Award Abstract # 0079484
SBIR Phase II: A New Vibration Mixer for Bone Cement

NSF Org: TI
Translational Impacts
Recipient:
Initial Amendment Date: September 13, 2000
Latest Amendment Date: February 21, 2002
Award Number: 0079484
Award Instrument: Standard Grant
Program Manager: Gregory T. Baxter
TI
 Translational Impacts
TIP
 Directorate for Technology, Innovation, and Partnerships
Start Date: September 15, 2000
End Date: August 31, 2002 (Estimated)
Total Intended Award Amount: $399,892.00
Total Awarded Amount to Date: $0.00
Funds Obligated to Date: FY 2000 = $0.00
History of Investigator:
  • Pamela Saha (Principal Investigator)
    pssaha@prodigy.net
Recipient Sponsored Research Office: Clinical and Industrial Technology Co
1570 Woodbury Road
Seneca
SC  US  29672-9153
(864)653-6472
Sponsor Congressional District: 03
Primary Place of Performance: Clinical and Industrial Technology Co
1570 Woodbury Road
Seneca
SC  US  29672-9153
Primary Place of Performance
Congressional District:
03
Unique Entity Identifier (UEI):
Parent UEI:
NSF Program(s): SBIR Phase II
Primary Program Source: app-0100 
Program Reference Code(s): 5342, 9102, 9150, 9184, BIOT, OTHR
Program Element Code(s): 537300
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.084

ABSTRACT

This SBIR Phase II project is aimed at developing a novel vibration mixer for the mixing of surgical grade bone cement. Self-curing polymethylmethacrylate (PMMA) or acrylic bone cement is used extensively in total joint replacements, in the repair of bony defects and in the fixation of pathological fractures. For surgical use, the methylmethacrylate polymer and the liquid monomer are hand mixed. This hand-mixing entraps air bubbles making the cement porous. Presence of these bubbles adversely affects the mechanical properties of bone cement, making it much weaker under load and may contribute to early failure of cemented artificial joints. Results of the Phase I study indicate that ultrasonic vibration during cement mixing
significantly reduced its porosity and increased the fatigue life and mechanical strength of bone cement, compared to hand-mixed cement. Recently, it was shown that combining sonication and vacuum mixing reduced the porosity and further improved the fatigue life, compared to either mixing methods alone.

During the Phase II study, the frequency and amplitude of sonication and the vacuum pressure to obtain the best mechanical properties of the cement will be optimized. Subsequently, a new cement mixer will be designed and built incorporating these mixing features. It is expected that the improved mechanical properties of vibrated bone cement will reduce the incidence of cement fracture and this will improve the success rate of total joint replacements. Considering that cement mixers are used in several thousand hospitals in the United States alone, we expect this new cement mixer to be adopted by a large number of Orthopaedic surgeons in these hospitals.

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