Outcomes of prosthetic rehabilitation Can we tell who is a candidate for prosthetic rehabilitation?

Statistics on amputations in Oklahoma and the US

"It ain't the shoes." (Spike Lee)

Therapists need to have realistic expectations concerning outcomes when they work with someone with a lower extremity amputation. This summary of recent research can guide those expectations. Some people will have special medical or social problems that interfere with their progress. Others have special talents and qualities that help them overcome daunting problems.

It makes sense that amputees' functional success relates to the level of their amputations. Those with above-knee amputations ought to be less independent, or use their prostheses less, than those whose amputations are below the knee. Some studies support this claim. A review of 157 patients with lower extremity amputations from a North Carolina hospital showed that all but 28 were fit with prostheses. Of the people who received prostheses, eighty-eight used them to walk while 41 did not. Sixty-six percent of those with trans-tibial (below-knee) amputations became functional prosthetic ambulators, as did 46 of those with trans-femoral (above-knee) amputations, but only 19 percent of those with bilateral amputations (Moore, Barron, Hutchinson, et al., 1989).

However, other studies indicate that pre-amputation function predicts success better than level of amputation. A prosthetic rehabilitation team in the VA system studied 95 adults with peripheral vascular insufficiency over three years. They used a seven-level functional grading system to rate patients' ambulation prior to amputation and found that 84 percent eventually walked within one functional level of their pre-amputation status. They concluded that "prosthetic use increased and the use of walking aids decreased with increased functional ambulation levels, but did not correlate with surgical levels" (Pinzur, Littooy, Daniels, Arney, Reddy, et al., 1992, p.239). One Australian study of 200 amputees concludes that "any person previously walking [should] be considered for a trial of prosthetic walking" (Penington, Warmington, Hull, & Freijah, 1992, p.774).

At one end of the functional spectrum are young people who lose limbs due to trauma rather than becaue of an underlying medical problem. A study of 25 young adults (Purry & Hannon, 1989) who had traumatic transtibial amputations revealed that, one year following prosthetic fitting, 84 percent wore their prostheses more than 13 hours a day, 72 percent could walk a mile, and 84 percent considered themselves "slightly or not at all disabled" (p.32).

On the other hand, the prognosis for prosthetic success is more controversial for people who experience serious disease like a stroke before being fit with prostheses. One study of amputees (Harris, van Schie, Carroll, Deathe, Marynia, et al., 1991) noted that people with a "remote or perioperative stroke" were often considered inappropriate for prosthetic fitting. However, the study also noted that of those who were fit with a prosthesis, age was not a factor, with 73 percent of the elderly amputees reaching their rehabilitation goals, "most frequently ambulation with the aid of a walker, which is only slightly less than the younger amputation group" (p.463).

Another study of the rehabilitation outcomes of 46 patients with both hemiplegia and amputation found twelve of the 17 patients who were fitted with prostheses walked independently. Eighteen achieved independence in their ADLs and transfers (O'Connell & Gnatz, 1989).

How do members of the rehabilitation team decide whether someone is likely to succeed using a prosthesis? O'Connell and Gnatz (1989) concluded that the regaining of independent ambulation was associated with the presence of only mild hemiparesis, with residual hand function, below-knee amputation, and a history of ambulation before the second disability. Those who were incontinent of bowel or bladder were significantly less likely to achieve independence in either ADL or ambulation.

Many amputees also have cardiopulmonary and metabolic problems, especially diabetes, and so are at risk at least for amputations of the other limb. A Belgian study (Greant & Van den Brande, 1990) reported a three year mortality rate of 76%, and noted that "contralateral amputation was required in one-third of the patients after a mean period of eight months" (p.288). Similarly, a Swiss study of bilateral amputees (Inderbitzi, Buttiker, Pfluger, & Nachbur, 1992) with advanced vascular disease reported a 69 percent mortality rate after 5 years. It also found the chance that the second leg would be amputated rose at 25 percent per year from the date of the first amputation.

Obviously, many amputees face less than sanguine prospects for long-term functional improvement. Their underlying disease is likely to cause additional problems over time. Cash-strapped (and in some cases, profit-driven) payers will increasingly ask therapists to predict whether an amputee will benefit from a prosthesis. Therapists must be conversant with "K codes," a set of prognostic patient categories initially developed within the Medicare system.

K0

The patient does not have the ability or potential to ambulate or transfer safely with or without assistance and a prosthesis does not enhance their quality of life or mobility.

K1

The patient has the ability or potential to use a prosthesis for transfers or ambulation on level surfaces at a fixed cadence. Typical of the limited and unlimited household ambulator.

K2

The patient has the ability or potential for ambulation with the ability to traverse low level environmental barriers such as curbs, stairs, or uneven surfaces. Typical of the limited community ambulator.

K3

The patient has the ability or potential for ambulation with variable cadence. Typical of the community ambulator who can traverse most environmental barriers and may have vocational, therapeutic, or exercise activity that demands prosthetic use beyond simple locomotion.

K4

Has the ability or potential for prosthetic ambulation that exceeds basic ambulation, exhibiting high impact, stress, or energy levels. Typical of the prosthetic demands of the child, active adult, or athlete.

How the therapist categorizes amputees is important, as it partly determines the limits of a payer's responsibility for prosthetic components and rehabilitation therapy. Most adults with amputations fall into the first three categories, primarily because they have underlying diseases like diabetes that affect many organ systems. I personally feel that "limited household mobility," even of a few months or years duration, improves peoples' quality of life sufficiently that therapists are justified in advocating they be fit with prostheses. However, based on the literature I have reported here, I am not quick to recommend a prosthesis if the person did not ambulate soon before the amputation. I endorse pre-prosthetic therapy for those patients to see if they can, through independent exercise, increase their upper and lower extremity strength, decrease contractures, and begin walking without a prosthesis using assistive devices.

I find it difficult to know when to recommend prostheses for those with advanced cardiopulmonary disease. Ambulation is energy-expensive and potentially risky for these people. At the same time, denying a prosthesis is somewhat paternalistic. Many patients have argued persuasively that the decision and the risk is theirs, not the clinician's: "This leg is not going to kill me; my heart is what's going to kill me." Still, we have to set limits on our humanism, since the fact is that someone other than the patient usually bears the economic costs of prosthetic prescription.

A final note relates to people with bilateral transfemoral (above-knee) amputations, whose condition often owes to advanced vascular disease, and whose cardiac function is often compromised. Although these patients deserve a chance to ambulate, I disagree with any approach unless it begins with foreshortened (stubby) prostheses. The prosthetist should fabricate these so that the posterior socket brims sit about one-half to one inch higher that a patient's wheelchair seat. The person can don and doff such prostheses independently. Any other approach, especially if it involves taller prostheses or the initial inclusion of knee joints, dooms the patient to frustration and failure.

Our role as therapists is not just to reduce edema, prevent contracture, or alleviate pain. Our primary role is to help people improve their function, however they define it. We also want to help people avoid further disability (including another amputation) due to their underlying disease. Remember above all that success owes as much to the person as it does to any skill we or the prosthetist might possess. Keep in mind Spike Lee's dictum for the ages: "It ain't the shoes."

References:

Greant, P., & Van den Brande, P. (1990). Amputation in elderly and high-risk vascular patients. Annals of Vascular Surgery, 4, 288-90.

Harris, K.A., van Schie, L., Carroll, S.E., Deathe, A., Maryniak, O., Meads, G.E., & Sweeney, J.P. (1991). Rehabilitation potential of elderly patients with major amputations. Journal of Cardiovascular Surgery, 32, 463-467.

Inderbitzi, R., Buttiker, M., Pfluger, D., & Nachbur, B. (1992). The fate of bilateral lower limb amputees in end-stage vascular disease. European Journal of Vascular Surgery, 6, 321-6.

Moore, T.J., Barron, J., Hutchinson, F, et al. (1989). Prosthetic usage following major lower extremity amputation. Clinical Orthopedics and Related Research, 238, 219-224.

O'Connell, P.G., & Gnatz, S. (1989). Hemiplegia and amputation: Rehabilitation in the dual disability. Archives of Physical Medicine & Rehabilitation,70, 451-454.

Penington, G., Warmington, S., Hull, S., & Freijah, N. (1992). Rehabilitation of lower limb amputees and some implications for surgical management. Australian & New Zealand Journal of Surgery, 62, 774-779.

Pinzur, M.S., Littooy, F., Daniels, J., Arney, C., Reddy, N.K., Graham, G., & Osterman, H. (1992). Multidisciplinary preoperative assessment and late function in dysvascular amputees. Clinical Orthopedics and Related Research, 281, 239-243.

Purry, N.A., & Hannon, M.A. (1989). How successful is below-knee amputation for injury? British Journal of Accident Surgery, 20, 32-36.

Additional resources:

Cutson, T.M., & Bongiorni, D.R. (1996). Rehabilitation of the older lower limb amputee: A brief review. Journal of the American Geriatrics Society, 44, 1388-1393.

Johnson, V.J., Kondziela, S., & Gottschalk, F. (1995). Pre and post-amputation mobility of trans-tibial ampoutees: Correlation to medical problems, age, and mortality. Prosthetics and Orthotics International, 19, 159-164.


AMPUTATIONS, UNITED STATES, 1991
(Mueller, Allen, & Sinacore, 1995)

90-96% of all amputations in the US involve lower limbs.

AMPUTATIONS, OKLAHOMA, 1987-1991
Lee and her colleagues (1993) obtained baseline information on 1012 Oklahoma Indians between 1972 and 1980, then rechecked about 875 of the same people between 1987 and 1991.

first time amputation rate
(per 10,000 people)

Oklahoma

180

Ontario

40

USA

60

UK

100

References:

Fylling, C.P., & Knighton, D.R. (1989). Amputation in the diabetic population: Incidence, causes, cost, treatment, and prevention. Journal of Enterostomal Therapy, 16, 247-55.

Lee, J.S., Lu, M., Lee, V.S., Russell, D., Bahr, C., & Lee, E.T. (1993). Lower-extremity amputation. Incidence, risk factors, and mortality in the Oklahoma Indian Diabetes Study. Diabetes, 42, 876-882.

Mueller, M.J., Allen, B.T., & Sinacore, D.R. (1995). Incidence of skin breakdown and higher amputation after transmetatarsal amputation: Implications for rehabilitation. Archives of Physical Medicine and Rehabilitation, 76, 50-54.


Last updated 5-18-01 ©Dave Thompson PT