When Are Wrist and Forearm Amputations Performed?

Amputation is a condition in which an extremity or a part of an extremity such as an arm, leg, foot, hand, toe, or finger is removed, usually due to injury, disease, or surgery. 

A prosthesis is an artificial limb used to replace the loss of function from amputation. When deciding on a suitable prosthesis, the patient will normally choose between a functional prosthesis and cosmetic prosthesis.

Surgical removal of the wrist and forearm is performed in patients in the following conditions:

• Severe injury with irreplaceable loss of blood supply to the wrist or/and forearm
• Diseases such as peripheral vascular disease [PVD] (blood vessel disease), diabetes, blood clots, or sepsis (severe infection)
• Burns, thermal injuries, and injury secondary to extreme cold exposure to the wrist or/and forearm
• Surgery to remove tumors or infected area from the bones and muscle
• Ulcers and pathological fractures

Following are the major goals of an upper-extremity amputation surgery:

• Preservation of function
• Durable coverage
• Preservation of sensation
• preservation of important nerves
• Minimization of short- and long-term risks
• Early prosthetic fitting, when applicable
• Early return of the patient to work and play

Usually, general anesthesia is considered for the wrist and forearm. The level of amputation will be determined by the surgeon during a thorough assessment. Often, the cause of amputation will affect the level of the required amputation. 

For example, if amputation is due to a severe injury or infection, the amount of arm that can be preserved will depend on its location. The surgeon will aim to preserve the length of the arm, but they also need to appropriately pad the remaining area to optimize the prosthetic (artificial) fitting. 

• After anesthesia is given, the surgeon will monitor the patient’s vitals throughout the procedure. An intravenous line for pain and antibiotics will also be started. 
• During amputation, the surgeon will remove the diseased part and the end of the exposed bone. This will prevent soft tissue injury from bony edges. 
• The surgeon will separate the nerves and remove them from the site of amputation and place them in healthy soft tissue to reduce irritation from the prosthetic socket or any other unwanted sources of contact from the wound healing.
• The surgeon will then perform either a myoplasty or myodesis (techniques to stabilize the bone and soft tissue).
• In myoplasty, the opposing muscles in the residual limb are stitched together to stabilize the arm.
• In myodesis, the muscles are stitched to the bone. 

Both the process will work well to pad the remaining area and facilitate the use of prosthesis. The surgeon may also consider the functional limitations of amputation levels and prosthetic designs. 

Below are the different types of wrist and forearm amputations.

Wrist amputation

• Transcarpal amputation: In this procedure, the arteries and their branches are separated and tied up together. The diseased bone is then removed. Rough edges are smoothened, and closure is done with padding from the finger tendons when possible. Usually, after thumb amputation, the patient will lose their pinch and grasp functions.
• Wrist disarticulation: In this procedure, the wrist and hand are separated from the arm. Lower arm bones are separated from the wrist bones. No bones are cut during this surgery.

Forearm amputation

• Forearm amputations can be partial or complete. Forearm amputations depend on the location, which include distal (away from the body) forearm amputation and proximal (near to the body) forearm amputation. 
• Krukenberg’s Operation: This procedure is done in patients who have a functional and neurologically intact forearm and upper arm but are missing one or both hands. The operation is accomplished by splitting the forearm bones and creating two sensate pincers that can be used to grasp objects. 

Patients who have amputations performed at the appropriate level and with proper surgical techniques do very well. Complications are generally prevented or successfully managed. A patient’s attitude, motivation and desire before amputation strongly influence the overall outcome after the procedure. 

However, if proper follow-up care and rehabilitation are not coordinated with a multispecialty team of surgeons, physical therapists, physiatrists, prosthetists, and psychologists, then recovery may be delayed.