responses to Van Nes prescription
Martin RJ Bell
Description
Collection
Title:
responses to Van Nes prescription
Creator:
Martin RJ Bell
Date:
3/25/2004
Text:
Hi list members.
Thankyou all for the somewhat overwhelming response, this has been
invaluable.
I have compiled the responses from the the two most helpful individuals, (I
suspect both individuals know each other) . The pertinent details of
specific prescription details have been itemised for your interest. If you
require the full document them please contact me directly.
I hope this is of benefit - I have some images that can be sent if required.
Best regards and have a good day
Martin
martin bell
BSc SR Prosth/Orth MBAPO,
Senior prosthetist/orthotist.
Orthopaedic Services Ltd.
Southmead Hospital,
Bristol.
tel; +44 01179595706
fax; +44 01179595712
serial casting to ensure max extension of foot, prior to definitive cast?
yes or no
No.Your trade off for increased P/flex is loss of power, as the
gastroc/quadswill be at maximum contraction already. Conversley,
the<?xml:namespace prefix = o ns = urn:schemas-microsoft-com:office:office
/>
trade off for increased power is decreased cosmesis posteriorly. Just cast
in maximum COMFORTABLE p/flex. The next prosthesis will allow a bit
morep/flex.
Since the foot is p/flexed, you lose a lot of horizontal weight bearing
surface. We counter this by casting and modifying almost as if the foot is
on the rung of a ladder, with the rung hooking in and under the calcaneus.
Does this make sense? Let me know if not and I'll try to clarify it.
You can also hydrostatically load the foot proximal to the met heads. You
will need to relieve met heads and toes in 3 dimensions. ie plantar
and dorsal surfaces. You also need 10-15mm relief distally to prevent
blisters. Check this in the check socket.
polycentric knee joints, what make? I usually find that the O/B ones are
not durable enough and you can't repair them effectively
These need to be polycentric since the ankle joint is not horizontal, and
the prosthetic joints need to be, to prevent a whip. It also helps to
protect the stability of the joint. It's a good idea to get a wtbearing
xray in the checksocket with ankle markers, and use these to position the
joints. Trying to move them later on is a real pain. We generally use OB
7U27 or 7U10 jts, but I'm open to suggestions here.
Anterior or posterior corset, leather or thermoplastic
Ideally, none. We used to make an anterior opening thermoplastic corset
with two straps. We've abandoned this in favour of a frame design, open
anterior and posterior. You're only adding the corset to protect the ankle,
not for weight bearing, so a frame is lighter, cooler, less bulky,
stronger. It needs to be high ant and lower posterior to get the heel thru,
and you may need to play with this shape at check fit time.
heel retaining strap?
It can help, but we didn't find that it was necessary all the time. Our
prostheses had laminated thigh cuffs lined with a grippy material.
Pistoning of the thigh cuff will cause you problems even if you use a heel
retaining strap. Relying on the retaining strap to decrease pistoning puts
a lot of pressure over the heel which may not be tolerated.
Mostly not, by wrapping the calcaneus just over the apex, but some times you
just need one. We Use heavy duty elastic, similar to ext assist strap
sureflex foot? what other would you suggest
Back home in Australia the children I worked with were pretty much all
fitted with SACH feet! I wouldn't fit anything with too soft a heel as that
will cause the vertical ground reaction force vector to pass anteriorly to
the knee very quickly during loading response and create an external knee
extensor moment which may cause pain or discomfort at the rotated ankle. Of
course if she can't maintain extension then a soft heel may help!
We use Seattle light foot, but this is because we do a lot of kids.
Something with a softer heel might be better for her.
What level of activity can this patient expect? - how soon?
The long term activity should be great. We have kids who compete in cross
country running against able body kids. it's a motivation/training thing,
more than a prosthetic thing. The biggest limiter on how soon is likely to
be the chemo/rad therapy and the state of the bone.
what are the key difficulties?
Aligning the mechanical joints to the anatomical ankle joint. Doing this
with X-ray helps. Screw the prosthesis together temporarily, do a check fit
and take a standing sagittal x-ray to check joint alignment. Some
physiotherapy training will also be beneficial in ensuring good gait.
Therapy should include strengthening and stretching of the plantarflexors.
Children seem to adapt the 'reflexive' use of the rotated calf muscles
fairly quickly and easily to the demands of walking, but adults may not be
as 'plastic'.
Biggest thing to remember IMO is that this is NOT a TT amp. The
Gastroc/quad is NOT as strong as Quads. Best success comes from setting up
with the weight line ANT to the joints, as for a TF. The gait is not QUITE
as good as posterior alignment, but it is much more consistent through out
the day. Otherwise we find they tend to collapse into knee flexion until
the gastroc/quad comes into an effective length
Watch out for glut weakness leading to Trendelenburg. Can't do a lot about
it unfortunately
You shouldn't need relief over malleolli as the joints will be over the
pelite and first lay up.
most of her success will depend on psyche issues
contacts
Rod Lawlor
Senior Prosthetist/Orthotist
Royal Children's Hospital
Melbourne, Australia
Stefania Fatone, PhD, BPO(Hons)
Research Assistant Professor
Prosthetist/Orthotist
Northwestern University Prosthetics Research Lab
,
DISCLAIMER: The information in this message is confidential and may be
legally privileged. It is intended solely for the addressee. Access to this
message by anyone else is unauthorised. If you are not the intended
recipient, any disclosure, copying, or distribution of the message, or any
action or omission taken by you in reliance on it, is prohibited and may be
unlawful. Please immediately contact the sender if you have received this
message in error. Thank you.
Thankyou all for the somewhat overwhelming response, this has been
invaluable.
I have compiled the responses from the the two most helpful individuals, (I
suspect both individuals know each other) . The pertinent details of
specific prescription details have been itemised for your interest. If you
require the full document them please contact me directly.
I hope this is of benefit - I have some images that can be sent if required.
Best regards and have a good day
Martin
martin bell
BSc SR Prosth/Orth MBAPO,
Senior prosthetist/orthotist.
Orthopaedic Services Ltd.
Southmead Hospital,
Bristol.
tel; +44 01179595706
fax; +44 01179595712
serial casting to ensure max extension of foot, prior to definitive cast?
yes or no
No.Your trade off for increased P/flex is loss of power, as the
gastroc/quadswill be at maximum contraction already. Conversley,
the<?xml:namespace prefix = o ns = urn:schemas-microsoft-com:office:office
/>
trade off for increased power is decreased cosmesis posteriorly. Just cast
in maximum COMFORTABLE p/flex. The next prosthesis will allow a bit
morep/flex.
Since the foot is p/flexed, you lose a lot of horizontal weight bearing
surface. We counter this by casting and modifying almost as if the foot is
on the rung of a ladder, with the rung hooking in and under the calcaneus.
Does this make sense? Let me know if not and I'll try to clarify it.
You can also hydrostatically load the foot proximal to the met heads. You
will need to relieve met heads and toes in 3 dimensions. ie plantar
and dorsal surfaces. You also need 10-15mm relief distally to prevent
blisters. Check this in the check socket.
polycentric knee joints, what make? I usually find that the O/B ones are
not durable enough and you can't repair them effectively
These need to be polycentric since the ankle joint is not horizontal, and
the prosthetic joints need to be, to prevent a whip. It also helps to
protect the stability of the joint. It's a good idea to get a wtbearing
xray in the checksocket with ankle markers, and use these to position the
joints. Trying to move them later on is a real pain. We generally use OB
7U27 or 7U10 jts, but I'm open to suggestions here.
Anterior or posterior corset, leather or thermoplastic
Ideally, none. We used to make an anterior opening thermoplastic corset
with two straps. We've abandoned this in favour of a frame design, open
anterior and posterior. You're only adding the corset to protect the ankle,
not for weight bearing, so a frame is lighter, cooler, less bulky,
stronger. It needs to be high ant and lower posterior to get the heel thru,
and you may need to play with this shape at check fit time.
heel retaining strap?
It can help, but we didn't find that it was necessary all the time. Our
prostheses had laminated thigh cuffs lined with a grippy material.
Pistoning of the thigh cuff will cause you problems even if you use a heel
retaining strap. Relying on the retaining strap to decrease pistoning puts
a lot of pressure over the heel which may not be tolerated.
Mostly not, by wrapping the calcaneus just over the apex, but some times you
just need one. We Use heavy duty elastic, similar to ext assist strap
sureflex foot? what other would you suggest
Back home in Australia the children I worked with were pretty much all
fitted with SACH feet! I wouldn't fit anything with too soft a heel as that
will cause the vertical ground reaction force vector to pass anteriorly to
the knee very quickly during loading response and create an external knee
extensor moment which may cause pain or discomfort at the rotated ankle. Of
course if she can't maintain extension then a soft heel may help!
We use Seattle light foot, but this is because we do a lot of kids.
Something with a softer heel might be better for her.
What level of activity can this patient expect? - how soon?
The long term activity should be great. We have kids who compete in cross
country running against able body kids. it's a motivation/training thing,
more than a prosthetic thing. The biggest limiter on how soon is likely to
be the chemo/rad therapy and the state of the bone.
what are the key difficulties?
Aligning the mechanical joints to the anatomical ankle joint. Doing this
with X-ray helps. Screw the prosthesis together temporarily, do a check fit
and take a standing sagittal x-ray to check joint alignment. Some
physiotherapy training will also be beneficial in ensuring good gait.
Therapy should include strengthening and stretching of the plantarflexors.
Children seem to adapt the 'reflexive' use of the rotated calf muscles
fairly quickly and easily to the demands of walking, but adults may not be
as 'plastic'.
Biggest thing to remember IMO is that this is NOT a TT amp. The
Gastroc/quad is NOT as strong as Quads. Best success comes from setting up
with the weight line ANT to the joints, as for a TF. The gait is not QUITE
as good as posterior alignment, but it is much more consistent through out
the day. Otherwise we find they tend to collapse into knee flexion until
the gastroc/quad comes into an effective length
Watch out for glut weakness leading to Trendelenburg. Can't do a lot about
it unfortunately
You shouldn't need relief over malleolli as the joints will be over the
pelite and first lay up.
most of her success will depend on psyche issues
contacts
Rod Lawlor
Senior Prosthetist/Orthotist
Royal Children's Hospital
Melbourne, Australia
Stefania Fatone, PhD, BPO(Hons)
Research Assistant Professor
Prosthetist/Orthotist
Northwestern University Prosthetics Research Lab
,
DISCLAIMER: The information in this message is confidential and may be
legally privileged. It is intended solely for the addressee. Access to this
message by anyone else is unauthorised. If you are not the intended
recipient, any disclosure, copying, or distribution of the message, or any
action or omission taken by you in reliance on it, is prohibited and may be
unlawful. Please immediately contact the sender if you have received this
message in error. Thank you.
Citation
Martin RJ Bell, “responses to Van Nes prescription,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 6, 2024, https://library.drfop.org/items/show/222793.
