Patient: I felt the tendon of my right middle finger was plucked when I was pulling something with my finger, but there was no pain, then I found that I could not straighten the first phalanx of my middle finger, and the next day I found a slight swelling and pain in the middle of the dorsal side of the second phalanx of my middle finger, but I did not feel any pain if I did not press on it, and I had a slightly swollen feeling in my middle finger! However, the middle finger is unable to straighten and is now immobilized with a small splint. It is sometimes accompanied by avulsion fracture of the end phalanges. In terms of treatment, (1) conservative treatment: external fixation with aluminum or plastic plates immediately after injury to flex the proximal interphalangeal joint about 60-70 degrees + hyperextension of the terminal interphalangeal joint, and removal after 4-5 weeks; avulsion fracture should be reset before fixation. However, the success rate is not high about 1/3. (2) Without avulsion fracture and external fixation failure, the extensor tendon can be surgically repaired, but there are more factors affecting the outcome, such as tendon adhesion, tendon re-rupture during functional exercise, joint stiffness, etc. The chance of reaching the pre-injury functional state is not very high. (3) For patients with very small avulsion fracture fragments or no fracture, failed conservative treatment and surgical repair, or even all patients with hammer fingers, functional end-joint fusion is recommended, especially for the ring and little fingers, or for the index and middle fingers in patients with non-occupational demand injuries. Depending on the patient’s occupation and needs, the joint is fused at 15-25 degrees with a high surgical success rate and a one-time solution. The disadvantage is the loss of motor function of the end joint.