Surface immobilized bisphosphonate improves stainless-steel screw fixation in rats

Biomaterials. 2004 May;25(11):2133-8. doi: 10.1016/j.biomaterials.2003.08.049.


An increase in the mechanical fixation in bone of metallic biomaterials is considered advantageous in joint replacement and fracture surgery. Different approaches to improve fixation may be e.g. surface roughening, Ca-mineral coating or surface immobilization of growth factors or drugs. In the present work, bisphosphonate, a class of drugs that inhibit bone resorption, was immobilized onto stainless-steel screws. The screws were first roughened and coated with immobilized and cross-linked fibrinogen. Subsequently, an N-bisphosphonate, pamidronate, was immobilized onto fibrinogen, and another N-bisphosphonate, ibandronate, adsorbed on top of this. The so coated screws were inserted into the tibiae of eight male Sprague-Dawley rats. Another eight rats received screws prepared in the same way, but without the bisphosphonate coating. Pullout strength tests were performed after 2 weeks of implantation. The results showed a 28% (p=0.0009) higher pullout force and 90% increased pullout energy for the bisphosphonate coated screws, and support the idea that surface immobilized bisphosphonates can be used to improve biomaterials fixation in bone.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Adsorption
  • Animals
  • Bone Resorption / physiopathology
  • Bone Resorption / prevention & control
  • Bone Screws*
  • Coated Materials, Biocompatible / chemistry*
  • Diphosphonates / chemistry
  • Diphosphonates / pharmacology*
  • Equipment Failure Analysis / methods*
  • Fracture Fixation, Internal / instrumentation*
  • Fracture Fixation, Internal / methods
  • Male
  • Materials Testing
  • Rats
  • Rats, Sprague-Dawley
  • Stainless Steel / chemistry
  • Tensile Strength
  • Tibial Fractures / physiopathology*
  • Tibial Fractures / surgery*


  • Coated Materials, Biocompatible
  • Diphosphonates
  • Stainless Steel