This document discusses different methods of alignment for a transfemoral prosthesis. It describes three main alignment methods: bench alignment, static alignment, and dynamic alignment. Bench alignment involves initially setting the socket flexion at 5 degrees and adduction at 7 degrees for stability and function. It also involves aligning the prosthetic knee and foot in relation to the socket in the anterior-posterior and medial-lateral planes using different standardized systems like the German, U.S., and modified systems. The goal of alignment is to provide support, a natural gait, and efficient ambulation for the transfemoral amputee.
2. ALIGNMENT:-The geometrical (angular and linear) relationship between
socket,knee joint,foot and ankle complex is known as alignment.
There are different types of alignment method.
Mostly used methods are;
(1)BENCH ALIGNMENT
(2)STATIC ALIGNMENT
(3)DYNAMIC ALINGNMENT
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A)Initial socket flexion:-The initial socket flexion of 5 degrees is generally provided for following
purposes.
1.It activates the hip extensors.
2.Knee stability
3.To sit the ischial tuberosity on the posterior brim of the socket.
4.To prevent excessive lumbar lordosis.
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B)Initial socket adduction:-(7 degrees of adduction is provided)
1.It maintains the adductor muscles of the hip.
2.It gives pelvic stability.
3.It maintains width of walking base with normal range.
4.It is cosmetically well accepted.
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C)A-P ALIGNMENT:-
(1)GERMAN SYSTEM (AIR SPACE)
(2)U.S. SYSTEM (T.K.A)
(3)MODIFIED SYSTEM (M.K.A)
(1)GERMAN ALIGNMENT SYSTEM:-In german alignment system because of the presence of air space the
plumbline draw from the mid of the lateral wall of the socket fall at the bisector of the foot keeping the
knee centre well posterior with respect to plumb line.
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(2)U.S SYSTEM:-(T.K.A) TROCHANTER -KNEE-ANKLE
In TKA system of alignment -the trochanter and ankle line passess 1/2 inch anterior on that line or
slightly posterior with respect to knee axis.
This alignment method is useful in the case of SHORT to MEDIUM stump,LONG stump VERY LONG
STUMP or knee disarticulation.
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(3)MODIFIED SYSTEM(MKA):-Mid of the medial wall of the socket in MKA system of alignment the
mid of the medial wall of the socket,knee and ankle are kept on the same line.To keep the in 5
degrees of external rotation the lateral location of the knee bolt pass 5 degrees posterior w.r.t.
location of previous reference line in transverse plane.
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(4)M-L ALIGNMENT:-In M-L
alignment the plumb line drawn
from the ischial tuberosity level
should fall between the knee axis
and centre of the heel ,this remains
constant for all the system of
alignment .
10. Alignment Considerations:-
The transfemoral alignment considerations in his statement that the
artificial limb
“… must provide both adequate support and a natural-appearing
gait
with as modest consumption of energy as possible.”
These standards have not appreciably changed.
Prosthetists at-tempt to create a stable and effective transfemoral
gait
pattern with proper socket fit; effective suspension; and
diligence in bench, static, and dynamic alignments.
11. • The socket is generally set in a flexion angle greater than
the individual’s maximum hip extension.
•This orientation is especially important for proper fitting of IC sockets .
•With the socket in the proper orientation, the focus is on the placement of
•the prosthetic knee and foot.
In able-bodied individuals, coronal alignment of the hip joint is
typically directly over the knee and ankle joints
(Figure 3, A).
For initial bench alignment of the transfemoral prosthesis,
the actual hip joint cannot be used as a ref-
erence point because it cannot be located on the prosthetic socket.
However, locating a point on the socket brim that is 1 inch (2.54 cm) lateral
to the location of the ischium will provide a reasonable
approximation.
12. .
The prosthetic knee and ankle
joints are placed directly
below this identified point. The
initial coronal
bench alignment allows for
stability.