There were an estimated 2.2 million individuals living with limb loss in the United States in 2020.¹ The number of individuals with major upper limb loss, defined as through or proximal to the wrist joint, represent approximately 3% of the total amputee cohort in the United States, resulting in an estimated 66,000 individuals in 2020.¹ Common causes for upper limb loss include trauma, vascular infection, congenital absence, and malignant tumors (cancer). The most frequently performed major upper limb amputation occurs at the transradial (TR) level as a result of trauma.^1,2,3 TR and wrist disarticulation (WD) amputations made up an estimated 60% of all major upper limb amputations from injuries sustained by U.S. military personnel since the turn of the century.² Loss involving the upper extremity causes significant physical and psychosocial challenges that must be addressed to minimize any negative impact on a person’s quality of life and participation in society. Interventions involving prosthetic devices are an important available tool to help address these needs.

Individuals who undergo amputations at the transradial level have more functional potential than those with more proximal amputations, and similarly show a much higher acceptance rate with using a prosthesis than those with upper extremity amputations at other levels.^4,5 Published data from the U.S. Department of Veterans Affairs shows TR and WD level prostheses represented approximately 74% of all active (ie, cable driven and externally powered) upper limb prostheses that were procured for veterans within the 7-year period from 2009 to 2016.⁶

Trauma, as the primary cause of upper extremity amputation, results in rare opportunity for the patient, doctor, surgeon, and prosthetist to collaborate on surgical considerations upon initial amputation. Surgeons and doctors who deal with upper limb amputees should maintain a regular, open line of communication with a prosthetist experienced in fitting this cohort, so that general concepts and advancements in prosthetic fitting procedures can be shared.

Advantages of wrist disarticulation (Figure 1, A) amputation include: the preservation of the entire forearm for maximal mechanical leverage and load bearing; retention of up to 120°
of active range of motion (ROM) with pronation/supination; eliminating the risk of impingement between the distal ulna and radius; and available use of the distal styloids as an anatomical suspension of a prosthetic device.

Although the preservation of full anatomic forearm length with WD is often considered advantageous for the patient for the reasons listed above, there are disadvantages which may contraindicate this level of amputation for consideration. WD amputations result in both limited choice of functional prosthetic options and aesthetic challenges with maintaining body symmetry. Insufficient space remains between the end of the limb and the prosthetic terminal device (TD) to both maintain proportional symmetry and allow use of a quick-disconnect wrist, which allows interchangeability of various TDs. In cases of unilateral amputations, this routinely results in a length discrepancy between the prosthesis and the sound limb. The result may create functional challenges with positioning the TD in space for activities at the body’s midline and/or be aesthetically unacceptable to the patient. In bilateral WD cases, although prostheses may be made symmetrical in length even with use of quick-disconnect wrists, there are similar concerns as the devices would be disproportionately long as compared with the patient’s body size. The additional length makes it more difficult to perform functional activities at the body’s midline (eg, fastening a belt, buttoning a shirt, bringing food to the mouth, etc), requiring more compensatory trunk and shoulder movements. Further, the additional length may also result in the need for the amputee to purchase new clothing with longer sleeves to maintain desired appearances in public, adding wardrobe expense and inconvenience. If it is not expected that the patient will experience the advantages of WD resulting in retention of most of their natural pronation/supination ROM or adequate soft-tissue coverage and durability to support suspension over the distal styloids, then amputation at the TR level will likely better serve their needs.^7,8,9,10

The TR amputation level (Figure 1, B), in contrast to WD, presents advantages including the potential for fitting various prosthetic designs, use of quick-disconnecting components, and is more likely to be aesthetically appealing, permitting the prosthesis to be made symmetrical in length to the sound side limb. TR amputations should aim to retain at least two-thirds of the forearm to provide optimal balance between forearm leverage, ROM in pronation/supination, and offer access to a wide variety of postoperative prosthetic options, including potential use of a quick-disconnect wrist unit to change TDs from hooks to hands and/or an electric wrist rotator to replace lost pronation/supination.^2,11 At least 5 cm of residual ulna is required to allow for prosthetic fitting and elbow motion.² A more distal transradial amputation results in a robust lever arm, allows for anatomical pronation/supination and preserved shoulder and elbow function, which allows the patient to more easily use the prosthesis to position the TD in space, for performing activities of daily living (ADLs).

Whenever possible, within the preoperative phase of care, the patient should be made aware of the advantages and disadvantages of undergoing a wrist disarticulation procedure versus a transradial amputation, so an informed team decision, centering on the patient as the lead influence, may be made. This will maximize the patient’s functional recovery and quality of life after surgery.

Postoperative interventions include those common for other amputation levels: wound care, controlling extremity volume with compression wrapping or shrinkers, desensitization training, and scar management. Edema control, pain management, and residual limb shaping can be achieved through an immediate postoperative wound dressing and figure-of-8 compressive wrap. The patient may progress to early application of a shrinker or compression sleeve over the surgical dressing for continuous wear, as wound drainage resolves. Once postoperative sutures are removed the patient may be issued an appropriately sized shrinker or elastomer liner to attenuate limb volume and/or pain.

Desensitization techniques such as massage, limb tapping, vibration, and the use of desensitization media/textures may be used to address areas of residuum hypersensitivity. As tolerated, gradual load-bearing on the residuum should be initiated to help reduce residual and phantom limb pain and prepare the limb for use of a prosthesis.¹⁰ It is beneficial for the patient to use the residual limb in active mobilization and stretching to reduce pain, maintain strength and ROM at the elbow and
shoulder joints, and improve the potential for prosthetic function and use.

Early postoperative involvement of a trained peer visitor or peer support group can provide important psychosocial benefit to the patient.¹⁰ Peer support provides an opportunity for patients to relate to one another and/or to disclose relevant emotions and experiences. Peers with experience relating to upper limb amputation can help the patient, as well as their caregiver(s), set realistic expectations, and provide insight to challenges yet to be faced. Connecting a patient with upper limb loss to a peer visitor, support group, or educational program may be accomplished through face-to-face programs or through telecommunication technology, which provides increased peer visitation access to individuals living in rural areas, who are otherwise often underserved with such opportunities.¹⁰

Early prosthetic fittings have been correlated with a higher level of successful outcomes with respect to device acceptance and use, suggesting prosthetic fittings should begin as early as within 30 days, or at least within 6 months, after amputation.^{12,13,14,15,16} The importance of early training of patients using prostheses can not be overstated. The patient’s exposure to quality training with the prosthetic device is another important factor that may be associated with successful outcomes of device acceptance and use.^{10,13,17,18,19,20}

As the patient and clinical team develop short-term and long-term goals, education on the various prosthetic options for consideration should be provided to the patient as well as their family and/or caregiver(s), before the initiation of a prosthetic prescription. Prosthetic options can be divided into six categories: no prosthesis, aesthetic/semiprehensile, externally powered, body powered/cable-driven, hybrid, and special purpose. Traditionally, these items have been presented in a linear fashion, in literature and within prosthetics education curriculums, implying a hierarchical progression as to the prosthetic options considered for prescription. However, an alternate paradigm better illustrates the nonhierarchical patient-centered approach of considering all prosthetic options (Figure 2), at any point in the patient’s stage of care.²¹ Preprosthetic training should be initiated as necessary, corresponding to the type of prosthetic option selected to best match the needs of the patient.

Externally powered prosthetic designs, because of the creation of less shear and end-bearing forces on the residual limb, can be used earlier after amputation than body-powered designs. In some instances the process to identify electrode sites and initiate the training necessary for the operation of a myoelectric prosthesis may begin even before surgical wound closure is achieved. However, special consideration and attention is needed before fitting a myoelectric device on a residual limb that has not matured in volume. Myoelectric designs require an intimate fit with the limb to maintain sufficient electrode contact with the skin. The anticipated changes in volume of the residuum as it continues to heal in the immediate weeks and months after surgery will require multiple interface replacements to maintain proper functioning of the device, increasing the burden and potential frustration of the patient and/or their caregivers resulting from more frequent servicing and clinic visits.

There are sound therapeutic rationales to consider a body-powered prosthesis for a new TR or WD amputee. These include: desensitizing the limb through applied pressure between the residuum and interface during active use; controlling edema as the residual limb is shaped for a more definitive interface design; improvement of proximal joint ROM through active control of the TD; and accommodation of shape/volume changes in the residual limb as the healing process progresses, using the addition of socks, minimizing the frequency of interface replacements. In addition, the body-powered design offers proprioceptive feedback through the applied forces within the socket as tension is applied through the harness.

In the case where a passive prehensile prosthesis is the desired design, then the process of using a preparatory prosthesis is not necessary, since the active function of the device for dynamic use will be minimal.

The design of a transradial prosthetic interface is influenced by several factors including residual limb length and the selected prosthetic control
strategy. Universal design goals for the prosthetic interface strive to comfortably spread load forces during active and static lift, maximize ROM, stabilize the prosthesis against rotary forces, and facilitate suspension on the residual limb. Patients with unilateral or bilateral amputations at this level should be able to independently don and doff their prosthesis(es) with relative ease.

Additionally, with self-suspending interface designs, the epicondyles, olecranon, and distal biceps tendon should be free of impingement or excessive pressure. The patient should be able to maintain prosthetic suspension passively without inadvertently losing suspension by flexing or extending the arm.

WD and long TR residual limbs permit a more distal interface trimline relative to the cubital fold, allowing for full ROM with elbow flexion. The interface should be made to intimately fit with the shape and contours of the distal forearm, specifically in the area of the distal interosseous space between the radius and ulna, which aids in more efficient translation of forearm rotation to the prosthetic TD. This produces an interface shape sometimes referred to as a “screwdriver fit,” which stabilizes the interface to the residual limb as the amputee performs tasks requiring rotary forces, such as turning a doorknob, allowing the wearer to use up to 50% of their available ROM for pronation and supination of the prosthetic TD. The fundamentals of fitting the WD interface involve adequate loading along the ulnar shaft, proper medial/lateral dimension to transfer natural pronation and supination to the TD, and anatomical suspension over the radial and ulnar styloids. Some designs may remove parts of the interface that are not necessary. A common issue with upper and lower interface designs involves heat retention within a fully enclosed interface, which can lead to excessive perspiration and discomfort (Figure 3). Opening the interface by removing areas that are not crucial to the fundamental design aspects assists to minimize heat retention and moisture build up within the interface (Figure 4). In addition, fenestration of the interface also provides the advantage of accommodating increases in limb volume, as the uncovered soft tissue has space to expand without restriction. Yet another advantage is the resulting opportunity to use the advantages of direct forearm sensation with the external environment.

Short transradial limbs are more vulnerable to medial/lateral instability of the prosthesis on the limb. Muscle strength and ROM are also adversely affected with shorter limbs. Elbow stability, active range of motion (AROM), and weakness because of loss of leverage are all significant concerns to be addressed in the prosthetic design. Shorter TR amputations require a more proximal trimline of the interface up to the cubital fold and, depending on the suspension strategy, encompassing the epicondyles and olecranon, to maintain stability of the prosthesis with the limb (Figure 5). As a result, ROM at the elbow is often limited. Prostheses designed for short TR limbs may use rigid hinges, mounted on the outside of the interface. This improves stability between the residuum and interface, while maximizing the available surface area to distribute load forces. At this amputation level, the absence of natural
forearm rotation eliminates concern of the rigid hinges restricting any functional pronation/supination. There are four basic types of rigid hinges for transradial level prostheses: single-axis hinges, polycentric hinges, step-up hinges, and limb-activated locking hinges. Each has unique features that make them favorable under various circumstances which have been covered in various texts.²²