Hand Joint Replacement

Question 1

What planes of motion occur in the MCP?

Answer 1

flexion extension
adduction abduction
small amount of pronation-supination

Question 2

What plane does most motion at the MCP occur in?

Answer 2

sagittal - flexion extension

Question 3

Describe the flexible hinge MCP prosthesis and how it maintains its alignment

Answer 3

silicon elastomer hinge
adjunct to resection arthroplasty
relies on encapsulation to maintain alignment

inserted into the medullary canals of MCP and phalanx

stems are not fixed so the joint flexes and extends as the stems glide within the canals

piston-like movement is thought to help force transmission and ROM

Question 4

How are grommets fixed into position in flexible hinge prostheses?

Answer 4

press-fit

interference

Question 5

List 3 problems associated with total MCP replacements

Answer 5

implant fracture
migration
loosening

Question 6

What is a more reliable and commonly performed procedure instead of implant arthroplasty?

Answer 6

arthrodesis

Question 7

What kind of joints are the DIP and PIP?

Answer 7

bicondyloid

Question 8

What stabilises the DIP and PIP joints?

Answer 8

bony articulation itself 
joint capsule 
collateral ligaments 
fibrocartilagenous palmar plate 
muscle tendons

Question 9

Are infections a major problem with flexible hinge hand joint replacements?

Answer 9

No - less than 0.5%