Biomedical Engineering Reference
In-Depth Information
There are additional elements of the system that are not shown since they are
rarely used and considered by the developers of dubious value such as an
adjustable eccentricity humeral head.
All metal components are made of titanium alloy coated with an extremely hard
titanium nitride ceramic. This is used since titanium is superior to the Co-Cr-Mo
alloys used in many orthopaedic applications. Titanium alloys are much more
corrosion resistant, and thus, more biocompatible; more flexible, and thus, a closer
match to bone; stronger; cheaper and easier to manufacture. Titanium alloy is inferior
only in its resistance to abrasion. The latter disadvantage is eliminated by the use of
the hard, ceramic coating that is far superior in abrasion resistance to Co-Cr-Mo
alloys. As a result properly polished ceramic coated titanium alloys used with the B-P
system are superior to those used by most orthopaedic manufacturers.
7.6 Sample Case Histories
7.6.1 Case Report #1
Resurfacing Shoulder Hemi-arthroplasty (Anatomic design for use with intact rotator
cuff).
7.6.1.1 History
A 62 year old, 185 pound (83 kg), 5 foot 6 inch (168 cm) tall, right hand dominant
white male retired wrestling coach and restaurant owner developed intractable pain
with significant crepitus and limited range of motion in his right shoulder (120
o
abduction, 0
o
external rotation, 60
o
internal rotation) over a 5 year period. Pre-
operative X-rays reveal advanced osteoarthritis of the right gleno-humeral joint with
complete joint space loss, significant inferior osteophytes of the humeral head and a
good subacromial space, signifying an intact or functioning rotator cuff, see Fig. 7.24.
INTERNAL
EXTERNAL
Fig. 7.24
Internal and external AP X-rays of an osteoarthritic right shoulder in a 62 year old
man with intractable pain and limited range of motion
