ARTIGO DE REVISÃO
Thinking on orthopedics and traumatology research methodology
William Dias Belangero
Prof. Dr. Head Departament of Orthopedics and Traumatology. Faculdade de Ciências Médicas - UNICAMP
"Watching the positivism, that faces phenomena and says: 'There are only facts', I say: 'There aren't facts. There are interpretations'."
(Nietzche)
Following the general tendency of growth of knowledge, scientific production in medical area is intensively growing during the last decades, making constant updating to be exhaustive.
However, if the amount of information is growing in a vertiginous fashion, gathering them is also tremendously easier by means of Internet progress.
This pattern of development looks to be parallel to the Evidence Based Medicine idea, which was brought to be concrete in 1992 by Dr. Iain Chalmers from Oxford (UK), through the "Cochrane Cooperation" foundation, which aims to perform, support and divulge systematic reviews of health interventions.
This kind of approach allows to clearly evaluate the efficacy of previously performed studies, selected by validation criteria but which could not reach a definite conclusion due to insufficient number of cases. So, by adding the number of cases from different but comparable studies, and by the application of rigorous statistic criteria, trustful conclusion can be drawn, which will result in clear conduct recommendations. Knowledge of the working methodology from one side, stimulates performing prospective studies with high quality scientific standards, and on the other hand, the use of this method as a potent tool in defining still questioned conducts.
Then, comes the question of how getting high quality surgical studies, in terms of methodology. In this area, prospective, controlled and randomized studies are usually ethically not possible. On the other hand, retrospective studies have low possibilities of giving trustful results. This happens because the case studies are not conducted according to pre-determined objectives, being always subject to criticism due to its subjectivity, even not intentional, in case selection and results analysis.
These studies, even when performed with large number of cases, use to be considered of an insufficient scientific level to warrant a therapeutic recommendation. Thus, every effort should be driven to an hypothesis development be always performed through a prospective study. Even though it is not possible to comply to all desired methodological aspects, it is possible to improve quality and results by following some strategies as follows.
The first step in any scientific research is to define theme and objectives, both general and specific. If the researcher is part of a group with a defined line of research, the theoretical basis and questioning related to the theme will probably be part of the group knowledge, and so the objectives are naturally driven by previously performed studies. However, when this doesn't happens, the researcher should proceed a wide literature review aiming to find polemical aspects, or those not yet defined, which could support the relevance of the research and help in objectives definition.
After this phase, the population and method should be chosen. It is not rare to find papers that simply inform the number of patients studied during a given period, without clearly reporting where they came from as well as the inclusion and exclusion criteria.
The sample size definition is also seldom considered, and frequently considered without criteria. As a matter of fact, it should be previously estimated, considering the kind of procedure, the variability of results and, when necessary, statistic studies should be used to its election. If the results of this calculation reach not feasible figures, or is impossible to be achieved in a reasonable time of study, the researcher will be able to choose between performing a study with doubtful perspectives or to propose multi-center study. This last option should anticipate a wide protocol discussion, emphasizing surgical technique, and the practicing experience of the involved professionals, and the analysis of the results from different services.
It is worthy to be stressed that statistic analysis is usually important, mainly when differences are not evident. It can even be considered that this tool would be more necessary the worst is the initial study planning. In works that involve technical factors as those represented by ability, surgeon experience and even material environment of the institution, it should be kept in mind that these variables can be minimized by increasing the sample size, and previous training in animals or cadaver. It is obvious that if surgeons of different skill levels participate in the study, or in different steps of the learning of the technique, this should be mentioned in the methodology and considered in result analysis.
From a scientific point of view, reporting results from pattern-scales or comparisons to the pre-operative period are less valued than if this is performed according to pre-established goals. Current trend is that this goal not only evaluates the result of the orthopedic procedure, but also its impact over quality of life and rehabilitation of the patient to social-economic environment. So, other criteria should be took into consideration to allow judging with more subsides if the procedure was good for the "femur" or was also good for the patient him/herself. For instance it could be mentioned the surgical procedures performed in children with congenital malformation, which frequently have as single objective to preserve the limb with a doubtful utility without considering the high psychological and social costs of the treatment.
The use of a control group brings a higher quality and makes the research more trustful, since it is rare that these studies can be randomized, and will never be double blind.
On the other hand, in this specialty it is also impossible to use an ideal control group, which is that where a patient is not treated. The alternative would be to use a "historical control group", which is however subject to criticism due to not including patients with the same conditions as those selected for the current study, and for having been performed in a different historic moment. On the other hand, if the objective is to compare results obtained from different treatment techniques over the same disease, concomitant studies could be performed at one or more institutions, taking into consideration the selection criteria and analysis of results. This practice is not very much used among us, and should be stimulated due to bringing benefits to all involved groups that could have a better accepted study. In order to have a sensible and impartial analysis of the results, it could also be requested help from other specialists not actively involved in the selection and intervention parts of the study.
Still considering the results, loosing follow-up due to migratory aspects of population, and social-economic conditions or due to distance, should be differentiated form those from bad results. It is clear that the bigger the loose of initial population, the more compromised is the study and its conclusions. It is up to the investigator to use his/her common sense and principles making sure that no doubt can be raised on the accuracy of the data. Final analysis, whether it is done considering patients or number of cases, has to be previously chosen to avoid bias. Influence of loosing cases can be minimized by using survival tables and time of follow-up, that will display the critical vision and care of the investigator.
Last, it should be kept in mind that in this phase no significance level can resist to a poor methodology, and finding a p 0.01 can not blind the reader to the basic aspects building all the study up.
Results discussion should be performed considering current literature data, emphasizing aspects of originality and specially analyzing the bad results, since their causes will always be the most important determinant of studied procedures review and modification.
By complying to the largest number of criteria it could be obtained, even in non-controlled studies, results that are of scientifically good quality. It should be kept in mind that, behind every study there is, additionally to scientific curiosity, the objective of divulgation and the use of its results for patient's welfare, which is the final goal of the researcher in the clinical and surgical area.
The above considerations will only bring effective results when editors and reviewers of scientific journals demand methodological quality from the papers accepted for publication.
Besides this, we suggest that this subject, so important for a quality development of this medical area, becomes a major theme in scientific meeting or our specialty.
REFERÊNCIAS
ATALLAH, A.N. & CASTRO, A.A.: Medicina baseada em evidencias: o elo entre a boa ciência e a boa prática clínica. www.epm.br/cochrane/ebm.htm, 29/03/2000
GARTLAND, J.J.: Orthopaedic clinical research. J. Bone Jt. Surg., 70(A) 9: 1357-1371, 1988.
MURRAY, D.W.; BULSTRODE, C.J.K. & CAN, A..: Survival analysis of joint replacements. J. Bone Jt. surg, 75(B): 697-705, 1993.
PYNSENT, P.B.; FAIRBANK, J.C.T & CAN, A.J.: Assessment methodology in orthopaedics. Butterworth Heinemann, 1997.
Publication Dates
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Publication in this collection
20 Feb 2006 -
Date of issue
Sept 2001
