A biomechanical study on five unilateral external fracture fixation devices

Design, analysis and testing of an external fracture fixation device manufactured from composite materials

“…If the fixator reaches the described load without being destroyed, it is considered to be static verified. The cyclic testing is based on Gardner method [5] and ASTM standard [1] (see Fig. 5).…”

“…In the case of a fracture of the tibia, the fixator is loaded by a compressive axial force in the direction of the tibia [15]. In [3], the static load capacity of three types of external fixators was analyzed, and the maximal axial force was determined to be 889 N. In [5], the maximal axial force during cyclic loading of five unilateral fixators and 10 000 cycles was evaluated to be 220 N. In [6], the fixators were tested with a static force of 700 N, which was considered to be the average gravitational force of a patient (which is directly proportional to the patient's weight). In [20], a multiplanar (circular) fixator for the tibia was measured in vivo during treatment.…”

Reconstructive surgery of the human tibia by use of external ring fixator and the Ilizarov method

“…In addition the TSF was fixed to the bone with half-pins and wires, while wires only were used with the IEF frames. The overall difference in LI could implicate that a too rigid frame was of disadvantage and did not produce the micromotion which Ilizarov and other authors describe as optimal for bone healing (Claes et al 1997, Gardner et al 1997, Goodship and Kenwright 1985, Ilizarov 1992, Kenwright and Goodship 1989, Lanyon and Rubin 1984, Waanders et al 1998). In our material, however, this difference in overall LI is more likely to be a result of low lengthening distance and the diagnosis leading to the reconstructive procedure.…”

“…However, a wide range of IFM obviously exists and it is assumed that a relatively wide, but still more specific and narrow range of IFM promotes healing (Gardner et al 1997). The classical IEF design with wires only or modified by use of halfpins has been used by many authors working with the Ilizarov method (Catagni et al 2005, Ilizarov 1992, Paley 2002.…”

“…This IFM value was high and may be the explanation of the observed slow bone healing. According to various authors the optimal degree of axial micromotion can be within a wide range of microns (Claes et al 1997, Gardner et al 1997, Goodship and Kenwright 1985, Kenwright and Goodship 1989, Lanyon and Rubin 1984, Waanders et al 1998, Wolf et al 1998. The size of the fracture gap represents an important contributory factor to the ideal displacement amplitude (Claes et al 1997), and the strain amplitude (displacement as % of fracture gap size or analogue length of callotasis zone) is the key factor.…”