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Letters to the Editor to:
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- Scientific Articles:
Richard Buckley, Suzanne Tough, Robert McCormack, Graham Pate, Ross Leighton, Dave Petrie, and Robert Galpin
- Operative Compared with Nonoperative Treatment of Displaced Intra-Articular Calcaneal Fractures : A Prospective, Randomized, Controlled Multicenter Trial
J Bone Joint Surg Am 2002; 84: 1733-1744
[Abstract]
[Full text]
[PDF]
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Electronic letters published:
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Response to Dr. Jones and colleagues
- Richard E. Buckley
(20 March 2003)
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A Bold Step in the Right Direction for Orthopaedic Clinical Research
- Kevin Jones, Geoffrey Haft, Aimee Klapach, University of Iowa Orthopaedic Journal Club
(18 February 2003)
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Response to Dr. Jones and colleagues |
20 March 2003 |
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Richard E. Buckley, Surgeon University of Calgary
Send letter to journal:
Re: Response to Dr. Jones and colleagues
buckclin{at}ucalgary.ca Richard E. Buckley
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Dr. R. Buckley responds RE: A Bold Step in the Right Direction for
Orthopaedic Clinical Research
Thank you for your kind words relating to our paper. We agree with a
number of your comments and will try to answer. Our statistician has been
most helpful in supporting us with our answers.
The use of the pre-randomization strategy(1) is in our minds, an underused
type of strategy. It works nicely in trials where there is operative
versus nonoperative strategy. Where there is an operative vs. operative
strategy (Widget 1 vs. Widget 2) it is really not difficult to obtain
consent for most prospective randomized trials. In trials however, that
are operative vs. nonoperative, this strategy is often helpful. We do not
agree that this particular pre-randomization strategy can be viewed as
unethical. Certainly as much information can be given in the education of
a patient with this strategy as in any other strategy. There simply has to
be the recognition that if surgery was an option, the patient would be
willing to proceed in that direction. The calcaneal fractures certainly
are a perfect example of this where both operative and nonoperative
strategies can be used. When in 1991 the study started, it was obvious
that nonoperative care or operative care were equal in there efficacy.
The most oft asked question in clinical trials recently, is whether
or not an intention to treat analysis was performed. We analyzed all the
data we had, on all the patients for whom any follow up material was
available. So, of the eligible patients, we had follow up data on 309
patients. We are not sure how we could have obtained any data on those
without follow up information. We would have included those who were
withdrawn in the analysis (as per an intention to treat) except we did not
have any information in the data base on them. We did however, come up
with a very strong study, which can be found in the Canadian Journal of
Surgery (2). This particular study dealt with those patients who are lost
to follow up in our paper. There are not too many prospective randomized
trials that go to the extent of actually writing up a “lost to follow up
paper” which deals with all of their patients who did not come back for
the conclusion of the period in the randomized trial.
We disagree completely with your statement that we did not define a
primary outcome. This was very clear that we were looking to see which
treatment group would have the best clinical outcome. This seems very
clear to us. It was interesting in this study, because there were no
validated outcomes when we started the study, we actually validated our
own using all techniques that are standard for validating outcomes. You
have picked up an interesting point that prospective trials often go on
for a long period of time and that they grow as they mature. We were able
to validate an outcome with the use of patients and proceed to use this
along with the SF-36 which was just being defined as we started our study.
We certainly knew that we would require a clinically relevant difference.
Because the literature was so poor beforehand (there is a lovely paper on
the history of calcaneal fractures by Crosby(3) there were no outcome
measures before 1991 used in identifying calcaneal outcomes. In relation
to our assigning of "clinically relevant difference" we took our interim
analysis and noted that we would not identify a clinically significant
difference unless we increased our numbers by four-fold and we proceeded
to do such. We do not think that we changed the question to fit the data
but only included enough patients to demonstrate just how difficult this
particular question is. We do not agree with your statement that "if one
cannot demonstrate a meaningful difference between two therapies, one
should not start looking for clinically meaningless difference that can be
proven numerically". Our study in fact, is a negative study. It shows no
difference between the two groups.
As this was one of the first studies in this particular area that
would be truly prospective and randomized, we decided to evaluate more
than one dependant variable and wanted to firstly describe the covariates
of surgical success as related to patient demographics, WCB status, etc.
This approach allowed us to generate hypothesis that could be evaluated by
others and also to describe to our peers the factors that influenced
outcome.
In relation to your comments regarding independent and dependant
variables, we bring to mind that statistics significance is truly clinical
significance. When odds ratio exceeds two and the confidence interval
excludes the null value, there is some evidence that findings are
clinically relevant. All significant odds ratios in the logistic
regression models are in excess of two, suggesting clinically relevant
findings. Much of the raw data is presented in the tables so that the
reader can determine for themselves what a clinical meaningful difference
is for them, example, odds ration of 8.09 for WCB - those on WCB were 8X
more likely to have lower values on the SF-36 than those who were not WCB
- is this clinically meaningful? This certainly allows the public,
including yourself, to have thoughts on the subject. We feel that
mortality is a very hard outcome, which many epidemiologists would argue
is not really relevant in our area of medicine; and morbidity, although
the concept is "harder to measure" is really key.
We agree completely that the data needs to be interpreted with regard
to clinical judgment and clinical meaning and not by epidemiology alone.
That is why team work is so important and we have included multi-centre
sites and many surgeons with experience and a PhD statistician.
In relation to your comments on the categorization of SF-36, etc, at the
mean - this is a great point, one that is often discussed by researchers
(and depends generally on your thoughts to "lump" or "split" the
generalist vs. the strategist approach). We thank you for highlighting
this and we feel that this was important and the idea was to describe in
broad terms what influences outcome. The decision to split that data at
the mean, was based on the absence of prior data that indicated a
different meaningful end point. We would acknowledge this limitation and
recognize it as arbitrary and a place for further study or analysis.
Interestingly, we are publishing(4) on the SF-36 and it's comparisons to
other populations of patients and the calcaneal patient tends to be as bad
as any chronic disease that affects a patient medically.
Thanks again for your kind words and we agree with you that it was an
enormous task. In fact we are happy that it is over. We have however,
made great strides and now in some ways, treat our displaced intra-
articular calcaneal fractures differently with a better and more positive
result. This particular paper, we feel, will help clarify many problems
and will lead to better care of these patients in the future.
Sincerely,
Richard E. Buckley, M.D., FRCS(C)
Suzanne Tough, PhD
Robert McCormack, MD, FRCSC
Graham Pate, MD, FRCSC
Ross Leighton, MD, FRCSC
Dave Petrie, MD, FRCSC
Robert Galpin, MD, FRCSC
REB/mk
1. Zelen, M, A New Design for Randomized Clinical Trials, New England
Journal of Medicine, 1979, 300 (22), page 1242-1245
2. Murnaghan, M.L., R.E..Buckley; Lost but not Forgotten: Patients Lost to
Follow-Up in a Trauma Data Base, Canadian Journal of Surgery, Vol 45,
No.3, pp 191-195, June 2002
3. Crosby, L, Camins, P., The History of the Calcaneal Fracture,
Orthopaedic Review, Vol 20, no 6, June 1991, page 501-509
4. Unpublished data |
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A Bold Step in the Right Direction for Orthopaedic Clinical Research |
18 February 2003 |
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Kevin Jones, Resident University of Iowa Department of Orthopaedics, Geoffrey Haft, Aimee Klapach, University of Iowa Orthopaedic Journal Club
Send letter to journal:
Re: A Bold Step in the Right Direction for Orthopaedic Clinical Research
kevin-jones{at}uiowa.edu Kevin Jones, et al.
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There is no question that surgical intervention for bone and joint
disorders profoundly alters their natural history. What is less apparent
is whether or not the altered results always represent meaningful
improvements over the natural history. As with most surgical specialties,
the field of orthopaedics has lagged behind other fields of medicine in
the procurement of rigorous evidence, in the form of randomized controlled
trials, to guide decisions. The problems of risk, consent, randomization,
cost, necessary length of follow-up, and lack of specific outcome measures
represent more weighty challenges to the study of orthopaedic surgical
interventions than to investigation of many pharmacologic therapies.
However, the importance of obtaining rigorously generated evidence to
guide clinicians in making rational treatment decisions is also heightened
by these same challenges.
The recent article, “Operative compared with nonoperative treatment of
displaced intra-articular calcaneal fractures,” by Buckley et al. [1],
published in the October issue of the Journal exemplifies the challenges
of prospective randomized trials of orthopaedic interventions. The
authors must be commended both for the tremendous effort expended and for
their willingness to question the efficacy of a surgical intervention that
many believe to be the standard of care [2]. While so much of our
literature is generated by the drive to instruct others in one’s own
methods or report on one’s own results, the scientific willingness to
question and to study should never go unnoticed or unappreciated.
One strength of the study is its sheer magnitude. The ability to
consent and randomize 424 patients to treatments with vastly different
psychological implications is truly astounding. This was, no doubt, aided
by the use of a pre-randomization strategy. This strategy, originally
described by Zelen in 1979 [3] randomizes eligible subjects prior to
obtaining consent. The patient is then consented for the treatment arm to
which they were randomized. This aims at increasing recruitment by
removing the anxiety of randomization for patients and improving the
physician-patient relationship by removing discussion of uncertainty in
treatment choice. In his original formulation of the plan, only subjects
randomized to experimental therapies would be consented, but the strategy
has been modified by others [4] subsequently to include post-randomization
consent for each treatment arm of the study. Patients are informed that
they were randomized, but the discussion focuses on the treatment arm to
which they were assigned.
The pre-randomization strategy has never been very widely used and has
recently been questioned due to ethical concerns about the possibility of
incompletely informed consent. Nonetheless, it represents a means for
bridging many of the obstacles to randomizing patients to surgical
treatments. While many treatments that are routinely offered to patients
have not yet been rigorously substantiated with evidence, surgeons do not
usually lay the entire burden of uncertainty upon the patients’ shoulders
during the consent process. The shouldering of some of that uncertainty
is considered to be part of the responsibility of patient care. Perhaps
pre-randomization strategies and the ethics involved need to be revisited
and revised by orthopaedic surgeons as necessary for public and
institutional approval.
Despite the recruitment power of their pre-randomization strategy, Buckley
et al. failed to include an intention to treat analysis. It is not
erroneous to include analyses limited to patients who received only their
randomized protocol, but these cannot be done to the exclusion of an
intention to treat analysis. Such an analysis is fundamental to the
validity of a pre-randomization scheme.
The drive to question is most usefully linked to carefully constructed,
testable hypotheses. One fault of the methods described for this study is
the lack of an unequivocally defined primary outcome. The investigators
utilized two validated outcomes instruments in patient follow-up, but the
failure to define a priori a focused, dependent variable that would be
used to evaluate and compare the treatment arms, ultimately hampered
analysis of the results. To their defense, the authors recognized ahead
of time that their selection of a clinically relevant difference for the
power analysis was necessarily arbitrary. That the investigators changed
the numerical value assigned to a clinically relevant difference after
interim analysis brings into question whether their statistically
significant difference was truly clinically significant. It is poor
science to change the question only to fit the data. What difference is
considered meaningful—or, worthy of a change in clinical practice--should
not be affected by the observed differences between two therapies. If one
cannot demonstrate a meaningful difference between two therapies, one
should not start looking for a clinically meaningless difference that can
proven numerically. The defined clinically meaningful difference should
be arbitrary only numerically. It should be a difference in the primary
outcome that is considered a sufficient benefit to the patient to balance
the costs and risks involved in the intervention. When the number
involves an outcome such as mortality by any cause, the investigator must
determine how many deaths are enough to warrant the use of an alternative
therapy. When the primary outcome is a score on a total quality of life
outcome instrument, the investigator must determine what difference in
quality of life is worth a change in practice. The clinical judgment
required for such decisions is why orthopaedic surgeons, rather than
epidemiologists alone, study orthopaedic conditions and treatments.
The reported analysis of the results demonstrates another missed
chance to apply clinical judgment to study design. Trends and
distributions, as part of the information provided by continuous
variables, can add significantly to understanding, but the process of
decision-making depends on lumping and splitting variables into
categories. It is therefore a rather common practice to categorize
independent or dependent continuous variables according to arbitrarily
limited groups. Two principles are wisely followed in this process of
categorization. First, the arbitrary limits should be determined prior to
data collection. Second, the limits should represent clinically relevant
groupings. In the case of an outcomes instrument, a clinician
investigator may choose to define a clinical failure as any score below a
certain number. While the limit may be numerically arbitrary, in that the
few scores falling just above and just below it may not be meaningfully
different, success and failure defined as the entire groups above and
below the limit might give a clearer clinical perspective on the data
overall. In contradistinction to these principles, the secondary analyses
of this study set the limit for dichotomizing continuous variables as the
mean value from all groups. This decision turned the clinically helpful
effort of categorization into a clinically arbitrary manipulation of
numbers.
More randomized trials of orthopaedic interventions are needed. The
time taken to plan them carefully from the details of randomization and
consent, through the planned statistical analyses must be invested to
secure the quality of the evidence. Buckley et al. undertook an enormous
task and should be commended for their overall success. Hopefully, we can
learn from both their example and their few mishaps along the way.
REFERENCES CITED
1. Buckley, R., et al., Operative compared with nonoperative
treatment of displaced intra-articular calcaneal fractures: a prospective,
randomized, controlled multicenter trial. J Bone Joint Surg Am, 2002. 84-
A(10): p. 1733-44.
2. Thermann, H., et al., Management of calcaneal fractures in adults.
Conservative versus operative treatment. Clin Orthop, 1998(353): p. 107-
24.
3. Zelen, M., A new design for randomized clinical trials. N Engl J Med,
1979. 300(22): p. 1242-5.
4. Chang, R.W., et al., Prerandomization: an alternative to classic
randomization. The effects on recruitment in a controlled trial of
arthroscopy for osteoarthrosis of the knee. J Bone Joint Surg Am, 1990.
72(10): p. 1451-5. |
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