Mc. Macavoy et al., STABILITY OF OPEN-BOOK PELVIC FRACTURES USING A NEW BIOMECHANICAL MODEL OF SINGLE-LIMB STANCE, Journal of orthopaedic trauma, 11(8), 1997, pp. 590-593
Objective: A new biomechanical model of single-limb stance was develop
ed to test the stability of intact, injured, and internally fixed pelv
es. Design: Single-limb stance was simulated by applying muscle forces
and body mass loading to cadaver pelves. We created a rotationally un
stable ''open-book'' pelvic injury in nine embalmed pelves by dividing
the ligaments of the pubic symphysis, pelvic floor, and anterior and
interosseus sacroiliac joint. All pelves were devoid of gross structur
al abnormalities. Intervention: Two methods of internal fixation of th
e pubis symphysis were compared: (a) a curved six-hole 3.5-millimeter
reconstruction plate across the superior pubic symphysis, and (b) the
same six-hole 3.5-millimeter reconstruction plate plus a perpendicular
ly oriented four-hole 3.5-millimeter reconstruction plate placed acros
s the anterior symphysis. Main Outcome Measurements: We measured verti
cal shear displacement at the pubic symphysis and horizontal displacem
ent at the anterior sacroiliac joint. The results for the injured and
fixed specimens were compared with each other and with the results for
the intact specimens. Results: The injured unfixed specimens showed m
arked instability that was prevented by both methods of fixation of th
e pubic symphysis. No significant differences could be demonstrated be
tween single and double plating of the disrupted pubic symphysis when
using this single-limb stance model. Conclusion: This model of single-
limb stance suggests that a single symphyseal plate across the pubic s
ymphysis can stabilize the open-book injury under short-term quasi-sta
tic loads.