Distal fibula fracture fixation: Biomechanical evaluation of three different fixation implants.
BACKGROUND
The goal of this study was to evaluate the biomechanical performance of three distal fibula fracture fixation implants in a matched pair cadaveric fibula model: (1) a 5-hole compression plate with lag screw, (2) a 5-hole locking plate with lag screw, and (3) the 6-hole tabbed-plate with locking screws.


METHODS
Three-dimensional motions between the proximal and distal fibular segments were measured under cyclic valgus bending, cyclic compressive axial loading, and cyclic torsional external-rotation loading. During loading, strains were measured on the surfaces of each fibula near the simulated fracture site, and on the plate, to assess load transfer. Bone quality was quantified globally for each donor using bone mineral density (BMD) measured using Dual X-ray absorptiometry (DEXA) and locally at the fracture site using bone mineral content (BMC) measured using peripheral quantitative computed tomography (pQCT).


RESULTS
Mean failure loads were below 0.2Nm of valgus bending and below 4Nm of external-rotational torque. Mean failure angulation was below 1degree for valgus bending, and failure rotation was below 7degrees for external-rotation. In the compression plate group, significant correlations were observed between bone quality (global BMD and local BMC) and strain in every one of the five locations (Pearson correlation coefficients >0.95, p<0.05). In contrast, in the locking and tabbed-plate groups, BMD and BMC correlated with far fewer strain locations.


CONCLUSIONS
Overall, the tabbed-plate had similar construct stability and strength to the compression and locking plates. However, the distribution of load with the locking and tabbed-plates was not as heavily dependent on bone quality.
The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedics, Los Angeles, CA, United States.
Ashleen R
AR
Knutsen
The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedics, Los Angeles, CA, United States.
Sophia N
SN
Sangiorgio
The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedics, Los Angeles, CA, United States.
Chang
C
Liu
The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedics, Los Angeles, CA, United States.
Steve
S
Zhou
Los Angeles County Harbor-UCLA Medical Center, Los Angeles, CA, United States.
Tibor
T
Warganich
Los Angeles County Harbor-UCLA Medical Center, Los Angeles, CA, United States.
John
J
Fleming
Los Angeles County Harbor-UCLA Medical Center, Los Angeles, CA, United States.
Thomas G
TG
Harris
The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedics, Los Angeles, CA, United States. Electronic address: Edward.Ebramzadeh@UCLA.edu.
Edward
E
Ebramzadeh
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D005360:Fibula / Q000293:injuries* / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D016268:Internal Fixators; D057072:Intra-Articular Fractures / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013718:Tensile Strength
Biomechanics; Sports; Trauma