Unit 5d: Hand Joint Replacement Flashcards
What problems were encountered with early hand joint replacement?
Migration into the bone
Loosening
Mechanical problems
What is the most frequently indicated hand joint replacement?
Replacements of MCP joint
What are the 2 types of MCP replacement?
Flexible hinge
Total MCP
What is the most commmon indication for replacement of MCP?
Pain and deformity associated with RA
What is the preffered option in younger patients requiring a strong pinch?
Arthrodesis of the index finger
What position is the index finger fused in arthrodesis?
40 degrees of flexion
What type of joint in the MCP joint?
Conyloid
What contributes to the stability of the MCP joint?
Joint capsule
Collateral ligaments
Fibrocartilaginous palmar plate
Muscle tendons
What motion occurs at the MCP joint?
Flexion-extension
Abduction-adduction
Pronation-supination (small amount with ab/add)
What range of flexion occurs at the MCP joint?
0-90 degrees flexion
How does the MCP joint contribute to total finger flexion?
Almost 80% of the total finger flexion arc
How are flexible hinge prostheses for the MCP joint inserted?
Inserted into the hollowed medullary canals of the metacarpal and proximal phalanx
How does the flexible hinge MCP prosthesis fixed and why is this beneficial?
Stems are not fixed - piston-like motion beneficial in terms of force transmission and increased range of motion
Why were titanium bone liners (grommets) introduced to the flexible hinge MCP prosthesis?
To shield the implant from sharp bone edges after high tear rates
What was the original purpose of the silicone implant?
To act as a spacer around which a new capsuloligamentous structure forms
What are total MCP replacements made of?
Metalllic component that articulates with a polyethylene component - both components cemented into medullary canals
Which has proved more successful to date, flexible hinge or total MCP replacements?
Flexible hinge prostheses
What patients are flexible hinge MCP replacements not particularly suitable for?
Younger patients and those who wish to perform manual tasks that place higher demands on the MCP joints
What are the main indications for replacement of the IP joints?
Pain and deformity associateed with RA, degenrative arthritis and post-traumatic arthritis
Why is implant arthroplasty of the DIP rarely indicated?
DIP contributes far less to the overall finger motion
What procedure is usually used instead of replacement for DIP joint?
Arthrodesis
What are the 2 types of IP joint replacement?
Flexible hinge
Total IP replacement
What type of joint are the PIP’s and DIP’s?
Bicondyloid joints
What contributes to the stability of the PIP and DIP joints?
Joint capsule
Collateral ligaments
Fibrocartilaginous palmar plate
Muscle tensons
What is the range of flexion of the PIP joint?
0-110 degrees of flexion
What is the range of flexion of the DIP joint?
0-90 degrees of flexion
What percentage do each IP joint contribute to interphalangeal motion?
PIP = 85% DIP = 15%
What range of motion can be expected with flexible hinge prosthesis of the IP joint?
40-60 degrees
Which prosthesis dominates finger joint replacement?
Swanson flexible hinge prosthesis
