gms | German Medical Science

Objectives/Interrogation: Avulsion fracture of flexor digitorum profundus (FDP) tendon is relatively rare fracture at the distal phalangeal base than avulsion fracture of terminal extensor tendon. Terminal extensor avulsion fracture, known as bony mallet finger, could be successfully treated by closed reduction and pinning, such as extension block technique. However, most of FDP avulsion fracture, known as Jersey's finger, needed open reduction, because of the proximal migration of fracture fragment and difficulty of pin fixation. We designed a new surgical technique for comminuted FDP avulsion fracture to treat with plating fixation.

Methods: A 16-year-old male patient visited our out-patient clinic with pain on his right ring finger with limitation of motion. He got a direct injury at finger tip during playing a baseball. On the plain radiograph, large avulsed fragment of distal phalanx was shown at the volar side of middle phalangeal level. And there was another small fragment was shown at the volar side of distal interphalangeal joint level. Magnetic resonance imaging (MRI) had revealed a comminuted FDP avulsion fracture in the ring finger. We performed open reduction. Under digital nerve block, volar zigzag incision was made from distal phalangeal level to proximal interphalangeal joint level. After dissection, A4 pulley was partially injured during proximal migration of FDP avulsion fracture fragment. The comminuted small fragment was too small to be fixated directly. However, the large fragment was large enough to be fixed by plate and screws. We performed internal fixation of large fragment with a two hole plate and two 1.2mm screws (Jeil medical, Korea). And we fixed small fragment by sutures.

Results and Conclusions: After two weeks from surgery, gentle flexion exercise was started. After six weeks from surgery, the range of motion was recovered fully. At the one-year follow-up, the patient had no pain and he had full range of motion. And there was no irritation sign or discomfort at the plate insertion site.

Up to date, most of FDP avulsion fractures were successfully treated by open reduction and internal fixation by suture button or suture anchor technique. However, in some cases with large or comminuted avulsion fragments, fixation with suture button or anchor might be impossible. And if fixation might be possible, their fixation power might be too low to allow early range of motion exercise. Therefore, we designed a new surgical technique to fix with a plate system, and we achieved good result.