The aim of this open, prospective, multicenter trial is to evaluate the use of a sterile, devitalized, processed umbilical cord amniotic membrane implant placed in joint interposition in the treatment of STT osteoarthritis.

Inclusion Criteria:

• Male or female; age between 18 and 75 years.
• Patient with symptomatic STT OA.
• Patient treated medically for functional signs for more than 3 months, without improvement, justifying a surgical intervention.
• Patient with a QuickDash score > 33 points (converted to 50%).
• Patient with wrist pain in front of the STT joint at rest = or > 4/10 on VAS.
• Patient who received the study information and provided consent.
• Member or beneficiary of a national health insurance plan.

Exclusion Criteria:

• Pregnant or breastfeeding woman; woman without effective contraception.
• Patient with functional rhizarthrosis that has not been stabilized or treated medically or surgically.
• Patient with signs of neuropathy with functional disorders such as hyperesthesia.
• Patient with uncontrolled epilepsy or neuropathy that contraindicates locoregional anesthesia.
• Person confined by a judicial or administrative decision.
• Adult subjected to legal protection measures or unable to provide his/her consent.