Maria Wilcke

Flexor tendon injuries are treated within specialized hand surgery due to the high demands for strong surgical tendon repair and controlled rehabilitation after surgery. It is significantly more common for a repaired thumb flexor tendon to rupture (up to 17%) compared to the same injury in the fingers (approximately 3%). This difference may be due to variations in anatomy and biomechanics. In current clinical practice, all tendon injuries are rehabilitated with early active motion training, which begins a few days after surgery. Objective The aim of this study is to investigate whether the rate of ruptures after flexor tendon injury in the thumb can be reduced by immobilizing the thumb in a cast for the first four weeks after surgery, delaying the start of motion training until after this period. Implementation All patients in Sweden with flexor tendon injuries are followed up regarding function and patient satisfaction at 3 and 12 months in HAKIR, the national quality register for hand surgery, in which all seven specialist clinics participate. In this study, we will create a function within the quality register that allows patients to be randomly assigned (randomized) to either early active motion training or immobilization of the thumb in a cast for four weeks. A total of 380 patients will be included in the study, which is expected to take 6–7 years to complete. Expected Results We aim to determine whether immobilizing the thumb for one month after surgery for a flexor tendon injury can reduce the risk of tendon rupture and whether this leads to increased stiffness in the thumb. If so, we will assess whether this stiffness affects hand function. Practical Implications If we can reduce the rate of tendon ruptures, it would be a significant benefit for both patients and society, as reoperation leads to increased suffering and work incapacity for patients, often resulting in worse final outcomes and higher healthcare costs. An additional important benefit of this study is the establishment of a system within the quality register for conducting randomized registry studies, which can later be applied to other medical questions within hand surgery.