Polyethylene Debris particle size ▪ 0.1-0.5 μm²6 ▪ 0.69 μm33 Wear rate

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
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Chapter11: Heat Transfer By Radiation
Section: Chapter Questions
Problem 11.54P
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Polyethylene
Debris particle size
▪ 0.1-0.5 μm²6
▪ 0.69 μm³3
Wear rate
▪ 0.04-0.26 mm per year³4
■ Non-crossed-linked polyethylene: 39 mm³ per 106
cycles (simulator) 35
. Cross-linked polyethylene: 5-9 mm³ per 106 cycles
(simulator)35
Transcribed Image Text:Polyethylene Debris particle size ▪ 0.1-0.5 μm²6 ▪ 0.69 μm³3 Wear rate ▪ 0.04-0.26 mm per year³4 ■ Non-crossed-linked polyethylene: 39 mm³ per 106 cycles (simulator) 35 . Cross-linked polyethylene: 5-9 mm³ per 106 cycles (simulator)35
A total hip replacement consisting of a 28 mm diameter Co-Cr femoral head articulating
against a UHMWPE cup functions in a patient for 5 years before it is removed during revision arthroplasty. You perform a detailed analysis of the
explanted cup. The articular surface of the explanted UHMWPE cup shows a change in geometry such that the cup is 0.75 mm deeper (see photo).
Radiograph of THR at the time of surgery
Assumptions:
28 mm
Patient weighs 70kg with an average load of a gate cycle of 2.5BW
Neglect creep for all questions
Assume 1 million steps per year
ANSWER COLUMN
THR at day 1
QUESTIONS
0.75 mm
THR at 5 years
Total angular motion per gait stride (hip flexion-extension-flexion OR heel strike to heel strike) is 80 degrees
Hint: Recall details of UHMWPE materials and applications in THR from Lecture 9 Notes.
Q1A: Calculate the annual volume of UHMWPE wear debris.
UHMWPE after 5 years
showing progression of
worn region (dark grey)
Transcribed Image Text:A total hip replacement consisting of a 28 mm diameter Co-Cr femoral head articulating against a UHMWPE cup functions in a patient for 5 years before it is removed during revision arthroplasty. You perform a detailed analysis of the explanted cup. The articular surface of the explanted UHMWPE cup shows a change in geometry such that the cup is 0.75 mm deeper (see photo). Radiograph of THR at the time of surgery Assumptions: 28 mm Patient weighs 70kg with an average load of a gate cycle of 2.5BW Neglect creep for all questions Assume 1 million steps per year ANSWER COLUMN THR at day 1 QUESTIONS 0.75 mm THR at 5 years Total angular motion per gait stride (hip flexion-extension-flexion OR heel strike to heel strike) is 80 degrees Hint: Recall details of UHMWPE materials and applications in THR from Lecture 9 Notes. Q1A: Calculate the annual volume of UHMWPE wear debris. UHMWPE after 5 years showing progression of worn region (dark grey)
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