To The Editor:
I read with dismay the well-intentioned case series "Outcomes of
Total Hip Arthroplasty and Contralateral Bipolar Hemiarthroplasty. A Case
Series" (2003;85:523-6), by Flören and Lester, regarding the
outcome of total hip arthroplasty compared with contralateral bipolar
hemiarthroplasty following a displaced subcapital hip fracture.
Notwithstanding the small numbers involved (nine patients) and the reduced
numbers at follow-up (just four patients at the final review), I have serious
concerns regarding any conclusions drawn from the study.
In a study of the outcome of a treatment, the subjects should have similar
pathologies. In this series, bipolar hemiarthroplasty was performed because of
a fractured femoral neck in eight of the nine cases and because of
osteonecrosis in one. In contrast, total hip replacement was performed because
of a fracture in only five of the nine cases and because of osteoarthritis or
osteonecrosis in the remaining four. This difference in primary pathological
process profoundly influences the outcome and surely precludes comparison.
Greenough and Jones1 showed that the outcome of total hip
replacement for the treatment of a fractured femoral neck was considerably
worse than that for the treatment of degenerative conditions. The patients who
had a total hip arthroplasty for the treatment of a degenerative condition
rather than a fracture could easily be falsely elevating the group
outcome.
We appreciate the interest of Mr. Board in our study despite his dismay and
concern about the findings and conclusions. The results of the study were
surprising even to us. We thought that patients with a bipolar hip prosthesis
did well. This turned out not to be true when the patient had his or her own
total hip replacement for comparison. Ultimately, all of the hips with a
bipolar hip prosthesis failed either clinically or radiographically and none
of the hips with a total hip replacement failed. We think that this
information is well worth reporting despite the small numbers.
After all, we had a rare situation in that the 750 patients who were
followed had the same surgeon, same surgical approach, same stem, and same
postoperative management. It would have been nice to have larger numbers and
more controlled diagnoses, but we live a clinical life. The fact that we had
nine such patients with only one variable among them provided us with a rare
opportunity, and we went to the trouble of reporting it.
The suggestion that the primary pathological process profoundly influences
the outcome of total hip arthroplasty may be true; however, the citation of
the study by Greenough and Jones from 1988 is of mostly historic interest and
can be misleading to the modern orthopaedic surgeon. One of the historic dicta
was to leave patients with some pain and they will protect the prosthesis. We
don't agree with that line of thinking, and we doubt that Mr. Board does
either. In our study, only the acetabulum in hips with a bipolar prosthesis
had failure. Three of the four surviving patients chose to live a sedentary
life rather than consider revision surgery. As those three patients would have
never returned for follow-up to report the failure of their bipolar hip
prosthesis, we may have mistakenly thought that they had good results with
both hips and had continued living an active senior life. In fact, it was our
bipolar hip prosthesis that had failed to provide them with pain-free
living.
Five recent
reports2-6
on the Alloclassic hip stem with a minimum follow-up of ten years revealed no
aseptic loosening in a wide variety of patients. It would seem that the
failure rate of 60% at an average followup of 4.6 years reported by Greenough
and Jones is probably associated with the former technology rather than
patient activity. We perform total hip arthroplasty for patients with a
subcapital hip fracture who desire to improve or maintain their previous level
of activity despite their senior age and other normal elderly morbidity. We
now know that we were adding to their morbidity by using a bipolar
hemiarthroplasty rather than a total hip arthroplasty. The study by Ravikumar
and Marsh7 should be
of particular interest.
It should be noted that our bibliography carefully depicted many of the
issues that should be considered, including the financial costs of failure,
financial cost of the implants, survival analysis of hemiarthroplasties,
function, rate of acetabular cartilage degeneration after bipolar
hemiarthroplasty, and degenerative conditions of the femoral head in otherwise
normal elderly patients.
Total hip arthroplasty for the treatment of patients with a hip fracture
does indeed have a higher rate of complications—in particular,
dislocation. Our current manner of dealing with this problem is the primary
use of a large femoral head or a constrained acetabular liner. We do not yet
know which is better. However, either method removes the restrictive and
unnatural need for prolonged avoidance of certain activities and forced
bedrest in the supine position.
Much study is currently being directed to the function of hip fracture
patients. The issues of prosthetic fixation are largely
answered8.
Nevertheless, a substantial number of these patients never regain their
previous level of vigor and vitality. This area is difficult to measure;
however, it is incumbent upon us to do so. We cannot be deluded by thinking
that patients who do not return for revision have had a successful result.
Frequently, they have progressive compromise and fail to notify the surgeon
and would not want to have a revision anyway. At least for some of these
patients, their lives are terribly compromised. It is just this kind of study
that begins to raise and answer these questions. If this study stimulated any
reader to consider the longer term results of bipolar hemiarthroplasty, then
the authors will be humbly gratified.
Greenough CG, Jones JR. Primary
total hip replacement for displaced subcapital fracture of the femur.
J Bone Joint Surg Br.1988;70:
639-43.70639
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Pieringer H, Auersperg V, Griessler
W, Bohler N. Long-term results with the cementless Alloclassic brand hip
arthroplasty system. J Arthroplasty.2003;18:
321-8.18321
2003
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Grubl A, Chiari C, Gruber M, Kaider
A, Gottsauner-Wolf F. Cementless total hip arthroplasty with a tapered,
rectangular titanium stem and a threaded cup: a minimum ten-year followup.
J Bone Joint Surg Am.2002;84:
425-31.84425
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Weissinger M, Helmreich C.
[Long-term results with Zweymuller cement-free Alloclassic stem]. Z
Orthop Ihre Grenzgeb.2001;139: 200-5.
German.139200
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Madero R, Ortega-Andreu M. Total hip arthroplasty with use of the
cementless Zweymuller Alloclassic system. A ten to thirteen-year follow-up
study. J Bone Joint Surg Am.2003;85:
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Lester DK, Floren M.Grit-blast tapered stem THA: 10 year minimum follow-up. Read at
the Annual Meeting of the American Academy of Orthopaedic Surgeons;
2003 Feb 6; New Orleans, LA.
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fixation versus hemiarthroplasty versus total hip arthroplasty for displaced
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Lester DK. Cross-section
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endoprotheses. J Arthroplasty.1997;12:
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