Currently there are nearly 2 million people living with limb loss in the United States [1]. Many of these individuals are either transtibial (below knee) or transfemoral (above knee) amputees and require an ankle-foot prosthesis for basic mobility. While there are an abundance of options available for individuals who require an ankle-foot prosthesis, these options fail to mimic an intact ankle when it comes to key evaluation criteria such as range of motion, push-off force, and roll over shape. The roll over shape is created by plotting the center of pressure during a step in a shank-based coordinate system. To address the need for a prosthesis that effectively replaces the ankle's contribution to an able-bodied gait, a biomimetic approach is taken in the design the Compliant & Articulating Prosthetic Ankle (CAPA) foot. The passive CAPA foot consists of four components connected by torsion springs representing the Phalanges, Metatarsal bones, Talus, and Calcaneus. Biomimetic functionality is exhibited by CAPA foot with regards to the roll over shape and a linear relationship between moment exerted and ankle angle, distinguishing the CAPA foot from other ankle-foot prostheses. A mathematical model of the CAPA foot is created to determine the roll over shape a specific CAPA foot geometry would produce and support eventual customization of the 3D printed components. The mathematical model is used to optimize the design to two distinctly different roll over shapes, one with a rocker radius closer to that of the Talus bone and the other closer to the energetically advantageous value of 0.3 times leg length [2, 3]. Compliant and stiff versions of the two CAPA feet were compared to a conventional Solid Articulating Cushioned Heel (SACH) foot and a passive dynamic response foot (Renegade® AT produced by Freedom Innovations). Ten able bodied subjects walked on the Computer Assisted Rehabilitation Environment normally, and then with a transfemoral prosthetic simulator. The study was separated into two experiments. For the second experiment (subjects 6-10), the versions of the CAPA foot had pretension in the dorsiflexion springs. Overall the ankle angles and sagittal plane ground reaction forces of the CAPA foot better mimicked an intact ankle-foot than the existing passive ankle-foot prostheses. Added pretension increased the sagittal plane ground reaction forces and roll over shape radius of curvature and arc length. Nine out of ten participants preferred the CAPA foot and there was a statistical significant difference (F=14.2, p<0.01) between the difficulty level rating given for trials with the CAPA foot versus the existing ankle-foot prostheses. The mathematical model is found to be capable of accurately predicting experimental roll over shape trends and the concept of roll over shape based design is demonstrated. Successful aspects of the CAPA foot can be applied to other ankle-foot prosthesis. The CAPA foot could provide a passive, cheap, and personalizable ankle-foot prosthesis that improves mobility the quality of life for individual’s lacking an intact ankle.

Spinal cord injury and stroke affect many people each year and can result in the loss of muscle function. Current research attempts to correct muscle paralysis through the use of mechanical braces or through open-loop stimulation methods. However, prosthetic systems that use closed-loop control strategies can offer improved functionality by accounting for the changing dynamics associated with the human body and external disturbances. In particular, closed-loop functional electrical stimulation (FES) offers the possibility of moving paralyzed muscles in a predetermined manner, allowing a paraplegic individual to regain the ability to perform some tasks. An experimental setup was designed for the development and testing of a closed-loop FES control system, as well as the characterization of muscle properties. Due to the complexities associated with using a human subject, an inverted pendulum model is utilized for this preliminary study. This model is a basic engineering control problem often used when studying postural control in humans. In particular, electrical stimuli will be applied to the gastrocnemius muscle of a frog in order to produce a contraction force that will drive an inverted pendulum and maintain its desired angle. The stimulation signal will be determined by control algorithms applied through the use of Matlab® and implemented in real-time with a data acquisition system. This setup will help provide an understanding of the muscle behavior and can be used to establish the validity of proposed controller methods.

Bakgrund: Ortopedingenjören har som uppgift att med sin kompetens och erfarenhet tillhandahålla en ortopedteknisk lösning som motsvarar patientens behov och önskemål. Handlingsutrymmet är det utrymme som en ortopedingenjör har till att ta självständiga beslut i sin yrkesutövning och är därmed summan av kompetens, bedömningar och rutiner inom verksamhetens ramar.  Syfte: Syftet med examensarbetet är att öka kunskapen om ortopedingenjörens upplevda handlingsutrymme i Sverige och Norge i relation till förskrivningsregler för protes på nedre extremiteter.  Metod: Examensarbetet baserades på en enkätundersökning med frågor gällande ortopedingenjörens upplevda handlingsutrymme utifrån mixed method. Enkäten publicerades via SOIF, Facebook gruppen Ortopedteknik i Sverige och NITO ortopedi.  Resultat: Faktorer som formade handlingsutrymmet, i situationer när ortopedingenjören upplevde stort inflytande, var främst patientrelaterade. De faktorer som beskrevs forma handlingsutrymmet vid upplevelsen av mindre inflytande var främst ekonomi och lagar/riktlinjer. Majoriteten av ortopedingenjörerna upplevde att de ofta kunde uppfylla patientens önskemål med avseende på sitt handlingsutrymme. Det förekom en delad mening om en förändring i förskrivningsprocessen behövde ske eller ej. En stor del av ortopedingenjörerna upplevde att de alltid haft möjlighet att påverka ett beslut vid förskrivning av en protes eller proteskomponent, medan ett mindre antal ortopedingenjörer har upplevt en eller flera situationer där beslutet inte kunnat påverkats. Slutsats: Ortopedingenjörer har varierande upplevelser gällande sitt handlingsutrymme, faktorer som formar handlingsutrymmet och möjligheten att påverka handlingsutrymmet vid förskrivning av proteser för nedre extremiteter. / Background: The task of the prosthetist is to provide an orthopaedic solution that meets the patient´s needs and wishes with expertise and experience. The discretion of action is the space that a prosthetist must make independent decisions in his professional practice and are thus the sum of skills, assessments and procedures within the discretion of the business. Purpose: The purpose of the study was to increase knowledge of the prosthetist perceived discretion in Sweden and Norway in relation to the prescription rules for lower limb prosthetics.  Method: The study was based on a survey that addressed questions regarding prosthetist perceived discretion for action through a mixed method. The survey was published via SOIF, the Facebook group Orthopaedics in Sweden and NITO orthopaedics. Results: Factors that affected the action of discretion, in situations when the prosthetist experienced great influence, were mainly related to the patient. In opposite, when the prosthetist experienced less influence, the main factors that affected a decision regarding a prosthetic where economy and laws/guidelines. The majority of prosthetists felt that they were often able to fulfil the patient’s request regarding to their discretion of action. In consideration to if the prescription process were in need of change or not, the opinion was divided. Many of the prosthetists have always experienced that they’re in charge of decision making or at least have been able to affect the decision. While a small number of prosthetists have experienced one or multiple situations where they could not affect the decision.  Conclusion: Prosthetists have varying experiences regarding their discretion, factors that shape the discretion and the ability to influence the discretion when prescribing prosthetics for lower limb.

Aim: The aim of this thesis is to evaluate patients’ satisfaction with prosthetic device and service on lower limb amputations in Danang, Vietnam and to implement comparisons between the subgroups gender, living area, amputation cause and level. Method: A cross-sectional study design was conducted using the Quebec User Evaluation of Satisfaction with assistive Technology (QUEST) 2.0 questionnaire to measure patients’ satisfaction. Fifty patients were recruited through the International Committee of the Red Cross (ICRC) and the data collection was performed in the patients own homes with an interpreter. The collected data was statistically analyzed with suitable tests using Statistical Package for the Social Sciences (SPSS). Result: The patients were quite satisfied with their prosthetic devices (mean 4.16 SD ± 0.561) and more or less satisfied with their given services (mean 2.83 SD ± 1.213). Significant differences were found between genders regarding the patients’ satisfaction with prosthetic device. There were no significant differences between the remaining subgroups; living area, amputation cause and amputation level. Conclusion: This thesis demonstrates that the patients in Danang appear to be quite satisfied with their prosthetic device, even though they reported problems with the durability of the device. Furthermore, the patients were more or less satisfied with their prosthetic services. The findings in this thesis also reveals that women were less satisfied compared to men regarding the prosthetic device. These conclusions should however be taken with caution, since the reliability and validity was lower than desired and it’s difficult to generalize the results to the population. / Syfte: Syftet med denna studie är att evaluera patienters nöjdhet med deras utgivna protes och service på nedre extremitetsamputerade i Danang, Vietnam och att implementera jämförelser mellan subgrupperna kön, bostadsområde, amputations- orsak och nivå. Metod: En cross-sectional studiedesign blev utförd genom användning av Quebec User Evaluation of Satisfaction with assistive Technology (QUEST) 2.0 enkäten för att mäta patienters nöjdhet. Femtio patienter blev rekryterade genom International Committee of the Red Cross (ICRC) och datainsamlingen blev utförd i patienternas egna hushåll med en tolk. Den insamlade datan blev statistiskt analyserad med lämpliga tester genom användning av Statistical Package for the Social Sciences (SPSS). Resultat: Patienterna var ganska nöjda med deras utgivna proteser (medelvärde 4,16 SD ± 0,561) och mer eller mindre nöjda med deras utgivna service (medelvärde 2,83 SD ± 1,213). Signifikanta skillnader hittades mellan kön gällande patienters nöjdhet med deras utgivna protes. Det fanns inga signifikanta skillnader mellan de resterande subgrupperna; bostadsområde, amputationsorsak och amputationsnivå. Slutsats: Den här studien demonstrerar att patienterna i Danang verkar vara ganska nöjda med deras utgivna proteser, fastän de rapporterade problem med protesens hållbarhet. Dessutom var patienterna mer eller mindre nöjda med deras utgivna service. Fynden i denna studie påvisar också att kvinnorna var mindre nöjda gällande protesen jämfört med männen. Dessa slutsatser skall dock tas med aktsamhet, eftersom reliabiliteten och validiteten blev lägre än önskat och det var svårt att generalisera resultaten till populationen.