Registry-randomized Comparison of Rehabilitation Regimens After Flexor Pollicis Longus Injury in the Thumb

Flexor tendon injuries in the thumb occur across all ages and genders. Each year, approximately 400 patients undergo surgery for a flexor tendon injury in Sweden. These injuries are exclusively treated at one of the seven specialized hand surgery clinics, as the surgery is technically demanding, and postoperative rehabilitation is critical, specialized, and requires expertise from hand therapists. To prevent tendon adhesions and stiffness in the thumb or fingers, controlled active motion therapy is usually initiated within a few days after surgery. Studies on finger flexor tendon injuries have shown that early active movement therapy leads to better mobility compared to immobilization. Consequently, early active training is now the standard treatment following flexor tendon repair. However, during postoperative rehabilitation, the repaired flexor tendon may rupture, often necessitating revision surgery.

The rupture rate after flexor tendon repair in the thumb is approximately three times higher than in other fingers (10% vs. 3%). While most studies on flexor tendon injuries focus on finger tendons, research on the outcomes of thumb flexor tendon injuries is limited. The biomechanics and anatomy of the thumb's flexor tendon differ significantly from those of finger tendons.

The objective of this study is to determine whether the rupture rate following thumb flexor tendon surgery can be reduced by immobilizing the thumb in a cast for four weeks postoperatively, compared to standard early active motion therapy, without negatively affecting joint mobility and thumb strength. Additionally, the study will evaluate patient-reported outcomes one year post-surgery for both rehabilitation regimens (immobilization vs. mobilization).

This study is a registry-randomized clinical trial (RRCT) involving five hand surgery clinics in Sweden. Data following randomization between the two rehabilitation protocols will be collected through follow-up in the Swedish National Hand Surgery Quality Registry (HAKIR).