Spontaneous Midsubstance Rupture of the Left Little Finger’s Flexor Tendon in the Absence of Trauma

Spontaneous midsubstance rupture of the flexor tendon without underlying pathology is rare. This case report describes a healthy 45-year-old man who experienced spontaneous midsubstance flexor tendon rupture at zone III. He presented with pain and disability in flexing his left little finger after carrying a plastic bag containing 20 kg and only sought medical treatment 10 days after the injury. Two-stage tendon reconstructive surgery was performed, involving the insertion of a nasogastric tube in the first stage followed by ipsilateral palmaris longus tendon grafting in the second stage. No underlying pathology was found to cause the tendon rupture. This report also describes the clinical diagnosis and treatment options for flexor tendon injuries, including primary tendon repair and two-stage tendon reconstructive surgery.