Unit 5d: Hand Joint Replacement

Question 1

What problems were encountered with early hand joint replacement?

Answer 1

Migration into the bone
Loosening
Mechanical problems

Question 2

What is the most frequently indicated hand joint replacement?

Answer 2

Replacements of MCP joint

Question 3

What are the 2 types of MCP replacement?

Answer 3

Flexible hinge

Total MCP

Question 4

What is the most commmon indication for replacement of MCP?

Answer 4

Pain and deformity associated with RA

Question 5

What is the preffered option in younger patients requiring a strong pinch?

Answer 5

Arthrodesis of the index finger

Question 6

What position is the index finger fused in arthrodesis?

Answer 6

40 degrees of flexion

Question 7

What type of joint in the MCP joint?

Answer 7

Conyloid

Question 8

What contributes to the stability of the MCP joint?

Answer 8

Joint capsule
Collateral ligaments
Fibrocartilaginous palmar plate
Muscle tendons

Question 9

What motion occurs at the MCP joint?

Answer 9

Flexion-extension
Abduction-adduction
Pronation-supination (small amount with ab/add)

Question 10

What range of flexion occurs at the MCP joint?

Answer 10

0-90 degrees flexion

Question 11

How does the MCP joint contribute to total finger flexion?

Answer 11

Almost 80% of the total finger flexion arc

Question 12

How are flexible hinge prostheses for the MCP joint inserted?

Answer 12

Inserted into the hollowed medullary canals of the metacarpal and proximal phalanx

Question 13

How does the flexible hinge MCP prosthesis fixed and why is this beneficial?

Answer 13

Stems are not fixed - piston-like motion beneficial in terms of force transmission and increased range of motion

Question 14

Why were titanium bone liners (grommets) introduced to the flexible hinge MCP prosthesis?

Answer 14

To shield the implant from sharp bone edges after high tear rates

Question 15

What was the original purpose of the silicone implant?

Answer 15

To act as a spacer around which a new capsuloligamentous structure forms

Question 16

What are total MCP replacements made of?

Answer 16

Metalllic component that articulates with a polyethylene component - both components cemented into medullary canals

Question 17

Which has proved more successful to date, flexible hinge or total MCP replacements?

Answer 17

Flexible hinge prostheses

Question 18

What patients are flexible hinge MCP replacements not particularly suitable for?

Answer 18

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

Question 19

What are the main indications for replacement of the IP joints?

Answer 19

Pain and deformity associateed with RA, degenrative arthritis and post-traumatic arthritis

Question 20

Why is implant arthroplasty of the DIP rarely indicated?

Answer 20

DIP contributes far less to the overall finger motion

Question 21

What procedure is usually used instead of replacement for DIP joint?

Answer 21

Arthrodesis

Question 22

What are the 2 types of IP joint replacement?

Answer 22

Flexible hinge

Total IP replacement

Question 23

What type of joint are the PIP’s and DIP’s?

Answer 23

Bicondyloid joints

Question 24

What contributes to the stability of the PIP and DIP joints?

Answer 24

Joint capsule
Collateral ligaments
Fibrocartilaginous palmar plate
Muscle tensons

Question 25

What is the range of flexion of the PIP joint?

Answer 25

0-110 degrees of flexion

Question 26

What is the range of flexion of the DIP joint?

Answer 26

0-90 degrees of flexion

Question 27

What percentage do each IP joint contribute to interphalangeal motion?

Answer 27

PIP = 85%
DIP = 15%

Question 28

What range of motion can be expected with flexible hinge prosthesis of the IP joint?

Answer 28

40-60 degrees

Question 29

Which prosthesis dominates finger joint replacement?

Answer 29

Swanson flexible hinge prosthesis