A Novel Flexor Tendon Reconstruction Technique in Children: A Potential Solution for a Rare Problem

BACKGROUND: Distal tendon graft fixation during 2-stage flexor tendon reconstruction in children remains challenging due to open physes, small phalangeal dimensions, and relatively soft bone. Although several fixation techniques have been described, biomechanical data regarding tendon-to-bone fixation in pediatric specimens are scarce. AIM: To evaluate the biomechanical properties of a novel palmaris longus-flexor digitorum profundus-anchor (PL-FDP-A) construct intended for distal tendon graft fixation during 2-stage flexor tendon reconstruction in pediatric patients. METHODS: Nine digits from pediatric donors aged 10 to 14 years and 9 palmaris longus tendons harvested from adult cadavers were used. A tendon graft was passed through the flexor sheath and attached to the distal FDP stump using a soft bone anchor inserted into the distal phalanx and a 3-strand locked suture configuration. Constructs were tested using a Zwick/Roell Z020 tensile testing machine. Elongation under a 20 N load and ultimate failure load were recorded. Failure mechanisms were analyzed. RESULTS: The mean ultimate failure load was 24.55 N (SD: 14.63; range: 7.34-54.00 N). Mean elongation under a 20 N load was 5.57 mm (SD: 1.39; range: 4.18-7.85 mm). Mean elongation at failure was 6.98 mm (SD: 4.41). Failure occurred predominantly through anchor pullout (7/9 specimens), while one specimen failed by suture rupture and one by a combination of anchor pullout and suture rupture. The observed elongation values were within ranges previously reported to permit functional tendon healing and early active mobilization. CONCLUSIONS: The PL-FDP-A construct demonstrated biomechanical properties that may support its use in pediatric 2-stage flexor tendon reconstruction. The technique is simple, reproducible, and provides sufficient stability for early active mobilization. Anchor pullout from pediatric bone was the predominant mode of failure and should be considered when selecting fixation methods in children. LEVELS OF EVIDENCE: Level II.