In recent years, the shortage of nurses has become a global problem. Furthermore, in large-scale surgeries such as total knee arthroplasty, a large number of surgical instruments with similar shapes are prepared, which places a heavy burden on operating room nurses who manage them. To solve these problems, we have developed an automatic surgical instrument recognition system to support operating room nurses. We have also developed a system that applies projection mapping technology to highlight automatically recognized surgical instruments in the real world in real time, making it easy for nurses in the operating room to understand. In this study, we propose a method to correct the highlighting using ArUco markers. In experiments, we confirmed object detection using surgical instruments and demonstrated the effectiveness of this system.

Parkinson's disease is a neurodegenerative disease characterized by slow progression and is never cured. Its symptoms include motor impairments such as bradykinesia, muscle stiffness, tremor at rest, and postural dysreflexia, as well as non-motor impairments such as depression and autonomic neuropathy. One measure to evaluate Parkinson's disease is the Unified Parkinson's Disease Rating Scale. One of the items in this scale that evaluate bradykinesia, one of the motor symptoms, is the finger tapping test. However, many of the expressions used there are subjective, and the evaluation criteria are ambiguous. Therefore, the purpose of this study was to develop a quantitative hand movement evaluation system using MediaPipe Hands, to analyze finger tapping test, and to evaluate the effectiveness of the system. With this developed system, hand movements can be analyzed by using a webcam. Hand motion was analyzed by calculating the length between hand joints, the speed of joint movement, and the angle between joints. To evaluate the accuracy of the system, we first measured the length between the joints of the fingers as the hand was moved away from and closer to the camera, and then examined the error. Then, the finger tapping test was conducted using the developed system to evaluate the bradykinesia. Accuracy evaluations have shown that MediaPipe Hands can detect hand movements with high accuracy. The finger tapping test also revealed that there was reproducibility in the magnitude of each finger movement, but not in the speed of the movement.

In total knee arthroplasty, nearly 100 types of surgical instruments are prepared in addition to the usual surgical instruments. Since there are many types of surgical instruments used and their shapes and sizes are similar, accidents due to incorrect selection of implants have occurred. In addition, there is concern that the shortage of nurses will accelerate around the world in the future. For these reasons, we developed a surgical instrument detection system for total knee arthroplasty to reduce the incidence of accidents and the burden on scrub nurses. The surgical instrument detection system in the previous study required a lot of labor and time to create training data. Also, when increasing the number of surgical instruments to be detected, it was necessary to retrain all the surgical instruments. To solve these problems, we developed an automatic annotation system using a turntable in this study. In addition, we develop learning and inference methods using standard objects. In the experiment, we verified the accuracy of the learning data created by the automatic annotation system and verified the object detection accuracy for five types of surgical instruments. As a result, all experiments showed the effectiveness of this system.

Manual testing is one of the most common diagnostic methods for anterior cruciate ligament (ACL) injuries in the knee joint. In particular, the Lachman test is superior to others. In this study, a 9-axis inertial sensor and a force sensor are used to measure the examiner's manual technique. In this study, we experimented on the accuracy of the inertial sensor and an experiment to measure the Lachman test. The results of Experiment 1 were within ± 1.7 degrees of the theoretical values for each axis throughout the experiment. The results of Experiment 2 showed that Endpoint could be estimated from the acceleration component of the subject's tibia, the acceleration component of the examinee's hand, and the force of each finger and that the motion of the knee joint and the examinee's hand technique could be measured. The development of this system is expected to have training effects for unskilled examinees.

Muscle of human weakens due to aging and injury. Therefore, it is important to recognize their current abnormality. As a method to know them, there is Manual Muscle Testing (MMT). Currently, MMT of Daniels et al. commonly used for clinical muscle strength assessment. Although the rough examination results of MMT are decided, the doctor decides the examination result of the patient in comparison with the judgment from the doctor's long experience. The problem point with MMT is that the results vary depending on the examination method of the doctor and length of the diagnostic time. As a previous study, there is a Hand-Held Dynamometer (HHD). This is isometric contraction and can be measured quantitatively. However, this does not have the ability to evaluate test results on behalf of MMT. Therefore, we will quantify MMT procedures and test results. And, there is no research that has measure dynamic force pattern mainly based on isotonic contraction yet. As a preparatory step to the above goals, we measured the subject's lower extremity movements and, the magnitude and direction of the examiner's force using MMT. This time, we measured the reliability of the system developed with one examiner. For the measurement, 9-axis inertial sensor which can use quaternion and force sensor were used. Three subjects measured three times. From the measurement results, the purpose of this research could be measured. In addition, we were able to measure the magnitude and direction of force of an examiner. From the above results, it can be said that the jig and measurement system developed in this research are very useful for measuring movement of lower limbs. There are two future issues. One is to improve the difference between the subject's leg movement and the direction of the examiner's force. The other is to measure the movement of the subject's leg when a greater force is applied to the subject's leg.

The knee anterior cruciate ligament (ACL) injury is caused by abnormal turning force to knee joint. In particular, cutting maneuvers often cause ACL injury. Therefore, analyze cutting maneuvers is important for preventing ACL injury. In the previous study, there are many things used force plates to measure foot pressure, motion capture using marker, and analyze electromyographic. Till now, there is no study to analyze center of foot pressure (COP). In the measurement of COP distribution, we use the insole type measuring device in this study. The insole type can be attached to the shoes used daily and measured in various environments. Therefore, it can be performed in various places in which the competition is carried out, and it can deal with various action. The purpose of this study is to analyze the motion of cutting maneuvers. The changes of COP distribution by changing angle of cutting maneuvers are clarified. In this study, we defined parameter and compared cutting maneuvers from the values. Our measurement system has 6-axis inertial sensor that attached to the instep. We estimated the timing of direction change and running cycle more accurately by measurement data. The angle of the cutting operation is increased, or non-dominant foot or female, the value of the parameter is large.

Sole pressure has been analyzed and reported in recent years in medical and sports fields. However, these studies used a force plate or wired pressure sensor systems which has to be limited to a measurement area. Therefore, it cannot be applied to general sports motion like a marathon. This study set a goal to develop a wearable measurement system for sole pressure to calculate center of pressure (COP) in sports activity. To avoid influence of sports performance, the system should be compact and lightweight. The proposed system is 28.5 g and rigidly hold on shoes. The proposed system was applied to one healthy person. Turning motions in normal step and cross step were measured. The analyzed COP shows the difference of steps. Therefore, this system could be used in real sports motion. A future work is to examine the accuracy and repeatability of the sensors.

A human performs simultaneously multiple actions in daily life. Especially, to perform two actions among them is called a dual task. Although dual tasks are unconsciously carried out in daily living actions, performing two actions decreases concentration and performance. Many studies showed that the difficulty of executing a dual task increase with aging. The elderly people often fall as they are performing a dual task which accounts for a large portion of the accidents among the elderly people. One of the causes about falls in the elderly people is the decrease of motor and/or cognitive abilities with aging. In this research, we focus on the decline of cognitive ability when executing dual tasks. To evaluate cognitive ability in dual tasks, we imposed cognitive task and / or motor task. Besides, we measured movement of gaze and response speed of finger during the experiments. We set up a task to identify ordered colors and specific shapes as a cognitive task and set a task to response with grasping as a movement task. We also set up a task to response with key input as a non-movement task and set a task to identify one sphere as a non-cognitive task. Eye Tracker is used for measuring gaze motion and Leap Motion is used for measuring grasp motion. Both of them enable us to evaluate reaction time. Experiments were conducted on five healthy people. In these experiments, we measured the time of migration of line sight and reaction.

Total Hip Arthroplasty (THA) recently becomes more famous in Japan. The number of operations is increasing more and more because of longevity. In the operation, inserting artificial femoral joint is important for clinical outcome (e.g., pain, and loosening). In addition, femoral stem which is one of the artificial joints, has a shape fitting to femur bone so that the fixation between the femur bone and the artificial joint. The fixation degree of the artificial joint strongly depends on the insertion angle of the artificial joint. However, THA requires fuzzy subjective judgement of surgeons due to the difficulty to define the fixation degree. To evaluate the fuzzy subjective judgement, this study aims to specify the curve shape of medial proximal part of stem by measuring the curve with ultrasound device. This study develops five probes with small size which enables us to embed the probes into inside stem. The probes measure reflected echoes from boundary of the femur contour, then the propagated time of the echo was converted into the distance from the surface of the probes and the femur contour by using ultrasound velocity. The experiments were performed with two femur models. As a result, the proposed system could show the contour which is corresponding with real shape. We indicated usefulness of the method using ultrasound proves for measuring a curve stem inside.

Stair walking requires more the function of balance relative to walking on level ground. The most common cause of falling is to lose of balance, and elderly people falling occurs most frequency in stairs. The posture of the passenger unit decides the lower limbs movements and effects to the function of balance. Various clinical tests are performed to assess gait ability and the function of balance. However, these tests cannot assess the quality of gait motion. Then, the movement of the passenger unit during stair walking has not ever been shown by using inertial sensors. The purpose of this study is to investigate the movement of the passenger unit during stair walking and to compare to during walking on level ground. Our measurement system has six inertial sensors that attached to the head, the shoulders, the waist and the distal femurs. The data during one gait cycle are extracted from the measurement data and compared. Significant differences between Descent, Ground and Ascent were shown by the values of j-axis in each segment. The movements of the passenger unit were large in the ascent stair trial. Stair ascent need large movement of the passenger unit to keep of balance and to raise up the lower limbs. On the other hand, the movement of the head was effected by the eye movement.

In total hip arthroplasty, a placement of stem, which is one of the parts of the artificial hip joint, is even difficult for skilled operators. An optimum location of stem is different for each patient. No system for specifying the optimum location has been established. We pay attention to the method using ultrasound in consideration of portability and high introduction ratio to the medical field. The purpose of this study is to compare the measurement results of different stems in specifying the shape of femur by ultrasound through stem. In this study, we developed a femur model and two stem models to reproduce bone condition which is similar to actual surgery. The femur model is made to hold only one stem tightly. Measurement was performed by two probes method, and two probes were placed on the back side of the stem. Reflected ultrasound echoes were measured by moving with a constant interval. By using these echoes, the reflected echoes from the outside surface of femur model were identified. The reflected position was coordinated to create a contour. The contour was compared to the theoretical value in each size of stem, and the error was calculated for them. As a result of the experiment, the small error was observed at any size, however, the result with the suitable size stem shows proper fitting. Therefore, the proposed method using ultrasound will be useful for identifying the curve shape of femur, and it can contribute to quantify the fixation rate by size.

Gait motion is strongly relating with human health. Therefore, it is important to analyze the gait motion. This study aims to develop a system to measure sole pressure, acceleration and angular velocity in gait motion. Then the system can measure the parameters by using seven force sensors and six-axis inertial sensor for each sole. The experiment was performed with three normal subjects by using the proposed system. An analysis method consists of three steps. The first step specifies gait cycle from the value of the acceleration. The second step calculates the excursion of ankle joint by integrating the angular velocity. The third step specifies foremost and hindmost points of gravity center in gait cycle from the seven force sensors and calculates anteroposterior distance of gravity centers. The target parameters were excursion of ankle joint and anteroposterior distance of gravity centers. In the experiment, stride lengths of the subjects were three patterns of 10 cm, 50 cm, and 100 cm. There was a tendency that the ankle excursion was small when the stride was small.

Total knee arthroplasty is a common procedure as a surgical solution to reduce pain and improve knee function. However, this procedure heavily depends on the skills and experience of a surgeon to determine the correct amount of soft tissue balancing during the procedure. Analysis of the contact point between the femoral and tibial component of the knee prosthesis is usually performed manually using radiographic images. This method requires much work and also expose the patient to radiation. A force distribution measurement system was developed in an attempt to address this problem. The current study investigates the in vitro kinematics of a posterior stabilized fixed bearing prosthesis. Eight malalignments experiments have been conducted in 0° extension and 90° flexion. The results show that there was a posterior femoral rollback phenomenon observed through the changes of the force center of gravity. The malrotation caused a higher concentration of force to the prosthesis especially during extension. Varus caused a higher concentration of force in medial condyle. Finally, the anteroposterior and mediolateral translation affect the prosthesis especially in extension position. The results obtained in this study were comparable with the past findings using radiographic images.

Posterior cruciate ligament (PCL) is important for the knee stability. The problem seems to lie in the fact that it is difficult to segment the PCL from a magnetic resonance (MR) image. To reduce massive measurement time and subjective judgment error, this paper proposes a segmentation method of the PCL in knee joint from MR image and computed tomography (CT) image using anatomical information. In the experiment, a normal knee was analyzed by the proposed method. In the result, the segmented PCL was visually observed. We concluded that the proposed method can segment the PCL from the knee MR image.

Blumensaat line is one of the most commonly used direct methods for the assessment of femoral diagnosis and therapy. Currently, the Blumensaat line is determined manually. Therefore, diversity of the determination happens due to the subjective judgment error. To reduce the diversity, we propose an automated determination of Blumensaat Une by using fuzzy logic based on physician knowledge from femur multi-detector row computerized tomography (MDCT) image. The experiment employed six different knees. The six femurs were evaluated by the manual and proposed method. In the results, the length of Blumensaat line was 24.12 ± 3.23 mm (manual) and 23.90 ± 2.41 mm (automated). The angle between Blumensaat line and bone axis was 27.80 ± 6.08 degrees (manual) and 30.68 ± 5.76 degrees (automated). There was no significant difference between the manual and proposed method. We concluded that the proposed method has enough accuracy as same as expert.

Wavelet analysis has been successfully applied in many applications such as image processing, communication and signal processing. Moreover, the wavelet theory covers more significant application. It is because the wavelet theory can be applied to the continuous and the discrete-time cases. In particular, the wavelet transform focuses on the analysis of non-stationary signals. When compared with classical Short-Time Fourier Transform and Fourier Transform analysis, both processing methods are unable to process the non-stationary signal. While wavelet analysis provides an alternative solution for this problem. Ultrasound signal is categorized as a non-stationary signal. Many techniques have been used for processing the ultrasound signal. The use of ultrasound in medical and civil area keeps increasing due to low cost, and accurate techniques. Therefore, this study focuses on the analysis of the multiple echoes of ultrasound in the cortical bone using wavelet decomposition processing method. Then, the appeared echo at both surfaces of bone was determined using a peak detection algorithm. Bone thickness was calculated based on measured flight time in the bone. The experimental results were compared with manual measurement using vernier caliper for validation process. The results show that the wavelet decomposition processing method provided small errors of cortical bone thickness measurement, which was 0.152 mm (4.104%), while standard deviation was 0.102 mm. This measurement values showed that the accuracy of bone thickness was almost 96.000% for this method. Furthermore, the experimental results were correlated with caliper values so that correlation coefficient was 0.9797.

The anterior cruciate ligament (ACL) is one of the most important ligaments in the knee. The ACL injury often occurs while doing sports. Lachman test is one of the manual tests for examining the ACL. Examiners discriminates an injured degree of the ACL by feeling their finger stress. Measurement devices for Lachman test have been reported, however, these devices aim to analyze not the stress but a motion of the knee joint. Therefore, we focused on a development of a measurement system for the finger stress during Lachman test. The developed system could record the finger stress with force sensor. This study aims to propose an evaluation method of the stress data for bimodality which can be a criterion of injured degree. In a basic experiment, we examined a string which can be considered as normal knee. The result indicated obviously bimodality in the stress data. This study applied this system to three subjects with healthy knees. In the result, bimodality was observed in one or more finger(s) for each trial. Average of discrimination rate of bimodality for each wave was 90%. Therefore, the criterion of the bimodality can contribute to diagnose the injured knee. Future work is to apply the developed system to injured knees.

Conductive rubber is used for various applications in engineering fields due to its advantages such as a wide range of electrical conductivities, low cost and ease of shaping. The rubber needs to be calibrated before it can be used in response to the applied force. Due to the highly nonlinear property of rubber, researchers usually apply methods such as mathematical model and neural network to map the voltage-force response. These methods, however, require complex calculation and large quantity of training data. In this paper, an implementation of cubic spline for calibrating the voltage-force response is reported. This method not only requires a small number of data, but also provides good curve fitting for nonlinear function. Two types of cubic spline are explained and carried out in experiments. The result shows that the cubic spline technique was able to map the voltage-force up to 50 N. The calculated average measurement error was 3.44±1.58 N, mean squared error for border sensing elements was 7.78 N2and inside sensing elements was 3.47 N2. Paired t-test for cubic spline and back propagation neural network shows significant difference (p <;0.001) where cubic spline performed much better than the latter method. The result indicated that the cubic spline method was able to estimate voltage-force response and feasible for force sensor application.

The anterior cruciate ligament (ACL) reconstruction is usually performed for the injured knee. The ACL reconstruction needs two bone tunnels. It is important to measure changing of the bone tunnel regions after surgery. Thus this study aims to propose an automated segmentation about anteromedial (AM) and posterolateral (PL) parts of the bone tunnels after double bundle ACL reconstruction using k-means clustering. Six patients were evaluated (Age 27 ± 7, four males/two females). As a result, this method could be divided for all patients. This study concluded that the proposed method is enough to divide the bone tunnels of double bundle technique after ACL reconstruction.

Pedicle Screw was used for spinal fixation since 1944 by King. There are several techniques were used for pedicle screw placement purpose. The common technique used by the surgeon was free hand and image guided technique. For the deepness measurement of pedicle screw insertion, it depends on a palpation of doctor to judge the boundary between the cortex and cancellous bone. This technique still has a possibility to give an error (e.g. misplacement of screw and injury) in surgical processes due to the subjective judgment. The existing bone thickness and screw dimension can be determined preoperatively using imaging procedures (CT Scan) which is off-line technique. This paper was discussed a new technique for measurement of bone thickness by using an infrared sensor. Three specimens were used in this study and the result showed that it has a good relationship between bone thickness and amount of light that received by an infrared sensor. This technique has high possibility to detect different bone thicknesses.

Currently, the number of Total Knee Arthroplasty (TKA) in Japan is 70,000. Because it is easy to expect increasing the number due to super-aging society, the clinical outcome of TKA surgery has been important The surgery requires proper soft tissue balance to avoid shortening fatigue life of prosthesis. Thus, a measurement system of force concentration about contacting region between femur component and polyethylene insert contributes to prolong the prosthesis. This study examined the force concentration by using our developed measurement system. This study performed two experiment consists of physical and simulated experiment As a result, our developed system could localize the force concentration point A future work is to apply this measurement system to the cadaveric knee.

The anterior cruciate ligament (ACL) is one of strong ligaments in the knee. The ACL has a role to prevent excessive internal rotation and forwarding movement of the tibia. The ACL reconstruction often occurs while doing sports. Lachman test is one of manual tests for examining the ACL. An examiner discriminates an injured degree of the ACL by feeling his/her finger stress. Rapidly stop motion during the Lachman test which is called as Endpoint, should be examined. Some measurement devices for Lachman test have been reported. However, these devices aim to analyze not the stress but a motion of the knee joint. Therefore, we set the goal of this study to develop a measurement system for the finger stress with force sensor during Lachman test. A quantitative measurement system during Lahcman test with force sensor was developed. Control method that was proposed to adjust sensor initial value for finger thickness by using fuzzy control was experimented to confirm the usefulness. Basic experiment before numerical analysis of Endpoint was revealed that the inclination of force can separate characteristic of string and elastic. Lachman test was measured by nine experts and one non-expert with this system. The five analyzed results of nine examiners were consistent with the estimated bimodality. It implies that the proposed analysis method and system have usefulness because they can estimate the bimodality from the measurement data in half of the all data. This study focused on not the injured knee but the normal knee. A future work is to apply this system to the injured knee.

Total knee arthroplasty nowadays becomes a common procedure to restore the knee function for patients who suffered either natural knee diseases or injuries. The procedure effectively reduces pain and improves knee function with high rate of success. However, the risk of failure is still a problem despite this particular issue has been discussed for the past decades by researchers all over the world. The current implementation of the procedures relies heavily on the feel of the surgeons to ensure the right implantation of the prosthesis on the tibiofemoral component. A force distribution measurement system which has a sufficient accuracy for determining the location of tibiofemoral contact forces is being developed to address this concern. The system consisted of two pressure sensitive sensors, embedded in the trial insert for each condyle. The sensors were made up of pressure-conductive rubber with 8 x 16 of electrodes arrays at the front and backside of the rubber. The current study focuses on the reliability and validity of the measurement performed using the developed sensors. The results indicate good response of the rubber against constant applied force within the first two minutes before the measurement error start increasing over time.

Unstable pelvic ring fractures are usually affiliated with high energy impact that inflicted upon the hip such as in vehicle, industrial and extreme sport accidents. These injuries are always associated with high rate of mortality due to excessive bleeding and involvement of surrounding organs. Early stabilization of the pelvic using an external fixation can be used to reduce the pelvic volume and consequently control the hemorrhage. However, not a single currently available external fixations are capable of stabilizing the unstable fracture sufficient enough to allow patient mobilization and early weight bearing. Hence, this study was conducted to introduce a new method of fixation known as lateral supra-acetabular and subsequently compare with anterosuperior and anteroinferior fixation methods. The comparison was made by means of physical experimentation and computer simulation. The physical experiment employed four sawbone models while the simulation was performed using virtual pelvic model reconstructed from an MDCT image with Type C1 fracture. Both experiment and simulation were performed for standing and sitting position to evaluate the strength of fixation before failure of the model occurs. Lateral supra-acetabular fixation method was found to be significantly performed better than anterosuperior and anteroinferior fixation for both physical experiment and computer simulation.

Lachman test is one of a manual tests for examining the anterior cruciate ligament (ACL). A medical personnel discriminates degree of the ACL injury by the feeling of stress on the finger. This method is subjective and dependent on the skill of medical personnel. Hence, a measurement device for Lachman test has been developed. This measurement system consists of finger braces and force sensors on each fingers. However due to low accuracy of the system, improvement of current device has been proposed by calibrating the finger braces for different finger thickness. The calibration made for the device was successfully detect the true force applied to the finger braces. Nevertheless, the system was only able to measure low load with high accuracy. Future works are already in progress to improve the resolution of A/D converter and to measure the force distribution during Lachman test with high accuracy using the force sensor.

Mosaicplasty is a surgery that transplants osteochondral grafts for osteochondritis dissecans. In mosaicplasty, cylindrical osteochondral grafts are harvested from normal area, and transplanted to injured area. The one of the most important things of this surgery is that the graft should be perpendicular to the surface of the cartilage. The navigation system that aims improvement of precision has been already studied, however cannot be applied to use an endoscope. In addition, it is a problem to have low precision of the transplant in the freehand. Therefore, we thought that the system would be widely used if we develop the mosaicplasty navigation system under an endoscope. This study proposes a navigation system to determine a proper position and pose for harvesting. In the experiments, a femoral imitation bone was used as a profile of the femoral joint surface. The experiment consists of the following three procedures: Scan and display of the femoral joint surface profile. Display of a normal vector for the femoral joint surface and a harvester. Measurement of the accuracy of the normal vector. In the results, the developed system could display the femoral joint surface and the normal vector for the femoral joint surface virtually. Also, the angle between the surface normal vector and the real normal vector was an average of 6.50 degree. As a future work, the stereographic system using camera should be downsized.

Anterior Cruciate Ligament (ACL) is one of the important ligaments in the knee. The ACL connects the femur and tibia, and has a role to prevent an excessive forward movement of the tibia. In the clinical sports medicine, ACL reconstruction is often preformed about the injured knee. The ACL reconstruction aims to recover the function of the knee. Although some studies have reported tension pattern of the reconstructed knee during knee bending, no reports have reported an evaluation method of a normal tension pattern. This study challenges to define the normality of the normal knee in considering with the tension pattern. The experiment used an imitation bone with imitation ligaments for measuring the tension pattern by using our developed micro-measurement system, and evaluated the normality of the tension pattern. A future work is to apply this evaluation to cadaver knees.

In ACL reconstruction, position and pose of the ACL is important for clinical outcome after surgery. Among several concerning parameters, graft bending angle affects bungee jump effect. In general intraarticular graft is hopefully perpendicular to the direction of the bone tunnel to prevent from the effect. However, it is difficult to know the angle between the graft and the bone tunnel. This study proposes a calculation method of graft bending angle in virtual model. The experiment used a 3D scanner and an electromagnetic device to obtain 3D profile and 3D motion of the knee, respectively. Then, the profile data is translated to adapt the 3D motion data by using registration method. Finally, an examiner virtually indicates two end points of bone tunnels of the femur and tibia. The virtual graft bending angle is calculated from them. The results compared change of bending angle of transtibial and far anteromedial techniques. As a result, the proposed method could calculate the bending angle in simulation. A future work is to explore the proper bone tunnels automatically.

Mosaicplasty is one of the surgeries for knee cartilage injury. It transplants the bone autograft with the cartilage to the injured area. In this surgery, it is important to harvest the cartilage graft vertically and transplant it vertically by using a harvester for preventing area around transplant from discontinuous of the cartilage surface. This study set the goal to develop a system to estimate the pose of harvester against the articular surface in considering with a force distribution measured by a force sensor. The proposal method measures a force distribution on the cartilage surface by using force sensors which is attached to the frontal edge of a holder instrument that keeps a proper direction of the harvestor. The force distribution can enable us to estimate the positional relationship between the articular surface and harvester. The experiment used a portable force tester for loading, and estimated the angle of the harvester. The result shows the maximum of the angle estimation error was 8 degrees. The experiment of angle estimation performed multiple times, it was confirmed reproducibility. This accuracy is sufficient for practical situation, because a study reported that the error of free-hand is about 10 degree. A future work is to apply this system to the cadaveric body.

Lachman test is one of manual tests for examining the anterior cruciate ligament (ACL). An examiner discreminates an injured degree of the ACL by feeling finger stress. Some measurement devices for Lachman test have been developed. However, these devices aim to analyze not the stress but a motion of the knee joint. Therefore, we set the goal of this study to develop a measurement system for the finger stress with force sensor during Lachman test. In the experiment, the developed system was applied to twelve healthy knees of six subjects by a beginner, and one injured and one healthy knee of two subjects by an expert. In the results, the maximum force of "endpoint" during Lachman test was analyzed. The variation of inter subjects was larger than intra-subjects. Future works are to improve the finger force sensors, and to apply more subjects, so that the system could classify an examiner into a skill level.

Mosaic plasty is a surgery that transplant osteochondral grafts for osteochondritis dissecans. In mosaic plasty, cylindrical osteochondral grafts are harvested from normal area, and transplanted to injured area. The one of the most important thing of this surgery is that the graft should be perpendicular to the surface of the cartilage. The navigation system that aims improvement of precision is already studied, however cannot be applied to use an endoscope. In addition, it is a problem to have bad precision of the transplant in the freehand. Therefore, we thought that the system would widely used if we develop the mosaic plasty navigation system under an endoscope. This study proposes a navigation system to determine a proper position and pose for harvesting. In the experiments, a femoral imitation bone is used as a profile of the femoral joint surface. The experiment consists of the following three procedures: Trace and display of the femoral joint surface profile and a harvester. Display of a normal vector for the femoral joint surface. Measurement of the deviation of the normal vector. In the results, the developed system could display the femoral joint surface and the normal vector for the femoral joint surface virtually. Also, the deviation of the normal vector was an average of 7.27 degrees. As future works, there are to decrease the deviation of the normal vector by improving the precision to acquire the femoral joint surface profile, and to visualize the normal vector for the generated surface.

The anterior cruciate ligament (ACL) injury can cause a reason of instability along anterior — posterior translation at extension. Thus, it is important to examine the knee joint quantitatively for understanding clinical outcome. However, an quantitative calculation method of the knee joint has not been reported. Therefore, we have developed six degree of freedom (6 DOF) calculation based on principal component analysis (PCA) for the knee joint in multi-detecter row computer tomography (MDCT) image. The proposal method was applied to six ACL injured knees obtained at two periods. As a result, the proposed methods could calculated 6 DOF of the knee joint quantitatively.

This study set the goal to provide a criterion to diagnosis the surgical treatment for the patellar subluxation. The proposed method was realized to proposed each calculation of the patellar gravity point, patellar profile, and femoral groove. In the experiments, the proposed method was applied to four healthy knees and four knees with subluxation patellar. In the results, the knees wit subluxation patellar were regarded as “bad” case in comparing to the health knees. A future work is to expand the calculation of the femoral groove to 3D region.

The anterior cruciate ligament (ACL) plays important role as a preventing excessive anterior movement of the knee. When the ACL is injured, ACL reconstruction is often performed. In ACL reconstruction, bone tunnels of the femur and tibia are made for passing graft to the bone. It is reported that the bone tunnel is usually enlargement. The bone tunnel enlargement affects much knee function. In serious case, ACL reconstruction should be required again. Therefore evaluation of the bone tunnel is important. It has been analyzed for only calculation of volume change in time course. However, the direction of the volume change has not been considered, due to the difference of bone coordinate systems between data. This study proposes determination method of the bone coordinate system with fuzzy inference. As a result, our proposed method could determine the tibial bone coordinate system. Then, the bone tunnel trans-position was examined. A future work is to apply this method to more data, then feed back the clinical outcome.

Mosaicplasty is a surgery name that transplant osteochondral grafts for osteochondritis dissecans. In mosaicplasty, cylindrical osteochondral grafts are harvested from normal area, and transplanted to injured area. A surface profile of the cylindrical osteochondral grafts effects clinical outcome after surgery. Therefore, this study proposed an analysis method of the surface profile. In this study, the knee is targeted for analysis. A proposal method analyses an effect harvested area for the surface profile. In the experiment, six cadaveric knee are used. A vertical interval of the surface profile was compared between edge and top. In the results, the vertical interval of the edge was larger than the top. In conclusion, the proposal method indicates a difference of the surface profile from the harvested and transplanted areas.

The anterior cruciate ligament (ACL) plays important role as a preventing excessive anterior movement of the knee. When the ACL is injured, ACL reconstruction is often performed. In ACL reconstruction, bone tunnels of the femur and tibia are made for passing graft to the bone. It is reported that the bone tunnel is usually enlargement. The bone tunnel enlargement affects much knee function. In serious case, ACL reconstruction should be required again. Therefore evaluation of the bone tunnel is important. However, it has not been analyzed in 3D image, because the bone tunnel is unclear at distal region in MDCT image. To overcome this problem, this study proposed extraction method with fuzzy inference. As a result, our proposed method could detect bone tunnel region. Then, the bone tunnel enlargement was examined. A future work is to specify the enlarge part within the extract volume.

Fixation plate for fracture is one of the most important devices for fractures of the human bone. In general, the fixed plate for medial care is selected from lineup of the maker. Therefore, the surgery is adapted to each plate due to limitation of the lineup. However, the surgery should be naturally adapted to each patient. To overcome this problem, this paper set the goal to develop a system which can proposed appropriate fixed plate model according to patient information, and make a prototype of the selected fixed plate with low cost. After evaluation of the prototype, the prototype is remade for practical use by the maker which has a license for medical device. By doing so, the longtime purpose of this study is to realize patient-oriented medicine (tailor-made medicine).

Anterior Cruciate Ligament (ACL) reconstruction is performed to recover the injured knee which often happens in sports activity such as skiing, and basketball. The ACL reconstruction makes two bone tunnels in the femur and tibia. Then, the harvested graft passes the bone tunnels so that the femur and tibia are connected. The graft is fixed to the femur by using EndoButton. However, loosening of the fixation sometimes happens due to movement the EndoButton. It results in instability of the knee motion. Examination of frequency of occurrence of fixation loosening contributes to improve surgery procedure. This study set the goal to propose an evaluation method of EndoButton Position in MDCT image after ACL reconstruction. The proposal system was examined with this manually results. In the results, the error of anteromedial and posterolateral EndoButton were 1.88±1.03 and 1.78±1.19, respectively. As a result, the proposed method could detect automatically anatomical reference points and evaluate EndoButton positions.

The anterior cruciate ligament (ACL) is one of the important ligaments which control the knee function. In general, the ACL contributes to diminish anteoposterior instability. When some accidents can cause injury of it, the ACL reconstruction is done to recover knee function. The ACL insertion (position of the ACL attachment) is important in the reconstruction, because it determines the knee function after the surgery. Our final goal is to develop a navigation system to provide a criterion of the ACL insertion from information of the condyle shape. The system requires a standardization method of the ACL insertion. Therefore, this study proposes a standardization method by using fuzzy logic to deal with information of the condyle shape. In this experiment, this method was applied for 14 cadaver knees. As a result, the deviation of the angle and distance rate of the ACL insertion on our method were within 13.4 degree and 12.1%, respectively.