PONE-D-19-17787

Opening gap width influences distal tibial rotation below the osteotomy site following open wedge high tibial osteotomy

PLOS ONE

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Reviewers' comments:

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Reviewer #1: Partly

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Reviewer #1: No

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Reviewer #1: Yes

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Reviewer #1: Yes

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5. Review Comments to the Author

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Reviewer #1: Q1. Regarding the hinge, you described that efforts were made to keep the lateral cortex and lateral capsular hinge intact (lines 94 to 95). However, the actual hinge situation was not reported. The rate of hinge fracture is said to be at least over 20% when evaluated CT scans. Fortunately, you have all CT data for making the 3D analysis. Could you examine the presence or absence of the hinge fracture and the type of the fracture according to Takeuchi classification? As you mentioned, large opening gap tend to make unstable hinge fracture. If the rate of hinge fracture was high in the large opening gap group than in the small opening gap group, hinge fracture could be the predictor of the distal tibial rotation.

Q2. You compared the demographic data of the two groups (distal tibial rotation <3 degrees and distal tibial rotation>3 degrees) including opening gap width, preoperative MA, postoperative MA, and alignment correction (Table 2). However, the alignment correction is estimated by the subtraction of the preoperative MA from the postoperative MA. Furthermore, the alignment correction would be calculated by the opening gap and the tibial width. Therefore, these parameters have too many confounding biases each other. On the contrary, there would be more parameters which could have some relationships with tibial rotation; such as the angle between the ascending cut and the transverse cut, the direction of the ascending cut on the axial slice, or lateral hinge fracture, and so on. Reconsider the necessary parameters to be compared in the both groups.

Q3. As you mentioned in the discussion section (lines 243 to 246), hamstring tendon acts as an internal rotator. Therefore how to treat the pes and MCL in OWHTO may affect the tibial rotation. Could you describe more detailed procedure regarding medial soft tissues in the Surgical Technique section? There seems to be some contradictions suggested in the following Q4.

Q4. In your technique, the oblique osteotomy line, i.e. transverse cut, is started from 5 to 6 cm from the joint line. In general, about 4cm is recommended for the starting point.

If you cut from 5 to 6cm from the joint line,

1) The cutting line is far below from the attachment of the hamstring tendons. Therefore the larger amount of the release in the pes would be required. It may create larger external rotation of the tibia.

2) You mentioned that the MCL distal insertion remained intact because the osteotomy was performed just distal to the insertion site of the MCL. However, the superficial MCL attaches 7 to 8 cm from the joint line. Therefore, when applying the 5 to 6cm cutting line, the MCL could be cut during the osteotomy.

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Reviewer #1: No

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Opening gap width influences distal tibial rotation below the osteotomy site following open wedge high tibial osteotomy

PONE-D-19-17787R1

Dear Dr. Lee,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

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With kind regards,

David Fyhrie

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I regret your wrong description on the surgical thchnique. Please check the whole manuscript with your co-authors. However, the suggested points were all corrected.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

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Reviewer #1: No