Flexor Tendon Entrapment at the Malunited Base Fracture of the Proximal Phalanx of the Finger in Child: A Case Report

The proximal phalangeal base is the most commonly fractured hand bone in children. Such fractures are rarely reported as irreducible due to flexor tendon entrapment. Here, we describe a patient who sustained a malunited fracture on the right fifth finger proximal phalanx with flexor tendon entrapment after treatment with closed reduction with K-wires fixation. A 13-year-old patient came to the clinic following a bicycle accident 6 weeks ago. He presented with flexion limitation in his small finger on the right hand. During physical examination, the patient felt no pain, and the neurovascular structures were intact. However range of motion (ROM) in his small finger was not normal. Plain radiographs displayed a Salter–Harris type II fracture of the small finger proximal phalanx base and volar angulation with callus formation. During the operation, it was established that the flexor digitorum superficialis (FDS) around the fracture had a severe adhesion, whereas the flexor digitorum profundus (FDP) was entrapped between the volarly displaced metaphyses and the epiphyses and united with the bone. We removed the volarly displaced metaphyses and freed FDP and repaired the A2 pulley. The bone was anatomically fixed with K-wires. In the treatment after the operation, on the 2nd day, the patient was permitted the DIP joint motion by wearing a dynamic splint. At the 12-months follow-up, the patient had regained full ROM with no discomfort and the proximal phalanx growth plate of the small finger closed naturally with normal alignment. When treating a proximal phalangeal base fracture in children, the possibility of flexor tendon entrapment should be considered and should be carefully dealt with in its treatment.