Biomedical Engineering Reference
In-Depth Information
5.5.1.4 Authors' Insights
Young patients need to be prepared for multiple joint replacements in their lifetime.
Resurfacing hip replacement is a reasonable option in very active young patients, but
bulk allograft failure (as seen in this case) can lead to acetabular component
loosening and the need for revision. Selective, proximal porous coating of the
femoral stem (as used in this case), minimizes stress shielding of the femur over the
long term, allowing retention of well-fixed components in case of revision.
Cementless acetabular components may remain stable through the network of
“bridging trabeculae” despite extensive osteolysis (as seen on CT images in this
case), which allows retention of the cup, bearing liner exchange and bone grafting of
defects to extend the life span of the joint replacement.
5.5.2 Case Report #2
Resurfacing Total Hip Replacement (Anatomic resurfacing total hip replacement
using polished titanium nitride ceramic and highly cross-linked UHMW polyethylene
bearings - state of the art).
5.5.2.1 History
A 45 year old, 185 pound (83 kg), 5 foot 4 inch (163 cm) tall, white male
sterilization logistics coordinator developed intractable pain and stiffness in his
left hip, due to advancing osteoarthritis, over a 3 year period, unresponsive to anti-
inflammatory medications and walking aides. Range of motion measured 100
o
flexion, 30
o
external rotation contracture with further 45
o
external rotation at 90
o
flexion, 20
o
adduction and 20
o
abduction; he reached full extension. Leg lengths
were equal. Pre-operative X-rays are seen in Fig. 5.60.
Fig. 5.60
AP X-ray of an osteoarthritic left hip in a 45 year old man with intractable pain
