A transradial amputation is the surgical removal of the arm below the elbow joint, often called a below-elbow amputation. The primary surgical goal is to maintain the maximum possible length of the forearm, as this directly influences future function and prosthetic success. Keeping the elbow joint intact allows the patient to retain the ability to flex and extend the elbow, which is a major functional advantage for rehabilitation.
When Transradial Amputation Becomes Necessary
The necessity for a transradial amputation typically arises from conditions where the forearm and hand are damaged beyond repair or pose a threat to the patient’s overall health. Severe trauma is the most frequent cause, accounting for a large percentage of acquired upper limb amputations, particularly crush injuries or those resulting from electrical burns. Such injuries often involve extensive damage to bones, nerves, and soft tissues that cannot be effectively reconstructed.
Certain aggressive infections, such as necrotizing fasciitis, can also necessitate the procedure to prevent the spread of toxins. Less commonly, this surgery is indicated for the removal of malignant tumors in the forearm. While vascular disease is a more common cause of lower limb amputation, it can still be a factor in the upper limb if blood supply is irreparably lost. Finally, some congenital limb differences or severe contractures may be addressed to improve function and quality of life.
The Amputation Procedure
The core objective of the transradial amputation procedure is to create a residual limb, or stump, that is durable, well-padded, and functional enough to interface with a prosthetic device. The surgeon divides the two forearm bones, the radius and ulna, often cutting them to equal lengths to ensure proper prosthetic fit and weight bearing. Before closure, the sharp edges of the bone are contoured and smoothed to prevent pain and skin breakdown against the eventual socket.
Managing the remaining muscles and nerves is a significant component of the surgery. The muscle groups are stabilized over the end of the bone using techniques like myodesis (suturing muscle tissue directly to the bone) or myoplasty (sewing opposing muscle groups to each other). This stabilization provides a protective soft tissue cushion, prevents muscle retraction, and allows for better movement control for a myoelectric prosthesis.
To prevent the formation of painful nerve tumors, called neuromas, the major nerves (radial, median, and ulnar) are identified and managed through traction neurectomy. This technique involves gently pulling the nerve before cutting it, allowing the severed end to retract into healthy tissue away from the pressure-bearing surfaces.
Healing and Initial Rehabilitation
The recovery process begins immediately after surgery with careful management of the incision site. Initial care focuses on monitoring the surgical wound for signs of infection and ensuring the skin flaps heal completely to create a durable residual limb. Effective pain management is a primary concern, addressing both acute surgical pain and nerve-related discomfort.
Many patients experience phantom limb sensation (the feeling that the removed part of the limb is still present) and sometimes phantom limb pain. Specialized desensitization techniques, such as mirror therapy, are often introduced early to help manage this nerve pain.
Controlling swelling (edema) is an immediate goal, accomplished through elevation and consistent use of compression wrapping or specialized shrinkers. Physical and occupational therapy starts early to prevent stiffness and maintain the full range of motion in the adjacent elbow and shoulder joints.
The therapy program includes active movement and strengthening exercises for the residual limb muscles to prepare them for controlling a prosthesis. The limb shaping process is ongoing for several weeks or months, as consistent compression helps the residual limb achieve a stable, cylindrical shape necessary for a comfortable prosthetic socket fit. Psychological support is integrated throughout this phase.
Choosing and Adapting to Prosthetics
Once the residual limb has healed and achieved a stable shape, the next step involves selecting and fitting a prosthetic device to restore function and balance. Transradial prostheses are generally categorized into three main types, each offering different levels of function and complexity.
Passive or cosmetic prostheses are designed solely for appearance and offer no active movement. Body-powered prostheses use a harness system and cables connected to movements of the shoulder or chest to operate the terminal device, such as a hook or a hand. Protraction of the shoulder, for example, can pull the cable to open or close the device, offering a durable and reliable option.
The most advanced option is the externally powered, or myoelectric, prosthesis. This device uses sensors placed in the socket to detect electrical signals generated by contracting muscles in the residual forearm. These signals are amplified and used to control a motorized terminal device, allowing for a more intuitive grip control.
The socket is the most critical component, as it forms the custom interface between the residual limb and the prosthesis. The prosthetist creates a custom-molded socket to ensure a secure fit and proper suspension, often utilizing a pin-locking system or suction. Intensive occupational therapy is then required to teach the individual how to operate the controls and integrate the prosthesis into daily activities.