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.
Descripción general del estudio
Estado
Intervención / Tratamiento
Descripción detallada
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.
Tipo de estudio
Inscripción (Estimado)
Fase
- No aplica
Contactos y Ubicaciones
Estudio Contacto
- Nombre: Isabelle Loiret, MD
- Número de teléfono: +33383529950
- Correo electrónico: isabelle.loiretpro@gmail.com
Copia de seguridad de contactos de estudio
- Nombre: Jonathan Pierret, PhD
- Correo electrónico: jonathan.pierret@ugecam.assurance-maladie.fr
Ubicaciones de estudio
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Clamart, Francia, 92140
- Reclutamiento
- Hôpital National d'Instruction des Armées (HNIA) Percy
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Investigador principal:
- Marie Thomas-Pohl, MD
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Contacto:
- Marie Thomas-Pohl, MD
- Número de teléfono: +33 1.41.46.62.82
- Correo electrónico: marie.thomas@intradef.gouv.fr
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Freyming-Merlebach, Francia, 57804
- Reclutamiento
- Hôpital Filieris de Freyming-Merlebach
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Contacto:
- Catherine Achour, MD
- Número de teléfono: +33 3 83 52 98 61
- Correo electrónico: catherine.achour@filieris.fr
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Investigador principal:
- Catherine Achour
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Grenoble, Francia, 38434
- Reclutamiento
- CHU Grenoble Alpes - Hôpital Sud
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Contacto:
- Solène Maret, MD
- Número de teléfono: +33 4 76 76 60 25
- Correo electrónico: smaret2@chu-grenoble.fr
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Investigador principal:
- Solène MAret, MD
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Sub-Investigador:
- Phillipe Escobar, MD
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Nancy, Francia, 54000
- Reclutamiento
- Institut Régional de Médecine Physique et de Réadaptation (IRR) - Filière Locomoteur
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Investigador principal:
- Isabelle Loiret, MD
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Contacto:
- Jonathan Pierret, PhD
- Correo electrónico: jonathan.pierret@ugecam.assurance-maladie.fr
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Contacto:
- Christelle REQUENA
- Número de teléfono: +33 3 83 52 98 61
- Correo electrónico: christelle.requena@ugecam.assurance-maladie.fr
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Paris, Francia, 75007
- Reclutamiento
- Insititution Nationale des Invalides
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Contacto:
- Joseph Bascou, PhD
- Número de teléfono: +33 3 87 51 30 30
- Correo electrónico: joseph.bascou@invalides.fr
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Criterios de participación
Criterio de elegibilidad
Edades elegibles para estudiar
- Adulto
- Adulto Mayor
Acepta Voluntarios Saludables
Descripción
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
Plan de estudios
¿Cómo está diseñado el estudio?
Detalles de diseño
- Propósito principal: Tratamiento
- Asignación: Aleatorizado
- Modelo Intervencionista: Asignación cruzada
- Enmascaramiento: Ninguno (etiqueta abierta)
Armas e Intervenciones
Grupo de participantes/brazo |
Intervención / Tratamiento |
|---|---|
|
Comparador activo: 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.
|
|
Comparador activo: 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.
|
¿Qué mide el estudio?
Medidas de resultado primarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
|
Patient Specific Functional Scale (PSFS) score
Periodo de tiempo: 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
|
One time at the end of each 4-week wear period (V1, V2 and V3)
|
Medidas de resultado secundarias
Medida de resultado |
Medida Descripción |
Periodo de tiempo |
|---|---|---|
|
Socket Comfort Scale (SCS) score
Periodo de tiempo: 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
Periodo de tiempo: 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
Periodo de tiempo: 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
Periodo de tiempo: 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
Periodo de tiempo: 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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Colaboradores e Investigadores
Colaboradores
Investigadores
- Investigador principal: Isabelle Loiret, MD, Institut Régional de Médecine Physique et de Réadaptation (IRR), Nancy, France
Fechas de registro del estudio
Fechas importantes del estudio
Inicio del estudio (Actual)
Finalización primaria (Estimado)
Finalización del estudio (Estimado)
Fechas de registro del estudio
Enviado por primera vez
Primero enviado que cumplió con los criterios de control de calidad
Publicado por primera vez (Actual)
Actualizaciones de registros de estudio
Última actualización publicada (Actual)
Última actualización enviada que cumplió con los criterios de control de calidad
Última verificación
Más información
Términos relacionados con este estudio
Palabras clave
Otros números de identificación del estudio
- 2026-A00019-42
Plan de datos de participantes individuales (IPD)
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Descripción del plan IPD
Información sobre medicamentos y dispositivos, documentos del estudio
Estudia un producto farmacéutico regulado por la FDA de EE. UU.
Estudia un producto de dispositivo regulado por la FDA de EE. UU.
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