The appraisal of functional status is routine in medical rehabilitation, including ambulation status after inpatient rehabilitation programs. [1-13] A review of the recent literature, however, failed to show reports of functional outcomes for bilateral lower limb amputation.
In 1984 a seven-year retrospective review of the population admitted to a major metropolitan rehabilitation center described the characteristics of patients with lower limb amputation.  The review, when compared with national surveys done one and two decades previously, [15,16] indicated an increase in mean age, an increase in the number of below-the-knee over other amputation levels, and an increasing number of amputees readmitted for bilateral prosthetic training.
Sakuma and co-workers reported in 1974 their study of 53 elderly patients who had undergone bilateral lower extremity amputations.  They found that 50% of amputees with preservation of at least one knee joint could become ambulatory with prostheses for self-care purposes. They also concluded that a rehabilitation program was beneficial for both users and nonusers of prostheses.
Also in 1974, Kerstein and associates reported their study of 194 major amputations over a ten-year period.  Of the total group, 23% had bilateral amputations. At the conclusion of a 22-week postamputation rehabilitation program, 80% of the patients were able to return home and 70% of all patients were able to walk with just the use of a single cane or without aids.
The purposes of this study was to document patients' functional results after bilateral lower limb amputation on discharge from an impatient rehabilitation program and at one month and three months after discharge. As the number of patients with bilateral lower limb amputations increases, there is a greater need to examine closely the efficacy of rehabilitation programs that have ambulation training as a goal. 
Patients and Methods
All patients with bilateral lower limb amputations who presented to a regional amputee rehabilitation center over an 18-month period (from July 1988 through December 1989) were selected. The outpatient records were reviewed retrospectively for the following information: Patient demographics, including age and sex, amputation levels, length of inpatient rehabiligation stay, and disposition on discharge; and functional mobility on discharge, at one month, and at three months after discharge.
The levels of amputation were defined as partial-foot, to include toe, Syme's, and transmetatarsal amputations; below-knee; and above-knee amputations. During the 18-month period, none of these patients had hemipelvectomy or hip disarticulation as their secondary amputation site.
Patients' functional status was examined on discharge and at one and three months after discharge in 41 cases; 20 were not included in this portion of the analysis because of transfers to acute care hospitals or loss to outpatient follow-up.
Patients' functional status falls into the following five groups:
* A limited household ambulator is a person who can use a prosthesis only in the home to ambulate independently and perform self-care activities. The distance for a limited household ambulator is less than 37 m (120 ft).
* A household ambulator can walk more than 37 m and performs all of the activities of daily living using prostheses.
* A limited community ambulator is a patient who can walk 152 m (500 ft), can participate in some avocational activity, but is not gainfully employed.
* A community level ambulator is one who can walk more than 152 m, engages in vocational and avocational activities, including driving with the prosthetic devices, and is gainfully employed.
* Although the wheelchair is used by all of them to attain greater mobility within the home or community, a person who uses a wheelchair exclusively for all mobility and activities of daily living is defined for the purposes of this study as a wheelchair user.
Over an 18-month period, 2,941 patients were admitted to a major metropolitan rehabilitation center. Of these, 314, or 11%, were admitted to the regional amputee rehabilitation program and 61, or 19.4%, had bilateral lower limb amputations. As illustrated in Figure 1, the most frequent level of amputation was below both knees (25 patients or 41%), followed by below and above the knees (14, or 23%), and above both knees (12, or 20%), with less frequency of bilateral partial-foot, partial-foot and below-knee, and partial-foot and above-knee amputations.
Of the 61 patients, 41, or 67%, were men. Ages ranged from 29 to 88 years, with the average age being 61.5 years.
Figure 2 shows the average length of stay on the impatient rehabilitation program, which for all amputations was 23.9 days and for bilateral amputations was 24.2 days, with the range being 3 to 78 days. The average length of stay for below-knee and partial-foot amputations was 37.8 days, although one patient's hospital stay was prolonged because of disposition problems, and the patient was eventually placed in a nursing home. The correlated average length of stay for this level of amputation was then 32.7 days.
Of the 61 patients, 47, or 77%, were discharged to home, 12 (20%) required transfer to acute care hospitals for medical or surgical complications, and only 2 patients were transferred to a nursing home for long-term care.
Of the 47 patients discharged to home, 17, or 36%, achieved a limited household level of ambulation at the time of discharge, 12 were dependent on a wheelchair for all mobility, while 10 attained a household level of ambulation. Only 8 achieved community ambulation of some level (Figure 3-A).
At the one-month follow-up, most patients were at the wheelchair level of function, with the other patients evenly scattered among the other categories. Further analysis of the data revealed that of those patients at a limited household level of ambulation at the time of discharge, 7 (41%) maintained their level of function and 6 advanced to the household level; 8 patients were lost to follow-up (Figure 3-B).
At the three-month follow-up, those patients who were previously walking at a limited household level regained this level. Most patients achieved limited household ambulation at three months (Figure 3-C).
The patients who were functioning at a higher level at the time of discharge were noted to maintain or improve their level of functioning over the three months. Those patients discharged at a wheelchair level were either lost to follow-up or remained at the wheelchair level. Few (3, or 8%) of these advanced to walking at some time in the three-month period.
Of the 17 patients with bilateral below-knee amputation (Figure 4), 6 (35%) achieved limited household ambulation at the time of discharge; of these, at the one-month follow-up some had maintained function but others declined. By three months, however, these patients had advanced to household walking and even limited community walking. Those patients achieving on discharge a high level of functional mobility were able to attain and maintain limited community and community ambulation during the three months.
Similarly, persons with below- and above-knee amputations (Figure 5) achieved limited household mobility on discharge and advanced to household walking, with few advancing to limited community and community ambulation; about a third remained at the wheelchair level.
Although most of the patients with above-knee amputations were independent at the wheelchair level at the time of discharge (Figure 6), some achieved a limited household level of walking and maintained this up to three months after discharge.
A review of the rehabilitation literature failed to elicity any recent information regarding the functional mobility outcomes of patients with bilateral lower limb amputations.
In this limited study, we found that person's with bilateral lower limb amputations deserve a comprehensive rehabilitation program to attain (and maintain) goals of limited household walking. Further studies should examine the role concurrent disease plays in determining the appropriateness for prosthetic management; the cost-effectiveness; and the longterm benefits, both physical and psychosocial, of attaining the highest possible functional level.