Lower-Limb Kinematic Change during Pelvis Anterior and Posterior Tilt in Double-Limb Support in Healthy Subjects with Knee Malalignment

Round 1

Reviewer 1 Report

Comments to the Author

 I think the topic is very interesting . However, I found that our article has several places that can be extended and strengthened. Can I suggest fixing this and then resubmit the manuscript when this has been addressed.

1. This is a valuable article, but the normal angle of the Q angle is a range. If the Q angle is too large or too small, it will be more likely to cause damage. This article seems to only discuss the relationship between the Q angle and the damage. This section can be written in the study limitations or explained in the preface.

2. Gender is also a factor affecting the Q angle. Is there a specific gender or ethnic group for the subjects in this study? Please provide additional explanations in the subject information of the research method.

3. Different postures and joint movements will indeed affect the change of the Q angle. Is it possible to add some examples of actual training movements in the last part of the discussion, such as running or cycling, Squat or Leg press, so that readers can understand more easily value of this study.

Author Response

I think the topic is very interesting . However, I found that our article has several places that can be extended and strengthened. Can I suggest fixing this and then resubmit the manuscript when this has been addressed.

 

1. This is a valuable article, but the normal angle of the Q angle is a range. If the Q angle is too large or too small, it will be more likely to cause damage. This article seems to only discuss the relationship between the Q angle and the damage. This section can be written in the study limitations or explained in the preface.

-> Thank you for your comment. We revised some sentences in the introduction as follows:

 

A Q-angle is considered normal if it is < 15° for men and < 20° for women, with an angle > 20° regarded as excessive. An increase in Q-angle can alter the biomechanics of the knee and lead to lateral patellar dislocation or increased lateral patellofemoral contact pressures which can further cause valgus knee, potential sports injuries, and pathological conditions such as patellofemoral pain syndrome or knee instability. Excessive Q-angle can appears in healthy young people without knee symptoms. In these situations, biomechanical analysis under various conditions is required to assess the ability of this condition to cause future pathological conditions.

 

A Q-angle is considered normal if it is between 12° and 20°; men tends to be at the low end of this range while women tends to have higher values. Q-angle is usually regarded as excessive when an angle > 20°. An increase in Q-angle can alter the biomechanics of the knee and lead to lateral patellar dislocation or increased lateral patellofemoral contact pressures which can further cause valgus knee, potential sports injuries, and pathological conditions such as patellofemoral pain syndrome or knee instability. Excessive Q-angle can appears in healthy young people without knee symptoms. In these situations, biomechanical analysis under various conditions is required to assess the ability of this condition to cause future pathological conditions.

 

2. Gender is also a factor affecting the Q angle. Is there a specific gender or ethnic group for the subjects in this study? Please provide additional explanations in the subject information of the research method.

-> Thank you for your comment. We did not consider gender when dividing subjects into groups. The only criterion for dividing groups was Q-angle. We added gender information to the Table 1.

 

3. Different postures and joint movements will indeed affect the change of the Q angle. Is it possible to add some examples of actual training movements in the last part of the discussion, such as running or cycling, Squat or Leg press, so that readers can understand more easily value of this study.

-> Thank you for your comment. We added a description in the Discussion as follows:

[line 105-018]

The increased VM(vastus medialis) muscle activity due to squats can reduce Q-angle, and the minimized change in Q-angle can optimize the biomechanics of cycling.

 

Reviewer 2 Report

Dear Author

The article is interesting and innovative.

I suggest only clarifying the objectives of the study and aligning them throughout the text.

Author Response

REVIEWER 2

Dear Author

 

The article is interesting and innovative.

 

I suggest only clarifying the objectives of the study and aligning them throughout the text.

-> We revised entire introduction for clarifying the objectives of the study.

 

Reviewer 3 Report

I think that this is an interesting approach to the kinetic chain during a pelvic movement in knee valgus subject. In this study, the description of the research method was systematically well written using 3d motion analysis. The effect of the pelvis movement on the entire lower extremity is summarized in a table and statistical analysis was also performed properly.  However, the fact that sample size of the present study was not enough to generalize the results and not very specific conclusion could be weakness of this study. Although it is obvious this is a well-written research, there are some points for improving this study. Minor revision's required.

1. The study titled " Lower limb kinematic change during pelvis anterior and posterior tilt in double-limb support in Healthy Subjects with knee malalignment: A randomized cross-over study," was not consistent with the study method. The research method is not a randomized study. It should be revised. If it is a randomized study, additional explanation of the research method is required.

2. Method.[line 107-108] At this time, 6 subjects whose position could not be maintained constantly because they did not understand the performing anterior and posterior pelvic tilt were excluded. ->It can be confusing when compared to Figure 1. Present clearly.

3. Results. .[line 153] The decimal point in the table is not unified.

4. Results. .[line 153] Add a description of the behavior movement of the +/- values ​​in the table.

5. Discussion. Additional explanation is needed for the meaning of the hip rotation value, which is the main result.

6. Conclusion. [line 236] The conclusion is overgeneralized. Provide specific conclusions.

 

Author Response

REVIEWER3

 

I think that this is an interesting approach to the kinetic chain during a pelvic movement in knee valgus subject. In this study, the description of the research method was systematically well written using 3d motion analysis. The effect of the pelvis movement on the entire lower extremity is summarized in a table and statistical analysis was also performed properly. However, the fact that sample size of the present study was not enough to generalize the results and not very specific conclusion could be weakness of this study. Although it is obvious this is a well-written research, there are some points for improving this study. Minor revision's required.

 

1. The study titled " Lower limb kinematic change during pelvis anterior and posterior tilt in double-limb support in Healthy Subjects with knee malalignment: A randomized cross-over study," was not consistent with the study method. The research method is not a randomized study. It should be revised. If it is a randomized study, additional explanation of the research method is required.

-> Thank you for your good point. We changed introduction and title. We delete the randomized study.

2. Method.[line 107-108] At this time, 6 subjects whose position could not be maintained constantly because they did not understand the performing anterior and posterior pelvic tilt were excluded. ->It can be confusing when compared to Figure 1. Present clearly.

->The position of the sentence was changed according to the test order.

[line 105-018]

At this time, 6 subjects whose position could not be maintained constantly because they did not understand the performing anterior and posterior pelvic tilt were excluded.

All measurements were taken in triplicate. The measurements were taken during the last 10 s as the participant halted to maintain the posture.

 

3. Results. .[line 153] The decimal point in the table is not unified.

-> We unified decimal points in the Table 2 into two digits.

 

4. Results. .[line 153] Add a description of the behavior movement of the +/- values ​​in the table.

-> We added a description of the behavior movement of the +/- values ​​in the Table 2.

 

5. Discussion. Additional explanation is needed for the meaning of the hip rotation value, which is the main result.

-> Thank you for your comment. We added a description in the Discussion as follows:

[line 205-207]

The most important factor in increased Q-angle and pelvic tilt in the standing posture may be considered the rotation of the thigh.

 

6. Conclusion. [line 236] The conclusion is overgeneralized. Provide specific conclusions.

-> Thank you for your comment. We revised some sentences in the Conclusion as follows:

The Q angle and pelvic tilting was strongly related to the rotation of the thigh, but it was not related to malalignment with other segments during double-limb support. The most important factor in increased Q angle and pelvic tilt in the standing posture is the rotation of the thigh. In addition, the Q-angle measurement should be performed with measurement of the pelvic tilt.

 

The Q angle and pelvic tilting was strongly related to the rotation of the thigh, but it was not related to malalignment with other segments during double-limb support. The most important factor in increased Q angle and pelvic tilt in the standing posture may be considered the rotation of the thigh. The increase in internal rotation of the thigh should be considered for pelvic tilt, and the measurement of the Q angle alone may not be sufficient to identify individuals at risk of injuries. In addition, the Q-angle measurement should be performed with measurement of the pelvic tilt.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript entitled “Lower limb kinematic change during pelvis anterior and posterior tilt in double leg support to the knee malalignment subjects: A Randomized Cross Over Study” aims to explore “the lower limb kinematic change during pelvis tilting to the knee malalignment subjects”. I have revised the manuscript and provide some comments and suggestions which I hope the Authors will revise. The following comments are offered to help strengthen the manuscript:

Introduction section:

The aim of the study is not clear and do not match with the methods of the study

Methods section:

Does the objective and the design of the study match with the methods?

When was the study performed?

How many times participants were evaluated?

There is an intervention for the participants?

No sample size calculation is provided

The sample size is too small.

Results section:

 

Flow diagram of the recruitment of the participants is not provided

Why characteristics of the participants are presented by gender?

 

Conclusion:

The conclusion should clearly answer to the objective of the study.

Reviewer 2 Report

This manuscript presents an investigation of lower limb kinematics. The investigation is performed as a randomised trial, which has been approved by an ethics committee and performed in accordance with the Helsinki Declaration. It is unclear to me whether a randomised trial is an adequate study type for investigating limb kinematics. Some other type of experiment may be more suitable for this specific purpose. However, as the authors have chosen to present their study as a randomised trial, these review comments refer to the requirements for reporting a randomised trial.

1. Please clarify if the trial has been registered in a public trial register according to the ICMJE requirements (http://icmje.org/recommendations/browse/publishing-and-editorial-issues/clinical-trial-registration.html). Note that some trial registries allow retrospective registration and some journals accept manuscripts with such registration, see e.g. https://blogs.biomedcentral.com/bmcblog/2016/04/15/retrospectively-registered-trials-editors-dilemma/.

2. No completed CONSORT Statement checklist is included with the manuscript, see http://www.consort-statement.org, and the manuscript does also not comply with the CONSORT Statement. I recommend strongly that the manuscript is revised to be in accordance with the CONSORT Statement, especially the CONSORT 2010 statement: extension to randomised crossover trials. BMJ 2019;366:l4378. I also recommend that the authors include a completed CONSORT Statement checklist with the manuscript.

3. P-values are not descriptive measures of practical importance but measures of inferential uncertainty. The current dichotomisation of the findings into p < 0.05 and p > 0.05 is just not meaningful, see the American Statistical Association's position paper on statistical significance and p-values, https://www.amstat.org/asa/files/pdfs/p-valuestatement.pdf. Instead, the presentation of results should be based on considerations regarding both practical importance (clinical significance) and inferential uncertainty (statistical significance). Descriptions such as "significant difference" and "significantly different" may be common in scientific publications but are ambiguous and contribute to the current reproducibility crisis.