The general objective of this study is to assess the performance and safety of the KeriFlex® silicone joint implant and its associated instruments, used in accordance with the labeling and instructions in force.

The performance and safety of the KeriFlex® joint implant will be established in the short and long term with regard to the life cycle of the implant.

Inclusion Criteria:

• Adult patients (age ≥ 18 years)
• Patients who are going to undergo arthroplasty of the metacarpophalangeal or proximal interphalangeal joint using a KeriFlex® implant in accordance with the instructions for use and the labelling in force.
• Patients with rheumatoid arthritis, osteoarthritis or post-traumatic osteoarthritis

Exclusion Criteria:

• Pregnant or breastfeeding women
• Patients with an intellectual disability who cannot follow their surgeon's instructions
• Patients with general surgery contraindications and particularly to the implantation of a KeriFlex® implant
• Patients with acute or chronic, local or systemic infections
• Metacarpal or phalanx destruction or poor bone quality preventing adequate fixation
• Muscle loss, alteration or vascular deficiency in the affected finger
• Patients with significant physical activity involving treated joint
• Children, young growing patients with open epiphyses

Any type of population requiring a surgical procedure covered by the device and presenting bone quality deemed satisfactory by the surgeon.