Techniques to improve the shear strength of impacted bone graft: The effect of particle size and washing of the graft

D.G. Dunlop, N.T. Brewster, S.P. Gopal Madabhushi, Asif Sohail Usmani, P. Pankaj, C.R. Howie

Research output: Journal article publicationJournal articleAcademic researchpeer-review

121 Citations (Scopus)

Abstract

Background: When fresh morselized graft is compacted, as in impaction bone-grafting for revision hip surgery, fat and marrow fluid is either exuded or trapped in the voids between particles. We hypothesized that the presence of incompressible fluid damps and resists compressive forces during impaction and prevents the graft particles from moving into a closer formation, thus reducing the graft strength. In addition, viscous fluid such as fat may act as an interparticle lubricant, thus reducing the interlocking of the particles. Methods: We performed mechanical shear testing in the laboratory with use of fresh-frozen human femoral-head allografts that had been passed through different orthopaedic bone mills to produce graft of differing particle-size distributions (grading). Results: After compaction of fresh graft, fat and marrow fluid continued to escape on application of normal loads. Washed graft, however, had little lubricating fluid and better contact between the particles, increasing the shear resistance. On mechanical testing, washed graft was significantly (p < 0.001) more resistant to shearing forces than fresh graft was. This feature was consistent for different bone mills that produced graft of different particle-size distributions and shear strengths. Conclusions: Removal of fat and marrow fluid from milled human allograft by washing the graft allows the production of stronger compacted graft that is more resistant to shear, which is the usual mode of failure. Further research into the optimum grading of particle sizes from bone mills is required. Clinical Relevance: Understanding the mechanical properties of milled human allograft is important when impaction grafting is used for mechanical support. A simple means of improving the mechanical strength of graft produced by currently available bone mills, including an intraoperative washing technique, is described.
Original languageEnglish
Pages (from-to)639-646
Number of pages8
JournalJournal of Bone and Joint Surgery - Series A
Volume85
Issue number4
DOIs
Publication statusPublished - 1 Apr 2003
Externally publishedYes

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

Fingerprint

Dive into the research topics of 'Techniques to improve the shear strength of impacted bone graft: The effect of particle size and washing of the graft'. Together they form a unique fingerprint.

Cite this