getting the finger

Monday, September 23, 2013

Another week, another finger injury. This time it’s Arizona Cardinal defensive back Rashad Johnson who lost the tip of his finger on the playing field. The mechanism of his injury is still a mystery; Mr. Johnson saw his glove covered in blood, took out his hand and found the tip of his middle finger missing. It’s a strange story but amputation is one of the most common fingertip injuries seen in the ER. Usually the finger is caught in a car door, cut off in the kitchen while chopping or being a home handy man using a table saw. The medical literature can now add football as a cause.

The anatomy of the finger is complex and hand surgeons spend years learning how to treat the structures in the hand with respect when they are injured. Nerves, arteries, nails, bone, tendons and ligaments are all crammed together in a tiny space with the ability to pinch, grasp, caress and feel a variety of sensations.

finger_anatomy1

Each finger, except for the thumb has three bones (phalanges) and three joints: the metacarpophalangeal joint (MCP) that attaches the finger the hand, the proximal interphalangeal joint (PIP) and distal phalangeal joint (DIP). Distal describes the direction away from the center of the body and in the finger towards the fingertip. Proximal describes closer to the center and in the finger toward the hand. The landmarks of the finger are also described by radial/ulnar and palmar/dorsal. Look at the palm of your hand: radial is towards the thumb which is on the radius side of the wrist. Ulnar is toward the little finger or the side of the wrist where the ulna bone is located. Tendons run both on the palmar and dorsal side to allow the fingers to flex and extend but are interwoven as they cross the MP, PIP and DIP joints. The fingertip is very sensitive and has numerous nerve fibers. In general, in the body when there are a lot of nerves, there are accompanied by a lot of arteries and veins. The finger is no different and that’s why fingers bleed and hurt like stink when they are cut.

Amputating a fingertip is a complex injury and the treatment options depend upon how much tissue is lost, whether the bone is involved and if the nail is damaged. It is a different injury if the amputation is oblique and involves more of the fat pad on the palm tip, as opposed to losing the nail and dorsum of the fingertip or amputating transversely or straight across. History is also important. Treatment may be different for a person who plays the guitar compared to a person with gnarled hands from end stage rheumatoid arthritis.

The treatment goal is always to maintain function.  Minimal skin loss can be left alone and the finger will heal itself and regenerate the skin covering of the tip, even though cosmetically, it may appear a little flat. The more tissue that is lost, the more difficult it is to maintain the cosmetic appeal. Any bone that is exposed needs to be covered with fat and skin. If there isn’t enough fat pad, the skin may not heal as it stretches across the bony edges plus chronic pain might be an added consequence. For that reason, the bone may have to be cut back. A shorter finger that works might be preferred to a more normal appearing finger that is stiff and can’t do the fine work expected of a finger. However, depending upon injury, orthopedic and hand surgeons can consider reconstructing fingers with skin grafts but the patient has to have patience because it can take weeks or months for the finger to heal. Fingers are a very emotional part of the body and are pampered and decorated. In the heat of the moment, the thought of losing even more of a finger is advice not well received. Fortunately, there is often time to make that decision once the dust has settled.

Kids are a special circumstance. For some reason they have the potential for regeneration just like a salamander. If the tip of a child’s finger is cut off, it may grow back, bone, nail and all. The younger the child the better and less than 2 years old is best. Still there is hope for kids that are up to 6 years of age.

Mr. Johnson is a little out of the pediatric age range. The bone of his amputated fingertip was exposed and he likely decided upon cutting back the bone to allow the skin to be closed instead of a finger reconstruction. With the immediate repair he should be playing again in a few days, preferring function over form.

 

 

 

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