Rupture of the extensor digitorum communis tendon in extensor zone V due to plant thorn injuries: a report of two cases

Penetrating injuries due to a plant thorn in the hand may occur during outdoor activities. We experienced two patients with rupture of the extensor digitorum communis (EDC) tendon in extensor zone V caused by plant thorn injuries. Both patients, presenting with pain and swelling around the third metacarpophalangeal joint, had a history of penetrating injuries due to plant thorns. The injuries had been ineffectively treated with oral antibiotics. Plain radiographs showed soft tissue swelling without a foreign body and bony lesions. Enhanced magnetic resonance imaging confirmed a rupture of the EDC tendon at the third extensor zone V. Tendon ruptures were diagnosed 27 and 60 days after injury, respectively. A plant thorn injury in the hand can cause persistent synovitis around the tendon, and as a result, progress to tendon rupture. A magnetic resonance imaging examination may be helpful if symptoms do not improve for a prolonged period after plant thorn injury.