Comparison of external fixation versus the trauma pelvic orthotic device on unstable pelvic injuries: a cadaveric study of stability.
BACKGROUND
Most institutions treating pelvic fractures use some method of acute mechanical stabilization. This typically involves use of pelvic binders or circumferential sheeting, and/or external fixation. The comparative value of these different modalities is controversial. We hypothesized that an external fixator would provide more stability to an unstable pelvic injury than a commercially available binder device (trauma pelvic orthotic device [T-POD]).


METHODS
Unstable pelvic injuries (Tile C) were surgically created in five fresh whole human cadavers. Electromagnetic sensors were placed on the same position of each hemipelvis. The amount of angular motion during testing was measured using a Fastrak, three-dimensional, electromagnetic motion analysis device. Maximum displacements were recorded during application of the stabilizing devices, bed transfer, logrolling, and head-of-bed elevation. External fixation frames were constructed by placing two 5.0-mm half pins into the iliac crest and then connected them with a 10-mm curved bar. The T-POD device was placed at the level of the greater trochanters as per manufacturer's recommendations.


RESULTS
While logrolling the patient and performing bed transfers, the T-POD conferred more stability in all planes of motion, although this did not reach statistical significance. During elevation of the head of the bed, the T-POD allowed less motion in the sagittal and coronal planes but permitted equivalent motion in axial rotation. These differences were not statistically significant.


CONCLUSIONS
There were no significant differences in stability conferred by an external fixator or a T-POD for unstable pelvic injuries. We advocate acute, temporary stabilization of pelvic injuries with a binder device and early conversion to internal fixation when the patient's medical condition allows.
Strong Memorial Hospital, University of Rochester, Rochester, New York 14618, USA. mark_prasarn@urmc.rochester.edu
Mark L
ML
Prasarn
MaryBeth
M
Horodyski
Bryan
B
Conrad
Paul T
PT
Rubery
Dewayne
D
Dubose
John
J
Small
Glenn R
GR
Rechtine
D001696:Biomechanical Phenomena; D002102:Cadaver; D019245:Compressive Strength; D016267:External Fixators; D005260:Female; D005592:Fracture Fixation / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007593:Joint Instability / Q000517:prevention & control; D008297:Male; D009989:Orthotic Devices; D010384:Pelvic Bones / Q000293:injuries / Q000601:surgery*; D011859:Radiography; D018570:Risk Assessment; D012680:Sensitivity and Specificity