The objective of this clinical trial is to evaluate whether a human umbilical cord amniotic membrane allograft can serve as an interposition implant in the surgical treatment of trapeziometacarpal osteoarthritis.

The main question this study aims to address is :

- Can interposition of a human umbilical cord amniotic membrane within the trapeziometacarpal joint reduces postoperative pain and improves thumb mobility, grip and pinch strength, and overall wrist function.

Participant will:

• Undergo surgical treatment of the trapeziometacarpal osteoarthritis with the interposition in articular joint of an amniotic membrane of umbilical cord allograft on Day 0
• Visit the center for a series of tests 1 month, 3 months, 6 months and 12 months after the surgical intervention.

Inclusion Criteria:

• Patient presenting with symptomatic osteoarthritis of the trapeziometacarpal joint, with wrist pain ≥ 40/100 according to the PRWE pain subscale (scaled to 100).
• Patient who has received medical treatment for functional symptoms for more than 3 months without improvement, and for whom surgical intervention is indicated.
• Patient with radiographic stage I-II trapeziometacarpal joint osteoarthritis according to the Eaton-Glickel classification.
• Patient able to understand, date, and sign the informed consent form.
• Patient affiliated with a social security system or beneficiary of such a system.

Exclusion Criteria:

• Pregnant or breastfeeding woman ; woman without effective contraception.
• Patient with scaphotrapeziotrapezoid (STT) joint osteoarthritis requiring prosthetic surgical treatment.
• Patient with thumb osteoarthritis secondary to a systemic inflammatory disease (e.g., rheumatoid arthritis).
• Patient with osteoarthritis experiencing an acute inflammatory flare, characterized by a warm, painful, and swollen joint at the time of enrollment.
• Patient with amputated hand(s).
• Patient presenting signs of neuropathy with functional impairment such as hyperesthesia. Neuropathy may be peripheral (nerve injury) or systemic (caused by diabetes or excessive alcohol consumption).
• Patient lacking capacity to participate in rehabilitation or to comply with study follow-up.
• Patient with a contraindication to anesthesia (poorly controlled epilepsy, neuropathy, etc.).
• Person deprived of liberty by a judicial or administrative decision.
• Adult subject under legal protection or unable to provide informed consent.