Self-test - Orthopaedic Biomaterials in Research and Practice - page 422

23. The goal(s) of fixation of joint replacement components are ( true
or false )

A. To eliminate or minimize relative motion between the implant
and the bone during loading

____

B. To reduce resultant stress in the surrounding bone to levels
below implantation of the device

____

C. To provide an interface between the implant and bone that is
much stiffer than the surrounding bone in order to absorb
forces generated during postoperative loading

____

D. To produce stresses on bone within a normal, acceptable
range

____

(4)

24. Fixation by biologic ingrowth ( true or false )

___

Is generally caused by bone growing into under 10 μm pores

Occurs in patients in femoral but not tibial components of TKRs ___

May produce local “stress shielding” ___

Occurs more rapidly for polymeric than for metallic components ___

Is an FDA-approved design feature of some THRs ___

(5)

25. “Micromotion” is the same as (select the term that best completes
the sentence)

A. Creep ___

B. Stress relaxation ___

C. Hysteresis ___

D. Fretting ___

E. None of the above ___

(5)

26. Immune responses to metals (select the phrase that best completes
the sentence)

A. Are more common in men than in women ___

B. Are caused by organometallic complexes ___

C. May occur at sites remote from metal implants ___

D. Are due to the amount of metal present rather than its
elemental composition

___

E. May play a role in TJR “loosening” ___

(5)