Lower limb amputation has a definitive impact on a person's locomotor abilities, considerably reducing his or her autonomy in everyday life. 50% of lower limb amputees in France are trans-femoral. The femoral prosthesis must be adapted to allow the amputee to walk in everyday situations and to make the range of activities practiced by non-amputees accessible to them. Sitting posture, which represents an important part of a day, must also be comfortable.

Comfort will be closely linked to the socket, which ensures the transmission of the mechanical actions of the prosthesis to the body of the amputee through the residual limb. This must be done without damaging the integrity of the biological tissues at the interface. The challenge is therefore to transmit the mechanical actions inherent to the use of the prosthesis while being as comfortable as possible. The most common form of femoral socket is the one with included ishions, which by its structure limits the rotation of the socket around the residual limb. However, it limits hip joint amplitudes, which significantly impacts comfort during walking, especially when the individual must evolve in constraining environments (irregular terrain, slopes, uphill, downhill). Comfort is also limited when putting the prosthesis in place and when sitting, because of the limits of the socket that go up into the groin and the buttock. Discomfort can also be induced by contact and clamping surfaces.

Only 42% of amputees are satisfied with their sockets. An uncomfortable or wound-inducing brace will not be worn or will be worn only a little, which can increase the risk of comorbidities. One solution to the comfort issue could be the Access Socket (AS) soft socket, which is exactly the same shape and manufacturing principles as the Rigid Included Carbon Socket (ER), but combines a rigid structure with soft areas. These soft areas allow pressure to be distributed within the socket, allowing for some deformation, while maintaining the mechanical properties necessary for walking.

The objective of this study is to compare the comfort perceived by amputees when wearing an AS soft socket versus their RE, both sockets being mounted identically on the patients' usual medical devices.

The hypothesize is that scores on the various comfort, satisfaction, and mobility scales should be better when patients wear the soft socket compared to the rigid socket.

In this multicenter, randomized, cross-over study, patients will wear the rigid socket and then the access-socket (or vice versa), over a 4-week period for each socket. The two sockets will have an identical shape and will be mounted in the same way on the patients' medical device. At the end of each 4-week period, patients will fill out self-questionnaires (PEQ, SCS, PLUS-M, ESAT and SF-36) to evaluate their comfort, satisfaction and ambulation.

Inclusion Criteria:

• Unilateral or bilateral trans-femoral amputees;
• Fitted with a rigid carbon insert;
• Any type of stump;
• Any etiology;
• Person able to understand simple commands, to read, write and give informed consent or having the possibility to be accompanied by a trusted person in case of inability to write or read independently;
• Person who has given informed consent;
• Person who has reached the age of 18 years;
• Person affiliated to the french social security system

Exclusion Criteria:

• Fitted with a collar fixed on a socket
• Using SHA for inserting the insert;
• Pregnant or nursing woman;
• Minor;
• Person of full age under legal protection or unable to give consent;
• Person under guardianship or curatorship;
• Person under legal protection.