Some Experience with Patellar-Tedon-Bearing Below-Knee Prostheses
Frank A. Witteck, B.M.E. *
In the latter part of 1958, prothetists
of the Limb and Brace Section of the U. S. Veterans Administration Prosthetics
Center, New York City, were indoctrinated in the technique of fabricating the
patellar-tendon-bearing (PTB) cuff-suspension below-knee prosthesis. Preliminary
experience encouraged VAPC to institute in the spring of 1959 a form of clinical
study. Selection of the patients fitted with the PTB prosthesis was not
rigorous, potential wearers being recruited from among veteran beneficiaries
having an approved request for a new or a spare below-knee prosthesis.
Availability for follow-up examinations was an important consideration, and many
patients otherwise acceptable were excluded because, as it turned out, they were
unable, for one reason or another, to make themselves available for the several
necessary one-hour follow-up visits to the VAPC clinic. Several patients sent to
VAPC from other VA Regional Offices were included in the study even though the
distance from residence to fitting facility posed problems.
Although from the standpoint of fitting
the study was concluded in November 1960, follow-ups continued through September
1961. During the 21-month period, 53 adult, male, below-knee amputees were
selected for participation. With a few exceptions, all had been wearing
conventional below-knee prostheses-carved wood socket, side joints, and leather
thigh corset, or lacer. Two had only recently undergone amputation, and their
initial fittings were with the PTB prosthesis. Fifteen cases
out of the 53 were selected for discussion in some detail in this summary. They
represent the types of adult male amputees seen in Veterans Administration
clinics throughout the country. In addition to those amputees who present no
problems and who are therefore fitted successfully with a minimum of difficulty,
there are included those who had been wearing a prosthesis with a thigh corset
that furnished either partial or full ischial weight-bearing, those whose
previous prostheses had sockets of varying types (i.e., soft, slip,
suction, etc.), those who had worn a number of different types of prostheses
over the years, and those who had worn the same prosthesis for 15 years.
Included also are recent amputees who were to be fitted for the first time, as
well as one typical bilateral below-knee amputee who benefited by use of PTB
fitting concepts.
Fifteen Case Histories
Case 5 (J. D.)
Case 5, a 43-year-old dock checker 5 ft.
11 1/2 in. tall and weighing 178 lb., lost his left leg below the knee as a
result of a mortar-shell explosion. Simultaneously, he lost some muscle power in
his left hand. While the patient was hospitalized from March 1945 to March 1947,
a revision was performed on the stump, and first fitting was with a prosthesis
having a wood socket large enough for two stump socks to be worn. A long thigh
corset had a strap-and-buckle arrangement to facilitate harnessing with the
right hand. Succeeding prostheses were of the same type. Gait was
fair.
When the patient was first seen at VAPC,
his stump was 4 in. long and conical. There was evidence of chronic infection in
the vicinity of the patellar tendon, the skin over the patella and over the medial tibial condyle was
tender, and there was some scarring over the head of the fibula. In February
1960, a PTB prosthesis with side joints and thigh corset was delivered, but the
patient did not report for follow-up examination until the following August. At
that time he returned the prosthesis and requested fitting with the conventional
type. Although he had worn the prosthesis only occasionally on weekends for a
few hours at a time, he complained of excessive piston action and irritation of
the skin in the popliteal area and claimed that he could not take time off from
his job for the necessary socket modifications.
The clinic recommended that a
conventional type of below-knee prosthesis be fabricated for this patient
because of his inability to cooperate through no fault of his own.
Case 9 (A. E.)
Owing to complications of diabetes, Case
9, a 44-year-old postal worker and part-time stevedore weighing 190 lb. and
standing 5 ft. 10 in., underwent a left below-knee amputation in 1944. The
prostheses issued over the years were always of the conventional type with
carved wood socket, side joints, and thigh corset.
When, in October 1959, the patient was
first seen by the VAPC clinic, the 6-in. stump was in excellent condition,
quadriceps and hamstring muscle groups were adequate. Gait was poor, and
training was recommended. A PTB prosthesis was delivered in late October 1959,
but the patient failed to report for any follow-up examinations until June 1960,
whereupon it was discovered that the prosthesis had been worn during the first
three months only. The patient claimed that during the following five-month
period he had never been able to come in for socket modifications. Gait was
still poor. A new PTB prosthesis was prescribed and finally delivered in October
1960, and the patient was cautioned to use it gradually until he could wear it
for eight-hour periods without difficulty. When seen again in March 1961, the
patient claimed that he could wear the prosthesis after work and on weekends
with little or no difficulty but that he found the conventional prosthesis with
sidebars and thigh corset better for the heavy labor in both
his regular and his after-hours jobs. The clinic team felt that the use of the
two different prostheses was a reasonable approach in this case. It was
recommended that this procedure be followed until the PTB prosthesis could be
worn full time without difficulty. A follow-up made several months later showed
that the patient was able to put aside the conventional prosthesis and wear the
PTB type comfortably.
Case 15 (D.H.)
Case 15, a 54-year-old information
officer weighing 220 lb. and standing 6 ft. 3 in., had his right leg amputated
in September 1944 as a result of wounds from shellfire. A final surgical
revision was performed in December 1944 leaving a stump 7 1/2 in. long. The
prostheses worn had all been of the conventional type- carved wood socket, side
joints, and thigh lacer.
The patient was fitted with a PTB
prosthesis in November 1958 prior to the institution of the study. He received a
second, or spare, prosthesis in the summer of 1959 and at that time accepted a
job assignment in the Midwest. Thereafter his prosthetic needs were accommodated
by a shop in his new location.
The patient is extremely active and does
not spare his prosthesis. The SACH foot, for example, required replacement after
several months of use. Because of wear, at least four socket inserts were made
within a six-month period. Although the horsehide linings were worn through in
the areas of weight-bearing, there was no stump discomfort. According to a
letter report, both the SACH foot and the socket insert had to be replaced again
because of wear. Despite these difficulties, the patient was extremely pleased
with the PTB prosthesis and continued to use it.
Case 17 (F. H.)
In June 1947, Case 17, a 42-year-old
salesman weighing 185 lb. and standing 6 ft. 3 1/2 in., had his right leg
amputated below the knee owing to gunshot wounds. Because of pain in the stump,
he later underwent surgery twice for removal of neuroma, and a sympathectomy
also was performed. Referred to the VAPC clinic in March 1959 by another VA
Regional Office, he complained of stump pain which could be relieved only by not wearing the
prosthesis, a slip-socket type worn over three stump socks. Examination of the 6
1/2-in. stump revealed a reddened scar in the popliteal area and discoloration
and sensitivity in the vicinity of the fibular head such that slight tapping
with the fingers produced shooting pains in the stump.
The initial prescription for this patient
was a soft-socket prosthesis with a thigh corset designed for ischial
weight-bearing. The prescription was filled in April 1959, but having worn the
prosthesis only four hours the patient complained of pain and numbness in the
stump. He felt that the thigh corset was cutting off circulation and "choking"
the stump. Because the patient claimed that he could take weight-bearing on the
stump, the thigh corset was loosened, whereupon he walked painlessly. Upon
re-evaluation of the case, the prescription was modified to PTB fitting. But
before the PTB prosthesis could be delivered the patient was hospitalized for
pancreatitis, and delivery could not be made until June 1959. In the three
months thereafter, several socket modifications were required-in the area of the
tibial crest, about the medial tibial condyle, and in the region of the patellar
tendon. Discharged from the hospital and back at work, the patient reported that
he was comfortable and free of stump pain with the PTB prosthesis. But later, in
February 1960, the patient was reported to have died, cause not
given.
Case 19 (W.H.)
Case 19, a 41-year-old VA prosthetics
specialist weighing 190 lb. and standing 5 ft. 8 in. tall, suffered irreparable
damage to both legs in March 1944 as a result of gunshot wounds. Amputation of
both legs below the knee was necessitated. Revision of the stumps was carried
out in July 1944.
This patient was able to tolerate almost
full end-bearing on both stumps (3 1/2 in.), and accordingly conventional
prostheses were made with closed-end sockets to take advantage of the ability to
carry weight on the stump ends. Some years later, when SACH feet were used on
his prostheses, the patient complained of insecurity and a poor gait pattern.
Hence, the feet and ankles used subsequently were of
the conventional type.
A pair of PTB prostheses was provided in
November 1959, the initial fittings being attempted without side joints and
thigh corsets. But it was quickly determined that there was mediolateral
instability and a tendency for the knee to hyperextend. Inasmuch as the patient
obviously did not have to rely upon full thigh corsets for weight-bearing,
whereas side joints were indicated, a combination of side joints with reverse
thigh bands (Fig. 1) was tried. This arrangement was found to be effective both
in providing mediolateral stability and in preventing hyperextension of the
knee. When, on one of his infrequent visits to the Center, the patient returned
to the shop for modification of the sockets, the distal ends of both were
modified to permit insertion of additional pads for increased weight-bearing,
the new inserts being prepared from a rubber of durometer higher than that used
formerly.
The modified prostheses are now worn for
periods of five to six hours per day, but major use is still made of the older
prostheses. The "weaning process" is a slow one.
Case 21 (J. M.)
Case 21, a 36-year-old, 140-lb. telephone
coordinator 5 ft. 11 in. tall, suffered irreparable injuries to his right leg
when he stepped on a landmine. Amputation of the leg below the knee was
performed early in 1944. There was no further surgery. For eight years the
patient had been wearing, with little or no difficulty, a conventional
below-knee prosthesis with a modified thigh corset giving ischial
weight-bearing.
The stump, 6 3/4 in. long, was conical in
shape. Pressure on a sensitive area over the posterodistal aspect of the stump
just above the end radiated pain up the thigh, apparently along the course of
the sciatic nerve. There was the usual atrophy of the thigh on the side of the
amputation, but knee motion was good.
Upon delivery of a PTB prosthesis in
August 1959, the patient's initial comments referred to a change in gait
pattern-to the inability to take a full step as he could with his old
prosthesis. During the first 90 days of use, several socket modifications were
made, relief being given about the medial tibial
condyle, the crest of the tibia, and the distal end of the stump. To accommodate
stump shrinkage, the patellar-tendon area was built up to restore proper
weight-bearing. A spare socket insert, to permit change of liner every day, was
provided in an attempt to alleviate a perspiration problem.
The patient continued to wear his
prosthesis without incident until June 1960, at which time a spare PTB
prosthesis was prescribed. The major complaint after 30 days of wear of this
limb had to do with excessive perspiration. The horsehide liner showed signs of
cracking, and a vinyl plastic ("Doe-Lon") was substituted for the horsehide.
Washing and drying this insert at the end of each day minimized the adverse
effects of perspiration on the liner.
At last report the patient was still
wearing his new prosthesis and had no wish to return to the older conventional one. He was
pleased with the coincident weight reduction of the prosthesis-from 7 1/2 to 4 1/2 lb.
Case 25 (S.M.)
Case 25, a 42-year-old retailer weighing
195 lb. and standing 6 ft., suffered irreparable damage to his right leg in
October 1944 when he stepped on a landmine. Amputation below the knee followed.
Numerous metallic foreign bodies remain in the left leg and in both
hands.
The first prosthesis worn by this patient
was of the conventional type-carved wood socket, side joints, and thigh corset.
Subsequent prostheses had soft sockets instead of the carved-wood type. Patient
was always fitted with, and wore, two wool stump socks, and he was a frequent
visitor to the shop for socket modifications and limb repairs. The stump was in
excellent condition, conical, and 6-3/4 in. long.
In March 1960, when a PTB prosthesis was
made, it was noted that, as usual, the patient wished to wear two stump socks.
The patient was insistent that the socket be made accordingly. With the new PTB
prosthesis, he was able to sit more comfortably because he could now flex his
knee to 145 deg. as compared with 80 deg. with his old prosthesis. The PTB
prosthesis also felt lighter than any of those previously worn.
In a follow-up examination three months
later, the patient claimed that the fit was still good even though he had lost
some weight. Some stump irritation was evidently due to excessive
perspiration.
The patient was seen again in September
1960, at which time a new cuff suspension strap was provided and socket
modification was required to relieve pressure in the antero-distal area. The
perspiration problem was alleviated by a change during the day of one of the two
stump socks he was wearing. The fresh, dry sock was worn next to the stump.
There had been no stump breakdown since application of the PTB prosthesis, and
at last report the patient was still wearing his appliance
comfortably.
Case 26 (W.O.)
Case 26, a 30-year-old claims adjuster
and part-time professional golfer weighing 150 lb. and standing 6 ft., had his
right leg amputated below the knee in November 1952 as the result of a landmine
explosion. A surgical revision of the stump was done later the same year. The
stump was cylindrical and 6 1/2 in. long, skin type was classified as tough,
there was minimum distal padding, the quadriceps muscle group was strong, and
there was only slight atrophy of the thigh on the side of the
amputation.
The first prosthesis had a soft socket
fitted in a laminated fiber shank with side joints and thigh corset, the foot
and ankle being of the Navy type (i.e., with a two-durometer rubber ankle
block). The second and third prostheses were similar except that the shanks were
made of wood. The Navy ankle assisted in providing the pivoting action necessary
in playing golf. Gait was excellent.
In April 1960, a PTB prosthesis with
SACH foot was delivered to the patient, but he
returned after a week and asked to have the SACH foot replaced with a Navy-type
foot and ankle. The SACH foot, he claimed, did not give him the function he
desired-primarily the pivoting action or rotation at the ankle. Replacement was
made to the patient's satisfaction.
After the prosthesis had been worn five
months, the socket was modified to provide additional relief for the medial
hamstring area. Perspiration was not a problem. The patient was well satisfied
and more comfortable. At last report the prosthesis had been in use for nine
months with an average wearing time of 12 to 16 hours per day. A spare PTB
prosthesis was fabricated.
Case 27 (C. Q.)
Case 27, a 43-year-old sheetmetal worker
weighing 175 lb. and standing 6 ft. 2 in., had his right leg amputated below the
knee in June 1945. In November 1947, a right lumbar sympathectomy was performed
in an attempt to relieve intractable pain. Several weeks later a revision of the
stump was carried out. But the patient continued to complain of pain in the
stump and was again admitted to the hospital in June 1948, when the sciatic and
saphenous nerves were sectioned. Stump pain persisted, and in January 1956
further surgery was performed. The remnant of the fibula was removed; the distal
portion of the right deep peroneal nerve was identified, resected out, and
divided high; and the stump was injected with 50-percent alcohol. Final
diagnosis on discharge in January 1956 was "abnormal amputation stump
characterized by pain, right lower extremity below the knee."
From 1946 to 1957, the patient had
received six conventional carved-wood-socket below-knee prostheses, six new
carved-wood sockets, and two major repair jobs, including the addition of
ischial-bearing thigh corsets. In February 1957, a soft-socket plastic-laminate
below-knee prosthesis was prescribed and delivered by VAPC. Numerous complaints
of pain and irritation made it necessary to deliver another prosthesis in
October 1957. In September 1958, the patient was hospitalized for removal of a
foreign-body granuloma from the right knee.
In January 1959, the patient was again
hospitalized for possible revision of the 6 1/2-in. stump to a Gritti-Stokes
type of amputation, but it was decided that conservative management should be
continued before institution of any further surgical procedures.
In February 1959, the patient reported to
the VA Prosthetics Center for delivery of a PTB prosthesis. At the time, he was
wearing a prosthesis with a slip socket and long thigh corset. The patient spent
ten days at the Center to assure a satisfactory fitting and returned in March
1959 for socket modifications. Contrary to advice given him he had tried to walk
with the prosthesis without using the cuff supension strap. The results were
predictable: prosthesis slipped off, patient fell and damaged his stump. A
modification of the socket corresponding to the area of the tibial tubercle was
made, and a spare insert was fabricated.
In December 1959, the patient again
reported to the Center with complaints of an ill-fitting prosthesis.
Arrangements were made to fit and fabricate a new PTB prosthesis. As a stopgap
measure, an insert using thicker rubber was provided, and the new prosthesis was
delivered later in the month. When the patient was seen again after 30 days
(mid-January 1960), he was experiencing pressure on the distal end of the stump.
Suitable relief was provided by building up the socket in the patellar-tendon
area. Because of excessive perspiration, a spare insert was furnished at this
time.
The patient has not been seen at the
Center since January 1960. Reports indicate that the litany of complaints is
again being recited. Patient's stump seems to be in good condition and is as
well fitted as possible, but the case remains a problem. The consensus is that
past objective difficulties, perhaps complicated by emotional overtones, have
resulted in an unusually strict standard for comfort.
Case 42 (E. B.)
Because of a landmine explosion in 1945,
Case 42, a 37-year-old accountant weighing 170 lb. and standing 5 ft. 10 1/2
in., was subjected to amputation of the left leg below the knee. A revision performed later that
year left deep folds and scars on the end of the stump. The right ankle had been
fractured, and with increased activity it became swollen and painful.
The first, second, and third prostheses
worn by this patient were of the conventional type- carved wood socket, side
joints, and thigh corset. The fourth prosthesis substituted a "muley" type of
suspension for the side joints and thigh lacer. The fifth and sixth prostheses
were suction-socket prostheses , a type worn by the patient for
almost two years. The patient claimed to be comfortable in the suction socket
but was concerned about the increasing edema at the stump end.
The 9-in. stump had an hourglass shape,
and the distal end was edematous and discolored (Fig. 2). There was evidence of
many old ulcerations on the distal end, and during weight-bearing the tissue
overlapped the socket brim (Fig. 3).
A course of whirlpool therapy was
instituted to reduce the edema as quickly as possible, and a PTB prosthesis with
a functional ankle was prescribed and delivered in July 1960. When, after 30
days, the patient was seen again, the edema had been reduced and the skin color
was lighter. Three months later, in November 1960, the patient again reported to
the clinic. The prosthesis had been worn routinely since delivery, and the
hourglass shape of the stump was not as prominent. Discoloration was still
evident but greatly reduced. The patient claimed that perspiration had increased
so that the liner had to be dried each evening. Accordingly, a spare insert was
furnished.
Case 44 (T. MCA.)
In February 1960, Case 44, a 38-year-old
sheetmetal worker weighing 185 lb. and standing 5 ft. 10 in., had his right leg
amputated below the knee because of chronic osteomyelitis. At the distal end the
stump was slightly edematous, a condition not unexpected at eight weeks
postamputation. The 7 1/2-in. stump was slightly bulbous. There were no
sensitive areas.
The prescription for the PTB prosthesis,
this patient's first artificial limb, contained instructions that the socket was to be
mounted on an adjustable pylon as a shank (Fig. 4). Because the amputation was
so recent, considerable stump shrinkage was anticipated, and it was felt that
the use of the adjustable pylon would facilitate socket replacement and the
necessary alignment changes as anticipated. A PTB prosthesis was delivered in
April 1960, the pylon shank being concealed by a plastic-laminate cosmetic
cover. After 30 days of wear, the socket needed modification in the areas of the
patellar tendon, the flare of the medial tibial condyle, and the crest of the
tibia. Several alignment changes were required, and the patient complained of
excessive perspiration of the stump.
The pylon-type prosthesis, with modified
socket and alignment, was worn until June 1960, at which time a new "permanent
type" PTB prosthesis was delivered. A spare socket insert was furnished to help
alleviate the perspiration problem. The new limb, lighter by 1 1/2 lb.
than the pylon-shank prosthesis, added to the patient's satisfaction. Subsequent
follow-ups revealed no new problems.
Case 46 (R.R.)
Case 46, a 58-year-old assistant director
of athletics weighing 192 lb. and standing 5 ft. 10 1/2 in., had his left leg
amputated in 1945 as a result of severe leg wounds suffered in 1944. No further
surgery was necessary. Prostheses had all been of the conventional type-carved
wood socket, side joints, and thigh lacer.
The stump was 9 in. long and bulbous. A
nonadherent, longitudinal scar, 7 3/4 in. long, extended up the back of the
stump from the anterodistal aspect to the mid-posterior aspect. There was some
sensitivity of the stump end to palm pressure. Skin type was classified as
delicate.
A PTB prosthesis was delivered in June
1960, and the patient returned two months later for socket modifications. During
this period, the patient had done some mountain climbing and stream fishing,
activities which probably expedited stump shrinkage. The weight-bearing areas
were restored by building up in the areas of the medial and lateral
tibial condyles and of the patellar tendon. After another 30 days, the patient
returned with the complaint that the posterior scar had been irritated and
opened up. Playing baseball did little to help the situation. Whirlpool
treatment expedited healing. The socket was relieved to prevent a recurrence of
this irritation, and a spare socket insert was provided.
As of last report, the patient continues
to wear the PTB prosthesis satisfactorily and without discomfort. He has
requested a spare prosthesis of the same type.
Case 47 (H.H.)
Case 47, a 44-year-old sales
representative weighing 160 lb. and standing 5 ft. 10 in., had his right leg
amputated below the knee in 1944 as the result of severe wounds. Two surgical
revisions were performed in 1947. The stump was 6 1/2 in. long,
cylindrical in shape, and classified as redundant. Because of discomfort, all of
his prostheses, though otherwise conventional, had been made with a modified
ischial-weight-bearing thigh lacer.
A PTB prosthesis was delivered in August
1960. At follow-up examinations it was learned that no difficulty had been
experienced as a result of going from one type of weight-bearing to a radically
different type. The patient preferred the intimate fit, and he expressed the
opinion that the prosthesis seemed more a part of him rather than an
appendage.
Case 49 (V.M.)
Case 49, a 43-year-old, 185-lb. VA
contact representative 5 ft. 10 in. tall, suffered severe injuries to his left
leg from a shell explosion. Amputation of the leg below the knee was performed
in July 1944. Two surgical revisions were done in 1950.
This amputee had worn the conventional
type of below-knee prosthesis with carved wood socket, side joints, and thigh
lacer. When seen at the VAPC clinic early in 1960, he was wearing a Blevens-type
prosthesis that had been issued him in 1956. He was satisfied with the
prosthesis, but it was badly in need of repair. The stump, cylindrical and 7
1/4 in. long, showed evidence of multiple skin ulcerations and numerous
areas of infection. A PTB prosthesis was prescribed and
delivered in July 1960.
Follow-up examinations showed great
improvement in the condition of the stump. The prosthesis was worn routinely for
14 to 16 hours a day.
Case 51 (J.W.)
Case 51, a 43-year-old editor weighing
165 lb. and standing 5 ft. 11 1/2 in. tall, lost his right leg below the knee as
the result of a landmine explosion. Amputation was performed in October 1944,
and a revision was effected early in 1945. The patient's stump was in excellent
condition, conical, and 7 1/2 in. long. Musculature was
active.
The prosthesis that the patient was
wearing was the first one issued to him, some 15 years earlier. It had a leather
socket in a fiber shank, side joints, and thigh lacer (Fig. 5). A second
prosthesis had been made in 1950, but it had never been worn because the
original prosthesis had been so comfortable and generally satisfactory. As a
result of the clinic team's examination and recommendation, the patient was
willing to try the PTB prosthesis.
In July 1960 a PTB prosthesis was
delivered. At a follow-up examination made after 30 days, the patient reported
great satisfaction with the prosthesis. He wore it 14 to 16 hours a day and felt
it was lighter, more comfortable, and "easier walking" than his old prosthesis.
He also appreciated the freedom from sidebars and thigh corset. Subsequent
follow-ups merely confirmed earlier impressions.
Summary
Details covering these 15 cases, and also
some information on the 38 others, are summarized in Table 1,Table 1 Cont.. Although the study
was concluded in November 1960, wear-experience data were carried to September
1961. Experience has shown that as stump changes occur certain modifications are
more prevalent than others. In 27 cases, modifications (build-ups) were required
in the area of the patellar tendon and in the popliteal region. The necessity
for this type of modification was evidenced by pressure at or on the distal end
of the stump, and the discomfort could be alleviated by restoring the stump to its proper
position in the socket by building up on the socket shell.
In 24 cases it was necessary to modify
the socket in the area of the flare of the medial tibial condyle, a modification
also of the buildup type. Since the medial flare has excellent weight-bearing
ability, a good fit in this area is essential.
The medial hamstring area of the socket
had to be relieved or lowered in 15 instances. In general, the socket brim was
made lower for proper accommodation of the medial hamstring than for the lateral
hamstring.
Seven cases experienced pressure on the
crest of the tibia, a condition that was relieved by building up the socket
shell on both sides of the tibial crest.
In 14 cases, stump shrinkage after one to
three months of wear made it necessary to fabricate new PTB sockets. These
amputees all had either fleshy or bulbous stumps and in some cases both
conditions prevailed.
Perspiration had been anticipated as a
major problem with the PTB socket, but only 16 cases complained of excessive
perspiration. For these cases spare inserts were provided. The facility with
which inserts can be changed makes such a measure practical.
Conclusions
Experience in the fitting of PTB
prostheses has led to some general prescription criteria. The amputee should
have a sound, stable knee. Instability of the knee that cannot be corrected by
physical therapy is a contraindication to the use of a PTB prosthesis without
thigh lacer.
Caution should be exercised in
prescribing a PTB prosthesis for heavy individuals. They often cannot tolerate,
for long, full weight-bearing on the stump and will often require the additional
support of a thigh lacer.
The amputee with a long stump (i.e.,
with an amputation in the lower third of the leg) can, and does, present
many problems. Often there are circulatory complications. Achievement of the
required intimate fit is much more difficult. Proper fit and alignment can be
arrived at initially but are difficult to maintain over long periods of
time.
Similar comments can be made regarding
sensitive stumps and those that are badly scarred. These should be treated with
particular care.
The bilateral below-knee amputee presents
another special situation. It is often feasible to limit the use of the PTB
prosthesis to one side only. After a period of successful, problem-free wear, a
fitting can be attempted on the other side. In general, one may say that
prescription for bilateral fitting should be limited to young, slender amputees
of average weight.
Another factor of prime importance is the
skill and ability of the prosthetist. His talents must be brought into full play
to achieve a good socket fit. Use of an adjustable
alignment device is mandatory. The old cut-and-try methods have no place in the
fitting and alignment of the PTB prosthesis.
Finally, the amputee should be oriented,
or indoctrinated, by the clinic team even before fitting of a PTB prosthesis is
attempted. In general, initial PTB fittings are much less troublesome to the
patient than are initial fittings with a conventional carved below-knee socket.
In the PTB case, therefore, the amputee may be lulled into an overly optimistic
belief that the initial level of comfort will always continue. To avoid any
disappointment on the part of the wearer, the clinic team should make clear the
substantial possibility that stump changes and other factors may later
necessitate socket modifications. Because, indeed, the usual indications for a
change in socket fit are not as sharply defined in the PTB socket as they are in
the conventional wood socket, it is essential that the clinic team plan for
periodic follow-up examinations over a relatively long period until the stump
reaches a comparatively stable condition. Similarly, the patient himself should
be prepared to give adequate time for the examinations (and, if need be, for
socket modifications), and he should be encouraged to be constantly on the alert
for subtle but progressive changes that might signal impending difficulties.
Persistence on the part of the team, together with investment of the amputee's
time and interest, leads eventually to a significant return in the form of a
comfortable, well-fitting, and functional prosthesis without the restrictions of
sidebars and thigh corset.
References:
- Murphy, Eugene F., The fitting of below-knee prostheses, Chap. 22 in Klopsteg and Wilson's Human limbs and their substitutes, McGraw-Hill, New York, 1954. Pp. 723-724.
- Murphy, Eugene F., Lower-extremity components, Chap. 5 in Atlas of orthopaedic appliances, Vol. 2, Edwards, Ann Arbor, Mich., 1960. P. 221.
- Murphy, Eugene F., Lower-extremity components, Chap. 5 in Atlas of orthopaedic appliances, Vol. 2, Edwards, Ann Arbor, Mich., 1960. P. 222.
|
