Clinical Evaluation of the Access Socket Flexible Socket for Transtibial Prosthesis (AS-TT)
Transtibial amputation significantly impacts patient autonomy and quality of life, primarily due to the limitations of conventional rigid sockets, which restrict comfort and joint range of motion. The Access Socket (AS) is an innovative prosthetic socket combining a rigid carbon-fiber structure in key load-bearing areas with flexible urethane-resin (ProtheFLEX®) zones in regions typically rigid in conventional sockets. This hybrid design aims to improve comfort and pressure distribution while preserving the mechanical properties required for ambulation.
The AS has already demonstrated benefits in transfemoral amputees and is now reimbursed in France for that population. A preliminary uncontrolled study in 12 transtibial amputees suggested significant improvements in perceived function, comfort, satisfaction, and mobility.
This multicenter, randomized, open-label, two-arm crossover study aims to compare the (AS) with the standard rigid socket (RS) in 25 adults with transtibial amputation. Participants will wear each socket for approximately 4 weeks (after a 1-2 week adaptation period) in a randomized order. The primary outcome is the Patient Specific Functional Scale (PSFS). Secondary outcomes include comfort (SCS), satisfaction (OPUS), psychosocial adjustment (TAPES-R), mobility (PLUS-M), prosthesis utility (PEQ-U), and the proportion of patients electing to keep the AS at study completion.
Studieoversigt
Status
Intervention / Behandling
Detaljeret beskrivelse
Background. Lower-limb amputation affects more than 7,500 people annually in France, with approximately 50% at the transtibial level. The socket is the critical interface between the residual limb and the prosthesis, transmitting mechanical forces while needing to remain comfortable. Currently, only RS (carbon or resin) are listed on the French reimbursable products list (LPPR) for transtibial amputation. Documented limitations of rigid sockets include restricted knee flexion, walking discomfort in challenging environments, donning difficulties, and suboptimal pressure distribution that does not adapt to residual-limb volume changes.
Investigational device. The AS follows the same molding and shaping principles as the standard RS but differs in two manufacturing steps: (1) carbon fibers are placed only on lateral, postero-inferior, and inferior areas to provide structural rigidity; (2) stratification uses urethane resin (ProtheFLEX®, already used in medical-device manufacturing) instead of epoxy or acrylic resin, creating soft zones in regions typically rigid in conventional sockets.
Comparator. Both sockets are manufactured from the same plaster mold to ensure strictly identical internal geometry. Only the material structure (carbon/urethane distribution) differs; all other prosthetic components (intermediate piece, prosthetic foot) are identical.
Design rationale. A double-blind design is not feasible because participants can perceive differences in socket rigidity and prosthesis weight. The crossover design controls for between-subject variability and order effects.
Sample size. Based on the preliminary study (Patient Specific Functional Scale (PSFS) standard deviation 1.74), to detect a difference of 1.3 points (the PSFS MDC₉₀ for 3 items) with 80% power and α=0.05, 19 participants are required. 25 will be enrolled to account for dropouts and to provide a more representative sample for secondary endpoints.
Visits. Four study visits over approximately 14-21 weeks per participant: inclusion (V0), evaluation after first socket period (V1), evaluation after second socket period (V2), and an optional follow-up visit (V3) one month later if the participant elects to keep the AS.
Undersøgelsestype
Tilmelding (Anslået)
Fase
- Ikke anvendelig
Kontakter og lokationer
Studiekontakt
- Navn: Isabelle Loiret, MD
- Telefonnummer: +33383529950
- E-mail: isabelle.loiretpro@gmail.com
Undersøgelse Kontakt Backup
- Navn: Jonathan Pierret, PhD
- E-mail: jonathan.pierret@ugecam.assurance-maladie.fr
Studiesteder
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Clamart, Frankrig, 92140
- Rekruttering
- Hôpital National d'Instruction des Armées (HNIA) Percy
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Ledende efterforsker:
- Marie Thomas-Pohl, MD
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Kontakt:
- Marie Thomas-Pohl, MD
- Telefonnummer: +33 1.41.46.62.82
- E-mail: marie.thomas@intradef.gouv.fr
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Freyming-Merlebach, Frankrig, 57804
- Rekruttering
- Hôpital Filieris de Freyming-Merlebach
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Kontakt:
- Catherine Achour, MD
- Telefonnummer: +33 3 83 52 98 61
- E-mail: catherine.achour@filieris.fr
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Ledende efterforsker:
- Catherine Achour
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Grenoble, Frankrig, 38434
- Rekruttering
- CHU Grenoble Alpes - Hôpital Sud
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Kontakt:
- Solène Maret, MD
- Telefonnummer: +33 4 76 76 60 25
- E-mail: smaret2@chu-grenoble.fr
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Ledende efterforsker:
- Solène MAret, MD
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Underforsker:
- Phillipe Escobar, MD
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Nancy, Frankrig, 54000
- Rekruttering
- Institut Régional de Médecine Physique et de Réadaptation (IRR) - Filière Locomoteur
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Ledende efterforsker:
- Isabelle Loiret, MD
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Kontakt:
- Jonathan Pierret, PhD
- E-mail: jonathan.pierret@ugecam.assurance-maladie.fr
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Kontakt:
- Christelle REQUENA
- Telefonnummer: +33 3 83 52 98 61
- E-mail: christelle.requena@ugecam.assurance-maladie.fr
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Paris, Frankrig, 75007
- Rekruttering
- Insititution Nationale des Invalides
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Kontakt:
- Joseph Bascou, PhD
- Telefonnummer: +33 3 87 51 30 30
- E-mail: joseph.bascou@invalides.fr
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Deltagelseskriterier
Berettigelseskriterier
Aldre berettiget til at studere
- Voksen
- Ældre voksen
Tager imod sunde frivillige
Beskrivelse
Inclusion Criteria:
- Unilateral or bilateral transtibial amputation
- Currently fitted with a definitive carbon rigid socket
- Any residual-limb shape
- Any etiology
- Able to understand simple instructions, read, write, and provide informed consent - or able to be accompanied by a trusted person in case of inability to read/write autonomously
- Provided free written informed consent
- Aged 18 years or older
- Affiliated to a social security system
Exclusion Criteria:
- Use of hydroalcoholic solution (HAS) for socket donning
- Currently fitted with a provisional socket
- Neurological pathology limiting capacity to participate in activities
- Orthopedic pathology limiting capacity to participate in activities
- Pregnant or breastfeeding women
- Minors
- Persons not under legal protection or unable to express consent
- Persons under guardianship or curatorship
- Persons under judicial protection
Studieplan
Hvordan er undersøgelsen tilrettelagt?
Design detaljer
- Primært formål: Behandling
- Tildeling: Randomiseret
- Interventionel model: Crossover opgave
- Maskning: Ingen (Åben etiket)
Våben og indgreb
Deltagergruppe / Arm |
Intervention / Behandling |
|---|---|
|
Aktiv komparator: Group 1 (RS -> AS)
Participants wear their standard rigid socket (RS) for 4 weeks, complete evaluation, then switch to the Access Socket (AS) for 1-2 weeks of adaptation followed by 4 weeks of wear, with a second evaluation.
|
Hybrid prosthetic socket combining a rigid carbon-fiber structure in load-bearing areas (lateral, postero-inferior, inferior) with flexible urethane-resin (ProtheFLEX®) zones in regions typically rigid in conventional sockets.
Manufactured from the same plaster mold as the rigid socket to ensure identical internal geometry.
Conventional definitive carbon-fiber rigid socket, currently the only socket type reimbursed in France for transtibial amputation (LPPR-listed).
Standard of care comparator.
|
|
Aktiv komparator: Group 2 (AS -> RS)
Participants receive the Access Socket (AS) first, with 1-2 weeks of adaptation followed by 4 weeks of wear and evaluation.
They then switch to the standard rigid socket (RS) for 1-2 weeks of adaptation and 4 weeks of wear, with a second evaluation.
|
Hybrid prosthetic socket combining a rigid carbon-fiber structure in load-bearing areas (lateral, postero-inferior, inferior) with flexible urethane-resin (ProtheFLEX®) zones in regions typically rigid in conventional sockets.
Manufactured from the same plaster mold as the rigid socket to ensure identical internal geometry.
Conventional definitive carbon-fiber rigid socket, currently the only socket type reimbursed in France for transtibial amputation (LPPR-listed).
Standard of care comparator.
|
Hvad måler undersøgelsen?
Primære resultatmål
Resultatmål |
Foranstaltningsbeskrivelse |
Tidsramme |
|---|---|---|
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Patient Specific Functional Scale (PSFS) score
Tidsramme: One time at the end of each 4-week wear period (V1, V2 and V3)
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Patient-centered self-report tool.
The patient identifies 3-5 specific activities they have difficulty performing, then rates their ability on a 0-10 scale (0 = unable to perform, 10 = able to perform at pre-injury level).
The final score is the mean of the ratings
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One time at the end of each 4-week wear period (V1, V2 and V3)
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Sekundære resultatmål
Resultatmål |
Foranstaltningsbeskrivelse |
Tidsramme |
|---|---|---|
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Socket Comfort Scale (SCS) score
Tidsramme: One time at the end of each 4-week wear period (V1, V2 and V3)
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0-10 numerical rating of socket comfort (0 = least comfortable imaginable, 10 = most comfortable imaginable)
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One time at the end of each 4-week wear period (V1, V2 and V3)
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Orthotics Prosthetics Users Survey (OPUS) score
Tidsramme: One time at the end of each 4-week wear period (V1, V2 and V3)
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Self-report instrument evaluating functional outcomes and quality of life specifically for orthosis and prosthesis users.
Assesses lower-limb functional status, health-related quality of life, satisfaction with the device, and satisfaction with services.
The higher the score, the more favorable the result for the device
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One time at the end of each 4-week wear period (V1, V2 and V3)
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Trinity Amputation and Prosthesis Experience Scale - Revised (TAPES-R) score
Tidsramme: One time at the end of each 4-week wear period (V1, V2 and V3)
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33-item multidimensional questionnaire evaluating psychosocial adjustment to amputation and prosthesis use, including general adjustment, social adjustment, activity restriction, and prosthesis satisfaction.
The higher the global score, the more favorable the result for the device
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One time at the end of each 4-week wear period (V1, V2 and V3)
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Prosthesis Evaluation Questionnaire - Utility subscale (PEQ-U) score
Tidsramme: One time at the end of each 4-week wear period (V1, V2 and V3)
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The score is calculated as the mean of the 8 items in the subscale.
Each item is rated on a Visual Analogue Scale (VAS) from 0 to 100.
The total score ranges from 0 to 100, where higher scores indicate a better outcome (greater satisfaction and prosthesis utility)
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One time at the end of each 4-week wear period (V1, V2 and V3)
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Proportion of participants electing to keep the Access Socket at study completion
Tidsramme: Through study completion, an average of 10 weeks
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Percentage of participants who choose the AS over the RS at the end of the study, reported with 95% confidence interval.
Participants are not informed of this option until the end of the study to avoid judgment bias
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Through study completion, an average of 10 weeks
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Samarbejdspartnere og efterforskere
Samarbejdspartnere
Efterforskere
- Ledende efterforsker: Isabelle Loiret, MD, Institut Régional de Médecine Physique et de Réadaptation (IRR), Nancy, France
Datoer for undersøgelser
Studer store datoer
Studiestart (Faktiske)
Primær færdiggørelse (Anslået)
Studieafslutning (Anslået)
Datoer for studieregistrering
Først indsendt
Først indsendt, der opfyldte QC-kriterier
Først opslået (Faktiske)
Opdateringer af undersøgelsesjournaler
Sidste opdatering sendt (Faktiske)
Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier
Sidst verificeret
Mere information
Begreber relateret til denne undersøgelse
Nøgleord
Andre undersøgelses-id-numre
- 2026-A00019-42
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IPD-planbeskrivelse
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