Background: We previously reported our two and
five-year results of arthroplasty with the Porous Coated
Anatomic total hip prosthesis. We now report on the performance
of this prosthesis at ten to fourteen years.
Methods: The results of 311 total hip replacements
in which a Porous Coated Anatomic prosthesis was inserted without
cement in 279 patients were analyzed prospectively. The average
age of the patients at the time of the replacement was sixty-one
years (range, twenty to eighty-one years). Sixty-four
patients (seventy-six hips) died postoperatively. Forty-five
patients (forty-seven hips) were lost to follow-up,
and four were excluded because of their medical condition. One hundred and
sixty-eight patients (187 hips) were followed for ten to fourteen
years (average, twelve years). Seventeen of those patients (seventeen
hips) had a revision.
Results: The overall survival rate (with any revision
as the end point) was 90.0% ± 5.4% at
fourteen years, with an average Harris hip score of 85 ±
14 points. The prevalence of thigh pain was 36% (fifty-six
of 157) in the late period (more than ten years postoperatively).
Radiographs showed stable fixation, with bone ingrowth, of 83% (130)
of the 156 acetabular components and 88% (137) of the 156
femoral components at the latest follow-up evaluation.
Men had a significantly higher rate of femoral osteolysis than did
women (p < 0.001). The rates of acetabular and femoral
osteolysis associated with 32-mm femoral heads (49% [twenty-three] of
forty-seven and 70% [thirty-three] of
forty-seven, respectively) were significantly higher (p < 0.01)
than those associated with 26-mm heads (26% [twenty-eight] of
109 and 30% [thirty-three] of 109, respectively).
Despite this, revision (removal or exchange of components) was not
directly related to head size; instead, it was related to polyethylene
Conclusions: There have been persistent problems
with the Porous Coated Anatomic hip system, including thigh pain
and an increasing prevalence of osteolysis with time. Revision because
of aseptic loosening was related more to the thickness of the polyethylene
liner than to the size of the femoral head. Femoral heads with a
32-mm diameter did not increase the risk for revision provided that
an adequate thickness of polyethylene had been used.