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Detailed Guidelines for Writing a Materials and Methods Section for a JBJS, Inc. Journal Article

Considerations for specific studies include:

Registration in a public trials registry is required for (1) randomized controlled trials and (2) studies where patients were randomized into two treatment groups OR were followed prospectively to compare two different treatments. Make sure to identify the public trials registry in which the study was registered and the registration number of the study. Additionally, all reports of randomized controlled trials that began patient enrollment after December 7, 2016, must have been prospectively registered in a trial registry in order to be considered for publication (see editorial for additional information).

Describe the study design in detail using standard methodological terms (retrospective or prospective cohort study, prospective randomized trial, case-control study, cross-sectional study, etc.). If applicable, include references to your previous publications describing details of the study design. (Mention these references in a cover letter in the event that they necessitate blinding by the journal prior to peer review.) If you included patients from a previous study, state this and explain why you did so.

Describe how your sample was assembled; your inclusion and exclusion criteria; and how the sample size was determined, including preliminary or previously published data relevant to that determination. Provide enough data to allow reviewers to replicate the sample-size calculation process. If a sample of convenience was used, state this in the Materials and Methods section and in your paragraph(s) on the study's limitations in the Discussion section.

Describe your methods for study selection, data extraction, and data synthesis succinctly but with sufficient detail so that the general approach can be replicated. Describe statistical methods in detail, with emphasis on the statistical strategy used to analyze the data. Justify your use of any complex statistical strategies, including those involving any kind of modeling approach. Identify any assumptions about the data that are implicit to the statistical strategy. Consider using multivariable analysis to address potential measured confounders in observational studies. In addition to point estimates of the effect, provide the measure of uncertainty expressed by 95% confidence intervals.

Include p values to support any statement regarding statistical significance, but keep in mind that the p value is a function of the sample size and smaller samples, even with large effects, may lead to p values greater than acceptable thresholds. Use 95% confidence intervals for any estimate appearing in the text or graphs. Use the word correlation only when reporting the correlation coefficient. Identify the software package that you used for the statistical analysis.

Use validated outcome instruments wherever possible. Employ novel measurement scales only when existing scales are insufficient to meet the needs of the study and provide references describing their psychometric characteristics such as reliability and validity. If an outcome system leads to a categorical ranking (excellent, good, etc.), provide the aggregate score for each patient. For OTA fracture classifications, use the most up-to-date reference: Kellam JF, Meinberg EG, Agel J, Karam MD, Roberts CS. Introduction: Fracture and Dislocation Classification Compendium-2018: International Comprehensive Classification of Fractures and Dislocations Committee. J Orthop Trauma. 2018 Jan;32 Suppl 1:S1-S10.