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DOS Kongressen 2016 ·
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5 year Radiostereommetry, Bone Mass Density,
and Whole Blood Cr Co levels in Resurfacing (RHA),
Large Diameter Head (LDH) and Standard THA.
Results from Randomized studies
Jeannette Penny, Ming Ding, Ole Ovesen, Søren Overgaard
Dept. of orthopedics, Næstved and OUH; , Clinical Institute OUH; Dept. of or-
thopedics, OUH; Dept. of orthopedics, Clinical Institute OUH
Background:
Most Metal-on-metal hips were abandoned due to high clinical
failure rates likely caused by metal wear products.
Purpose / Aim of Study:
We report 5 year results of a randomized study of
RHA, LDH-THA and THA with implant micro motion, Cr & Co ions and BMD.
Links between outcome measures is investigated
Materials and Methods:
19 RHA 17 THA and 15 LDH-THA for 5 year follow-
up All were followed with Bone mass density RHA and THA had prospective
Co and Co ions, LDH-THA only at 5 y. Marker based RSA of both RHA com-
ponents. Cup only for LDH-THA. We used a total translation measure: TT= ã
(x2+y2+z2). Data collected at baseline, 8 w, 6 m 1, 2 and 5 y Statistical tests:
Pearson correlations. ANOVA and MANOVA
Findings / Results:
Presented as: median (mean (s.e)) and quartiles RSA: The
5 y TT results were 1.1(1.3 (0.2))1.0 to 1.7 mm for the LDH-THA Cup, 0.6
(0.7(0.1)) 0.3 to 0.8 mm for the RHA Cup and 0.5 (0.8(0.3)) 0.3 to 0.6 mm
for the RHA head. The migration between the cups differed at 5 but not at 2
years (p<0.05) Co ions were; RHA: 1.1(2.8 (0.7)) 0.8 to 4.9, THA: 0.2 (0.4
(0.1)) 0.1 to 0.4 and LDH-THA: 1.2 (1.4(0.3)) 0.7 to 2.9 ppb. Similar levels
for Cr. LDH-THA and RHA ions did not differ at 5 year, Co was higher than THA
(p<0.01) We found better preservation of the acetabular BMD in the LDH-RHA
group (p<0.05) and an advantage of the RHA in the femoral Gruen zones 6 and
7 (p<0.01) TT migration correlated negatively with BMD in the femoral collum
and proximal femur (p<0.05), but had no link to acetabular BMD or metal ions
Conclusions:
In contrast to registered revision rates, we found significantly
larger movement for the LDH-THA cup than the RHA cup. Despite this, the
LDH-THA cup maintained the acetabular BMD best at 5 years. Movement of
the implant may adversely affect the femoral BMD, but - in this study - does
not increase metal ion release
No conflicts of interest reported
130.