1. Introduction:

   Investigators think that surgery with preservation of healthy joints (hemitrapeziectomy) in trapeziometacarpal osteoarthritis without affecting sapho-trapezo-trapezoid joints, is better for scaphoid stability by preventing its collapse and thus preserving the stability of the carpus.

2. Objectives and Hypothesis:

   Ligamentoplasty with partial trapeziectomy in grades II-III Eaton presents better results in the pollicis-lateral pinch (key pinch) strength than ligamentoplasty with total trapeziectomy.

   Main Objective:

   To demonstrate using the dynamometer that the postoperative key pinch strength higher using ligamentoplasty with partial trapeziectomy in grades II-III Eaton.

   Secondary objectives:

   To measure the collapse of the first column of thumb using calibrated radiographic analysis. Pain (E.V.A Scale). Range of motion (measured with goniometer). Quality of life (DISABILITIES OF THE ARM, SHOULDER AND HAND questionnaire).

3. Methodology:

It is a single-center randomized trial, parallel-group, in which two types of surgical techniques (TT - TP) will be compared. Patients will be randomized in this two techniques will be followed for one year, in routine clinical practice.

Inclusion Criteria:

• Patients with Osteoarthritis in the trapeziometacarpal joint determined by the classification of Eaton-Littler (stages II-III) with trapeziometacarpal joint pain, loss of function, that were included in surgical waiting list and have accepted under informed consent, including the study.

Exclusion Criteria:

• Patients with osteoarthritis Eaton-Littler (stage IV).
• Patients with huge affection of trapezium subchondral cysts and poor quality of trabecular bone.
• Cognitive impairment.
• Old fracture with impairment of the same extremity.
• Rheumatic active illness.
• Patients who withdraw their informed consent, or in case of impossibility of opinion by clinical status, whose legal guardians or close relatives to withdraw their informed consent to participate in the study.
• Patients who for any reason not related to the indication needed discontinue study participation or impossible to carry out assessments under more than two follow-up visits.
• Patients in whom it is considered that participation in the clinical study can be a prejudice, the physician responsible for patient care opinion.