Transhumeral amputation involves the surgical removal of the arm above the elbow, presenting a significant life change for individuals. This procedure alters how a person interacts with their environment and performs daily activities. While the decision for such an amputation is complex, advancements in prosthetics and rehabilitation offer pathways to regaining independence and improving quality of life.
What is Transhumeral Amputation?
Transhumeral amputation refers to the surgical removal of the arm through the humerus, the bone of the upper arm, at a point above the elbow joint. The remaining portion of the arm is called the residual limb.
The specific length of the humerus preserved can vary, affecting the leverage available for prosthetic use and shoulder motion. For instance, a long transhumeral amputation retains 50-90% of the humerus, which is considered ideal for function and cosmetic appearance. In contrast, a very short amputation, where only 0-30% of the humerus remains near the humeral neck, may be fitted similarly to a shoulder disarticulation prosthesis due to limited leverage. Preserving at least 5-7 cm of the humerus is generally important for maintaining adduction and abduction at the glenohumeral joint, which helps with prosthetic fitting and function.
Common Causes
Transhumeral amputations are most frequently necessitated by traumatic injuries. Accidents involving machinery, power tools, motor vehicle crashes, explosions, and even self-inflicted injuries are common reasons for such severe arm loss. In the military, traumatic amputation, often due to explosive devices, is a primary cause of upper limb loss.
Other medical conditions can also lead to transhumeral amputation. Severe infections, such as necrotizing fasciitis, can rapidly destroy tissue and pose a systemic threat to the patient’s life, making amputation a necessary measure to control the infection. Vascular diseases, which compromise blood flow to the limb, and certain types of cancer affecting the bones and soft tissues of the arm, like osteosarcoma, are also significant causes.
Prosthetic Options
For individuals with a transhumeral amputation, several prosthetic options are available, each offering different levels of function and control. These generally fall into three main categories: body-powered, externally powered (myoelectric), and passive/cosmetic prostheses. The selection depends on individual needs, functional goals, and personal preferences.
Body-powered prostheses operate through a system of cables and harnesses that capture movements from more proximal joints, such as the shoulder or chest, to control the terminal device, like a hook or hand. These devices are known for their durability, lighter weight, and provide direct sensory feedback to the user through tension in the cables. However, they can be less cosmetically appealing and require significant body movement to operate.
Externally powered, or myoelectric, prostheses use electromyographic (EMG) signals generated by muscle contractions in the residual limb to control motors within the prosthesis. Electrodes detect these electrical signals, which are then translated into movements. Myoelectric prostheses offer a more natural appearance and greater grip strength compared to body-powered devices. Recent advancements, such as targeted muscle reinnervation (TMR) surgery, reroute nerves to new muscle targets, creating more distinct EMG signals and allowing for more intuitive and multi-functional control. Implanted sensors and pattern recognition technology further enhance precision and control, allowing for more fluid and complex movements.
Passive or cosmetic prostheses do not offer active movement but are designed to restore the appearance of the limb and can assist with bimanual tasks by stabilizing objects. These are the lightest options and can be used to support clothing or provide a counterweight. While they lack active function, they can still contribute to overall independence by providing a stable platform for the intact hand to work against. Hybrid prostheses combine elements of both body-powered and myoelectric systems, often using a body-powered elbow with a myoelectric terminal device to balance function and control.
Rehabilitation and Adaptation
Rehabilitation following transhumeral amputation is a comprehensive, multi-faceted process that begins even before surgery with pre-surgical counseling. This initial phase helps prepare individuals for the physical and psychological changes ahead. Immediately after the amputation, post-operative care focuses on wound management to promote healing and pain control, which can include addressing both residual limb pain and phantom limb pain. Mirror therapy, a non-pharmacological intervention, has shown short-term benefits in reducing phantom limb pain.
Physical therapy (PT) and occupational therapy (OT) are central to the rehabilitation journey. Physical therapists work on overall strength, balance, and mobility, while occupational therapists focus on preparing the residual limb for prosthetic use and helping individuals regain independence in daily activities. This includes exercises to maintain range of motion, strengthen the remaining muscles, and desensitize the residual limb to prepare it for a prosthetic socket. Early intervention is important, with studies suggesting a higher success rate for patients fitted with a prosthesis within 30 days post-amputation.
As individuals progress, therapy transitions to prosthetic training, where they learn to don and doff the prosthesis and operate its various functions. Therapists also provide guidance on adapting to daily life, which may involve identifying and utilizing assistive devices or suggesting home modifications to enhance accessibility. The psychological impact of limb loss is also addressed, with support systems and counseling playing a significant role in helping individuals adapt to their new body image and regain confidence. The rehabilitation process requires a collaborative approach from a multidisciplinary team, including physicians, therapists, and prosthetists, to optimize outcomes and support long-term independence.