IP & DIP Joint Replacement

Question 1

What is the main indication for replacement of the IP joint?

Answer 1

Pain and deformity associated with RA, degenerative arthritis and post-traumatic arthritis

Question 2

Why is implant arthroplasty of the DIPs rarely indicated?

Answer 2

DIPs contribute far less to the overall finger motion

Question 3

What is the best treatment for DIP pathology?

Answer 3

Arthrodesis

Question 4

What are the two types of IP joint replacement?

Answer 4

Flexible hinge

Total interphalangeal

Question 5

How does joint replacement in IP joints compare to that in MCP joints?

Answer 5

Actual prostheses are similar but IP ones have smaller dimensions
Total IP replacement has been associated with similar problems as total MCP replacement (implant fracture, migration, loosening)

Question 6

What type of joint are the PIPs and DIPs?

Answer 6

Biocondyloid (proximal condyle + distal cavity)

Question 7

What contributes to stability in the IP joints?

Answer 7

Bony articulation 
Joint capsule 
Collateral ligaments 
Fibcocartilaginous palmar plate 
Muscle tendons

Question 8

What is the major plane of motion of the IP joints?

Answer 8

Flexion-extension (although a small amount)

Question 9

What is the ROM in the PIP joint?

Answer 9

110 degrees flexion

Question 10

What is the ROM in the DIP joint?

Answer 10

90 degrees flexion

Question 11

Why is the preservation of the PIP joint more important than the DIP?

Answer 11

As it contributes more to the overall IP motion (PIP = 85%, DIP = 15%)

Question 12

What have been the clinical results with flexible hinge PIP replacements?

Answer 12

Generally satisfactory (complete pain relief in as many as 90% of patients)
ROM of 40-60 degrees
Infections rare (<0.5%)
Fracture rates low (5%)