Clinical and cost-effectiveness of flexor digitorum profundus (FDP) versus FDP and flexor digitorum superficialis (FDS) repair for complete zone 2 flexor tendon injuries (FLARE): protocol for a randomised controlled trial

Background

Flexor tendon injuries are common and lead to over 3200 admissions for specialist surgical repair annually in England and Wales. Surgery to repair complete division of both flexor tendons in zone 2 of the hand is technically challenging. There is variation in surgical repair techniques with no high-quality evidence to support decision-making. In particular, the decision to repair both tendons or just one is contested. Surgery is followed by specialist rehabilitation, which takes at least 12 weeks. The resulting hand function can impact the patient’s income, life satisfaction, well-being, self-worth, and mental health. The FLARE trial aims to determine the clinical and cost-effectiveness of repairing the flexor digitorum profundus (FDP) alone (intervention) versus the repair of both FDP and flexor digitorum superficialis (FDS) (control) for the treatment of complete zone 2, single-digit flexor tendon injuries in adults.

Methods

A multi-centre, two-arm, blinded, non-inferiority, parallel group, randomised controlled trial with an internal pilot, economic evaluation, and nested qualitative study. Participants will be randomised 1:1 to receive either repair of FDP alone or repair of both FDP and FDS. A total of 310 adults will be recruited from NHS Trusts within the UK, randomised at surgery, and followed up within 7 days, 6 weeks, 3 months, and 6 months post-randomisation. The primary outcome measure is the patient evaluation measure (PEM) administered 6 months post-randomisation. Secondary outcomes include the PEM at other timepoints, Patient Related Wrist/Hand Evaluation (PRWHE), EuroQol 5 Dimensions Score (EQ-5D-5L), complications, total range of motion, grip strength, adherence to splint and therapy regimens, work outcomes, treatment and outcome satisfaction, and healthcare resource use.

Discussion

FLARE is designed with sufficient power and rigour to provide evidence on the clinical and cost-effectiveness of two surgical repair methods for single-digit, complete zone 2 flexor tendon injuries in adults. If the repair of FDP alone is as beneficial to the patient as the repair of FDP and FDS, this could save the NHS £1.8 million annually through reduced time and material costs. Furthermore, the trial findings will facilitate better shared decision-making discussions between clinicians and patients.

Trial registration

ISRCTN 10918157. Prospectively registered: 12.01.2023.