A modified cementing technique using BoneSource to augment fixation of the acetabulum in a sheep model.
OBJECTIVE
Our aim was to assess in an animal model whether the use of HA paste at the cement-bone interface in the acetabulum improves fixation. We examined, in sheep, the effect of interposing a layer of hydroxyapatite cement around the periphery of a polyethylene socket prior to fixing it using polymethylmethacrylate (PMMA).


METHODS
We performed a randomized study involving 22 sheep that had BoneSource hydroxyapatite material applied to the surface of the acetabulum before cementing a polyethylene cup at arthroplasty. We studied the gross radiographic appearance of the implant-bone interface and the histological appearance at the interface.


RESULTS
There were more radiolucencies evident in the control group. Histologically, only sheep randomized into the BoneSource group exhibited a fully osseointegrated interface. Use of the hydroxyapatite material did not give any detrimental effects. In some cases, the material appeared to have been fully resorbed. When the material was evident in histological sections, it was incorporated into an osseointegrated interface. There was no giant cell reaction present. There was no evidence of migration of BoneSource to the articulation.


CONCLUSIONS
The application of HA material prior to cementation of a socket produced an improved interface. The technique may be useful in humans, to extend the longevity of the cemented implant by protecting the socket interface from the effect of hydrodynamic fluid flow and particulate debris.
Timperley
A John
AJ
Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, UK. jtimperley@bigfoot.com
Nusem
Iulian
I
Wilson
Kathy
K
Whitehouse
Sarah L
SL
Buma
Pieter
P
Crawford
Ross W
RW
D000077:Acetabulum / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D000818:Animals; D019644:Arthroplasty, Replacement, Hip; D001843:Bone Cements; D002484:Cementation / Q000379:methods*; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D008422:Materials Testing; D016348:Osseointegration / Q000502:physiology; D019904:Polymethyl Methacrylate; D011475:Prosthesis Failure; D011859:Radiography; D012756:Sheep
D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D019904:Polymethyl Methacrylate; D017886:Durapatite