TY - JOUR
T1 - Effects of rasp mismatch on plasma spray radial head stems
AU - Shukla, Dave R.
AU - Fitzsimmons, James S.
AU - An, Kai Nan
AU - O'Driscoll, Shawn W.
N1 - Funding Information:
This study was not supported by any outside funding or grants. The Mayo Clinic IRB that convened on November 30, 2010 approved the project, entitled “Prosthetic Radial Head Stability.” (IRB protocol number 10-008186.)
Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2012/7
Y1 - 2012/7
N2 - Background: Radial head prosthetic stems designed for bone ingrowth are available with both plasma spray and grit blasted surfaces. A recent study comparing micromotion between the 2 demonstrated greater micromotion in the plasma spray than grit blasted stems, even though the latter had lower surface roughness. This raised the question that perhaps the size mismatch for grit-blasted radial head stems (0.5 mm) might be inadequate for plasma spray stems. Hypothesis: A tighter initial press-fit with plasma spray radial head stems may be gained by preparation with an undersized rasp. Methods: Paired cadaveric radii were implanted with plasma spray stems. The surgical control was prepared with a rasp designated for its corresponding stem size (" size-matched"), while the experimental group was prepared with a rasp 0.5 mm smaller than designated (" undersized"). Results: The micromotion for the undersized rasp group (46 ± 12 μm) was not significantly different than for the size-matched rasp group (21 ± 12 μm) (P = .1). Discussion: Contrary to our hypothesis, no reduction in micromotion was observed when using an undersized rasp with a plasma spray stem. The micromotion results were not different from those observed when using a size-matched rasp, and actually approached significance in the opposite direction. This may be due to the rough stem surface chipping away bone fragments, rather than the bone being cut away precisely as is done with a rasp. Conclusion: The use of an undersized rasp prior to implantation of a plasma spray radial head prosthesis does not confer any added benefit in terms of initial stability.
AB - Background: Radial head prosthetic stems designed for bone ingrowth are available with both plasma spray and grit blasted surfaces. A recent study comparing micromotion between the 2 demonstrated greater micromotion in the plasma spray than grit blasted stems, even though the latter had lower surface roughness. This raised the question that perhaps the size mismatch for grit-blasted radial head stems (0.5 mm) might be inadequate for plasma spray stems. Hypothesis: A tighter initial press-fit with plasma spray radial head stems may be gained by preparation with an undersized rasp. Methods: Paired cadaveric radii were implanted with plasma spray stems. The surgical control was prepared with a rasp designated for its corresponding stem size (" size-matched"), while the experimental group was prepared with a rasp 0.5 mm smaller than designated (" undersized"). Results: The micromotion for the undersized rasp group (46 ± 12 μm) was not significantly different than for the size-matched rasp group (21 ± 12 μm) (P = .1). Discussion: Contrary to our hypothesis, no reduction in micromotion was observed when using an undersized rasp with a plasma spray stem. The micromotion results were not different from those observed when using a size-matched rasp, and actually approached significance in the opposite direction. This may be due to the rough stem surface chipping away bone fragments, rather than the bone being cut away precisely as is done with a rasp. Conclusion: The use of an undersized rasp prior to implantation of a plasma spray radial head prosthesis does not confer any added benefit in terms of initial stability.
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U2 - 10.1016/j.jse.2011.05.009
DO - 10.1016/j.jse.2011.05.009
M3 - Article
C2 - 21856176
AN - SCOPUS:84862662148
VL - 21
SP - 955
EP - 960
JO - Journal of Shoulder and Elbow Surgery
JF - Journal of Shoulder and Elbow Surgery
SN - 1058-2746
IS - 7
ER -