Hand joint replacement

Question 1

whats the most commonly indicated hand joint replacement

Answer 1

MCP joint

Question 2

2 main reasons for MCP joint replacement

Answer 2

pain and deformity from RA

impaired hand function from soft tissue imbalance

Question 3

what type of joint is the MCP

Answer 3

condyloid

formed from ovoid head of metacarpal and the elliptical cavity of the base of the proximal phalanx

Question 4

where does major motion of the MCP joint occur

Answer 4

saggital plane

0 - 90 degrees flexion

Question 5

how much to total finger flexion arc does the MCP joint contribute

Answer 5

80%

Question 6

what is thought to be advantageous about not fixing the stems of MCP joint replacements

Answer 6

as the joint flexes and extends they glide within the medullary canals and this piston-like motion is thought to be beneficial in terms of more even force transmission

Question 7

what is the purpose of a grommet

Answer 7

shielding the implant from sharp bone edges

Question 8

in what way is the ROM of the wrist improved post op

Answer 8

active ROM is shifted to a more a function arc of extension

Question 9

what are more successful - flexible hinge replacements or total MCP replacements

Answer 9

flexible hinge

Question 10

for whom are flexible hinge replacements not very suited?

Answer 10

younger patients and those who wish to perform manual tasks that place higher demands on the MCP joints

Question 11

how are grommets fitted?

Answer 11

press-fitted into position (interference fit)

Question 12

list 3 problems assoc with total MCP replacements

Answer 12

total MCP have suffered from implant fracture migration and loosening

Question 13

what type of joint is the IP joint

Answer 13

bicondyloid

Question 14

major plane of motion for IP joints

Answer 14

f-e

Question 15

which is more important functionally - PIP or DIP

Answer 15

PIP

- contributes to around 85% of IP motion