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The PDF of the article you requested follows this cover page.
This is an enhanced PDF from The Journal of Bone and Joint Surgery
2007;89:2550-2551.J Bone Joint Surg Am.Jan Paul M. Frlke
with Wrist Fractures?Can Vitamin C Prevent Complex Regional Pain Syndrome in Patients
This information is current as of November 6, 2007
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Letters to The Editor
Calcaneal Osteomyelitis Caused
by Exophiala jeanselmei
in an Immunocompetent Child
To The Editor:
In reference to our case report entitled Cal-
caneal Osteomyelitis Caused by Exophiala
jeanselmeiin an Immunocompetent Child.
A Case Report (2007;89:859-62), my coau-
thors and I would like to bring to the notice
of the readers of The Journalthat the same
case report has been published by one of us
in the Indian Journal of Medical Microbiology
as an article entitled Eumycetoma Pedis
Due to Exophiala jeanselmei.1
The publication in the Indian Journal
of Medical Microbiologywas meant to high-
light the microbiological aspects of the dis-
ease as the said fungus is extremely rare. The
authors regret any confusion this might have
caused to the readers of both articles.
Shah A. Khan, MS, MRCS(Ed)
Department of Orthopaedics, All IndiaInstitute of Medical Sciences, AnsariNagar, New Delhi 110 029, India, e-mail:[email protected]
This letter originally appeared, in slightly different form, onjbjs.org. It is still available on the web site in conjunctionwith the article to which it referred.
Reference
1. Capoor MR, Khanna G, Nair D, Hasan A, Rajni,
Deb M, Aggarwal P. Eumycetoma pedis due to
Exophiala jeanselmei.Indian J Med Microbiol.
2007;25:155-7.
Navigated Total Knee Replacement
To The Editor:
We read with interest and concern the arti-
cle, Navigated Total Knee Replacement.
A Meta-Analysis (2007;89:261-9) by Bau-
wens et al. We submitted a similar meta-
analysis to The Journal of Bone and Joint Sur-
geryover one year ago, which was appropri-
ately rejected for publication because of the
inclusion of data from abstracts and uncon-
trolled case series. The reviewers and edi-
tors also expressed concern that our finding
of an advantage for navigated total knee ar-
throplasty compared with conventional total
knee arthroplasty based on radiographic
alignment end points needed to be balanced
against the lack of evidence with regard to
differences in cost-effectiveness, complica-
tion rates, and long-term outcomes be-
tween the two procedures.
We were in the process of updating
our meta-analysis in light of more recent
publications (excluding data from abstracts
and uncontrolled case series) when the
study by Bauwens et al. was published.
Having reviewed essentially the same data-
base, we were perplexed by the authors
conclusion that navigated knee replace-
ment provides few advantages over conven-
tional surgery on the basis of radiographic
end points, as our own meta-analysis re-
vealed a significant improvement in radio-
graphic end points with computer-assisted
navigation.
Our concerns about the discrepancies
between our findings and those of Bauwens
et al. prompted us to investigate their source
data. We contacted them, and they gra-
ciously provided us with the raw data for
all studies included in their meta-analysis.
On further review, we discovered multipleinaccuracies of data extraction and/or data
entry in their analysis.
In four of the studies1-4reviewed in
the article by Bauwens et al., the data for
conventional techniques were entered into
the data set for navigated replacement for
analysis while the data for the navigated re-
placements were entered into the data set for
conventional techniques. We were also able
to determine errors of data extraction, data
entry, patient count, or patient group as-
signment from four additional studies5-8.
One paper9was included and counted as
reporting mechanical axis data when thesedata were not reported in the study. A kin-
ship study10(i.e., a study sharing overlapping
data with an already included study) was in-
cluded when it should have been excluded.
There were two additional studies11,12in
which the numbers that we extracted were
slightly different from those in the report by
Bauwens et al.; we note these only as dis-
crepancies (not errors) in extraction.
Our further review of their paper also
suggested that their labeling and descrip-
tion of results were misleading. Specifically,
they describe their meta-analyses as those
of relative risk of malalignment and label
their figures accordingly. In the Discussion,
they state that the available data suggest
that navigation reduces the relative risk of 3
of malalignment by 25%. This statement
is in error because their meta-analysis was
not of the relative risk of malalignment, but
rather the relative risk of alignment (i.e., the
chance that a patient has alignment after the
procedure). It would, therefore, have been
accurate for them to state that conventional
total knee arthroplasty decreases the relative
chance of alignment by 25%. When misfit,
instead of fit, is the outcome of choice, the
results are quite different from those re-
ported by Bauwens et al. Correctly stated,the risk of malalignment with conventional
replacement is appropriately three times
that with computer-assisted surgery.
In conclusion, our findings of data
extraction and entry errors cause us to chal-
lenge the conclusions in the article regarding
the meta-analysis of radiographic end
points following conventional compared
with navigated knee replacement surgery.
A correct data analysis demonstrates over-
whelming evidence of a much lower error
rate with navigation. Reversal of some of the
extracted data and misreporting of relative
risks for fit as risks of malalignment are par-tially responsible for the muted difference
that Bauwens et al. described between navi-
J Bone Joint Surg Am.2007;89:2547-55
LETTERSTOTHEEDITORMUSTBESUBMITTEDELECTRONICALLY;
INSTRUCTIONSAREATWWW.JBJS.ORG/LETTERS
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gated and conventional total knee arthro-
plasty. These errors, however, do not obviate
their other discussion points regarding the
methodological limits of the available trials,
including a dearth of evidence on long-term
outcomes, quality of life, and costs.While we recognize and understand
the challenges inherent in performing meta-
analyses, our intent is to bring these errors
to the attention of the readers of The Journal
to correct any erroneous impression that
this work may have left with the readership.
J. Bohannon Mason, MD
Thomas Fehring, MD
Kyle Fahrbach, PhD
Corresponding author: J. Bohannon Mason,MD, OrthoCarolina Hip and Knee Center,1915 Randolph Road, Charlotte, NC 28207,e-mail: [email protected]
Disclosure:In support of their research for orpreparation of this work, one or more of theauthors received, in any one year, outsidefunding or grants in excess of $10,000 fromDePuy, and Johnson and Johnson, Warsaw, In-diana. Neither they nor a member of their im-mediate families received payments or otherbenefits or a commitment or agreement toprovide such benefits from a commercial en-tity. No commercial entity paid or directed, oragreed to pay or direct, any benefits to any re-search fund, foundation, division, center, clini-cal practice, or other charitable or nonprofitorganization with which the authors, or a
member of their immediate families, are affili-ated or associated.
D. Stengel, K. Bauwens, G. Matthes,
M. Wich, F. Gebhard, B. Hanson,
and A. Ekkernkamp reply:
We read with great interest the letter from
Dr. Mason and colleagues. Since they raised
substantial concerns about the validity of
our findings, we carefully reviewed the data
set that formed the basis for all analyses and
figures presented in The Journal.
We reviewed the references cited by
Mason et al.1-4and found no data shift betweenthe conventional and navigated-surgery
groups. Such a shift was unlikely since the
forest plots consistently showed an advan-
tage for the navigated-surgery cohort.
Mason et al. also claimed that they
found additional errors of data extraction
from four other studies that we reviewed5-8,
but unless they are more specific in their
criticisms, we cannot respond properly.
We would refer Mason et al. to the
Materials and Methods section of our pa-
per, where we stressed that the numbers of
patients were extracted from histograms
whenever possible. This may explain most
of the differences that they noted between
their and our data sets. Additional differ-ences might be related to different handling
of the unit of interestthat is, the patient or
the knee. Bolognesi and Hofmann9did in-
deed report the alignment of the femoral
and the tibial component rather than the
mechanical axis. However, if navigation im-
proves both femoral and tibial component
alignment, it is very likely that the resulting
mechanical axis will be optimized as well.
Since the observed effects were consistent
with others, we decided to include that
study in our analysis. We definitely identi-
fied and excluded some kinship studies, but
we could not retrieve a dual publication byMielke et al.10.
When posing a null hypothesis, it is
important to define the accepted standard of
care. Risk ratios and other relative measures
are asymmetric. This was the reason why we
also provided risk differences, which can be
used for calculating the number needed to
treat. Currently, navigation is an experimen-
tal add-on and may either decrease the risk
of malalignment or increase the chance of
alignment. It is, however, not justified to ar-
gue that conventional surgery would in-
crease the relative risk of malalignment over
that associated with navigated componentplacement. With regard to health-policy de-
cisions, this is a dangerous statement since it
would imply that all patients who are not
operated on with computer assistance but
undergo conventional total knee arthro-
plasty by an experienced surgeon are at a
higher risk of having malalignment when
compared with those who undergo total
knee arthroplasty with navigated compo-
nent placement.
Importantly, our analyses and plots
showed a significant advantage of navigated
over conventional knee replacement in
terms of radiographic surrogates, so we arein complete agreement with Mason et al.
Yet, unless these advantages are consistent
with improved outcomes, we think that our
conclusion Navigated knee replacement
provides few advantages over conventional
surgery on the basis of radiographic end
points is valid.
Finally, we regret that Mason et al.,
after receiving our data set (the sending of
which shows our openness and willingness
to engage in scientific debate), did not con-
tact us again to compare both data sets and
to discuss, explore, and resolve any possible
differences jointly before submitting a Letter
to the Editor challenging our scientific repu-
tation. We are sorry that Dr. Masons groupcould not publish their paper, but we are
deeply disappointed in their behavior.
Dirk Stengel, MD, PhD, MSc
Kai Bauwens, MD
Gerrit Matthes, MD
Michael Wich, MD
Florian Gebhard, MD, PhD
Beate Hanson, MD, MPH
Axel Ekkernkamp, MD, PhD
Corresponding author: Dirk Stengel, MD,PhD, MSc, Department of Trauma and Or-thopedic Surgery, Center for Clinical Re-search, Unfallkrankenhaus Berlin, Warener
Strasse 7, 12683 Berlin, Germany, e-mail:[email protected]
J.N. Katz and E. Losina
comment on the above letters:
In their meta-analysis of the effectiveness of
navigated total knee replacement, Bauwens
et al. found that navigation was associated
with favorable results in terms of several ra-
diographic parameters. The data were insuf-
ficient to evaluate effects on complication
rates or functional outcomes. The article
stimulated the above letter from Mason et
al. and a letter from Gregori and Holt13,which prompted additional letters of clarifi-
cation from Bauwens et al.
Caught in the crossfire, readers might
well ask why a meta-analysis led to such edi-
torial dueling. Of note, controversy over
meta-analysis is long-standing14. The de-
bates stem in part from the methodological
complexity of meta-analysis, a powerful but
challenging analytic technique that permits
pooling of estimates across studies. We will
discuss a few of the many methodological
complexities of meta-analysis to put the cor-
respondence about navigated total knee re-
placement in perspective.
Why Pool? Meta-Analysis Compared
with Traditional Literature Review
If pooling raises so many questions, why
bother to pool estimates quantitatively
across studies? In many reviews, the authors
simply array the findings of separate studies
in evidence tables without attempting to
synthesize them quantitatively into single
estimates of effect. A key rationale for pool-
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ing is that the available evidence may consist
of small studies that show positive (or nega-
tive) effects but lack power to establish the
associations with significance. Pooling these
smaller studies may avoid false-negative re-
sults due to Type-II error.A useful example of this application
of meta-analysis was provided by Felson and
Anderson in a meta-analysis of the effect of
cytotoxic therapy and corticosteroids com-
pared with that of corticosteroids alone for
patients with lupus nephritis15. Prior small
studies had suggested a beneficial effect of
cytotoxic therapy. The meta-analysis over-
came the small sample sizes of the compo-
nent studies and illustrated the beneficial
effect of cytotoxic therapy across studies.
Pooling also permits the investigator
to examine whether particular study charac-
teristics are associated with the principaloutcome. This technique is termed metare-
gression.The investigator develops a regres-
sion model in which each study serves as a
single observation, contributing a single es-
timate of outcome and of each covariate.
The investigator can weight studies differen-
tially in order to give greater importance in
the regression to those that have larger sam-
ple sizes or that are of higher methodologi-
cal quality. Metaregression can yield insights
about sources of variability in outcome
measures across studies. For example, it may
be that trial designs are associated with
larger effects and nonrandomized designs,with smaller effects, or vice versa.
Why Not Pool?
Pooling the results of separate studies into
single estimates of effect involves several as-
sumptions that frequently are not satisfied
by the literature under review. Clearly, the
outcome variable must be consistent across
studies. This constraint poses no problem
when the outcome is unambiguously de-
fined, such as thirty-day all-cause mortality
following hip replacement. However, when
studies measure satisfaction, pain relief,
functional status, and other such complexoutcome variables, the task becomes more
complicated. These domains are often mea-
sured with different tools in different stud-
ies, or different cutoffs are used to define
success. For example, the authors of some
studies of the outcome of total knee replace-
ment might use the WOMAC (Western
Ontario and McMaster Universities Os-
teoarthritis Index) as the principal outcome
measure whereas others might use the SF-36
(Short Form-36) or the Knee Society Scale.
Attempting to synthesize results in these
circumstances involves essentially com-
bining apples and oranges and is not
advisable. Standardization of outcome
assessment and reporting in specific fieldswould assist investigators who wish to per-
form meta-analysis.
In addition, the underlying statistical
methodology of meta-analysis assumes that
each of the studies to be synthesized repre-
sents one observation from a single distribu-
tion of studies. This assumption is validated
with tests of homogeneity of the odds ratios
(or other effect estimates) across studies. If
the group of studies to be synthesized ap-
pears to emanate from a single distribution,
the homogeneity criterion is met and the
studies may be synthesized in a meta-analysis.
If, on the other hand, the assumption ofhomogeneity is not met, and the studies ap-
pear to be heterogeneous, then the investi-
gators should be cautious about pooling.
The investigators could simply choose not to
pool the studies quantitatively. Alternatively,
the investigators might wish to perform a
metaregression to identify sources of hetero-
geneity. For example, it may be that higher-
quality studies or a particular study design
(e.g., trials) are associated with higher effect
estimates.
What to Pool?
A meta-analysis is essentially an observa-tional study of individual studies16. As with
all observational studies, the results are in-
fluenced by the selection criteria that dic-
tate which studies are included in the meta-
analysis and which are excluded. An issue
that arises frequently, and was a major focus
of contention about the paper by Bauwens
et al., is whether to include unpublished
studies. Excluding unpublished studies risks
publication bias, a form of selection bias in
meta-analyses that arises because positive
studies are, on the average, more likely to
be published than negative studies. How-
ever, including unpublished studies thathave not passed peer review risks the in-
clusion of studies with results that may not
be credible.
Another important decision is
whether to restrict the analysis to random-
ized controlled trials or to include observa-
tional designs. The advantage of restricting
the analysis to randomized controlled trials
is that randomization greatly reduces the
risk of selection bias in each component
study of the meta-analysis. Including obser-
vational studies permits the meta-analysis to
simply propagate the biases inherent in the
component studies. The disadvantage of
restricting the sample to randomized
controlled trials is that for many clinicalproblems, including navigated total knee
replacement, there are few randomized
controlled trials and most of the relevant
literature includes observational designs.
Returning to Navigated
Total Knee Replacement
Bauwens et al. handled most of the above-
mentioned issues with sophistication. They
decided to pool because they were concerned
that multiple underpowered studies would
fail to establish an effect that might become
apparent in a pooled analysis. They included
nonrandomized trials because they were notcomfortable restricting the analysis to ran-
domized controlled trials. (An alternative ap-
proach would be to use metaregression to
examine whether the magnitude of effect dif-
fered between randomized and observational
studies; if it did, the meta-analysis could be
done in subgroups.) The authors weighted the
studies according to sample size and quality.
They used appropriate analytic techniques to
look for publication bias and, finding no evi-
dence of such a bias, they restricted the analy-
sis to published studies. In addition to stating
the results of these analyses of publication bias,
displaying the graphical evidence would havebeen helpful to readers.
Bauwens et al. concluded that the
studies that they wished to synthesize were
heterogeneous. Having established heteroge-
neity, the authors could have simply decided
not to pool the studies at all. Alternatively,
they could have developed a metaregression
model, which would have been useful in
identifying and ultimately controlling for
sources of heterogeneity. They could have
stratified according to such characteristics
and tested whether the stratified meta-
analysis would have yielded less heteroge-
neity. The authors did indeed perform ametaregression, but they did not use it to
identify strata in which studies were more
homogeneous, as discussed here. By docu-
menting heterogeneity and not doing any-
thing about it, the authors in a sense made a
diagnosis without offering a remedy.
Data Sharing
Synthesizing the results of various studies is
ultimately a collaborative activity. The in-
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vestigator will often wish to contact other
scientists who have access to original trial
data or who themselves have attempted a
data synthesis. These collaborations can
help move the field forward. In fact, the Na-
tional Institutes of Health (NIH) and otherresearch sponsors have developed specific
provisions for facilitating data sharing in or-
der to best leverage the precious data gar-
nered in NIH-funded studies. In this regard,
we were particularly impressed by the will-
ingness of Bauwens et al. to share their data
and we were disappointed that Mason et al.
chose to communicate their observations in
a letter to The Journalwithout discussing the
findings with the original authors. Readers,
and ultimately patients, were not served well
by this failure to behave collaboratively.
Concluding RemarksThe meta-analysis by Bauwens et al.
prompted questions about selection of stud-
ies, choice of common outcome measures
across studies, assessment and management
of heterogeneity, interpretation of results,
and approaches to collaboration. The les-
sons learned from these studies of navigated
total knee replacement are that investigators
should make individual studies as definitive
as possible by using the most rigorous de-
signs feasible, powering studies adequately,
and using standardized measures of out-
come. Pooling is a powerful method for ag-
gregating information across studies, but itis ultimately a collaborative effort. Leaders
in the field should designate standard mea-
sures of outcome to facilitate pooling, and
investigators should work collaboratively
with one another so that data syntheses
move the field forward, bringing quality and
value to patients.
Jeffrey N. Katz, MD, MSc
Elena Losina, PhD
Corresponding author: Jeffrey N. Katz, MD,MSc, Orthopaedic and Arthritis Center forOutcomes Research, Brigham and WomensHospital, 75 Francis Street, PBB-B3, Boston,MA 02115, e-mail: [email protected]
Disclosure: The authors did not receive anyoutside funding or grants in support of theirresearch for or preparation of this work. Nei-ther they nor a member of their immediatefamilies received payments or other benefits ora commitment or agreement to provide suchbenefits from a commercial entity. No com-mercial entity paid or directed, or agreed topay or direct, any benefits to any research fund,
foundation, division, center, clinical practice,or other charitable or nonprofit organizationwith which the authors, or a member of theirimmediate families, are affiliated or associated.
These letters originally appeared, in slightly different form,on jbjs.org. They are still available on the web site in conjunc-tion with the article to which they refer.
References
1. Bthis H, Perlick L, Tingart M, Lring C, Zura-kowski D, Grifka J. Alignment in total knee ar thro-
plasty. A comparison of computer-assisted surgery
with the conventional technique. J Bone Joint Surg Br.2004;86:682-7.
2. Perlick L, Bthis H, Lerch K, Lring C, Tingart M,
Grifka J. [Navigated implantation of total knee en-
doprostheses in secondary knee osteoarthritis of
rheumatoid arthritis patients as compared with con-ventional technique]. Z Rheumatol. 2004;63:140-6.
German.
3. Saragaglia D, Picard F, Chaussard C, Montbarbon
E, Leitner F, Cinquin P. [Computer-assisted knee
arthroplasty: comparison with a conventional proce-
dure. Results of 50 cases in a prospective random-
ized study]. Rev Chir Orthop Reparatrice Appar Mot.
2001;87:18-28. French.
4. Sparmann M, Wolke B, Czupalla H, Banzer D, Zink
A. Positioning of total knee arthroplasty with and with-
out navigation support. A prospective, randomised
study. J Bone Joint Surg Br. 2003;85:830-5.
5. Chauhan SK, Scott RG, Breidahl W, Beaver RJ.
Computer-assisted knee ar throplasty versus a
conventional jig-based technique. A randomised,
prospective trial. J Bone Joint Surg Br. 2004;86:
372-7.
6. Confalonieri N, Manzotti A, Pullen C, Ragone V.
Computer-assisted technique versus intramedullary
and extramedullary alignment systems in total knee
replacement: a radiological comparison. Acta Orthop
Belg. 2005;71:703-9.
7. Kim SJ, MacDonald M, Hernandez J, Wixson RL.Computer assisted navigation in total knee arthro-
plasty: improved coronal alignment. J Arthroplasty.
2005;20(7 Suppl 3):123-31.
8. Perlick L, Bthis H, Tingart M, Perlick C, Grifka J.
Navigation in total-knee arthroplasty: CT based im-
plantation compared with the conventional technique.
Acta Orthop Scand. 2004;75:464-70.
9. Bolognesi M, Hofmann A. Computer navigation
versus standard instrumentation for TKA: a single-
surgeon experience. Clin Orthop Relat Res. 2005;
440:162-9.
10. Mielke RK, Clemens U, Jens JH, Kershally S.
[Navigation in knee endoprosthesis implantation
preliminary experiences and prospective compara-
tive study with conventional implantation technique].
Z Orthop Ihre Grenzgeb. 2001:139:109-16. German.
11. Anderson KC, Buehler KC, Markel DC. Computerassisted navigation in total knee arthroplasty: com-parison with conventional methods. J Arthroplasty.
2005;20(7 Suppl 3):132-8.
12. Haaker RG, Stockheim M, Kamp M, Proff G,Breitenfelder J, Ottersbach A. Computer-assisted nav-
igation increases precision of component placementin total knee ar throplasty. Clin Or thop Relat Res.
2005;433:152-9.
13. Gregori A, Holt G. Letter regarding Navigated
total knee arthroplasty. A meta-analysis. (2007;89:261-269). J Bone Joint Surg Am. epub 2007
Mar 27. http://www.ejbjs.org/cgi/eletters/89/2/
261#31862.
14. Goodman SN. Have you ever meta-analysis you
didn't like? Ann Intern Med. 1991;114:244-6.
15. Felson DT, Anderson J. Evidence for the superi-ority of immunosuppressive drugs and prednisone
over prednisone alone in lupus nephritis. Resultsof a pooled analysis. New Engl J Med. 1984;311:
1528-33.
16. Kaizar EE. Metaanalyses are observational stud-
ies: how lack of randomization impacts analysis. Am
J Gastroenterol. 2005;100:1233-6.
Can Vitamin C Prevent Complex
Regional Pain Syndrome in
Patients with Wrist Fractures?
To The Editor:
In the article Can Vitamin C Prevent Com-
plex Regional Pain Syndrome in Patients
with Wrist Fractures? A Randomized, Con-
trolled, Multicenter Dose-Response Study
(2007;89:1424-31), Zollinger et al. studiedthe prophylactic effect of vitamin C on the
prevalence of complex regional pain syn-
drome in 416 patients with a wrist fracture.
They concluded that vitamin C is indeed ef-
fective, and they recommended giving 500
mg of vitamin C daily for fifty days to each
patient with a wrist fracture to prevent com-
plex regional pain syndrome.
Some limitations of this study men-
tioned in the article include a large selection
bias (416 of 2137 eligible patients were en-
rolled) and a low event rate due to an unex-
pected low prevalence of complex regional
pain syndrome (4.2% compared with 22%in the authors previous study1). This means
that only eighteen patients (eight of the
328 in the treatment group and ten of the
ninety-nine in the placebo group) fulfilled
the criteria for complex regional pain syn-
drome. In one patient with fractures of both
wrists, complex regional pain syndrome de-
veloped on one side, where the fracture
turned out to be badly reduced, and the
other side healed without complications.
This example reveals dramatically how this
study demonstrates a strong confounder: al-
though the number of fractures needing re-
duction was equal in both groups, thequality of the reduction was not mentioned.
Open reduction and internal fixation
of wrist fractures generally achieves a better
reduction than closed reduction with appli-
cation of a cast. Retrospective studies of sur-
gically treated wrist fractures have therefore
demonstrated a lower incidence rate of
complex regional pain syndrome, of around
3.5%2. To my knowledge, no prospective
study has ever demonstrated an association
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between the incidence of complex regional
pain syndrome and the quality of reduc-
tion, but pain syndromes in general occur
more frequently when fractures are not ade-
quately reduced.
Much scientific effort has been putin attempts to achieve prophylaxis and
treatment for complex regional pain syn-
drome with pharmacological means, but
these efforts did not result in any clinical
recommendations3. Conservative physical
therapy has provided some benefit for pa-
tients with complex regional pain syn-
drome4. Since the introduction of functional
and time-contingent pain-exposure phy-
sical therapy in children with complex re-
gional pain syndrome by Sherry et al. in
19995, more reports on this approach are
to be expected for adult patients as well.
A difference is therefore to be ex-pected between patients with complex re-
gional pain syndrome who are treated by
a physical therapist and those who are not.
The use of any form of physical therapy is
not mentioned in this paper, introducing
another possible confounder. This paper
therefore does not provide support for the
effectiveness of vitamin C in preventing
complex regional pain syndrome.
Jan Paul M. Frlke, MD, PhD
University Medical Center St. Radboud, P.O.Box 9101, 6900 HB Nijmegen, The Nether-lands, e-mail: [email protected]
Disclosure: The author did not receive anyoutside funding or grants in support of his re-search for or preparation of this work. Neitherhe nor a member of his immediate family re-ceived payments or other benefits or a com-mitment or agreement to provide such benefitsfrom a commercial entity. No commercial en-tity paid or directed, or agreed to pay or direct,any benefits to any research fund, foundation,division, center, clinical practice, or othercharitable or nonprofit organization withwhich the author, or a member of his immedi-ate family, is affiliated or associated.
P.E. Zollinger, W.E. Tuinebreijer,
R.S. Breederveld, and R.W. Kreis reply:
We read the letter of our colleague, Dr.
Frlke, with great interest. First, on the ba-
sis of our study, we believe that vitamin C
does prevent complex regional pain syn-
drome. Unfortunately, most of Dr. Frlkes
comments do not apply to our study.
The number of enrolled patients in
our study in relation to the number of eligi-
ble patients was mentioned in the Discus-
sion of our article. The quality of reduction
was studied in this paper and in our paper in
Lancet1as well. In both studies, there was no
relationship between the occurrence of
complex regional pain syndrome and theneed to undergo fracture reduction. More-
over, the quality of reduction did not influ-
ence the chance of complex regional pain
syndrome developing. We performed the
current study because, to our knowledge,
there have been no published studies since
19991that either confirm or refute our origi-
nal findings.
To our knowledge, no prospective
study has ever demonstrated an association
between the prevalence of complex regional
pain syndrome and the quality of reduc-
tion. Retrospective studies do not have the
level of evidence that is needed. Dr. Frlkemakes a misjudgment by citing the article by
Arora et al.2. Arora et al. found that, of 114
patients followed for one year, five had type-
I complex regional pain syndrome and three
had type-II complex regional pain syn-
drome. Thus, the prevalence of type-I com-
plex regional pain syndrome in their study is
4.39% (not 3.5% as stated in Dr. Frlkes let-
ter) and is higher than our overall preva-
lence of 4.2%; it stands in contrast with the
2.4% for all of our patients treated with vita-
min C. The difference is even more striking
when the 4.39% rate is compared with the
prevalence of only 1.8% in our group receiv-ing 500 mg of vitamin C and 1.7% in the
group receiving 1500 mg.
Why the articles by Rowbotham3, Oer-
lemans et al.4, and Sherry et al.5are cited is
unclear to us. Our study is about the possible
prevention of complex regional pain syn-
drome after a wrist fracture in adults treated
with a prophylactic dose of vitamin C and
not about the therapy for complex regional
pain syndrome itself. The end point of our
study was defined as the presence of complex
regional pain syndrome at any time within
one year after the fracture (see the Study De-
sign section). The article by Rowbotham3deals with pharmacotherapy in patients with
complex regional pain syndrome.
The article by Oerlemans et al.4is a
very well-respected trial comparing adjuvant
physical therapy with occupational therapy
for patients with complex regional pain syn-
drome. Here lies the difference with our frac-
ture patients. If we had treated our patients
with physical therapy as well, we would have
created our own confounding factor. Skep-
tics would have challenged our conclusions
and pointed to the positive effect of the physi-
cal therapy rather than to the effect of vita-
min C, as Dr. Frlke does now.
When complex regional pain syn-
drome develops in patients who have sus-tained a wrist fracture, it is of course treated
with physical therapy and medication, if
necessary6. The article by Sherry et al.5deals
with the outcome in children with complex
regional pain syndrome after exercise ther-
apy. However, we believe that complex re-
gional pain syndrome in children is a
completely different entity than complex
regional pain syndrome in adults, and so
is the approach to its treatment. This was
confirmed by Wilder et al.7, who reminded
us that, in children, complex regional pain
syndrome most often involves the lower ex-
tremity (87% [sixty-one] of seventy cases),which is in contrast to the situation in
adults, who have more upper-extremity
complex regional pain syndromes. The
therapie used by Sherry et al.5consisted of
aerobic functionally directed exercises, hy-
drotherapy, and desensitization. Which
therapy achieved the desired outcome? Can
it get more confounding than this?
Paul E. Zollinger, MD
W.E. Tuinebreijer, MD, PhD, MSc, MA
R.S. Breederveld, MD, PhD
R.W. Kreis, MD, PhD
Corresponding author: Paul E. Zollinger, MD,Department of Orthopaedic Surgery, Zieken-huis Rivierenland, President Kennedylaan 1,4002 WP Tiel, The Netherlands, e-mail:[email protected]
These letters originally appeared, in slightly different form,on jbjs.org. They are still available on the web site in conjunc-tion with the article to which they refer.
References
1. Zollinger PE, Tuinebreijer WE, Kreis RW, Breeder-
veld RS. Effect of vitamin C on frequency of reflex
sympathetic dystrophy in wrist fractures: a random-
ized trial. Lancet. 1999;354:2025-8.
2. Arora R, Lutz M, Hennerbichler A, Krappinger D, Es-
pen D, Gabl M. Complications following internal fixa-
tion of unstable distal radius fracture with a palmar
locking-plate. J Orthop Trauma. 2007;21:316-22.3. Rowbotham MC. Pharmacologic management ofcomplex regional pain syndrome. Clin J Pain.
2006;22:425-9.
4. Oerlemans HM, Oostendorp RA, de Boo T, Goris
RJ. Pain and reduced mobility in complex regional
pain syndrome I: outcome of a prospective ran-
domised controlled clinical trial of adjuvant physical
therapy versus occupational therapy. Pain.
1999;83:77-83.
5. Sherry DD, Wallace CA, Kelley C, Kidder M, Sapp
L. Short- and long-term outcomes of children with
complex regional pain syndrome type I treated with
exercise therapy. Clin J Pain. 1999;15:218-23.
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6. The Netherlands Society of Rehabilitation Special-
ists. Guidelines: Complex regional pain syndrome
type I. 2006. http://www.posttraumatischedystro-
fie.nl/pdf/CRPS_I_Guidelines.pdf.
7. Wilder RT, Berde CB, Wolohan M, Vieyra MA,Masek BJ, Micheli LJ. Reflex sympathetic dystrophy
in children. Clinical characteristics and follow-up
of seventy patients. J Bone Joint Surg Am. 1992;
74:910-9.
Exposure to Direct and Scatter
Radiation with Use of
Mini-C-Arm Fluoroscopy
To The Editor:
We commend Giordano et al. on their excel-
lent work in quantifying the risk of radia-
tion when using a mini-C-arm fluoroscopy
unit, as reported in their study entitled
Exposure to Direct and Scatter Radiation
with Use of Mini-C-Arm Fluoroscopy(2007;89:948-52). Their methodology, how-
ever, does not accommodate for the mea-
surement of increased radiation exposure
when the C-arm is used in the conventional
method, with the image intensifier verti-
cally above the radiation source1. Nor does it
estimate what the exposure dose would be
immediately level to the receiver. Their data,
however, remain of value to advance the
overall safety of fluoroscopy in theater.
In our as yet unpublished survey of
more than seventy-five orthopaedic trainees
and theater staff in the United Kingdom, we
found that the majority had poor workingknowledge of conventional image intensi-
fier usage and surprisingly little insight into
ionizing radiation protection issues. Al-
though most orthopaedic trainees in the
United Kingdom do not push the button,
they do guide the radiographer and super-
vise the surgical assistant and theater staff.
Therefore, the patient, surgical teams, and
theater staff may be at risk of exposure. With
appropriate training of surgeons, the mini-
C-arm may be adopted more widely in the
National Health Service, thereby releasing
overburdened radiographers from theater
while increasing throughput and safety intheater, as alluded to by White2. However, we
believe that this can only occur once the re-
cently disbanded ionizing radiation protec-
tion course has been reinstigated.
Narlaka Jayasekera, MRCS
Richard Roach, FRCS(Orth)
Corresponding author: Narlaka Jayasekera,Department of Orthopaedics, Princess RoyalHospital, Telford, Shropshire TF1 6TF, UnitedKingdom, e-mail: [email protected]
Disclosures:The authors did not receive anyoutside funding or grants in support of theirresearch for or preparation of this work. Nei-ther they nor a member of their immediatefamilies received payments or other benefits ora commitment or agreement to provide suchbenefits from a commercial entity. No com-mercial entity paid or directed, or agreed topay or direct, any benefits to any research fund,foundation, division, center, clinical practice,or other charitable or nonprofit organizationwith which the authors, or a member of theirimmediate families, are affiliated or associated.
J.F. Baumhauer and
B.D. Giordano reply:
We appreciate the comments of Mr. Jayasek-
era and Mr. Roach and acknowledge that
our methodology does not reflect a number
of conventional techniques that have beenemployed in the past during the routine use
of mobile C-arm fluoroscopy.
In our paper, we make note of several
dose-reducing measures that have been
studied over the years and have enabled
mobile C-arm operators to produce high-
quality images while optimizing the overall
safety to the patient and operating room
staff. These measures include minimizing
exposure time, reducing exposure factors,
manipulating the x-ray beam with collima-
tion, maximizing distance from the beam,
using protective shielding, and imaging with
the C-arm in an inverted orientation relativeto the specimen.
Positioning the phantom limb di-
rectly on the platform of the image intensi-
fier increases the distance from the radiation
source to the specimen, subsequently reduc-
ing the amount of scatter produced. Al-
though many of these measures have been
studied with use of a standard large C-arm
unit, the literature regarding similar param-
eters with the mini C-arm unit is limited. In
our experimental design, we attempted to
create a best-case scenario by utilizing
known dose-reducing techniques to quan-
tify radiation exposure just as a surgeonwould likely strive to achieve in a true op-
erating room setting.
With regard to the second portion
of the correspondents comments, we point
out that at positions of 15 and 25 cm from a
focal point on the phantom hand, we found
minimal radiation exposure (1 to 2 mrem) as
measured with our dosimeters. These mea-
surements were made in the plane of the im-
age intensifier. In contrast, when the radiation
dosimeter was placed directly in the phantom
hand, substantial exposure levels (181 to 272
mrem) were recorded. We did not collect data
points between these two locations.
We concur with Jayasekera and Roach
that many orthopaedic trainees and, for thatmatter, a great number of mini or large C-
arm operators, have a poor understanding of
the science behind image intensifier usage.
This may lead them to grossly underestimate
the potential for high-dose radiation expo-
sure if these mobile fluoroscopy units are not
used judiciously and with proper intent.
A common error made by novice
trainees is the use of the mini C-arm to im-
age larger body parts such as the tibia, fe-
mur, humerus, elbow, or shoulder. As the
tissue density and cross sectional area of the
imaging subject increase, technique factors
automatically adjust, in the normal mode,to produce an image with optimal penetra-
tion and visual quality. To accommodate for
the increased tissue density of a larger body
part, technique factors increase by a sub-
stantial margin, leading to a much higher
radiation exposure rate than may have been
encountered when using a large C-arm.
We appreciate the interest in our pa-
per and strive to advance science safety with
the commonly used fluoroscopy units.
Judith F. Baumhauer, MD
Brian D. Giordano, MD
Corresponding author: Judith F. Baumhauer,MD, Division of Foot and Ankle Surgery, Uni-versity of Rochester Medical Center, 601 Elm-wood Avenue, Box 665, Rochester, NY 14642,e-mail: [email protected]
These letters originally appeared, in slightly different form,on jbjs.org. They are still available on the web site in conjunc-tion with the article to which they refer.
References
1. Tremains MR, Georgiadis GM, Dennis MJ. Radia-
tion exposure with use of the inverted-C-arm tech-
nique in upper-extremity surgery. J Bone Joint Surg
Am. 2001;83:674-8.
2. White SP. Effect of introduction of mini-C-arm imageintensifier in orthopaedic theatre. Ann R Coll Surg
Engl. 2005;87:53-4.
Integrity of the Lateral Femoral
Wall in Intertrochanteric Hip
Fractures: An Important
Predictor of a Reoperation
To The Editor:
The article Integrity of the Lateral Femoral
Wall in Intertrochanteric Hip Fractures: An
Important Predictor of a Reoperation,
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(2007;89:470-5), by Palm et al., is particu-
larly important because it confirms previous
reports on the critical role played by the
lateral wall in the reconstruction of pertro-
chanteric hip fractures1-3. While devices such
as the dynamic hip screw and sliding hipscrew have been considered the gold stan-
dard in the treatment of pertrochanteric hip
fractures for fifty years, this type of iatro-
genic complication has been reported only
recently1; thus, I would like to offer some
observations.
The lateral wallexists in conjunction
with a pertrochanteric hip fracture; it does
not exist, as an anatomical structure, in a
normal intact femur. It is important to dis-
tinguish between those fractures where the
lateral wall does not exist preoperatively and
those where it does exist preoperatively and
is fractured either intraoperatively or post-operatively. The former have already been
defined in the Fracture and Dislocation
Compendium, where, in fact, the term lat-
eral wallis not used4. This classification sys-
tem does distinguish types 31-A1 and 31-A2
fractures, which are defined as pertrochan-
teric fractures, from a type 31-A3, which is
defined as an intertrochanteric fracture. It is
unfortunate that the authors do not use
both terms. Rather, they use only the term
intertrochanteric fracture, which may lead to
misunderstanding and confusion. On the
other hand, the iatrogenically fractured lat-
eral wall, occurring during or following asurgical procedure, converts a pertrochan-
teric A1 or A2 fracture into an intertrochan-
teric A3 fracture and is certainly different
and deserves special attention. The clear dis-
tinction between the two did not emerge
from the paper.
Because of the nature of this compli-
cation, it has been considered to be a dis-
tinct entity: the pantrochanteric fracture5.
Once a fracture of the lateral wall is
recognized as an iatrogenic complication,
and the events leading to the fracture are
understood, a reevaluation of the situation
is indicated. First, new definitions are neces-sary. It is important to distinguish between
fracture collapse, the outcome of fracturing
the lateral wall (an adverse postoperative
event), and controlled fracture impaction
(a desirable postoperative event). This has
previously been defined together with other
relevant definitions1and could have been re-
ferred to by the authors.
Careful definition will not only
contribute to better understanding of the
postoperative radiograph, and hence the
patient's condition, but will also facilitate
decision-making in the postoperative reha-
bilitation period, e.g., the type of weight-
bearing to be instituted.
In addition, when it is possible to at-tribute the collapse to certain procedures
and/or devices, this should enable us to set
new surgical standards designed specifically
to avoid this kind of complication.
Yechiel Gotfried, MD, MS
Bnai Zion Medical Center, 47 GolombStreet, P.O.B. 4940, Haifa 31048, Israel.E-mail: [email protected]
Disclosure: The author did not receive anyoutside funding or grants in support of his re-search for or preparation of this work. Theauthor, or a member of his immediate family,
received, in any one year, payments or otherbenefits in excess of $10,000 or a commit-ment or agreement to provide such benefitsfrom a commercial entity (Orthofix, Inc.). Nocommercial entity paid or directed, or agreedto pay or direct, any benefits to any researchfund, foundation, division, center, clinicalpractice, or other charitable or nonprofit or-ganization with which the author, or a mem-ber of his immediate family, is affiliated orassociated.
H. Palm, S. Jacobsen, S. Sonne-Holm,
and P. Gebuhr reply:
We appreciate the interest by Dr. Gotfried inour recent article and are delighted that he
finds our study to be particularly important.
In a large number of patients, our study
does, in fact, confirm previous reports of the
importance of the integrity of the lateral
femoral wall, including the fact that a frac-
ture of the lateral femoral wall is most often
an iatrogenic complication.
Dr. Gotfried raises good questions
regarding the nomenclature used in the ar-
ticle. The general nomenclature for these
fractures is quite confusing. As the terms
trochanteric, pertrochanteric, pantrochan-
teric, and intertrochanteric, etc., are oftenmixed up, we also find it highly relevant to
achieve international consensus on this
matter. In our article, we simply used the
term intertrochantericfor all type 31-A
fractures, in part, because we found that
Dr. Gotfried also previously did this1, al-
though not in a later article2referred to in
our study. We now agree that using the
termspertrochantericfor the type 31-A1
and 31-A2 fractures and intertrochanteric
only for the type 31-A3 fractures would
have been more precise. On the other hand,
we still find that we enable the reader to
distinguish between the fracture types by
using the AO/OTA classification numbers,
including the very important subtypes inthe text and tables, and by showing an il-
lustrating diagram.
We agree that new definitions of bio-
mechanical complications are necessary
and that the knowledge that the lateral
femoral wall is an iatrogenic complication
could contribute to a better understanding
of the treatment of these fractures. We cur-
rently treat type 31-A1 and 31-A2.1 frac-
tures with a sliding hip screw fixed to a
lateral plate and type 31-A3 fractures with
a sliding hip screw fixed to an intramedul-
lary nail.
As a third of the 31-A2.2 and 31-A2.3 fractures in our study were converted
to 31-A3 fractures, we now also treat these
fractures using the sliding hip screw fixed
to an intramedullary nail. In the future,
perhaps other systems designed specifi-
cally to avoid a perioperative fracture of the
lateral femoral wall1might prove to be su-
perior to treat these specific fracture sub-
groups. To date, it has not been feasible to
categorize fractures into all of the AO/OTA
subgroups as this demands very large
groups of patients.
Henrik Palm, MD
Steffen Jacobsen, MDStig Sonne-Holm, MD, DMSc
Peter Gebuhr, MD
Corresponding author: Henrik Palm, MD,Department of Orthopaedic Surgery, Copen-hagen University Hospital of Hvidovre, Kette-gaard Alle 30, DK-2650 Hvidovre, Denmark,e-mail: [email protected]
These letters originally appeared, in slightly different form,on jbjs.org. They are still available on the web site in conjunc-tion with the article to which they refer.
References
1. Gotfried Y. Percutaneous compression plating of
intertrochanteric hip fractures. J Orthop Trauma.
2000;14:490-5.
2. Gotfried Y. The lateral trochanteric wall: a key
element in the reconstruction of unstable pertro-
chanteric hip fractures. Clin Orthop Relat Res.
2004;425:82-6.
3. Im GI, Shin YW, Song YJ. Potentially unstable inter-
trochanteric fractures. J Orthop Trauma. 2005;19:5-9.
4. Fracture and dislocation compendium. Ortho-
paedic Trauma Association Committee for Codingand Classification. J Orthop Trauma. 1996;10 Suppl
1: v-ix, 1-154.
5. Gotfried Y. Pantrochanteric hip fracture: an entity.
J Bone Joint Surg Br. (Suppl III) 2000;82:235.
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Comparison of the Vastus-Splitting
and Median Parapatellar Approaches
for Primary Total Knee Arthroplasty:
A Prospective, Randomized Study.
Surgical Technique
To The Editor:The otherwise excellent article, Compari-
son of the Vastus-Splitting and Median
Parapatellar Approaches for Primary Total
Knee Arthroplasty: A Prospective, Random-
ized Study. Surgical Technique (2007;89
Suppl 2 Part 1:80-92), by Kelly et al., was
marred by an error in the legend to Figure
1. The axial radiograph of the knee was
mislabeled as a Merchant radiograph of
the patella.
The shape and appearance of the
dista part of the femur on the radiograph
demonstrates that it is really a Settegast
view. This technique requires the knee to beacutely flexed well beyond 90, drawing the
patella, which might otherwise be severely
subluxated laterally at the trochlear level,
into the intercondylar space to articulate
with the distal, or weight-bearing, surface
of the femoral condyles.
Conversely, the Merchant axial
view radiograph is exposed with both
knees flexed no more than 45, showing
the patellas true relationship to the
trochlea1,2.
This may seem to be a minor point,
but if the surgeon is not aware that the
patella is subluxated laterally prior to sur-gery, he or she may not take sufficient mea-
sures to correct that subluxation during
surgery. Many postoperative patellofemo-
ral complications can be avoided if the sur-
geon is aware of this problem before
surgery.
Alan C. Merchant, MD
Stanford University, 124 Marvin Avenue,Los Altos, CA 94022, e-mail: [email protected]
Disclosure: The author did not receive anyoutside funding or grants in support of his
research for or preparation of this work.Neither he nor a member of his immediatefamily received payments or other benefits ora commitment or agreement to provide suchbenefits from a commercial entity. No com-mercial entity paid or directed, or agreed topay or direct, any benefits to any researchfund, foundation, division, center, clinicalpractice, or other charitable or nonprofit or-ganization with which the author, or a mem-ber of his immediate family, is aff iliated orassociated.
V.D. Pellegrini Jr., M.J. Kelly,
M.N. Rumi, M. Kothari, K.J. Bailey,
W.M. Parrish, and M.A. Parentis reply:
We thank Dr. Merchant for correctly identi-
fying our error as it relates to patellofemoral
imaging of the knee. We concur with hiscomments and, indeed, customarily per-
form patellofemoral imaging with the knee
in 30 of flexion to more sensitively identify
lateral subluxation of the patella. The patel-
lar view presented in our paper does not re-
flect our usual practice.
We appreciate Dr. Merchants efforts
in bringing this inadvertent misrepresenta-
tion to our attention as well as that of the
readership of The Journal.
Vincent D. Pellegrini Jr., MD
Matthew J. Kelly, MD
Mustasim N. Rumi, MD
Milind Kothari, DOKatrina J. Bailey, PT
William M. Parrish, MD
Michael A. Parentis, MD
Corresponding author: Vincent D. PellegriniJr., MD, Department of Orthopaedics, Univer-sity of Maryland School of Medicine, 22 SouthGreene Street, Suite S 11 B, Baltimore, MD21201, e-mail: [email protected]
These letters originally appeared, in slightly different form,on jbjs.org. They are still available on the web site in conjunc-tion with the article to which they refer.
References
1. Merchant AC, Mercer RL, Jacobsen RH, Cool CR.
Roentgenographic analysis of patellofemoral congru-ence. J Bone Joint Surg Am. 1974;56:13916.
2. Merchant AC. Patellofemoral imaging. Clin Orthop
Relat Res. 2001;389:1521.
Cost-Effectiveness of Extended-
Duration Antithrombotic Prophylaxis
After Total Hip Arthroplasty
To The Editor:
We read with interest the recent paper The
Cost-Effectiveness of Extended-Duration
Antithrombotic Prophylaxis After Total Hip
Arthroplasty (2007;89:819-28), by Skedgel
et al., regarding economic decision-making,with reference to extended thrombopro-
phylaxis after total hip arthroplasty. The
authors refer to a study by Lapidus et al.1,
who stated that 38.4% of patients receiving
low-molecular-weight heparin required a
community nurse for administration. For
cost-effectiveness, the number requiring a
community nurse must be
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heparin could meet a threshold of $50,000
per quality-adjusted life year gained with
home care rates of