PhD defence I.W.F. (Ingmar) Legerstee

Below is a brief summary of the dissertation:

This thesis evaluated treatment outcomes for injuries of the thumb metacarpophalangeal (MCP) joint to better support clinical decision-making. A systematic review showed that different surgical techniques for primary repair of ulnar collateral ligament (UCL) ruptures result in comparable and generally favorable outcomes. Immobilization with K-wires caused more pain without clear improvement in stability or function compared with cast or splint immobilization.

Biomechanical and diagnostic aspects of UCL injury were also investigated. The shape of the metacarpal head was not associated with an increased risk of UCL rupture. In avulsion fractures, fragment size varied considerably relative to ligament insertion length. Joint instability, rather than fragment size, appeared to be the key factor guiding surgical decision-making.

Operative and nonoperative treatments for UCL and radial collateral ligament (RCL) injuries, chronic instability, and osteoarthritis were further evaluated. Both primary repair and tendon graft reconstruction improved clinical and patient-reported outcomes at 12 months. Primary repair also yielded good results when surgery was delayed up to six months. In addition, UCL reconstruction may be valuable in early MCP osteoarthritis. For RCL avulsion fractures, successful nonoperative treatment was achieved even in patients with clear fragment displacement, suggesting that joint instability is a more important indication for surgery than fragment displacement. Finally, screw fixation for MCP arthrodesis was associated with fewer hardware-related complications than K-wire fixation. Future research should focus on nonoperative treatment options for unstable UCL and RCL injuries to further clarify the role of joint instability in treatment selection.