Page 273 - Handbook of Biomechatronics

Lower-Limb Prosthetics 267

combined with pain at loading” meaning that the survival of the fixture
could be predicted by bone resorption with an X-ray (Lenneras et al., 2017).
All the potential benefits of osseointegration do not come with issues and
problems to solve. The biggest problem of this technique is its long-lasting
battle with bacteria at the skin interface and its unknown long-term impact
on the quality of the bone fixture (Lenneras et al., 2017). Therefore, long-
term studies are needed. Radiologically found endosteal bone resorption
accompanied with pain at loading might be associated with potential weak-
ness of the bone fixture (Lenneras et al., 2017). Different osseointegration
research groups are taking engineering variants of the implant designs and
materials in order to achieve a stable mechanical interface between the bone
and the implant.

6.2 Inexpensive/Easy and Automated Fabrication
Effective prosthetic feet can be easily and cheaply fabricated as shown by
Adamczyk et al. (2006), Adamczyk and Kuo (2013), Hansen and
Childress (2000), and Sam et al. (2000, 2004). The key is to know the exis-
ting science behind the design of prosthetic feet as dictated by the rollover
theory of walking (see Section 4) and use inexpensive fabrication methods
and materials for the developing countries. This led to the design of the
NUPRL foot. Another modular inexpensively fabricated leg that was
intended for the developing countries was the Center of International
Rehabilitation (CIR) leg.
The CAD/CAM has been around for at least three decades for prosthet-
ics. Its biggest value is that a scan of the residual limb can be taken by dif-
ferent technologies (e.g., laser), then the CAD model of the personalized and
pressure-relieved socket can be generated by the CAD software, and finally
the socket is fabricated in minutes by the CAM techniques. Commercially
available solutions exist in the market (CAD/CAM SYSTEMS, 2018).

6.3 Targeted Muscle Reinnervation

The targeted muscle reinnervation (TMR) has also been performed for per-
sons with transfemoral amputations (Kuiken et al., 2017a). As reported by
Hargrove et al. (2013), a TMR procedure was performed on a 31-year
old during knee disarticulation amputation due to a motorcycle accident.
The nerve transfer is shown in Fig. 19. The sciatic nerve was split into its
tibial and common peroneal branches. The tibial nerve branch was sewn
over the motor area of the semitendinosus, and the peroneal nerve branch