AK Scuba Prosthesis Replies

AK Scuba Prosthesis Replies

Robert Leaber, CP

Thanks to all who responded to the AK scuba prosthesis. I spoke to Kevin
Carroll, CP and he told me that the bilateral amputee on the video scuba
diving was using a Mauch SNS knee with an Active Ankle. Mr. Carroll did
confirm that knee flexion was limited by using parachute cord tied to the
knee frame.

The consensus seems to be that attaching the fin directly to the socket or
not using a prosthesis at all would be more efficient than using a knee. My
patient has both an Aulie Knee and a Mauch knee. He never uses the Aulie
knee because he has a hard time with the transition from the Mauch and he has
a shock pylon on the Mauch setup which he feels is more comfortable for
boating. The salt water is not very kind to the Icon nor the Mauch. I've
had to replace both of them a few times. I also gathered from the responses
that it depends on the type of diving and location as to what setup would be
more beneificial to him. My patient just needs to get wet, now that we have
some ideas.



Replies:


Alan Aulie makes a great single axis nylon and stainless steel knee if the
guy really wants to scuba with an AK (seems like more work than its
worth).(Maybe Boat dive with a BK only?) Aulie also makes the knee that Otto
bock marketed for awhile. So he has two knees to choose from-They both can
be locked into full extension. Even if he doesn't use the Ak underwater, it
would be a good leg to have at the beach and around the boat and water.

I have made swim fins for several  active patients over the years. It is a
fin I modify to length ( to approx. ankle length) and laminate to a suction
socket with flexible inner socket.  These have worked well and enabled the
patient to continue their active swimming activity.

Aulie device makes the only waterproof knee that I am aware of. It has a pin
to lock it straight or allow flexion for walking. Aulie devices is located
out in Oregon last I checked. The problem from a biomechanical standpoint
concerning just attaching a fin might be the disproportionate acceleration
from one long lever arm and one short lever arm. I have a bi-lateral BK who
is getting back into snorkling and I am attacking fins directly to the
sockets, but the lever arms will be of equal lengths. Just food for thought.

I have fit a unilateral AK for SCUBA diving. It was about 20 years ago in
Denver. What I did was make a loose socket (easy 3-ply fit) with a balsa wood
build-up shaped to fit the toe section of a fin and adjusted to length so
that when he knelt his hips were level. After final lamination I glued a thin
piece of crepe to the end to add traction on a slippery deck. I also wound up
having to add some molten lead in a hollowed out area to make it less
bouyant. At the time I felt the individual would be safer on deck if he moved
around on his knee and end of socket. Today I would probably build in a
Ferrier Coupler and use a manual locking knee with a flattie SACH foot. A
rolling, wet, slippery deck is a dangerous place, as I am also a SCUBA diver
and when you get a whole boat full of divers and equipment you want something
very secure.

Check out the Nylon Knee which is marketed for swimming and SCUBA diving. 
Their web site is www.auliedevices.com   Their email is <Email Address Redacted>  
It is also advertised in the O&P Business News. 

Robert...I agree with you that a fin attached directly to the socket makes
the most sense as to the amount of power inparted to fin, but you need to
find out the type of diving this patient normally does.  Shore or boat?  If
boat, private or charter?  If shore diving, does he normally enter from a
parking lot close to the water or does he have to transverse an uneven set
of rocks, steep slope, etc?  Does he have a regular buddy to assist him or
will he be partnered with another diver who may or may not be helpful?  I
have made a fin attachment to a BK socket, it's not too difficult to do as
you do not need an exact fit to the fin but you need a positive area for the
strap to hold on to.  (Fins are expensive.)  You can also speak to an
instructor with the Handicapped Scuba association.  The dive shop I use has
an instructor certified by that agency. 

I think if your patient
has good swimming skills there will be no need for a scuba fin!!  There
are lots of gadgets out there and I feel that balance is lost with a fin
on the amputated side!   In my opinion all the patent may need is a
socket to protect the stump and maybe keep it warm!!