Tendons that move the fingers can sometimes rupture with a sudden force, but more often are cut by a sharp object. Lacerations may be partial or complete. If complete, the function of that tendon will be lost forever unless the tendon is repaired. There is a limited period of time after injury during which repair is possible. Examination right away by an expert in hand trauma is needed to prevent serious long-term problems with hand function.

Major trauma to the upper extremity may result in amputation or such extensive damage that amputation appears to be the only option. To save the body part whether it is one finger, the hand, or the whole arm requires complex reconstruction. First and foremost the body part must have blood supply coming in and going out. Nerves must connect to the organs for movement and feeling. The skin layer covering all the other tissues must be stable, durable, and healthy. The bone and joints that provide structure to the limb must be stable and mobile. The tendon systems that move the body part must connect and glide back and forth.

Infections can be of the acute pus producing type that will rapidly destroy tissue or of the slow chronic type that is hard to permanently eliminate. For the acute type, it is critical that the infection be recognized and treated surgically right away to avoid serious permanent tissue damage. For the chronic type, it is critical that the correct diagnosis be made so that the specific antibiotics needed to eradicate the infection can be administered.

There are many different nerves within the arm and hand that work together to provide feeling to touch, muscle movement, and numerous other functions including the ability to feel pain. Some nerves do all functions and are called mixed nerves. Other nerves do only a single function and are named after that function (ie: sensory nerve). Lacerations can occur anywhere along the arm to either mixed or single function nerves. After nerve injury, function is lost and the nerve ends will separate. Only if the nerve is surgically repaired soon after injury will it be possible to avoid using nerve grafts to span a gap between the cut nerve ends.

The small bones of the hand are easily broken and often shift out of place. The two main issues are to prevent deformity and function loss due to healing in the wrong position and to also prevent stiffness. Most of the stiffness comes from the injury itself, but treatment choices must be considered since the more invasive the treatment, the more final stiffness the patient faces.

The scaphoid is the most frequently fractured wrist bone. Many wrist fractures also have wrist ligament injuries that must be treated at the same time. The scaphoid is the most difficult bone in the body to get to heal due to its bad blood supply, location inside a joint, and heavy stresses applied by the neighboring bones. If a scaphoid fracture has 1 mm displacement, the chance of it not healing in a cast is up to 50%.