[The internal fixation of fractures in children]

Osteosynthesis of supracondylar humerus fractures in children: a biomechanical comparison of four techniques

BACKGROUND

Crossed k-wire osteosynthesis is a widely used procedure for displaced supracondylar humerus fractures in children, but the rate of secondary displacements is up to 31%. Alternative techniques including casts, elastic stable intramedullary nailing, and the fixateur extern, have been used, but there are no biomechanical data comparing these methods. We developed a biomechanical model to compare four osteosynthesis techniques for stabilizing supracondylar humerus fractures in children.

METHODS

An osteotomy to simulate a fracture was made in a total of 32 adult cadaver humeri. The pseudofractures were then stabilized by crossed k-wires, elastic nailing, a fixateur extern with either k-wires, or Schanz screws. We measured the stiffness values in flexion and extension and torsion with static loading. The movements in cyclic loading were chosen to resemble the mechanism described in the development of a clinical cubitus varus.

FINDINGS

No significant differences were found with static loading. With cyclic loading all methods showed an irreversible torsional deformation less than 20 degrees . Crossed k-wires and elastic nailing showed significantly lower reversible torsional deformation than the external fixateurs.

INTERPRETATION

Our biomechanical data reveal that the crossed k-wires have the highest stiffness and lowest loss of reduction under cyclic loading. The external fixators proved to be good alternatives.

Pitfalls und Komplikationen der elastisch stabilen intramedull�ren Nagelung (ESIN) von Femurfrakturen im Kindesalter

BACKGROUND

The aim of this prospective study was to evaluate the intra- and postoperative problems as well as the complications of elastic stable intramedullary nailing (ESIN) of femur fractures in children.

PATIENTS AND METHODS

47 consecutive children, mean age 6 years, were reviewed clinically and radiologically until hardware removal and after this annually. Mean time of follow up was 37 months.

RESULTS

Intraoperatively one cortex perforation and one displacement of a third fragment occurred. Two correction operations were necessary: In one case due to an implant displacement and in another case due to an unacceptable loss of reduction. There were no infections, non union, implant breakage, refracture or disturbance of growth.

CONCLUSIONS

ESIN is a safe procedure in femoral shaft fractures of children. Most of the problems and complications can be avoided by a careful consideration of the indication and a correct operation technique.