A rear locking prosthetic knee joint with a durable, rear Automatic Stance-Phase Lock (ASPL), was developed to investigate the versatility of the (ASPL) mechanism in improving the functionality of prosthetic knees appropriate for a global market. An international survey and a Quality Function Deployment identified deficits with existing prosthetic knee mechanisms and established the most influential design parameters. Work on the knee design was completed following a comparative stability analysis of different knee mechanisms which justified the initial design. Solid models were generated with computer design software and a prototype was produced and structurally tested. Finally, clinical pilot testing was conducted on a unilateral transfemoral amputee, and various gait variables were assessed. As hypothesized, the knee performed close to the level of a conventional six-bar knee providing highly effective stance-phase control and the pilot test showed that improvements to the swing-phase response could further reduce the asymmetry of gait.

A rear locking prosthetic knee joint with a durable, rear Automatic Stance-Phase Lock (ASPL), was developed to investigate the versatility of the (ASPL) mechanism in improving the functionality of prosthetic knees appropriate for a global market. An international survey and a Quality Function Deployment identified deficits with existing prosthetic knee mechanisms and established the most influential design parameters. Work on the knee design was completed following a comparative stability analysis of different knee mechanisms which justified the initial design. Solid models were generated with computer design software and a prototype was produced and structurally tested. Finally, clinical pilot testing was conducted on a unilateral transfemoral amputee, and various gait variables were assessed. As hypothesized, the knee performed close to the level of a conventional six-bar knee providing highly effective stance-phase control and the pilot test showed that improvements to the swing-phase response could further reduce the asymmetry of gait.

Quadriceps muscle weakness is a condition that can result from a wide variety of causes, from diseases like polio and multiple sclerosis to injuries of the head and spine. Individuals with weakened quadriceps often have difficulty supplying the knee-extension moments required during common mobility tasks. Existing powered orthoses that provide an assistive knee-extension moment are large and heavy, with power supplies that generally last less than two hours. A new device that provides a knee-extension-assist moment was designed to aid an individual with quadriceps muscle weakness to stand up from a seated position, sit from a standing position, and walk up and down an inclined surface. The knee-extension-assist (KEA) was designed as a modular component to be incorporated into existing knee-ankle-foot-orthoses (KAFO). The KEA consists of three springs that are compressed, as the knee is flexed under bodyweight, by cables that wrap around a sheave at the knee. The KEA returns the stored energy from knee flexion as an extension moment during knee extension. During swing or other non-weight bearing activities, the device is disengaged from the KAFO by decoupling the sheave from the KAFO knee joint, allowing free knee joint motion. A prototype was built and mechanically tested to determine KEA behaviour during loading and extension and to ensure proper KEA function. For biomechanical evaluation, able-bodied subjects used the prototype KEA while performing sit-to-stand, stand-to-sit, ramp ascent, and ramp descent tasks. The KEA facilitated sitting and standing, providing an average of 53 % of the required extension moment for the two participants, which allowed one participant to reduce quadriceps usage by 38 % and the other to perform sit-to-stand in a slower and more controlled manner that was not possible without the KEA. KEA use during ramp gait caused an overall increase in quadriceps activation by 76 %, on average, with use. Future efforts will be made to modify the design to improve functionality, especially for ramp gait, and to reduce device size and weight.

この論文は，筆頭著者の博士論文（膝蓋大腿関節痛を有する成人女性の膝蓋骨可動性についての研究（http://hdl.handle.net/2237/10676）の副論文として提出された。和文によるタイトル，抄録は博士論文提出の際に付けられた。

It was demonstrated in recent studies that Complementary Limb Motion Estimation (CLME) is robust approach for controlling active knee prostheses. A wearable sensor system is then needed to provide inputs to the controller in a real-time platform. In the present work, a wearable sensor system based on magnetic and inertial measurement units (MIMU) together with a simple calibration procedure were proposed. This sensor system was intended to substitute and extend the capabilities of a previous device based on potentiometers and gyroscopes. The proposed sensor system and calibration were validated with an Optical Tracking System (OTS) in a standard gait lab and first results showed that the proposed solution had a performance comparable to similar studies in the literature.

Vertical jumping ability is an important fundamental skill for many athletic activities. The present work is focused on developing an understanding of the role of various movement strategies on vertical jump performance. The overall objective of this study was to determine if higher hip than knee joint contribution was more effective in enhancing vertical jump height. Additionally, the study explored possible links between the muscle activity and mechanical outputs, and to develop understanding of the role of the lumbar spine and hip. Twenty male university varsity athletes performed ten repetitions of three jumping strategies: preferred, hip dominant and knee dominant. Kinematics, kinetics and muscle activity of the lower limb and trunk were collected. The main observation was that the vertical jump height was positively associated with higher hip than knee work done. However, the within-subject comparisons between the trained hip and knee dominant tasks did not provide additional support for the importance of the hip. Higher hip work appeared associated with greater biceps femoris than gluteus maximus activity. The knee work increased with higher activity of the vastus lateralis and rectus femoris. Finally, higher trunk muscle activity and tighter coupling were associated with the vertical jump height and the max force. This study provides some evidence that encouraging hip dominance together with higher spine stiffness may improve two-foot vertical jump performance. This work has potential implications for training protocols that may be used to improve vertical jump performance.

Skillnaden i muskelstyrka mellan dominant och ickedominant ben hos fotbollspelare hartidigare studerats. Det finns inget enhälligt resultat om vilket ben som är starkast eller om detalls föreligger någon skillnad. Tidigare forskning har utfört mätningarna i sittandeutgångsposition vilket inte stämmer överens med fotbollspelares huvudsakliga aktivitet. Syftetmed uppsatsen var att, hos en grupp fotbollspelare i division ett och två, beskriva och jämföraden maximala muskelstyrkan mellan dominant och ickedominant ben. Datainsamlingenutfördes i en liggande utgångsposition då detta ger liknande muskellängdsförhållandet somvid stående. Mätinstrumentet var dragapparaten Genesis Single från Inmotion Intelligence.Studien är en beskrivande, jämförande tvärsnittsstudie. Urvalet bestod av en grupp manligafotbollspelare i svenska division ett och två.Resultatet i studien visade ingen signifikant skillnad i maximal muskelstyrka mellan dominantoch ickedominant ben. Vinkeln av knäflexion vid vilken knäflexorer respektive knäextensorerutvecklar maximal muskelstyrka, skiljer sig inte mellan dominant och ickedominant ben. Vadgäller den, ur maximal muskelstyrkesperspektiv, optimala vinkeln visar resultatet attknäflexorer inte utvecklar maximal styrka vid samma grad av flexion som knäextensorerna.Detta gäller både dominant och ickedominant ben. Fotboll är en sidodominant idrott menstudiens resultat tyder på att fotbollsutövande inte leder till muskulär obalans mellandominant och icke dominant ben. / The difference in muscle power between dominant and non-dominant leg in soccer has beenpreviously studied. There is no consensus on which leg is stronger or whether a differenceexists or not. Previous research conducted measurements in a seated starting position whichdoes not conform to the soccer player's main activity.The purpose of this study was, in a group of soccer players in Swedish first and seconddivision, to describe and compare the maximum muscle power between dominant and nondominantleg. Measurements were performed in a horizontal starting position as this givessimilar muscle length ratio as when standing. The machine used during the measurements wasGenesis Single from Inmotion Intelligence. The study was conducted with a descriptive andcomparative cross-sectional design. The sample consisted of a group of male soccer players inthe Swedish first and second division.The results of the study showed no significant difference in peak muscle power betweendominant and non-dominant leg. The angle of knee flexion in which knee flexors and kneeextensors develop maximum muscle power, did not differ between dominant and nondominantleg. The results showed that knee extensors did not produce maximum musclepower at the same degree of knee flexion as the knee flexors did. This applied to bothdominant and non-dominant leg. Football is a side dominant sport, but the study's resultssuggest that football practice will not lead to muscular imbalance between dominant and nondominantleg.

The kinematics characteristics of the human knee joint can be represented by its centrodes. This paper provides a method, called the photograph method, to construct the centrodes by using commercial digital camera to take the sequential pictures. In order to eliminate the undesired movements, a testing chair and a brace are specially designed. Two types of curve fitting methods are introduced to smooth the measured data. The differential method is applied to construct the centrodes of knee joints from the measured data. This paper provides a safe way to measure the centrodes of human knee joints.

Vibroarthrograpyhy (VAG) is an innovative, objective and non-invasive technique to obtain diagnostic information concerning the articular cartilage of knee joints. Knee VAG signals can be detected by putting a contact sensor on the surface of the knee joints during the movement such as flexion and extension. Before this research, there are many VAG group studies that contribute in signal processing and database building. The adaptive segmentation method and autoregressive modeling are developed to segment the nonstationary VAG signals. This thesis tries to investigate the accuracy of some database containing root mean square (RMS) value and intraclass distance (ID) feature parameters of physiological patellofemoral crepitus (PPC) signals. This research is first setting up two diagnosis standards for RMS and ID. According to the two standards, all signals are divided into three types: normal, unknown and injured, and those appear both in normal type of RMS and ID parameters are picked out. The same does the injured type. In conclusion, by checking the anamneses of these signals, we can be aware of the numbers of real normal and real injured in normal type and injured type; therefore the accuracy of the database can be derived. Consequently the accuracy of database in this thesis is quite certifiable.

The purpose of this thesis was to explore the use of cost effectiveness for interventions in orthopaedics. This was done through three cost effectiveness articles that have been published by the author. In each of these articles, similar methodologies were used. Decision models were constructed for cost-effectiveness analyses of competing orthopaedic interventions. Outcome probabilities and effectiveness values were derived from the literature. Effectiveness was expressed in quality adjusted life years gained. Cost data were compiled and verified from either hospital cost data or from Medicare data. Costs and utilities were discounted in accord with the United States Panel on Cost Effectiveness in Health and Medicine. Principal outcome measures were average incremental costs, incremental effectiveness, incremental quality-adjusted life years, and, in the case of one article, net health benefits. In particular the articles compared the following: 1. Core decompression versus conservative management for osteonecrosis of the hip as a way to delay hip replacement; 2. Total knee arthroplasty versus unicompartmental knee arthroplasty; and 3. Periacetabular osteotomy versus total hip arthroplasty for a young adult with developmental dysplasia of the hip. The more cost effective intervention was identified in each case, along with implications of the results for clinical and operative decision-making. Cost effectiveness was found to be a useful tool in orthopaedic surgery under limited circumstances of either scarce data on new interventions or the need to use more resources to achieve greater effectiveness. It also can provide excellent insight into ways to direct future clinical research.