Prosthetics and Orthotics International

This survey analyses the levels of all major lower limb amputations in Denmark performed in 1980. During that year a total of 2,404 amputations were carried out on 2,177 patients.

The healing in 20 through-knee amputations was compared with preoperatively measured skin perfusion pressure, determined as the minimal external pressure required to stop the washout of isotopes injected intradermally 10 cm distal to the knee joint. Out of 18 amputations with a skin perfusion pressure of above 20 mmHg only 2 failed to heal, whereas 2 out of 4 cases with skin perfusion pressure below 20 mmHg failed to heal. It is concluded that the through-knee amputation must be considered in cases where the circulation is borderline for healing in below-knee amputation.

Laser Doppler velocimetry is a newly available technique for the continuous and non-invasive measurement of capillary perfusion. The technique is presented and preliminary results of its use in the evaluation of amputation levels in 16 patients discussed.

Prediction of healing of ulcers in ischaemic limbs can preclude unnecessary treatment for ulcers that cannot heal. Non-invasive methods are of marked value as the ischaemic limb is susceptible to further ulceration from local skin penetration. Relative hyperemia of the ulcer was measured by scintillation count over the ulcer and at points 2.5 cm from the edge of the ulcer. Relative hyperemia was determined by dividing the count per unit area of the ulcer by the counts per unit area of the surrounding tissue. All ulcers with a relative hyperemia over 1.5 healed.

There is a continuous search for more reliable, locally non-invasive tests for prediction of leg viability and for the selection of amputation levels in dysvascular lower limbs. Refinement of the dermofluorometer by addition of a shielded probe and fibreoptic bundles has reduced the bulk of the instrument and permitted rapid testing. Excitation light is carried to the tissues and emitted fluoresence is returned to a photo multiplier. The Index of Fluorescein Uptake is 20–30 units in control areas. Healing is constant above 15 units, inconstant from 5 to 15 units, and absent below 5 units. Reliability has been virtually 10% in preliminary tests.

The operative technique is described in detail. Pitfalls are emphasized and comparisons made with other techniques.

This paper reviews different types of treatment of the amputation stump. Following an examination of the historical development there are sections on bandaging, semi-rigid dressings, rigid cast dressing and controlled environment treatment. The merits and demerits of each type of treatment are discussed.

Physiotherapeutic treatment considerations specific to the through-knee amputee are presented. Treatment is determined by the assessment findings. The physiotherapy programme includes post-operative exercises, early weight-bearing, bed to chair transfers, bandaging techniques, the counteracting of contractures and gait training. Physiotherapy is a vital part of the rehabilitation of through-knee amputees. Principles of treatment are based on normal human locomotion, the individual patient's health status, biomechanical changes and expected stump functions. The through-knee stump is generally problem free, functional and end-bearing, allowing for a high rehabilitation rate in independent ambulation. It is therefore well suited for the geriatric amputee.

A pneumatic walking training aid for amputees is described. It was developed by the late Biomechanical Research and Development Unit, Roehampton, from an original design by Professor Little in Australia. The walking aid has been used successfully on the majority of below-knee and through-knee patients rehabilitated in the Roehampton Walking Training School since 1976. There have been no complications that could be attributed to the use of the pneumatic walking aid.

In order to reduce the need for repeated changes of socket due to postoperative atrophy and resorption of oedema simple temporary limbs are required to delay the casting of individual sockets until the stump is more mature. A randomized study of 95 below-knee amputees was performed with a re-usable temporary one-size prosthesis of endoskeletal type with adjustable tube length. Total contact was obtained by moulding a thin plastic pillow containing small plastic pellets around the stump in parallel connected sections. As air was evacuated the pillow became rigid. The pillow was kept in place about the stump by Velcro bands. Physiotherapists were able to make all adjustments and ambulate the patient 1–2 hours a day. The training started 2–4 weeks after amputation and lasted for 1–4 weeks. Healing problems due to training did not occur in well healed stumps where training started 3 weeks or more after amputation. No negative influence on maturing of stump, hospital stay and walking ability three months after amputation was found.

The biomechanics of the through-knee prosthesis is considered in detail and comparisons made with the above-knee case. Socket shape and suspension are discussed and comment offered on knee function in both stance and swing phases.

This paper describes a socket design and manufacturing technique for through-knee stumps, based on 14 years experience with 290 prostheses. The bulbous shape of the stump and its full end-bearing quality requires a socket which has very little resemblance to above-knee sockets. The requirements of the through-knee socket are listed and the manufacturing technique is described and illustrated in detail. Emphasis is put on the quality of the negative plaster mould. The socket is manufactured according to the double wall technique commonly used in below-knee sockets. It provides a maximum of comfort and cosmesis without extra costs.

The general characteristics of the through-knee stump are outlined and the casting technique is described in detail.

The most widely used knee mechanisms for through-knee amputees can be characterized as three principal types of design. These types are metal side bars with heavy duty joints, conventional knee mechanisms for above-knee amputees and special polycentric linkage mechanisms for through-knee amputees. An investigation in Sweden in 1979 showed that over 50% of the fittings were using the special polycentric linkage mechanisms for through-knee amputees.

The stability diagram illustrates how voluntary and involuntary stability can be utilized by using different polycentric linkage mechanisms for through-knee amputees. The polycentric linkage mechanism can be designed for different stance phase characteristics as well as incorporation of different swing phase control mechanisms. The cosmesis of the available designs is acceptable but there is need for lighter and more compact designs especially for the young and small amputee.

Amputation surgery for gangrene of the lower limb has two primary goals, to save life and to bring the patients back to their previous living conditions. If this can be achieved with restored walking ability the result of the treatment is considered a full success.

The purpose of this paper is to describe the risk of death and possibility of returning through-knee amputees to their own home, relating the results to other major levels of amputation of the lower limb.

Long-term results over a period of more than 10 years give evidence of the superiority of the through-knee compared to the above-knee stump. However, failures in through-knee stumps before, during and after operation and pitfalls in prosthetic fitting are still too frequent. They are mostly due to errors because the peculiarities of the stump and the prosthetic management are not recognised. This paper emphasizes frequent causes of failure in the selection of the level of amputation, the operative technique, post-operative treatment and prosthetic rehabilitation in order to reduce the complication rate.

Rehabilitation after amputation at through-knee level is described and analysed in relation to amputations at above-knee and below-knee levels.