Finger bone contusion knuckle swelling for two months can not straighten the fist can not grasp the consideration for the finger extensor tendon healing, finger flexor tendon healing, capsular contracture and other reasons. 1. Poor healing of finger extensor tendon: Finger bone contusion can lead to injury of finger extensor tendon, due to braking during the healing process, resulting in adhesion with the surrounding tissues, or the injury is more serious, there is not enough time for braking and healing, which can lead to poor healing of the extensor tendon, and the occurrence of weakness in extending the finger or inability to straighten the finger and other phenomena. 2. Poor healing of finger flexor tendon: when finger bone contusion causes injury or rupture of finger flexor tendon, poor healing can lead to weakness of finger flexion or inability to hold a fist. 3. Joint capsule contracture: finger bone contusion can cause damage to the joint capsule, swelling, deformation, etc. When the joint capsule contracture, the finger is in a mildly flexed position, and the shortening of ligaments and joint capsule will lead to the finger not being able to straighten out or hold a fist. Finger bone contusion joint swelling for two months can not straighten the fist, it is recommended to consult a doctor in time to clarify the diagnosis, under the guidance of the doctor for targeted treatment.