Thumb Hemi-Arthroplasty With Natural Kinematics (THANKS) Trial

Inclusion Criteria: * The patient is at least 18 years of age; * The patient has a confirmed Grade 1-111 osteoarthritis of the CMG joint on clinical examination and X-ray; * The patient agrees to abstain from enrolment in any other clinical trials that will conflict or interfere with the interpretation of the results of this study, in the opinion of the Investigator, for the duration of the study; * The patient is able to understand the aims and objectives of the trial and is willing to consent; * Be willing and able to return for all study-related follow-up procedures; * If female, is either using contraception or is postmenopausal, or male partner is using contraception; and * Have been informed of the nature of the study, agreeing to its requirements, and have signed the informed consent approved by the institutional review board/ethics committee. Exclusion Criteria: * The patient is \<18 years of age; * The patient is suffering from Rheumatoid Arthritis; * The patient is suffering from Grade IV osteoarthritis of the CMG joint; * The patient is suffering post-traumatic arthritis of the CMG joint; * The patient is a pregnant/lactating female (tested as per institutional requirements); * Active or latent infection, or sepsis; * Insufficient quantity or quality of bone and/or soft tissue; * Metal or polymer material sensitivity; * Patients who are unwilling or incapable of following postoperative care instructions or protocol requirements; * Muscular imbalance, peripheral vascular disease that prohibits adequate healing, or a poor soft-tissue envelope in the surgical field, absence of musculoligamentous supporting structures, or peripheral neuropathy; * Patient with previous thumb surgery; * In the opinion of the investigator, any medical condition that makes the subject unsuitable for inclusion in the study, including, but not limited to, subjects with a diagnosis of concomitant injury that may interfere with healing; subjects with clinically significant renal, hepatic, cardiac, endocrine, hematologic, autoimmune, or any systemic disease or systemic infection that may make interpretation of the results difficult; subjects who have undergone systemic administration within 30 days prior to implantation of any type of corticosteroid, antineoplastic, immunostimulating, or immunosuppressive agents; * Comorbidity that reduces life expectancy to less than 36 months.