Collagen is a structural protein biopolymer consisting of three polypeptide chains wrapped around to form a right-handed triple helix. Its structure, characterized by the presence of glycine every third residue, a high content of proline and hydroxyproline, is stabilized by interchain hydrogen bonds and electrostatic interactions, giving the molecules high mechanical resistance, incompressibility, and simultaneously, extensibility, plasticity, and flexibility, making tissues abundant in collagen particularly resistant to stress and load. In humans, collagen is present especially in the skin, subcutaneous tissue, cartilage, bone, joint capsule, tendons, muscles, and ligaments. Growing evidence supports the infiltrative use of type I collagen in the treatment of musculoskeletal pathologies. In particular, the intra-articular and peri-articular use of collagen has been proposed in the treatment of osteoarthritis in various body districts with the intention of limiting joint hypermobility, stabilizing the structure of joint and peri-articular components, reducing pain, and consequently improving function. Several clinical studies have demonstrated that its intra-articular infiltrative use could result in pain reduction and improvement of functionality in various cases of gonarthrosis and coxarthrosis. Regarding the conservative management of symptomatic thumb base osteoarthritis, some studies, albeit on limited case series, have highlighted how the use of type I collagen at the joint and peri-articular level can lead to better control of painful symptoms, improvement in functionality, and reduction of joint instability. Recently, Randelli F. et al. studied the in vitro effects on tenocytes induced by type I swine collagen (MD-Tissue Collagen Medical Device). In vitro results seem to demonstrate that this medical device can induce proliferation and migration of tenocytes and synthesis, maturation, and secretion of type I collagen, favoring tendon repair. Randelli F. et al. also demonstrated the mainly mechanical activity of MD-Tissue Collagen Medical Device, which is able to induce modifications of morpho-functional properties of tenocytes. In this Clinical Investigation, we aim to investigate the performance and safety of an injectable medical device based on type I collagen of swine origin called MD-Small Joints Collagen Medical Device, in the treatment of symptomatic thumb base osteoarthritis. The purpose of this research project is to understand through a multicenter Clinical Investigation, the performance and safety of an intra-articular and peri-articular treatment with a medical device (MD-Small Joints Collagen Medical Device) based on type I collagen in terms of pain reduction and joint function recovery in subjects with symptomatic thumb base osteoarthritis. The primary endpoint will consist of evaluating, through the Visual Analogue Scale (VAS), the performance of MD-Small Joints Collagen Medical Device in reducing pain associated with trapeziometacarpal osteoarthritis, at time T6 weeks (T6w) compared to T0 (day0). A reduction of at least 30% in the VAS score is considered clinically significant. Secondary endpoints will consist of evaluating the performance of MD-Small Joints Collagen Medical Device through: * VAS score assessment at T3 week and T16week /FU compared to T0; * Disability of the Arm Shoulder and Hand score assessment at T6 week and T16 week /FU compared to T0 (day0); * Functional Index for Hand Osteoarthritis assessment at T6 week and T16 week /FU compared to T0; * Pinch Strength Test assessment at T6 week and T16 week/FU compared to T0; * Evaluation of analgesic drug consumption through clinical diary in various study phases; * Assessment of Adverse Event incidence.