Perren, J Bone Joint Surg Br 2002 - Evolution of the Internal Fixation of Long Bone Fractures. The Scientific Basis of Biological Internal Fixation: Choosing a New Balance between Stability and Biology
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Evolution of the Internal Fixation of Long Bone Fractures. The Scientific Basis of Biological Internal Fixation: Choosing a New Balance between Stability and Biology
Perren·J Bone Joint Surg Br·2002·1,251 citations·Review article
Grossly unstable fractures may still heal on their own, whereas even invisible motion may harm a small gap that is held rigidly.
In Perren's model, 5 mm of displacement across a single 5 mm gap gives 100% strain, but shared across five gaps it gives only 20% at each, so multifragmentary fractures tolerate more instability.
Locked threaded bolts remove the need to contour the fixator to the bone at surgery, so it can be inserted percutaneously as MIPO.
Early porosity under plates matched the width of implant contact and cleared with the implant still in place, which raises questions about a Wolff's Law explanation.
In cited sheep experiments, tibial bending strength at 12 weeks (as a percentage of the intact opposite tibia) was 64.5% with the PC‑Fix vs 45.8% with the DCP (p < 0.001), with no significant difference at 24 or 48 weeks.
In a rabbit tibia model, the Staphylococcus aureus inoculum needed to cause infection differed about 450‑fold between a steel surface‑contact DCP and a titanium point‑contact PC‑Fix, and about 7000‑fold with polylactide.
Board pearl
The locked internal fixator looks like a plate but works by pure splinting rather than compression, and its flexible stabilization induces callus.
Authors' conclusion
Minimal surgical trauma and flexible fixation allow prompt healing when the blood supply to bone is maintained or can be restored early.
Evolution of the Internal Fixation of Long Bone Fractures. The Scientific Basis of Biological Internal Fixation: Choosing a New Balance between Stability and Biology
Perren·J Bone Joint Surg Br·2002·1,251 citations·Review article
Grossly unstable fractures may still heal on their own, whereas even invisible motion may harm a small gap that is held rigidly.
In Perren's model, 5 mm of displacement across a single 5 mm gap gives 100% strain, but shared across five gaps it gives only 20% at each, so multifragmentary fractures tolerate more instability.
Locked threaded bolts remove the need to contour the fixator to the bone at surgery, so it can be inserted percutaneously as MIPO.
Early porosity under plates matched the width of implant contact and cleared with the implant still in place, which raises questions about a Wolff's Law explanation.
In cited sheep experiments, tibial bending strength at 12 weeks (as a percentage of the intact opposite tibia) was 64.5% with the PC‑Fix vs 45.8% with the DCP (p < 0.001), with no significant difference at 24 or 48 weeks.
In a rabbit tibia model, the Staphylococcus aureus inoculum needed to cause infection differed about 450‑fold between a steel surface‑contact DCP and a titanium point‑contact PC‑Fix, and about 7000‑fold with polylactide.
Board pearl
The locked internal fixator looks like a plate but works by pure splinting rather than compression, and its flexible stabilization induces callus.
Authors' conclusion
Minimal surgical trauma and flexible fixation allow prompt healing when the blood supply to bone is maintained or can be restored early.