Main manuscript

Introduction

This is the part in which you introduce the topic to your reader. Typically, it consists of one page and guides the reader into the topic of your article. The introduction should answer the two key questions: What is the paper about? Why is it worth being read and published? Arrange your paper from basic to more complex. You should start with a paragraph giving very basic information on the background of your topic. Imagine the structure of the introduction as a funnel. The background information represents the broadest part at the top, which is narrowing down to the specific information of your research topic. However, this first paragraph should not start from “Adam and Eve”, furthermore jump more directly into the topic covered.

Please write in a manner that even non-experts in the field would be able to follow.

Please provide the reader with your hypothesis and the purpose of your study. This is a mandatory part at the end of the introduction.

Materials and Methods

The methods section should meticulously describe the study design and ideally serve as an instruction for the readership to redo the study. Consider your research study as a specific dish and your methods section as its recipe. You need to list all ingredients and give a detailed description of the cooking process. Only then the dish can be prepared repetitively with a reproducible result.

Try to create a clear story line. The methods section links the introduction with the results. Hence, it should be structured from basic to more complex. Generally, one should start with the study design. Here, the authors need to clarify the type of study done.

Then, you need to proceed with a clear description of your study sample. The study sample description should include exact number of patients or subjects included. When dealing with patients` basic demographics such as mean age ± standard deviation, gender, body mass index, alignment information and other important variables should be given here. A clear flow chart should allow the reader to understand how many patients were screened, how may were excluded and how many finally included for this study. It is important to give exact numbers here. Along with an exact description of inclusion and exclusion criteria the article needs to allow the reader to judge a possible bias in patient selection.As a general rule this part should be sufficiently detailed so that an independent researcher could reproduce the results and thereby validate the study findings.

A common error of many authors is to describe the study sample in the results section, but it clearly belongs to material and methods and should be given here. This is also true for review papers.

The description of the study sample is followed by a detailed description of tests and experiments done for experimental studies and description of outcome instruments used for clinical studies. In the case a novel methodology is applied a more detailed description is required. If standard methods are applied such as well-established outcome instruments it is only necessary to refer to these.

For all measurements done inter- and intra-observer reliability needs to be tested and presented. All measurements, in particular measurements on any image such radiographs, CT, MRI or other imaging modalities, should be done by at least two independent blinded observers twice with an interval of six weeks.

Inter- and intra-observer reliability as well as accuracy values need to be presented. This could be done for example as intra-class correlation coefficients (ICCs), kappa values or Bland-Altman plots.

A statement that ethical approval was obtained from the local ethical committee or institutional review board approval should be included. An increasing number of journals require a document showing ethical approval to be included in your submission. For clinical studies also state that informed consent was obtained by each patient or subject in the study.

KSSTA also requires a statement that the study was done in agreement with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

The final paragraph should consist of a proper and complete description of the statistical methodology used.

First you have to state which and how the data was presented. For example: “Continuous variables were described using means, standard deviations, and medians. Categorical variables were tabulated with absolute and relative frequencies.”

Another relevant part of the statistical methodology is the exact description of tests used. It is important to differentiate parametric from non-parametric tests. In order to use parametric tests the data needs to be tested for normality. Please also report if this was done and the result. Every statistical test used need to be mentioned here. The level of statistical significance needs to be reported as p-value. Generally, it is considered to be p<0.05.

A sample size calculation needs to be presented in all clinical studies. The sample size is an estimation of the number of subjects required to detect a significant difference in a study. If the sample size is too small, then a true difference might turn out non-significant, although being significant. If the sample size is too large, this would mean that you unnecessarily waste scientific resources, it might also make even small difference significant.

Results

This section should be brief and concise. Results are the only thing shown here. It should not contain any description of methodology. Do not interpret your results, simply describe what you have found. Please organize your results in the same logical order and structure as previously reported in material and methods. This makes it better accessible for the reader. It should be clear, that all data is reported and not only the data supporting your hypothesis. Do not report data which has not been mentioned in material and methods. No referencing is allowed in results section.

Sometimes it appears difficult to decide what exactly is considered a result. For example, if inter- and intra-observer variability is tested for measurements on radiographs for validation of your measurement methods, however, it is not the main study question, but the radiological results, then the measurements of inter- and intra-observer reliability should be reported not in results, but in material and methods.

Figure, tables and graphs might help to make it better understandable to the reader. Do not duplicate results in text and figures, tables or graphs. Often not much supporting text is needed here.

Discussion

This section should put your findings into the context of current literature. Please do not duplicate your results. Start the discussion with a sentence such as “The most important findings of the present study were…”. The compare your findings with relevant previous studies.

At the end of discussion please provide the reader with a comprehensive list of all limitations with regards to your study.

Conclusions

The conclusion should be not more than one or two sentences long and provide the reader with a summary of results and discussion. In particular, the clinical implications of the findings should be highlighted. Please explain why the study is significant to the research world. This part should provide the key message you want to convey with regards to your study. In addition, it is also possible to provide an outlook of future research direction. However, do not just write further investigation is needed or do not announce future studies that might not be completed.