Biomechanical evaluation of intramedullary nail versus tension band fixation for transverse olecranon fractures.
OBJECTIVE
To compare the biomechanical stability of an alternative custom-designed intramedullary nail (IMN) fixation with that of traditional tension band wiring (TBW), the gold standard for stabilizing transverse olecranon fractures.


METHODS
Ex vivo biomechanical study.


METHODS
Biomechanical laboratory.


METHODS
Six pairs of elderly cadaver elbows.


METHODS
A simulated transverse olecranon fracture was created in each elbow after it had been denuded of most of its soft tissue. The right and left olecranons of each pair were alternately assigned to the IMN or TBW group. A tensile force was applied via the triceps tendon while the elbow was secured in 90 degree of flexion.


METHODS
Displacement at the simulated fracture segment was measured optically. Fixation failure was defined as >2 mm of fracture displacement. The differences in stiffness and maximum load to failure between the two treatments were analyzed for significance (P < 0.05) using a one-tailed paired t test.


RESULTS
IMN fixation was significantly stiffer and stronger than TBW fixation.


CONCLUSIONS
The locked IMN provided stronger and stiffer fixation than did TBW. Theoretically the IMN fixation would require less surgical exposure and would be expected to require fewer revisions than TBW fixation. IMN fixation warrants consideration as a clinical alternative to TBW.
Molloy
Sean
S
Department of Orthopaedic Surgery, Johns Hopkins University/Johns Hopkins Bayview Medical Center, Baltimore, MD 21224-2780, USA.
Jasper
Louis E
LE
Elliott
David S
DS
Brumback
Robert J
RJ
Belkoff
Stephen M
SM
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001858:Bone Nails; D002102:Cadaver; D005260:Female; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000601:surgery; D006801:Humans; D004204:Joint Dislocations / Q000601:surgery*; D007593:Joint Instability / Q000517:prevention & control; D008297:Male; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D000092464:Elbow Injuries