Active and Passive Prosthetic Limbs - Introduction to Biomechatronics - page 584

FIGURE 10-67 Osseointegration. (a) Schematic. (b) Scanning electron microscopy (SEM)
of bone fusing onto titanium. (c) Photo of attachment for artificial knee. (Courtesy of Össur,
with permission.)

stud, machined to have threads much like a screw at one end, is inserted into the cavity
of one of the long bones in the arm or leg at the site of the amputation as illustrated in
Figure 10-67. Living bone cells migrate into the threads and attach themselves firmly to
the titanium so that after about 6 months the insert is firmly anchored.
A second titanium component called an abutment is attached to the implant, and it
protrudes through the skin at the end of the amputee's stump, as shown in Figure 10-64.
The limb can be attached to this abutment using a wrench or a quick-release coupling.
The main complication is that the abutment permanently pierces the skin, which increases
the possibility of infection (Mooney, 2001). However, this is a small price to pay for the
advantages of this method suspension, as listed:
• No feeling of increased weight.
• No lack of positive prosthesis control.
• No increase in energy consumption to operate the prosthesis.
• No need to bear weight on other parts of the body.
• No fitting problems due to weight gain or loss.
• No socket induced skin irritation.
• No problems attaching or removing the prosthesis.
Because the procedure is still experimental, it is generally performed only on younger
unilateral amputees who cannot be successfully fitted by conventional means. Additionally,
candidates must have a sound bone in the residual limb, not have systemic diseases such
as diabetes or peripheral vascular disease, and not be smokers.

10.11 REFERENCES

Adee, S. (2007). “Artificial Arm Researchers Restore Feeling of Missing Limb.” IEEE Spectrum
45(12).
Adee, S. (2008). “Dean Karmen's “Luke Arm” Prosthesis Readies for Clinical Trials.” IEEE Spec-
trum: Biomedical/Bionics, February.
Andrianesis, K. and A. Tzes. (2008). “Design of an Anthropomorphic Prosthetic Hand Driven
by Shape Memory Alloy Actuators.” 2nd IEEE RAS & EMBS International Conference on
Biomedical Robotics and Biomechatronics, 2008.