In
an attempt to develop affordable socket fabrication techniques that
require little or no prosthetic skill for people living with lower-limb
loss in developing countries, a study was conducted using a water-pressure casting technique (PCAST) to fabricate and fit transtibial prosthetic sockets.
In
the study, highlighted during the International Conference on the
Development of Biomedical Engineering in Vietnam, and published online
September 24, 53 adults with unilateral transtibial amputations were
recruited from the Vietnamese Training Centre for Orthopaedic
Technologists (VIETCOT) (Hanoi). VIETCOT staff with International
Society for Prosthetics and Orthotics category II qualifications
fabricated and fitted the prostheses.
To
begin, a cotton sock was placed over the patient’s residual limb
followed by a plaster wrap. Each patient stood with the intact limb on a
body weight scale and placed the residual limb into a plastic bag-type
diaphragm housed in a water-filled cylindrical tank until able to stand
normally with half of his or her body weight supported. Once the plaster
wrap hardened, a positive plaster model was made and a socket
fabricated with a distal Pelite cap. A polypropylene socket was then
molded and attached to prosthetic components designed by the
International Committee of the Red Cross and a rubber foot. The same
technician fabricated, fitted, and aligned the prosthesis.
Once
the patient felt comfortable with the fit, the following tasks were
completed: Timed Up and Go (TUG), six-minute walk (6MWT), and walking
(GAITRite mat). Patients also completed a Satisfaction with Prosthesis
(SAT-PRO) questionnaire. The tasks were also completed after an extended
usage period, roughly 146 days.
Results
of the study showed that 31 of the 53 patients were successfully
fitted; 14 fittings failed and eight patients failed to return,
withdrew, or became deceased. Responses to the questionnaire showed high
levels of satisfaction, 81 percent on both test occasions. The 6MWT
increased by 28 meters after the usage period. TUG, SATPRO, and gait
measures remained unchanged. No differences were found in a subanalysis
that compared PCAST performance to each participant’s original socket
and prosthesis.