DOS BULLETIN - Dansk Ortopædisk Selskab

2010-378_DOS nr. 3 2010 29/09/10 10:08 Side 131
Bone remodeling around HA-coated acetabular cups:
DEXA study with an 8-year follow-up
in a randomised trial
Kestutis Valancius, Mogens Berg Laursen
Ortopædkirurgien, Klinik Aalborg
Background: The aim of this study was to compare clinical outcome and
changes in bone mineral density around a specific cup with and without HA
coating in cementless THA. The previous, 3-year follow-up, study found no difference
with regard to bone mineral density changes or clinical outcome
Purpose: The aim of this study was to compare clinical outcome and changes
in bone mineral density around a specific cup with and without HA coating in
cementless THA. The previous, 3-year follow-up, study found no difference
with regard to bone mineral density changes or clinical outcome
Methods: This controlled randomized study includes 100 patients who underwent
unilateral cementless total hip arthroplasties from October 1998 to May
2000. All patients suffered from primary osteoarthrosis and had no competing
medical conditions. Randomisation was performed between porous coated Trilogy,
standard cup, and Trilogy Calcicoat (HA/TCP coated), study cup. The cup
was inserted in press-fit fixation. The femoral component was a cementless
porous coated titanium alloy stem (Bi- Metric), with a modular 28-mm CrCo
head. The Harris Hip Score (HHS) and bone mineral density (BMD), determined
by DEXA scanning, were used to study the effect. DEXA measurements
were performed with a dual energy X-ray absorptiometer using the model of
four regions of interest (ROI) – ‘the Wilkinson regions’.
Findings: 19 patients were lost to 8-year follow- up: 13 patients died of unrelated
causes, 4 underwent revision surgery and 2 were lost because of other reasons.
Of the 81 patients who were participating in the follow-up 40 had Trilogy
Calcicoat (HA/TCP coated) cup and 41 - porous coated Trilogy cup. The Harris
Hip Score rose from 53 to 96 in the study group (Trilogy Calcicoat) and from
48 to 92 in the control group. Measurements of periprosthetic bone mineral density
in the ROI 1, 3 and 4 revealed no difference between the two groups after 8
years. However, measurements in the ROI 2 were significant favourable to
porous coated Trilogy cup.
Conclusion: We found no difference with regard to clinical outcome in 81
patients followed up for 8 years after randomisation between HA or standard
porous coated cups. Measurements of periprosthetic bone mineral density were
significant favourable to porous coated Trilogy cup in one of the ROI.
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