Sharif Digital Repository

Knee pain and injuries are very common in athletes. Anterior cruciate ligament (ACL) injury is one of the most important reason of knee acute and chronic pains. As ACL plays a significant role in knee stability and due to amount of reported ACL related injuries, much effort has been placed on finding proper and on time diagnosis and treatment of these injuries. Arthrometric methods are the most non-invasive reliable diagnosis option; however they are not fully capable of separating partial injuries from intact joint. This weakness can be investigated by quantifying the tests using computer simulations; so far few studies have been conducted toward this goal. In this study a two dimensional... 

Bones adapt their form and structure to make an efficient use of their mass against the applied mechanical loads. So, it is not surprising to assume that the geometry and density distribution of a bone contains information about its loading history. The objective of this work was to develop a framework to simulate the bone remodeling procedure as a topology optimization process and then use this framework to develop a simple technique for estimating the dominant joint loads based on the bone’s density distribution.
At first, the remodeling equation was derived from the structural optimization task of minimizing the strain energy in each time step, using the level set method. Employment... 

One of the best methods of gait analysis is to use analytical models. In this project, first, the normal human gait was simulated using a two-dimensional biped model with 7 segments, i.e., a HAT segment representing head, arms and trunk, and 6 segments representing thighs, shanks and feet of the two legs. The foot-ground contact was simulated using a five-point penetration contact model. The elastic impact and friction effects are considered in the ground reaction force modeling. Optimization of the normal human walking model provided constant coefficients for simple PD controllers’ (driving torque) equations that could reasonably reproduce the normal kinematical pattern. Then, in the second... 

A high percentage of patients with lower extremitiy disability consists of those suffer from paraplegy, hemiparety, spinal cord injuries and chronic stroke. Currently, a wast variety of methods are used for gait rehabilitation of these patients. Beside physiotherapy and different types of exercises, gait trainer systems have been devloped and used recently to help patients to obtain their walking abilities. The main goal of this work was to design and develope a device to lift a patient from sitting position on a chair to standing position in a safe and balanced mode besides obtaining enough space for physiotherapist that can easily help the patient in gait training on treadmill, also to... 

Laparoscopic surgery is a branch of minimally invasive surgery that is implemented in the abdominal cavity. This kind of surgery is conducted using surgical instruments that are inserted into the abdomen through some small incisions created on its wall and the necessary vision is provided for the surgeon using a laparoscope lens that is inserted through the first created incision. In recent years, because of its advantages, controlling and manipulation of the lens is done using some robots instead of surgeon assistant. To facilitate the controlling procedure of these robots for the surgeon, several controlling modes such as keyboard, foot switch, and voice commands are presented. Robolens is... 

In the recent years, medical application of robots has been widely developed. Transforming open surgeries to close surgeries has distinguished this novel method to decrease limitations in this type of surgery. In this procedure, two or three small incisions on the skin are used as guides for robotic instruments to enter the cavity, to improve the surgeon’s manipulation and function in surgery. One of challenges in this field is surgeon’s training for laparoscopic surgery. Surgical simulators are used to solve this problem. Lack of instrument for large organs gripping and tissue palpation loss are existing difficulties in available surgical simulators in such a manner that surgeons has no... 

Stroke is the main cause of disability in the world and the third cause of death, so spreading rehabilitation technique for post stoke patients is one of the most important targets un these days. The first prototype hand rehabilitation device was designed and fabricated in RCSTIM in 2008. Since the first prototype had been proved its effectiveness in clinical tests in the next phase industrial production of the device had to be considered at first all of the problems that had been observed during the clinical tests had to be solved for the future production. In the first series of experiments, clinical limitation and the interaction between the patient and the physiotherapist with the device... 

Patellofemoral joint has an important role in knee extension. Because of this joint importance and complicated mechanical behavior, a lot of mathematical models have been used, to obtain a better understand of this joint, considering this joint as a part of knee joint or as a separate joint. Although these works have comprehensively studied the patellofemoral joint but they don’t emphasis on dynamic aspects. Also there is no work to compare the experimental and theoretical results calculated from one specified subject knee.In this study, the kinematic and dynamic of patellofemoral joint has been studied, constructing a three dimensional dynamic model of patellofemoral joint and experimental... 

All humanare subject to a physiligical phenomenon known as tremor, which introduces unintended, relatively high frequency movments into various limbs. This involuntary movment is main reason of human disability in doing of precision tasks. Precision surgery like eye surgery is among them that surgeons must have very ittle tremor to enable them to oprate on the small anatomy of the eye. In this reaearch by emphasizing on reduction of muscle fatigue in precision surgery, weight balancing mechanism designed and analyzed. Fatigue is most important cause of tremor, thus we expected tremor amplitude reduce by reduction of muscle fatigue. Purpose mechanism is passive mechanism that balances the... 

The capability to control and maintain upright posture is a fundamental requirement for humanoid robots. Although many control algorithms were successfully presented, it seems developing a new controller inspired from human balance strategy would greatly improve performance and reduce energy consumption. To study the control strategy used by human nerves system more precisely, a balancing exercise was designed and implemented. Five human subjects were asked to stand on an unstable tilting board and balance the board. Instantaneous Eulerian angles of body segments of human subjects were captured by utilizing Xsense orientation sensors. A humanoid robot standing on the tilting board was... 

This research describes the design and analysis of an actuating robot to manipulate the disposable Endo-wrist robotic surgery instruments. Analyzing the mechanism of common manual Endo-wrist instruments, it was found that the rotations of handle of the instrument are transferred to its wrist using a snake-like element and four connecting cables. Based on this observation, a 2DOF parallel actuating robot was designed to rotate the instrument handle, in which the degrees of freedom are controlled by two linear spindle motors. The Inverse kinematic analysis of the manual instrument was performed by minimizing the potential energy of cables. Also the inverse kinematic solution of the actuating... 

in laparoscopic surgeries, act zone tissues are not directly palpable for the surgeon. Therefore, evaluating the mechanical behavior of the tissue and distinguishing healthiness or illness of that, are not achievable for the surgeon. In this treatise, the matter of discerning the soft and bulky tissues mechanical properties by a robotic arm during the laparoscopic surgery, is regarded. In first step, a tool like a two finger miniature hand was designed in which either of fingers have utilized a parallelogram mechanism for opening and closing. The dimensional design of the mechanism was undertake in away that the tool has the ability of going through a 10mm diameter path and grabbling and... 

Human joints wear gradually by diseases like arthrosis and will fail. The Pain from joint erode, preventing tracking daily activities, wont disappear by medicines and joint replacement is a common treatment. Hip joint as one of the most important, largest and heaviest joints of the body,is no exception.
Over 600,000 worldwide annual hip replacement surgery is done. The joints are designed in such a way that it can move 15 years without significant wear. Different materials such as ceramics, polymers and metals are used in making it which before in vivo use, itmust succeed many tests like wear test.
Since making artificial joints become increasingly important in recent years and... 

2D-3D image registration has been adopted in many clinical applications such as kinematic analysis of bones in knee and ankle joints. Because it is not possible to take dynamic images in 3D and 2D dynamic images such as fluoroscopic images lack spatial information. For comparing two images it’s necessary to make their dimensions the same. So in this research we prepared a code in MATLAB to generate digitally Reconstructed Radiograph (DRR) from the CT image in different positions and then be compared with 2D fluoroscopic image. Registering two images could be done either with comparing their intensities or their mutual features. We combined these two methods and developed a cost function with... 

According to the statistical studies, knee pain is the most common and costliest disorder after low back pain. One of its types is the patello-femoral disorder and instability. Patellar instability can be affected by different factors, such as: low depth of the trochlear groove, low height of the lateral femoral condyle, high length of the patellar tendon, abnormal lateral rotation of the tibia, unusual tibial attachment of the patellar tendon, small patellar size, general loosening of ligaments, etc. So, the mechanical properties of knee joint including patello-femoral joint, surrounding soft tissues, and incoming forces must be examined carefully, in order to find out suitable and... 

Long bone reduction is one the conventional but hard and time consuming process in orthopedic surgery. This difficulty becomes harder when it comes to lower limbs which are under large tensile forces by strong muscles surrounding. With considerable progress in technology development robotic surgery in recent years, using robotic systems for simplification, accuracy improvement and quality of long bone fracture surgery is considered. In this study a six degrees of freedom parallel mechanism is considered for femoral reduction. The purpose of this project is designing a master robot for moving the mentioned mechanism with considering hardware limitation of this mechanism. This limitations... 

Aside from many advantages of minimally invasive surgery, it has some drawbacks. Surgeons` loss of dexterity dexterity, lack of force feedback and the consequent reduced sensation of forces are some of these drawbacks. Also, surgeons` ergonomically inappropriate posture gets him fatigued, causing hand tremor which is furthermore magnified by the long instruments. Robotic surgery systems have overcome some of minimally invasive surgeries limitations. But still some drawbacks such as high cost of maintenance or lack of haptic force feedback have impeded their widespread application. The high cost of maintenance is mostly caused by instrument changing and sterilization.The main goal of this... 

Bashti Bone Plug Technique (BBPT) is an implant-less method which can be used in an Anterior Cruciate Ligament (ACL) reconstructive surgery. The technique uses a core bone plug to fix the tendon graft into the bone tunnel. This study investigates the effect of the core bone density on fixation strength in BBPT method. A series of experimental test has been performed to examine the hypothesis of the study. Thirty fresh bovine digital extensor tendon used in three different groups. Sawbones blocks with densities of 160, 240 and 320 kg/m^3 used in substitute of the bone to model the effect of density on the strength of the fixation. The core bone plugs and tunnels created using a custom made... 

Sina surgical system is a telesurgery robotic system which is capable of using the conventional laparoscopic tools. In order to provide the wrist degree of freedom and increase the surgical maneuverability, a mechanism is introduced here which enables Sina to use and activate the wristed laparoscopic instrument Laparo-Angle. At first, the kinematics and dynamics characteristics of Laparo-Angle were identified experimentally. This tool contains 4 degrees of freedom, pitch, yaw, grasp and distal Roll. Activation of pitch and Yaw degrees of freedom requires a mechanism which at least has two rotational degrees of freedom to move the tool handle in a cone shape workspace with an apex angle of 36... 

Torsional misalignment of lower extremities is a bone deformity of femur, tibia, knee twist or a complex of all these factors. These deformities affect the patient's gait kinematics. These patients are usually treated with osteotomy surgery with the aim of correction of anatomy. But it doesn't necessarily lead to the modification of gait. Therefor development and application of subject-specific musculoskeletal models to analyze patient's specific condition and predict corrective surgery results are considered. Accordingly, the aim of this project is to create a subject-specific musculoskeletal model for a patient with femoral anteversion in order to predict result of anatomical correction...