Biomechanical analysis of screw-augmented intramedullary fixation for tibiotalocalcaneal arthrodesis.
BACKGROUND
This study compared intramedullary (IM) fixation for tibiotalocalcaneal arthrodesis with and without a tibiotalocalcaneal augmentation screw.


METHODS
Each specimen in six matched pairs of fresh frozen cadavers underwent tibiotalocalcaneal arthrodesis with an IM nail. One specimen from each pair also received a tibiotalocalcaneal augmentation screw. Initial and final stiffness, load to failure, and construct deformation at failure were calculated with dorsiflexion loading. Bone mineral density of each pair was determined. Statistical analysis was done using a paired Student t-test and a Pearson correlation.


RESULTS
Initial and final stiffness and load to failure were significantly higher for the tibiotalocalcaneal screw augmented fixation group as compared with the specimens with no additional screw (initial stiffness, 128.0 versus 78.4 N/mm, p = 0.04; final stiffness, 230.9 versus 164.7 N/mm, p = 0.04; load to failure, 875.5 versus 660.2 N, p = 0.03). There was a significant negative correlation between bone mineral density and average construct deformation in the samples without the added tibiotalocalcaneal screw (r = -0.90, p = 0.02).


CONCLUSIONS
In tibiotalocalcaneal arthrodesis with intramedullary nail fixation, a tibiotalocalcaneal augmentation screw provides more stable fixation.


CONCLUSIONS
Use of an augmentation screw as described in this study may lead to lower complication rates, particularly in patients with osteopenic bone.
O'Neill
Patrick J
PJ
Department of Othopaedics, Union Memorial Hospital, Baltimore, MD 2118, USA.
Parks
Brent G
BG
Walsh
Russell
R
Simmons
Lucia M
LM
Schon
Lew C
LC
D001174:Arthrodesis / Q000295:instrumentation* / Q000379:methods; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001863:Bone Screws; D002102:Cadaver; D002111:Calcaneus / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D013628:Talus / Q000503:physiopathology / Q000601:surgery; D013977:Tibia / Q000503:physiopathology / Q000601:surgery