Static Strength Evaluation of Six External Skeletal Fixation Configurations

Abstract

The relative strength of six different configurations of external skeletal fixation was determined by subjecting them to axial compression, and shear and torsion forces while measuring the load they would sustain before failing. The double clamp, single connecting bar, double connecting bar, quadrilateral frame, full pin splintage and three‐ dimensional tent configurations were found to be successively stronger in all three of the tests with the exception of the quadrilateral frame being more resistant to shear force than the full pin splintage configuration.

Stabilisation of a mandibular fracture in a cow by means of a pinless external fixator

“…The development of osteomyelitis with bone sequestration is clearly visible one month after surgery. After removal of the sequestrum the radiograph taken four months later revealed a good bony callus 228 pppidkpt: resistance of the apparatus to axial compressive and shear forces (Egger 1983). In this case an increase in clinical stability was also achieved using six clamps instead of four.…”

Evaluation of a Nontoxic Rigid Polymer as Connecting Bar in External Skeletal Fixators

“…The experimental model we studied was chosen because it replicates a model used in other studies and because it represents a common clinical situation 7,18,19,34 . Assembly and mechanical behavior of the SS‐ESF construct was very reproducible, as demonstrated by very low inter‐ and intraconstruct variation.…”

“…To assess mechanical properties of the RP columns as connecting bars, tests were performed on an in vitro fracture bone model with a bilateral uniplanar ESF similar to previously described protocols 7,18,19 . Nonthreaded medical quality (316L) 3‐mm diameter, stainless‐steel fixation pins (Génia, Vertou, France) were inserted in hardwood dowels (24‐mm diameter, 330‐mm length) using a low‐speed power drill.…”

“…Currently available systems differ in rigidity, weight, ease of application, safety of use, and cost. The comparative standard is set by the Kirschner Ehmer apparatus (KE‐ESF), 6,7 the key element of which is a single connecting clamp to affix each fixation pin to the connecting rod 6 . To overcome the expensive and uniplanar feature of the KE‐ESF type II frame, several materials have been investigated, bypassing the use of costly clamps and linear rods.…”

Relative Stiffness and Stress of Type I and Type II External Fixators: Acrylic Versus Stainless‐Steel Connecting Bars A Theoretical Approach

“…Physical models of external fixator systems have undergone various biomechanical evaluations 10–12 . Most studies have examined the relative static strength of various configurations.…”