Trans-radial myoelectric socket design

Trans-radial myoelectric socket design

Caroline Ward

5/15/2009

Hello list

 

I have a bilateral below elbow amputee who is an established user of a 2
site control myoelectric prosthesis with flexion/extension wrist and
Otto Bock hand on his left side. Due to several attempts at revision
surgery on his right side he has not yet worn a prosthesis on this side.
He is only interested in having a myoelectric limb on the right to match
the one he wears on the left and he has 2 good myoelectric sites for
this.

 

Unfortunately his right stump is significantly bulbous due to a large
thick muscle flap over the cut ends of the bones. This muscles flap is
flaccid and he has areas of hypersensitivity around the edges of it. He
also has significant areas of grafting on this stump, but these are all
well healed. Other than his grafted areas his soft tissue is generally
very flaccid.

 

Despite several attempts I have been unable to design a socket which is
stable enough to provide enable him to have good myoelectric control as
well as allowing him to don/doff it independently. So far I have tried
the following socket designs and encountered these difficulties:

 

:-) Standard one piece supracondylar socket - pt is unable to don
socket due to his bulbous stump shape

:-) Laminate two piece supracondylar socket split longitudinally,
two pieces separate completely and fasten with Velcro straps - pt is
able to don socket by simply laying his stump down into it, but is
unable to attach top section

:-) Laminate two piece supracondylar socket split longitudinally,
upper section half flexible acrylic riveted onto lower section, Velcro
fastening - pt is able to lay his stump into the bottom section and
manoeuvre the top section roughly into position using his other
myoelectric hand, but traps his flaccid soft tissue when attempting to
do this up tightly causing significant discomfort

:-) One piece supracondylar socket with lower half
(longitudinally) laminate and open upper half with fixed elastic over it
- pt unable to don socket due to bulbous shape of stump and pain from
edges of the muscle flap preventing him pushing past the elastic

:-) One piece supracondylar socket, lower half laminate
(longitudinally) and upper half custom made silicone - pt unable to don
socket due to bulbous shape of stump and pain from edges of the muscle
flap preventing him pushing through the silicone section

 

We also considered many other designs, but other factors such as the
complication of the wires needing to run between the electrodes and the
hand made them unworkable.

 

Does anybody have any ideas of other socket designs I could try with
this patient before I have to resort to referring him back for further
revision surgery?

 

Kind regards

 

Caroline Ward

Prosthetist

opcare ltd.