even the slight pulse beating. Surprisingly, the flexible sensors could evidently perceive body motions from large movements (knee bending) to tiny signals (pulse beating). In addition, it exhibited excellent durability after repeated cycles. This method of prepared self-healing nanocomposite hydrogels will have a potential prospect in the design of biomedical, biosensors, and flexible electronic devices.

Finite Element Analysis of a Novel Approach for Knee and Ankle Protection during Landing

There is a high risk of serious injury to the lower extremities during a human drop landing. Prophylactic knee and ankle braces are commonly used to reduce injury by restraining the motion of joints. However, braces that restrain joint range of motion (ROM) may have detrimental effects on the user’s kinematical performance and joint function. The present study aimed to propose a novel set of double-joint braces and to evaluate its protective performance in terms of the ankle and knee. Accordingly, the finite element method was performed to investigate the biomechanical responses of the ankle and knee in braced and unbraced conditions. The results showed that the semi-rigid support at the ankle joint can share the high impact force that would otherwise be inflicted on one’s lower extremity, thereby reducing the peak stress on the inferior articular surface of the tibia, menisci, and articular cartilages, as well as the horizontal force on the talus. Moreover, with knee bending, the elongated spring component at the knee joint can convert the impact kinetic energy into elastic potential energy of the spring; meanwhile, the retractive force generated by the spring also provides a more balanced interaction between the menisci and articular cartilages. This biomechanical analysis can accordingly provide inspiration for new approaches to place human lower extremities at lower risk during landings.

Three-dimensional light-weight piezoresistive sensors based on conductive polyurethane sponges coated with hybrid CNT/CB nanoparticles

Low-cost production of piezoresistive strain/pressure sensor with high sensitivity, fast response, good stability and repeatability is still one of the critical challenges for the practical applications of flexible piezoresistive materials in human motion detection, health monitoring, wearable electronics, and e-skins. Herein, we develop a simple and efficient route to fabricate the three-dimensional (3D) light-weight piezoresistive sensing materials via the surface coating the polyurethane (PU) sponge with hybrid carbon nanotube (CNT)/carbon black (CB) nanoparticles. It is found that the CNT/CB@PU sponge exhibits high sensitivity, fast response, instant recovery, and stable compression-release signals to the strain/pressure stimuli, which can be designed into the versatile piezoresistive sensors to detect various human motions within a wide strain range, such as blowing, swallow, deep breath, finger bending, elbow bending, and knee bending. More importantly, this work illuminates the sensing mechanisms of conductive sponges coated with different dimensional nanoparticles and paves a new way toward large-scale and low-cost production of wearable pressure/strain sensors.

MANAGEMENT OF DISTAL FEMUR FRACTURES IN ADULT WITH LOCKING COMPRESSION PLATE

Objective: To evaluate the clinical outcomes and radiological union of distal third femur fractures by using distal femur locking plate, in Zagazig university hospitals and KafrSaad emergency hospital. Design: Clinical trial. Methods: Data collected for the study was from the patients admitted in orthopedic department in Zagazig university hospitals and KafrSaad emergency hospital, with distal femur fracture AO 33,during the period of August 2019 to July 2020 and treated with open reduction and internal fixation with distal femur locking compression plate with 4.5 system. All patients were followed up for an average of 6 months. Outcomes were assessed by Neers score. Results: Outof 12 patients (4 were females&8were males), mean age was 45.6 years (20 to 70 years). 10 cases wereduo to high energy trauma and 2 cases wereduo to low high energy trauma.5 out of total 12 cases had open fractures and rest 7 cases had closed fractures.Out of total 12 cases, five cases were extra-articular and rest 7 cases were intra-articular. Out of 12 fractures treated, 8 fractures showed radiological signs of union within 12-16 weeks,3 fractures showed radiological signs of union within 20 weeks and one fracture showed radiological signs of union within 24 weeks.1 patient got superficial infection and no implantfailure, mean range of motion of all patients was 113°. Conclusion:ORIF of distal femur fractures with locking compression plate provides good angular stability, restoration of limb alignment, length, rotation and give a good purchase in osteoporotic patientswith minimal complications. Best results are optioned when standard protocol of locking plate fixation is followed with good soft tissue care, early knee bending exercises and physiotherapy.

Biomechanical Study of a Tricompartmental Unloader Brace for Patellofemoral or Multicompartment Knee Osteoarthritis

Objective: Off-loader knee braces have traditionally focused on redistributing loads away from either the medial or lateral tibiofemoral (TF) compartments. In this article, we study the potential of a novel “tricompartment unloader” (TCU) knee brace intended to simultaneously unload both the patellofemoral (PF) and TF joints during knee flexion. Three different models of the TCU brace are evaluated for their potential to unload the knee joint.Methods: A sagittal plane model of the knee was used to compute PF and TF contact forces, patellar and quadriceps tendon forces, and forces in the anterior and posterior cruciate ligaments during a deep knee bend (DKB) test using motion analysis data from eight participants. Forces were computed for the observed (no brace) and simulated braced conditions. A sensitivity and validity analysis was conducted to determine the valid output range for the model, and Statistical Parameter Mapping was used to quantify the effectual region of the different TCU brace models.Results: PF and TF joint force calculations were valid between ~0 and 100 degrees of flexion. All three simulated brace models significantly (p < 0.001) reduced predicted knee joint loads (by 30–50%) across all structures, at knee flexion angles >~30 degrees during DKB.Conclusions: The TCU brace is predicted to reduce PF and TF knee joint contact loads during weight-bearing activity requiring knee flexion angles between 30 and 100 degrees; this effect may be clinically beneficial for pain reduction or rehabilitation from common knee injuries or joint disorders. Future work is needed to assess the range of possible clinical and prophylactic benefits of the TCU brace.

Evaluation of the bent knee fall out test pre- and post- an adductor longus tenotomy

ObjectiveTo investigate the immediate effect of an adductor longus tenotomy on the results of the bent knee fall out test, and whether there was a correlation between pre-tenotomy measures and the magnitude of change. DesignObservational study. MethodsWe included recreational to elite athletes with longstanding adductor-related groin pain (specifically adductor longus insertion pain) undergoing unilateral or bilateral full adductor longus tenotomy. The bent knee fall out test was performed immediately prior and immediately after the surgical procedure. We used Wilcoxon signed-rank test to compare test results pre- and post-tenotomy, and Spearman’s rho (rs) to analyse correlation between pre-tenotomy values and the magnitude of change in the bent knee fall out test. ResultsWe consecutively included 60 male adult athletes. There was a statistically significant difference (p < 0.001) in the bent knee fall out result from pre-surgery (median 11.5 cm [IQR 9–15], range 5–25 cm) to post-surgery (median 8 cm [IQR 6–10], range 3–15 cm). The mean difference was 3.9 ± 2 cm, range 0–11 cm, corresponding to a large effect size, d = 1.92. There was a moderate correlation between the bent knee fall out measurement pre-tenotomy and the difference from pre-to-post, rs = 0.75, p < 0.001. ConclusionThe bent knee fall out measurements changed considerably immediately after an adductor longus tenotomy, showing that the test is assessing adductor longus flexibility in male athletes with longstanding adductor-related groin pain. There was a moderate correlation between the bent knee fall out measure pre-tenotomy and the magnitude of change.

Reconstruction of knee anatomy from single-plane fluoroscopic x-ray based on a nonlinear statistical shape model.

.Purpose: Reconstruction of patient anatomy is critical to patient-specific instrument (PSI) design in total joint replacement (TJR). Conventionally, computed tomography (CT) and magnetic resonance imaging (MRI) are used to obtain the patient anatomy as they are accurate imaging modalities. However, computing anatomical landmarks from the patient anatomy for PSIs requires either high-resolution CT, increasing time of scan and radiation exposure to the patient, or longer and more expensive MRI scans. As an alternative, reconstruction from single-plane fluoroscopic x-ray provides a cost-efficient tool to obtain patient anatomical structures while allowing capture of the patient’s joint dynamics, important clinical information for TJR.Approach: We present a three-dimensional (3D) reconstruction scheme that automatically and accurately reconstructs the 3D knee anatomy from single-plane fluoroscopic x-ray based on a nonlinear statistical shape model called kernel principal component analysis. To increase robustness, we designed a hybrid energy function that integrated feature and intensity information as a similarity measure for the 3D reconstruction.Results: We evaluated the proposed method on five subjects during deep knee bending: the root-mean-square accuracy is for reconstructed femur and for reconstructed tibia.Conclusions: The proposed method demonstrates reliable 3D bone model reconstruction accuracy with successful elimination of prior 3D imaging and reduction of manual labor and radiation dose on patient as well as characterizing joints in motion. This method is promising for applications in medical interventions such as patient-specific arthroplasty design, surgical planning, surgical navigation, and understanding anatomical and dynamic characteristics of joints.

Impact of surgical alignment, tray material, PCL condition, and patient anatomy on tibial strains after TKA

Bone remodeling after total knee arthroplasty is regulated by the changes in strain energy density (SED), however, the critical parameters influencing post-operative SED distributions are not fully understood. This study aimed to investigate the impact of surgical alignment, tray material properties, posterior cruciate ligament (PCL) balance, tray posterior slope, and patient anatomy on SED distributions in the proximal tibia.Finite element models of two tibiae (different anatomy) with configurations of two implant materials, two surgical alignments, two posterior slopes, and two PCL conditions were developed. The models were tested under the peak loading conditions during gait, deep knee bending, and stair descent. For each configuration, the contact forces and locations and soft-tissue loads of interest were taken into consideration. SED in the proximal tibia was predicted and the changes in strain distributions were compared for each of the factors studied.Tibial anatomy had the most impact on the proximal bone SED distributions, followed by PCL balancing, surgical alignment, and posterior slope. In addition, the thickness of the remaining cortical wall after implantation was also a significant consideration when evaluating tibial anatomy. The resulting SED changes for alignment, posterior slope, and PCL factors were mainly due to the differences in joint and soft-tissue loading conditions. A lower modulus tray material did result in changes in the post-operative strain state, however, these were almost negligible compared to that seen for the other factors.