INTRODUCTION
Recent decades have seen advances in the management and rehabilitation care of individuals with upper limb amputation. Prostheses for the person with upper limb amputation have changed greatly, with improvements in components, socket fabrication, fitting techniques, suspension system and sources of control, electronics, and power. Higher levels of limb amputation can now be fitted with functional prostheses, which allow more patients to achieve independent lifestyles. This is of particular importance for the multilimb amputee.
For the upper limb amputee, myoelectrically and proportional controlled terminal devices and elbow joints are now used routinely in some rehabilitation programs. These devices have greatly improved the functional outcomes of patients with upper limb amputation. Progress in the areas of prosthetic fitting techniques and devices (eg, use of osseo-implantation for suspension of the prosthesis) and development of control systems is ongoing, and further developments are expected to take place as technology and the human–machine interface improves.
EPIDEMIOLOGY
The exact number of people around the world who have a major amputation is difficult to ascertain as many countries do not keep records of the number of people with limb amputation. Based on information available from the National Center for Health Statistics, there are approximately 100,000 new amputations every year in the United States. Extrapolating from these and other sources of health statistics worldwide, the major causes of amputation in order of incidence are trauma (including war-related injuries), diseases (eg, malignancies and arterial insufficiency), and congenital limb deficiencies. The causes of amputation vary from country to country. Because medical comorbidities leading to limb loss most often imperil the lower extremity, more lower limb than upper limb amputations occur, at a ratio of almost 5 to 1. Congenital limb deficiencies account for a small proportion of the total number of reported limb amputations, with a reported incidence of 4.1 per 10,000 live births.
Trauma-related amputations usually occur as a result of motor vehicle, military conflict, industrial, or farming accidents and may account for up to 30% of new major limb amputations. Traumatic amputations occur in a much younger, active, and economically productive population. Sixty percent of arm amputees are between the ages of 21 and 65 years, and 10% are younger than 21 years. Because of the higher risk of work-related accidents in men, there is a higher number of trauma-related amputations for this gender and, overall, a higher incidence of upper limb amputation.
Amputation of the distal segment of the upper limb is more common than proximal amputation and can occur at any age. Men between the second and fourth decades are most frequently affected, with involvement of the right more often than the left limb (related to dominance). The transradial level accounts for 65% and the transhumeral level for 25% of upper limb amputations. Shoulder, elbow, and wrist disarticulation levels together account for the remaining 10%.
CLASSIFICATION & LEVELS OF UPPER LIMB AMPUTATION
Amputations are best classified based on the anatomic level and site at which the amputation has taken place (Table 27–1). Thus, an amputation between the wrist and elbow is termed a transradial amputation. Other common levels of amputation in the upper limb include transhumeral; shoulder, elbow, and wrist disarticulation; and partial hand. Forequarter amputation involves the removal of the complete arm, including the clavicle, scapula, and portions of the chest wall. This type of extensive amputation is performed primarily in cases of malignancy or very severe trauma.
| Level of Amputation | Key Considerations |
|---|---|
| Forequarter amputation | Extremely rare, accounting for < 2% of UL amputations, most often for malignancy or severe trauma Produces the greatest degree of functional loss due to removal of all upper limb joints, and greatly compromises prosthetic suspension |
| Shoulder disarticulation | Accounts for 4% of UL amputations, most often for malignancy or severe trauma Produces a significant disability due to loss of all upper limb joints |
| Transhumeral amputation | Accounts for 25% of UL amputations, with the majority of cases at the mid-humerus level Length of the residual limb is essential to improve suspension and transfer of forces to prosthesis, but the longer level may interfere with elbow selection and placement |
| Elbow disarticulation | Few patients undergo elbow disarticulation because it limits the type of prosthetic elbows available for use; however, this level of residual limb can afford excellent suspension and force transmission to the prosthesis |
| Transradial amputation | Accounts for 65% of UL amputations, providing the highest level of functional rehabilitation at the mid-forearm level because the residual limb can accommodate most types of prosthetic devices and offers excellent control and suspension (Caveat: The shorter the residual limb, the greater is the loss of forearm pronation supination) |
| Wrist disarticulation | A small number of patients will greatly benefit from suspension and transfer of forces to the prosthesis, but the longer level may interfere with terminal device selection or result in arm length discrepancy |
| Carpal disarticulation and transmetacarpal amputation | Both levels of UL amputation are managed similarly and present many challenges from the cosmetic perspective; however, a simple mechanical device for opposition may afford adequate gross grasp with retention of pronation supination |
Nomenclature exists that describes a range of congenital limb deficiencies, from partial to complete omission of a limb or digit (Table 27–2). However, in the context of rehabilitation of the upper limb amputee, these deficiencies are best classified following the International Organization of Standards and the International Society of Prosthetics and Orthotics classifications, as modified from Frantz and O’Rahilly. The limb deficiencies can be transverse or longitudinal. The word terminal is used to describe the fact that the limb has developed normally to a particular level beyond which no skeletal element exists. In the intercalary limb deficiency, there is a reduction or absence of one or more elements within the long axis of the limb; in this case normal skeletal elements may be present distal to the affected segments. The incidence of congenital upper limb deficiency is approximately 4.1 per 10,000 live births.
| Term | Definition |
|---|---|
| Acheiria | Absence of a hand or foot |
| Adactyly | Absence of fingers or toes including metacarpal or metatarsal bones |
| Amelia | Absence of a limb |
| Aphangia | Absence of a finger or toe |
| Hemimelia | Absence of half of a limb |
| Meromelia | Partial absence of a limb |
| Phocomelia | Absence of the proximal portion of the limb with distal appendage attached to the trunk |
Amputation of the distal segment of the upper limb is more common than proximal and can occur at any age, with more frequent involvement of the right limb (related to dominance). Amputations stemming from medical co-morbidities result in greater numbers of lower limb than upper limb amputations, at a ratio of almost 5 to 1. Consequently, while most rehabilitation teams are prepared to deal with lower limb amputation, infrequently (in view of the limited exposure) will they have extensive experience in caring for the upper limb. Among upper limb amputations, the transradial level accounts for 65% and the transhumeral level for 25% of amputations. Shoulder, elbow, and wrist disarticulation levels together account for the remaining 10%.
