cadera / hip - Active Congress.......

MARTES / TUESDAY
92
en implantes no cementados, dejando de
ser un mito.
Nuestra experiencia en prótesis no cementadas
recubiertas de hidroxiapatita ha sido
satisfactoria, pero en ocasiones la morfología
femoral no nos facilita la concordancia
de tamaños entre la región metafi saria y la
diafi saria, lo cual nos fuerza mucho en la
elección del tamaño de la prótesis. Con el
diseño de un implante femoral modular hemos
conseguido mejorar la discordancia que
a veces se producía debido a los diferentes
tipos morfológicos.
Desde abril del 2000 hasta noviembre del
2005 hemos implantado 283 vástagos modulares
con buenos resultados clínico-radiológicos.
El estudio por TC en 43 pacientes
demostró la correcta osteointegración del
implante, así como la distancia de salto que
era capaz de osteoconducir la HA.
HYDROXYAPATITE ON
THE STEM IN PRIMARY
THA – DOES IT HELP?
C. H. Rorabeck, MD
Health Sciences Centre, Ontario, Canada
HA coated tapered femoral stems work
extremely well, however, I don’t believe that
there’s any added value when compared to
porous coated tapered femoral stems. Studies
have been done comparing H.A. coated
stems with a grip blasted femoral stems.
Hamudoch, in a prospective randomized
study comparing 25 grip blasted and 25 HA
coated stems found, at a mean 8.6 year follow
up that there was slightly more migration
in the grip blast stems compared to the HA
coated stems; however, neither stem required
revision. Retrieval studies, looking at the
bone remodeling around HA porous coated
and grip blasted stems noted that HA coating
seems to increase the amount of ingrowth.
Thus, the early data would suggest that
HA coating is indeed helpful for promoting
early bony ongrowth or ingrowth; however,
as the Swedish Arthroplasty Register noted,
in a comparison of primary cemented versus
uncemented total hip replacements in
patients less than 60 - that uncemented
circumferentially porous coated or HA coated
had comparable survivorship and that both
were better than cement. The concern, as it
relates to hydroxyappetite is the possibility of
debris generation when the implant has been
inserted. Several papers have documented
the issue of polyethylene wear and osteolysis
associated with HA debris in the interface.
The other concern related to HA is associated
with cost.
The experience which I am reporting today,
relates to1300 Synergy cementless stems
inserted at our institution with an average age
of 61.5 years and a predominance of males.
Osteoarthritis was the underlying disease in
90% . A subset of this group underwent a
prospective randomized comparison, comparing
Synergy grip blasted and Synergy
HA coated.
Sixty-eight (68) HA grip blasted tapered
Synergy cementless stems were prospectively
randomized with 68 proximally porous
coated Synergy tapered cementless stems.
Data is now out to 7 years in both groups.
There had been no failures of fi xation in either
group and no evidence of aseptic loosening
or stem subsidence in either group. Detailed
radiographic analysis of the patients failed
to reveal any difference between the HA
coated stem versus the proximally porous
coated stem. A careful clinical assessment
likewise demonstrated no difference. Harris
Hip Scores in excess of 94% were similar in
both groups. Similarly, an analysis of the
WOMAC revealed a signifi cant improvement
in the WOMAC scores which was consistent
out to 7 years. There was no statistical
difference between WOMAC scores in the