Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Arthroplasty - Hip
Abstract number: 24244
STABILITY OF UNCEMENTED ACETABULAR CUPS - WITH AND WITHOUT
BONE GRAFT
Saqeb MIRZA 1 , Vitali GORIAINOV 1 , Andy JONES 1 , Adam BRISCOE 2 , Andrew
NEW 2 , Douglas DUNLOP 1
1 Southampton General Hospital, Southampton (UNITED KINGDOM), 2 University of
Southampton, Southampton (UNITED KINGDOM)
Introduction:The use of cement is believed to be an essential supplement to
extensive impaction bone grafting in hip surgery. This study aimed to compare the
stability of uncemented and cemented acetabular components. Materials and
Methods: Two types of uncemented cup (TrabecularMetal(TM) & Trilogy) and
cemented cup were compared. The cups were tested without bone graft and on
100% graft bed. Cavitary defects were then introduced and repaired with the graft
with cups making contact with 30:70, 50:50 and 70:50 graft/host bone respectively.
These were then tested under physiological axial and torsional loads with an Instron
testing machine measuring maximum torque. Results.Trabecular and cemented cups
were significantly more stable then Trilogy cups when mounted directly onto host
bone (p0.1). On 100% graft bed, there was no difference between all three cup types
(p>0.1). Incremental cavitary defects resulted in gradually reducing stability, although
again there was no difference between TM and cemented cups (p>0.1). Discussion:
Uncemented cup integration with living bone is known to be excellent, but takes a
few weeks to develop. A scratch-fit design of TM provides a satisfactory initial
stability in bone graft constructs, when compared to cemented cups. This study
suggests that TM and cemented types of cup fixation perform similarly. Further
testing is currently undertaken to determine the ratio of graft/host bone contact
required for stability with segmental defects.
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