[Effect of additive fiber cerclage of the rotator cuff in angle-stable plate-stabilized proximal humeral fractures: a biomechanical study of human shoulder specimens].
OBJECTIVE
Can additive fiber cerclage (FC) reduce secondary displacement in unstable 3-part proximal humeral fractures stabilized by angle-stable plates? Is there any effect of different head screw configurations?


METHODS
An unstable 3-part fracture model of the humeral head was developed by preserving the rotator cuff in 24 paired, osteoporotic shoulder specimens. 6 pairs were stabilized by PHILOS plates, and 6 others by HSP. Each left shoulder received FC. 4 groups arose (n=6): I) HSP with FC, II) HSP without FC, III) PHILOS plate with FC, and IV) PHILOS plate without FC. 4 physiological load cases were simulated by a robot-assisted shoulder simulator. Using real-time analysis, interfragmentary motion was measured.


RESULTS
Matched-pair analysis of the groups with FC vs. those without FC showed no significant differences in motion at gap I (greater tuberosity head) or II (subcapital) in any load case, apart from interior rotation in groups III and IV at gap II; in these, motion was greater without FC. No differences were seen with different head screw configurations in any load cases.


CONCLUSIONS
In cases of anatomical reduction and optimally placed implants, FC did not show an additional stabilizing effect in the unstable 3-part fracture model. Different head screw configurations did not influence stability.
Voigt
C
C
Klinik für Unfall- und Wiederherstellungschirurgie, Diakoniekrankenhaus Friederikenstift gGmbH Hannover, Humboldtstr. 5, 30169 Hannover, Deutschland. christine.voigt@friederikenstift.de
Hurschler
C
C
Althainz
J
J
Vosshenrich
R
R
Lill
H
H
D000368:Aged; D000369:Aged, 80 and over; D001860:Bone Plates; D003198:Computer Simulation; D004548:Elasticity; D005260:Female; D006801:Humans; D006810:Humeral Fractures / Q000503:physiopathology* / Q000601:surgery*; D066298:In Vitro Techniques; D008297:Male; D008954:Models, Biological; D009068:Movement; D013314:Stress, Mechanical; D013536:Suture Techniques / Q000295:instrumentation*; D013537:Sutures; D016896:Treatment Outcome