REDENTOMORA, BARBARABERTANI, LUISELLAPEDROTTI
Introduction
Bone loss of traumatic origin is more frequent at the lower limb and particu- larly at the leg, where it is usually associated with soft tissue loss. In these cases the possible therapeutic options must be accurately evaluated (recon- struction and amputation) according to the features of the patient and the lesion [1, 2]. Furthermore, all the alternatives must be explained to the patient before the final decision is made [3].
Patient features that may suggest amputation are principally: old age, chronic diseases such as diabetes and peripheral arteriopathy, vascular dis- eases caused by smoking, and inability of the patient to collaborate in the reconstructive program. Features of the lesion that may indicate amputation are represented by: damage of the posterior tibial nerve, injury of the ipsilat- eral foot, severe vascular lesion, and a severely contaminated lesion.
Various scoring systems were developed in the last few years in order to help in decision making (Mangled Extremity Syndrome Index, Mangled Extremity Severity Score, Predictive Salvage Index, and Limb Salvage Index).
However, they did not prove to be practical for clinical application [4, 5].
An amputation may be the only alternative when reconstruction has failed (or is impossible), when the functional result of a reconstruction will proba- bly be poor [6], or when the danger of major operations in elderly patients is too high [3].
It is important to mention that post-traumatic amputations are carried out most frequently in younger adults, while in the 50-to-75-year age group amputations are more related to peripheral vascular diseases.
Concerning the amputation site, it was calculated that approximately 85%
of all amputations are performed through the lower limbs [3]. Therefore, con- siderations expressed in this chapter will deal mainly with amputation and prosthetic fitting of lower limbs.
Amputation Site
Thanks to today’s construction technologies, the amputation site has become less important than in the past, and it is now determined by surgical consid- erations. Historically, amputation levels at the lower limb can be classified [7]
as outlined in Table 1.
Table 1.Classification of amputation levels at the lower limb
Amputation site Levels
Hip disarticulation
Thigh amputations Very short Short Medium Long Very long
A/K A/K A/K A/K A/K
Knee Disarticulation
Leg amputations Very short Short Medium Long
B/K B/K B/K B/K
Ankle amputations Syme Boyd
amputation amputation
Evaluation Before Prosthetic Fitting
After amputation, a careful evaluation of the general and local clinical fea- tures helps decide which kind of prosthesis is the most appropriate for that patient to achieve the highest level of autonomy and the most complete inte- gration into the familial and social network, and to set a specific rehabilita- tion program that is planned by a team composed of the orthopaedic sur- geon, psychologist, technician, and physiotherapist. This evaluation is essen- tially based on three elements: the patient’s general condition, the condition of the stump, and the condition of the opposite limb [8].
Patient’s General Condition
Evaluation of the patient’s general condition is mandatory to obtain detailed information on problems that may obstruct or impede rehabilitation. This includes information about limited physical resources and impaired function of one or both upper limbs. Concerning the former problem, it is important that the prosthesis be light and safe during ambulation (to reduce as much as possible the mental effort in using it and to avoid falling).
Concerning the latter problem, an impaired function of the upper limbs (caused by trauma or chronic disease) can make rehabilitation difficult.
Condition of the Stump
A preprosthetic treatment must sometimes be planned in order to maintain or improve the articular, muscular, and cutaneous situation and to regularize the stump itself. Moreover, the choice of the most appropriate socket for the prosthesis is fundamental.
An optimal stump should have these features: good articular range of movement, good muscle trophism, good skin condition, efficient blood and lymphatic circulation, and absence of pain. Another fundamental element is the stump length, which determines the choice of prosthesis and the type of socket.
In thigh amputations a distal rather than a proximal amputation site is desirable, and the bone stump should be well covered by soft tissue, without tension. At the leg site, in transtibial amputations, the ideal level is 12–24 cm from the knee joint. The minimum utilizable stump length is 4 cm, provided that the patellar tendon insertion is preserved.
Condition of the Opposite Limb
The opposite lower limb provides fundamental support for a limb with a prosthesis. Therefore, its condition is important to define the duration and the methods to be used in the rehabilitation program. These are determined by a number of circumstances (presence of fractures or nonunion, joint dis- eases, and neurological diseases such as diabetic neuropathy or sequelae of ictus cerebri).
Prostheses
The Evolution of Prostheses
The technological evolution of prostheses for the lower limb was slow. Until the end of the 1970s, prostheses were built almost exclusively by the exoskele- tal method, also called the “traditional” method, since most components were made of wood. It is interesting to remember that, in the same period, electro- mechanical prostheses with myoelectric control were already available for the upper limbs.
Only since the 1980s, with the development of new and sophisticated materials (aluminium alloys, titanium alloys, and carbon fibers) and compo- nents with functional features and thanks to the integration of electronics,
was it possible to significantly improve the performance of prostheses, built with the so-called endoskeletal (or skeletal-modular) method. Therefore, modern prostheses enable recovery of both the function and autonomy dam- aged by amputation significantly better than in the past.
Features of Prosthesis Manufacturing
Prostheses for the upper limb can be classified as follows: passive prostheses (e.g., cosmetic hands), lightweight and simple to use, and active prostheses.
There are three kinds of active prostheses: myoelectric prostheses, acti- vated by electric signals produced by muscular contraction; kinematic pros- theses, activated by bodily energy; and hybrid prostheses, which combine a myoelectric control of the hand function and a kinematic control of the elbow function.
The main components of a prosthesis for the lower limb are: socket, liner (interface between the skin and the socket), knee (in prostheses for tight amputation), adapters, feet, and cosmetic finishing [9]. Lower limb prostheses are built in two different ways, as previously underlined: the exoskeletal (or traditional) method and the endoskeletal (or skeletal-modular) method. The exoskeletal method has now almost been completely abandoned. This kind of prosthesis is strong, lasting, and requires little maintenance but it cannot generally satisfy the functional needs of patients today. The endoskeletal method is the method mainly employed currently. The prosthesis has a car- rying structure, inserted between socket and prosthesic feet. Moreover, it has an adjustable alignment system at the knee and foot level.
Prosthetic knees are classified on the basis of the mechanical or electron- ic control of flexion and extension. Knees with mechanical control have some limitations because they require continuous control by the patient. This kind of knee may be monofunctionally articulated (polycentric or friction-driv- en), monofunctional with a manual locking device, or polyfunctional (poly- centric or friction-driven), with higher speed and safety. In prosthetic knees with electronic control, the device that generates the movement is controlled by a microchip. This kind of knee offers higher performance than a mechan- ical knee with regard to speed and safety.
Two kinds of prosthetic feet can be produced: rigid (without energy return) and dynamic (with energy return).
Thank to these innovations, the components of prostheses can be assem- bled quickly, they are modular (providing easy interchangeability of the mod- ules, and mainly of the articulations), the components can be easily aligned to obtain the best setting, they are light, and a wide range of components are built in different materials.
Particular prosthesis types are:
- Junior prostheses, which can be employed from 10-12 months of age and must be periodically replaced due to growth (on average every 8–10 months).
- Geriatric prostheses, characterized by lightness and safety, due to the poor physical resources and the frequent coexistence of collateral diseases in these patients.
- Bath prostheses, fit for immersion into water. These are endoskeletal pros- theses provided with a “filling tank”, which can be filled with water or emptied through two holes in the upper portion and in the lower portion.
Rehabilitation Program
A fundamental component of this kind of treatment is rehabilitation, which aims to recover an adequate ambulation in a physiological way. The rehabili- tation program is planned in two steps: the preprosthetic treatment and training to use the prosthesis.
The preprosthetic treatment must be started as soon as possible and includes: contracture prevention, stump handwraps (to reduce the postoper- ative edema), physiotherapy (including respiratory gymnastics, upper limb reinforcement, healthy limb physiotherapy, and stump physiotherapy).
Training to use the prosthesis is composed of a starting phase of exercis- es while waiting for the prosthesis to be delivered and a second phase of learning the right technique to wear it. The next steps include assisted ambu- lation with a walking device, nonassisted ambulation with a walking device, ambulation with two crutches, ambulation with one crutch, and free ambula- tion.
References
1. Prokuski LL, Marsh JL (1994) Bone transport in acute trauma. Curr Orthop 8:152–157
2. Mora R, Pedrotti L, Bertani B, Tuvo G (2003) Le perdite di sostanza ossea nel trau- matizzato. Proceedings of the 16th Congress OTODI, Vieste
3. Crenshaw AH (1987) Delayed union and non-union of fractures. In: Crenshaw AH (ed) Campbell’s Operative Orthopaedics, 7th edn. Mosby, St. Louis
4. Bonanni F, Rhodes M, Lucke JF (1993) The futility of predictive scoring of mangled lower extremities. J Trauma 34:99–104
5. Mora R (1998) Fissazione esterna: metodiche chirurgiche nel trattamento delle frat- ture esposte. Inquadramento e classificazione. Proceedings of the 9th Congress CIOD, Capri
6. Hulnick A, Highsmith C, Boutin FJ (1949) Amputations for failure in reconstructive surgery. J Bone Joint Surg Am 31:639–647
7. Wilson AB Jr (1967) Classification of amputations by level. Artif Limbs 2:1–16 8. Verni G, Ammaccapane A (2003) La protesizzazione delle amputazioni della gamba.
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9. Ossur Prosthetic Product Catalog (2005). Ossur, Reykjavik
