Common Upper Limb Deficiencies

Digital Deficiencies

Digital deficiencies are common but rarely present in isolation. Removal of additional digits or intervention with Z-plasty procedures produce acceptable results for the children with polydactyly and syndactyly, respec­tively.

Etiologies such as Moebius syndrome and Poland syndrome (sequence) result in digital deformities associated with a more serious underlying condition. Moebius syndrome often affects the sixth and seventh cranial nerves, which compromises the child’s abil­ity to visually follow objects, swallow, and communi­cate. In addition to hand anomalies, Poland syndrome involves a partial absence of the ipsilateral pectoralis muscle and hypoplastic chest.

Absence of individual digits creates a multitude of surgical and nonsurgical options. These include no intervention, therapy to enhance hand function, pollicization, or toe transfers. Due to the physiologi­cal function of the normal thumb, hand impairments can vary widely, depending upon which digit(s) is/are absent. There is often greater consideration for sur­gery if the thumb is absent. Pollicization can occur to the most radial digit in order to provide oppositional grasp (80). Toe transfers can now be transplanted from the second or third ray and minimize effects on gait mechanics (81,82).

Partial Hand and Wrist Disarticulation Deficiencies

Partial hand deficiencies are quite common and are often treated as wrist disarticulation-level limbs. Nubbins (very small underdeveloped vestigial digits) are present in a majority of these cases, as are short­ening of the ipsilateral radius and ulna.

Transverse Deficiencies of the Forearm

Transverse deficiency of the upper third of the forearm is the most common (major) upper limb deficiency (83). The clinical presentation of these children is sim­ilar to that of children with longer, transradial residual limbs. Ipsilateral humeral shortening and the presence of smaller nubbins are common to this level. The prox­imal radius in these shorter residua is often unstable, subluxing anteriorly during full extension. This cre­ates a challenge to prosthetic fitting. The longer resid­ual limbs, in the middle third of the forearm, tend to be more easily fit with prostheses, as they have more surface area over which to distribute the forces of the socket interface. They also have longer lever arms with which the patient can control the prosthesis.

Rarely will there be any surgical intervention to this level of limb deficiency (84). If prosthetic inter­vention is not attempted or accepted, bimanual tasks will be performed via grasping of objects in the cubital fold, between one's legs, in the axilla region, or under the chin.

Elbow Disarticulation

and Transhumeral Deficiencies

The more articulations that are involved, the greater is the functional deficit. When the elbow joint is compro­mised or absent, the child has fewer options to assist in prepositioning his or her distal limb in space. The child relies solely on the muscles and range of motion of the shoulder complex. The true elbow disarticulation limb has the distal epiphysis present, which is important to overall growth of the residuum. A drawback of any dis­articulation is the lack of room to fit prosthetic compo­nents and maintain humeral length equality.

Transverse deficiencies of the humerus are analo­gous to acquired transhumeral amputations in chil­dren. The residual limbs are often medium to short in length compared to their contralateral limb. This level of deficiency has been previously noted as the most common to experience diaphyseal overgrowth. This leads to a short, nonfunctional residuum when multiple surgeries have been completed.

Shoulder Disarticulation

and Intrascapulothoracic Deficiencies

It becomes increasingly difficult to restore the func­tions of the anatomical arm as the level of deficiency reaches the shoulder and higher. Children with rem­nant humeri have the ability to use these segments to assist in their activities. Often, the axilla will be used to assist these individuals to grasp and manipulate objects. If the child has unilateral limb deficiencies, the contralateral noninvolved limb will be the dom­inant side for grasping, with holding for manipula­tion taking place between the knees, in the mouth, or trapped between chin and chest or chin and shoulder. When the child has bilateral deficiencies at the shoul­der level, the latter method is all that is possible to grasp objects. In these cases, the child will be strongly encouraged to use his or her feet to grasp and manip­ulate objects.

Many designs of upper-extremity prostheses require a degree of body movement (excursion) to operate the mechanical components. Most of this excursion is not present in the shoulder disarticulation level, as gle­nohumeral flexion no longer exists as a source of con­trol input. This is further magnified when the child has an intrascapulothoracic (forequarter) level of involve­ment, as they only have uniscapular motion to capture for prosthetic limb control. These two issues will be discussed at length in the following sections.