Biomechanical Evaluation With Finite Element Models in Thumb Carpometacarpal Osteoarthitis: Prospective Comparative Analysis of Loads in Arthroplasty With or Without Implants

Biomechanical Evaluation With Finite Element Models in Thumb Carpometacarpal Osteoarthitis: Prospective Comparative Analysis of Loads in Arthroplasty With or Without Implants

To better understand the load distribution in the Thumb Carpometacarpal Joint (CMC joint) in presence of osteoarthritis and how surgery by means of a suspension-resection arthroplasty or a joint replacement by means of a metal prosthesis affects this load distribution. These studies allow to supporting medical decisions and surgical treatments results with biomechanical evidence.The clinical management of the patients will be adapted to the treatment standards of the Orthopedic Surgery and Traumatology Service of the Hospital de la Santa Creu i Sant Pau, without the performance of this study influencing this process.

For determine the normal kinematics of the thumb carpometacarpal (CMC) joint, Imaeda et al. (1994) examined in specimens four conditions which simulated normal function of the thumb: a) passive circumduction, b) active circumduction, c) static loading, and d) single-axis loading. Changes in normal kinematics predispose the CMC joint to osteoarthritis (OA). Previous studies used radiographic techniques that usually were static or measured the end range of motion.

For thumb CMC joint OA the prosthesis or total joint arthroplasty is one of the surgical option. Murai (2022) studied in ten healthy men with reconstruction 3D bone models the optimal center of rotation of the implant and found that the center of rotation change across various thumb positions. In the study by D´Agostino et al. (2018) a CT scan was used to quantify the 3D thumb kinematics in four female patients, before and after trapeziometacarpal joint replacement surgery with the Arpe implant. Thumb CMC joint OA led to a marked decrease of internal rotation and abduction of the first metacarpal during thumb flexion and a decrease of metacarpal adduction during thumb adduction. The abcense of first metacarpal translation in the ball-and-socket implant seems to indicate a decrease of first metacarpal adduction. Advanced thumb CMC joint OA mainly restrict the first metacarpal mobility. Whereas prosthesis is able to restore thumb function, it cannot fully replicate the kinematics of the healthy trapeziometacarpal joint.

This study will include 40 adults patients with chronic pain and carpometacarpal osteoarthritis that need surgical intervention. For the biomechanical evaluation, 3D modeling and finite element methods of evaluation of the CT scan before and after the surgical intervention in each patient will be performed with the computed specific software Epylisis and Ansys in Dimension Lab 3D, Hospital de la Santa Creu i Sant Pau by biomedical engineers.

The source of information is the journals and journals specialized in hand surgery, bioengineering, biotechnology and biomedical engineering.

The principal investigator and collaborators are responsible for creating the database and entering data. Statistical analysis requires support from the statistics unit of the UICEC/Hospital de la Santa Creu i Sant Pau. All data will be collected in REDCap.

Inclusion Criteria:

• Primary Osteoarthritis in thumb CMC joint in the hand
• Adults aged between 50 and 88 years old included.
• Thumb CMC joint osteoarthritis, radiographic stages II, III and IV by Eaton- Littler classification (1973).

Exclusion Criteria:

• Asymptomatic primary osteoarthritis in thumb CMC joint
• Patients with osteoarthritis and age less than 50 years or more than 88 years.
• Patients who have had previous interventions in the area, in this joint, injuries in this hand or fractures.
• Patients with rheumatic diseases or collagen diseases that create joint instability.
• Patients with physical or mental conditions that preclude intervention.
• Thumb CMC joint osteoarthritis, radiographic stages I by Eaton-Littler classification (1973)