Advertisement for orthosearch.org.uk
Orthopaedic Proceedings Logo

Receive monthly Table of Contents alerts from Orthopaedic Proceedings

Comprehensive article alerts can be set up and managed through your account settings

View my account settings

Visit Orthopaedic Proceedings at:

Loading...

Loading...

Full Access

ALLOGRAFT SIZE AND IMPACTION FORCE IN REVISION HIP ARTHROPLASTY



Abstract

It is well known that the integrity of the bone cement interface is crucial for the long-term survival of a primary total hip arthroplasty (THR). Revision THR with impaction bone grafting has recently offered a solution to gross bone loss due to osteolysis. As graft becomes incorporated, clearly the bone graft/cement interface is as crucial as the equivalent interface in primary THR.

The aim of this study was to examine factors that influence this interface. The effects of bone particle size, cement mixing time, and impaction force were examined.

The study was designed to mimic clinical practice. Fresh femoral heads were harvested from primary THR. These were morcelised into large and small particles. The bone was impacted into a purpose built jig with measured force. Cement was pressurised onto the dried surface of the impacted bone after measured mixing times. Cement pressurisation was measured. The cement/graft specimen was extracted and transected with a band saw. Cement penetration was measured with digital image analysis.

Large fragment size was 29 mm², and small was 7. 1mm². Light impaction was 2. 2 Atm. Medium and heavy were 2. 6 Atm. and 3. 2 Atm. respectively. Cement penetration was inversely proportional to impaction force. Cement mixing time also significantly affected cement penetration. Particle size had no effect.

Allograft should be adequately but not excessively impacted, to allow good cement incursion. Cement should be introduced and pressurised perhaps as early as two minutes. Fragment size does not affect cement penetration.

The abstracts were prepared by Mr Simon Donell. Correspondence should be addressed to him at the Department of Orthopaedics, Norfolk & Norwich Hospital, Level 4, Centre Block, Colney Lane, Norwich NR4 7UY, United Kingdom