A comparison of compressive force generation by plating and intramedullary nailing techniques in a transverse diaphyseal humerus fracture model.
BACKGROUND
The null hypothesis to be tested in this study is that the compression forces generated with a novel compressible intramedullary nail are not different from compression plating techniques.


METHODS
A custom sensor was used to measure the compressive force at a transverse midshaft humeral sawbone osteotomy (OTA 12-A3.2) in four groups. The groups included: standard compression plating using a limited contact dynamic compression plate (LCDC) with eccentric screw placement (ED-LCDC), compression plating using an LCDC plate with an articulated tensioner and eccentric compression screw (AT-LCDC), locked humeral nail compressed using the manufacturer's long stainless steel screwdriver (T2-IMN), and locked humeral nail compressed using a short stainless steel AO screwdriver (SF-IMN). From continuous measurements recorded during osteotomy compression, the maximum force (CMax) and force at 60 seconds after the peak measurement (CMax +60) were analyzed.


RESULTS
The mean CMax was 2043 N for SF-IMN, 1109 N for AT-LCDC, 799 N for T2-IMN, and 365 N for ED-LCDC. Mean CMax +60 was 1648 N for SF-IMN, 944 N for AT-LCDC, 650 N for T2-IMN, and 319 N for ED-LCDC. The difference in both CMax and CMax +60 was statistically significant between all groups (p < 0.002).


CONCLUSIONS
A new humeral nail can generate higher compression than plating using eccentric drill holes or the articulated tensioner when used with a short stainless steel screwdriver shaft. Clinical studies are needed to analyze whether this compression could improve the union rate of humeral fractures and nonunions beyond those of standard nails.
Virkus
Walter V
WV
Department of Orthopaedics, Rush University Medical Center, Chicago, Illinois, USA. orifer1@aol.com
Goldberg
Steven H
SH
Lorenz
Eric P
EP
D001858:Bone Nails; D001860:Bone Plates; D002102:Cadaver; D019245:Compressive Strength; D018483:Diaphyses / Q000293:injuries; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation*; D006801:Humans; D006810:Humeral Fractures / Q000601:surgery*; D008422:Materials Testing; D008954:Models, Biological; D013314:Stress, Mechanical