Neuflex Joint Implant Restores Motion to Hand
In this study scientists and mechanical engineers at the University of Illinois looked at the Neuflex finger joint replacement. They measured changes in patterns of motion in the finger joints before and after the implant was put in.

Joint implants must be tested and studied before use in humans. This type of research is done on cadavers (human hands saved after death for use in studies). In the lab, the Neuflex MCP arthroplasty implant was used in the index, middle, and ring fingers of several cadaver hands. The MCP or metacarpophalangeal joints form the joints we usually call "knuckles" on the back of the hand.

The Neuflex MCPs are designed with a slight amount of flexion. This position helps mimic the normal MCP joint during rest when the hand tends to remain in a slight fist. The scientist who first designed this implant believed the constant stress of being straight would cause implant failure.

Joint and tendon motion along with joint forces were measured for all three joints in each finger. These measures were compared to unoperated fingers. The pattern of motion with the Neuflex MCP implant was similar but not exactly the same as the unoperated side.

There was more flexion in the fingertip and middle finger joints compared to the unoperated side. There was slightly less total flexion at the MCP joints. Overall, total motion was the same.The authors think the changes observed occur because the Neuflex implant is already slightly bent.

The results of this study show that the Neuflex MCP implant does restore normal motion. Cadaver studies don't give any idea how long the implants and normal motion last over a long period of time. Human studies are needed for that.
References
Bassem Elhassan, MD, et al. Experimental Investigation of Finger Dynamics Before and After Metacarpophalangeal Joint Arthroplasty. In The Journal of Hand Surgery. February 2006. Vol. 31 A. No. 2. Pp. 228-235.