Although sitting is a large part of everyday life is the influence of the sitting positions and chair design on pressure and load distribution as well as comfort for transfemoral amputees quite unexplored. The aim of this study was therefore to examine this further. Two transfemorally amputated females (49 and 57 years old) participated in the study. Three positions were examined for each subject; sitting without foot support and sitting with the knee joints flexed 90◦ and 105◦. The pressure inside the socket was measured by two pressure sensors, placed distally and proximally on the posterior wall inside the socket. The lengthwise pressure distribution and the sidewise load distribution between the socket and the underlying material was measured by a pressure mat. In addition to this, the subjects answered a questionnaire regarding the subjective comfort for each position.  The result showed that the pressure underneath the socket were higher distally than proximally without foot support. The pressure transferred proximally as the knee became more flexed. The most even load distribution sidewise was found when the subjects sat with their knees flexed 105 degrees. Sitting with the knees flexed 90◦ was ranked as the most comfortable position. No conclusion could be made regarding the pressure inside of the socket. Additionally, according to this study the level of comfort does not have any clear relation with the sidewise load distribution or the longitudinal pressure distribution. / En stor del av livet spenderas sittandes, men den påverkan som sittposition och stoldesign har på tryckfördelning och komfort för transfemoralt amputerade är ganska outforskat. Studien ämnar därför undersöka detta. Två transfemoralt amputerade kvinnor (49 och 57 år) medverkade i studien. Tre sittpositioner undersöktes för varje testperson; sittande utan fotstöd samt sittande med knäleden i 90◦ respektive 105◦ flexion. Trycket inuti hylsan mättes med hjälp av två trycksensorer, som placerades distalt och proximalt på den bakre hylsväggen. Tryckfördelningen i längsriktningen och lastfördelningen i sidled mellan hylsan och underlaget mättes med en tryckmatta. Förutom detta svarade testpersonerna även på ett frågeformulär angående den subjektiva komforten för varje position. Resultatet visade att trycket under hylsan var högre distalt än proximalt när inget fotstöd användes. Trycket förflyttades proximalt då knät böjdes. Den mest jämna lastfördelningen mellan sidorna påträffades när knät var flekterat 105◦. Enligt frågeformuläret var den mest bekväma positionen den med 90◦ i knäleden. Ingen slutsats kunde göras angående trycket inuit hylsan. Ingen tydlig relation kunde heller inte hittas mellan den subjektiva komforten och tryck- eller lastfördelningen.

Syfte: Syftet med det här examenarbete är att undersöka behovet av snabbkopplingsadaptrar för protesbrukare.   Bakgrund: Snabbkopplingsadapter är en förhållandevis ny produkt som både Otto Bock och Lindhe Xtend erbjuder, men ingen forskning på behovsområdet finns ännu gjord. Fördelen med produkten är enligt leverantörernas hemsidor bl a att man med den enkelt kan byta mellan olika proteskomponenter utan att behöva skruva på några protesinställningar eller byta hylsa.   Metod: För att undersöka behovet av snabbkopplingsadaptrar utfördes semistrukturella intervjuer av fenomenologisk karaktär. En serie med sju frågor sammanställdes som intervjuunderlag, vilka togs fram utifrån de tre behovsfokusområdena: Funktion, delaktighet och livskvalité. I undersökningen ingick n=6 deltagare, varav n=3 transtibialt amputerade och n=3 transfemoralt amputerade. Insamlade data analyserades vidare för framtagning av olika teman och resultat.   Resultat: Utifrån intervjuunderlaget togs följande teman fram: Byte av protesfötter/protesknäleder, På- och avtagning av byxor, Hylspassform, Transport samt Biomekanik. Varje tema utgjorde ett eget potentiellt användningsområde, där de största behoven visade sig ligga inom temana Byte av protesfötter/protesknäleder, Hylspassform samt Transport.   Slutsats: Behovet av snabbkopplingsadaptrar är högst subjektivt, och beror snarare på deltagarens liv än några allmänna faktorer. Däremot upptäcktes ett antal tänkbara användningsområden för den. / Aim: The aim of this thesis was to investigate the necessity of the quick change adapter for lower limb amputees.   Background: Quick Change Adapter is a relatively new product that both Otto Bock and Lindhe Xtend offers, but no research has been done on the area of its necessity yet.  According to the supplier´s websites the benefits of the product is that you with it easily can change prosthetic components without affecting the alignments or change socket.   Method: To investigate the necessity of the Quick Change Adapter, semi structural interviews of phenomenological characteristic were used.  A series of seven questions were compiled as a basis for the interview from the three focus areas: Function, participation and quality of Life. The thesis involved n=6 participants, of who n=3 was trantibial amputated and n=3 transfemoral amputated. Collected data was later analysed to find general themes and results.   Results: From the interviews these themes were exposed: Changing prosthetic feet/prosthetic knee joints, Donn and doff of pants, Socket fit, Transport and Biomechanics. Each theme presented a potential application area where the biggest needs seemed to be in Changing prosthetic feet/prosthetic knee joints, Socket fit and Transport.   Conclusions: The necessity of the Quick Change Adapter turned out to be very subjective, and depended more on the participant´s life then any general factors. Still there were some potential application areas detected for it.

Several studies have been devoted to the metabolic costs of amputees walking on prostheses with different masses added to their components. However, limited study has been directed at quantifying the mass differences of the actual materials available to amputees and the metabolic and mechanical work required to walk on these materials. The energetics of two materials currently used in the design of lower extremity prosthetics were examined in an attempt to determine if mass differences had an effect on amputee walking. A total of fifteen, unilateral amputees (8 transfemoral and 7 transtibial) performed treadmill walking on prostheses assembled from titanium and stainless steel components. Standardized components (knees, pylons, adapters, feet) made from each material were added below the level of the socket. Submaximal oxygen consumption {W/kg} and mechanical power allowing transfers within and between segments {W/kg} were calculated as subjects walked at self-selected velocities until steady state was achieved. Results show that despite significant mechanical differences [F(1,12)= 4.85, p<.048], the decreased mass associated with the use of titanium materials does not have an effect on the metabolic costs [F(1,14)=1.45, p<.249] of the subjects in this study. In addition, stride rate and stride length showed little differences when walking with both materials. Further division of subjects by age and experience walking on a prosthesis do suggest that older amputees and established walkers do benefit most from the use of titanium, both metabolically and mechanically. The choice of materials for use in every day walking will display differences in the mechanical work of amputees however, these differences are not great enough to realize metabolic consequences. / Thesis / Master of Science (MS)

Yes / Walking down ramps is a demanding task for transfemoral-amputees and terminating gait on ramps is even more challenging because of the requirement to maintain a stable limb so that it can do the necessary negative mechanical work on the centre-of-mass in order to arrest (dissipate) forward/downward velocity. We determined how the use of a microprocessor-controlled limb system (simultaneous control over hydraulic resistances at ankle and knee) affected the negative mechanical work done by each limb when transfemoral-amputees terminated gait during ramp descent. Methods: Eight transfemoral-amputees completed planned gait terminations (stopping on prosthesis) on a 5-degree ramp from slow and customary walking speeds, with the limb's microprocessor active or inactive. When active the limb operated in its ‘ramp-descent’ mode and when inactive the knee and ankle devices functioned at constant default levels. Negative limb work, determined as the integral of the negative mechanical (external) limb power during the braking phase, was compared across speeds and microprocessor conditions. Findings: Negative work done by each limb increased with speed (p < 0.001), and on the prosthetic limb it was greater when the microprocessor was active compared to inactive (p = 0.004). There was no change in work done across microprocessor conditions on the intact limb (p = 0.35). Interpretation: Greater involvement of the prosthetic limb when the limb system was active indicates its ramp-descent mode effectively altered the hydraulic resistances at the ankle and knee. Findings highlight participants became more assured using their prosthetic limb to arrest centre-of-mass velocity. / ZA is funded by the Higher Committee of Education Development in IRAQ (HCED student number D13 626).

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