Background The trapeziometacarpal (TMC) joint plays an important role in routine tasks. However, little consensus exists on the composition of its ligaments and their contribution to joint stability. 
Aim This thesis aimed to develop a physical model of the TMC joint to investigate the influence of ligaments on joint stability. 
Method The model was constructed using 3D-printed bones and ligaments represented by Dyneema rope, actuated through tendon routing. Its kinematics were compared to subject-specific in-vivo data from 4D CT. Both active and passive actuation trials were performed. 
Results The model successfully reproduced circumduction motion, but its range of motion deviated from in-vivo results. Active and passive actuation produced comparable outcomes for circumduction, but discrepancies in pure motions revealed an oversimplification of the actuation system. 
Conclusion This thesis presents, to the best of the author’s knowledge, the first physical model of the TMC joint. Although simplifications in ligament representation and actuation reduced anatomical accuracy, it lays the foundation for further research and clinical application in thumb biomechanics.

Goal: Nerve injury is a typical complication of a fasciectomy, a surgical treatment for Dupuytren's contracture. This research focuses on the creation of a surgical device to prevent this medical complication.
Design: A mechanical feedforward-based device with a spreading and cutting mechanism was proposed. Stretching the target tissue causes a larger biomechanical difference between this tissue and the nerves. This helps to avoid damaging the nerves during the dissection phase. The DisDis prototype with a precision handling grip was develop. It uses a nitinol tube for the spreading mechanism and a conventional scalpel for the cutting mechanism.
Evaluation: The performance and ergonomics of the prototype are disappointing, compared to the conventional fasciectomy dissection method. Despite this unfavourable result, it is thought that mechanical feedforward-based devices could be still make a positive impact.