Gait, cost and time implications for changing from PTB to ICEX® sockets

The ICEX® system (Ossur, Iceland), allows a socket to be manufactured directly onto the stump and is thought to provide improved comfort due to better pressure distribution whilst being easier to fit and manufacture.

The aims of this project were to a) compare gait performance by measuring several gait characteristics, b) compare production and fitting times, c) investigate financial implications and d) attempt to gauge the amputees' subjective opinions of socket comfort.

A randomised, controlled trial was conducted on 27 trans-tibial amputees with an existing patellar tendon bearing (PTB) socket on the Endolite™ system (Chas A. Blatchford, UK). Twenty one (21) subjects completed the study. Of these, 10 in the control group received new PTB sockets while 11 in the experimental group received ICEX®.

Gait analysis wearing existing sockets was performed and kinetic data obtained from a force plate. This was repeated with the new sockets after a 6 week period of adjustment. Mann-Whitney tests were used in statistical evaluations with a significance level of 5%. Subjects were asked to score their prosthesis for comfort using the Socket Comfort Score (Hanspal et al., 2003) and the frequency of visits for socket adjustments over a three-month period post-delivery of the sockets was recorded.

This study demonstrates no significant difference in any of the gait parameters measured. Though the time required to manufacture a PTB prosthesis was found to be considerably longer than the ICEX®, the overall cost for producing the ICEX® was significantly greater. Subjects showed only minor comfort preference for the ICEX® design and there was no significant difference in the mean number of visits for socket adjustments.

In view of the considerable additional cost of providing ICEX® and the lack of evidence of improvement in any parameter tested, the routine provision of ICEX® prostheses to unselected trans-tibial amputees cannot be recommended.