Introduction. Trapeziometacarpal osteoarthritis (TMC OA) is a degenerative condition characterized by pain, stiffness, and reduced hand function, significantly impairing daily activities. Non-surgical management strategies include activity modifications, nonsteroidal anti-inflammatory drugs (NSAIDs), splinting, and corticosteroid injections. When conservative treatments fail, surgical options are considered. The Eaton-Littler classification stratifies TMC OA into four stages based on radiographic joint degeneration.

ChondroFiller Liquid®, a cell-free collagen scaffold composed of native type I collagen and chondrostimulating factors, facilitates cartilage regeneration by creating a protective environment for chondrocyte proliferation. It is indicated for treating cartilage lesions up to 3 cm². A prior study demonstrated its efficacy in alleviating pain, improving grip strength (Jamar test and pinch test), and enhancing Patient-Reported Outcome Measures (PROMs) using the Disabilities of the Arm, Shoulder, and Hand (DASH) score.

Aims. This study aims to extend the follow-up to 24 months to evaluate the long-term sustainability of clinical improvements following ChondroFiller Liquid® infiltration.

Materials and Methods. A total of 40 patients from the initial study were enrolled and categorized into two severity groups based on the Eaton-Littler classification. Clinical evaluations were conducted at 18 months post-infiltration (T1) using the Numeric Rating Scale (NRS) and DASH score. A subsequent assessment at 24 months (T2) included the Jamar test, pinch test, NRS, and DASH score. An additional cohort of 51 patients underwent infiltration with a mean follow-up of 14 months, including 9 patients previously treated in the preliminary study.

Inclusion Criteria:

• patients with rhizarthrosis diagnosed on X-rays performed in the last year;
• patients aged > 18 years;
• enrollment in the study through informed consent;

Exclusion Criteria:

• patients who have undergone cortisone and/or hyaluronic acid infiltrations in the last 6 months;
• patients following trauma involving the ATM;
• patients with underlying rheumatological diseases;
• patients under 18 years of age
• ongoing pregnancy;
• patients affected by metabolic disorders (e.g. diabetes)

All participants were adults with unilateral or bilateral RA, diagnosed via radiographs obtained within the past year. Participation in the study required signing an informed consent form.