Assessment of Gait Following Locking Plate Fixation of a Tibial Segmental Defect and Cast Immobilization in Goats

Round 1

Reviewer 1 Report

Overall this is an interesting and well-written manuscript that illustrates how a locking plate stabilization and cast immobilization of a rear-limb affect goat gait biomechanics. The results of this study provide some insight into how similar methods may affect bone healing and gait on other models and potentially humans, particularly regarding the long-term effects of joint immobilization.

Minor Comments:

- There is no information provided on the sex of the goats. Were they all male, all female, or a mix? Do the authors expect that there may be any differences in healing time or mobility based on sex?

- During the immobilization period, it is my understanding that only the affected limb was immobilized, and that the goats were free to otherwise move as they pleased. How much overall mobility did the goats exhibit during this time (e.g. mostly sedentary? active?) Did some seem to move more than others, and if so, could there be a high degree of inter-goat variation that affected the results?

- Lines 212-213 state that all goats were trained to "walk at a uniform pace". Do the authors mean that all goats walked at the same pace, or that each goat walked at an individually constant pace that varied between animals? If all goats walked at the same speed, could this have contributed to abnormal gait biomechanics as an animal walked faster or slower than comfortable? If each goat walked at a constant self-selected pace, were the data normalized for walking speed? Could speed-induced effects have contributed to the fairly high variance in the results?

- In general, there is a fairly high degree of variance in all of the kinematic and kinetic results that could be masking some otherwise interesting trends, particularly in the immobilization period. Do the authors expect that some of these trends might be shown to be statistically significant with larger sample sizes?

-How large is a goat footprint relative to the sensel size in the pressure-sensing mats? Did the rubber-mat covering distribute the contact pressure over a larger area? When calculating ground reaction forces for a specific limb, over how much area was the spatial integration of pressure performed?

- 15Hz is fairly low for measuring ground contact, especially with some stance times <400 ms. Typically sampling rates are >45 Hz for these types of measurements. (https://doi.org/10.1016/j.jbiomech.2022.111034). Could these fairly low sampling rates have affected your spatiotemporal and kinetic estimates as well?

Author Response

Please see attachment. 

Author Response File: Author Response.pdf

Reviewer 2 Report

Review of article no. biomechanics-1919698  with title ‘’Assessment of Gait Following Locking Plate Fixation of a Tibial Segmental Defect and Cast Immobilization in Goats’’.

Congratulates the authors on the idea. In my opinion, the article is well written. There are minor editorial errors and a few understatements.  I have posted all comments in the comments below. Thank you for the opportunity to review.

1.     L5 –‘’ Anderson 2 ‘’ - Next to the name Anderson there is a number 2 o suggests a different affiliation from the other authors. Please add it.

2.     L48 - I would suggest adding statistical data: number of annual operations, cost of operations.

3.     In the introduction, I would suggest adding information on rehabilitation measures after this type of surgery.

4.     L120 –‘’ Thirteen Boer-cross” - Why such a number?  Was it dictated by proper statistical analysis? Please provide your sample size calculations.

5.     2.4. Biomechanical Data Collection - I would suggest adding photos of the data collection process. This will help in understanding the course of the experiment.

6.     L252 - There is a lack of elucidation of what constitutes a positive result and what constitutes a negative result. By way of example:

7.     ‘’ The value of SI = 0 indicates perfect gait symmetry. Values of SI > 0 indicate asymmetry for the right limb, and values of SI < 0 indicate asymmetry for the left limb’’.

Kano, W.T., Rahal, S.C., Agostinho, F.S. et al. Kinetic and temporospatial gait parameters in a heterogeneous group of dogs. BMC Vet Res 12, 2 (2016). https://doi.org/10.1186/s12917-015-0631-2

8.     L258 – ‘’ 2.5. Asymmetry Indices’’ - Wrong title. Please correct.

9.     L268 - Suggests adding a confidence interval either/or and effect size.

10.  Figure 1. and 2 - I would suggest enlarging the graphics. In my opinion they are unreadable.

11.  Table 1 – ‘’L364-367 – ‘’ a represents value significantly different from preoperative baseline in pairwise comparison; p<0.05; b represents value significantly different from Day 7 in pairwise comparison; p<0.05; c represents value significantly different from Day 30 in pairwise comparison; p<0.’’ - These data please post under the table. 

  Please apply the note to the other tables.

12.  L480 -  Limitations please start with a new paragraph.

13.  L513 – ‘’. 6.’’ – delete.

14.  References - The references are written in different styles, none of which match the style of the journal. Please correct.

 

Author Response

Please see attachment. 

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper is well written and organized. 

I do not have any comment.

 

Author Response

We thank the reviewer for their compliments and offer this updated manuscript for further review. 

Reviewer 4 Report

Brief summary: The present study deals with the biomechanical analysis in goats walking to investigate the effects of locking plate fixation. The starting hypothesis suggested that stable fixation of a segmental bone with a locking plate construct would reveal negligible changes in biomechanical gait variables, while a full-limb immobilization would reveal important alterations. Experimental tests were conducted with a pressure sensing walk-way and data were collected pre-surgery and over 12 months post-surgery. Results pointed out no significant alterations in hindlimb kinematics or maximum force in the comparison pre-surgery and post cast immobilization. Significant decreases in forelimb stride length and velocity were noted postoperatively but normalized prior to cast placement.

 

Broad comments: The present work is generally well described and written. The topic well fits current researches and interest in biomechanical analysis of gait in veterinary field. Additional references could be added in the introduction in order to give a complete overview of the topic. The quality and readiness of figures and tables must be improved. In the following section I give specific suggestions referred to the text in order to improve the completeness of the work, to better emphasize explicit points and to simplify the comprehension of some concepts.

Specific comments:

1.      The introduction section is well written and the most important concepts are well presented. The principal aim of the study is clearly reported at the end of the section. Before introducing the use of pressure sensor system, I suggest to report one or two sentences stressing the importance of biomechanical investigation of gait in veterinary field and current applications in different situations (animals and clinical questions). Here some references that can be added to support the sentences:

·        Piras, L. A., et al. "Post-operative analgesia following TPLO surgery: A comparison between cimicoxib and tramadol." Research in veterinary science 136 (2021): 351-359.

·        Egenvall, Agneta, Celia M. Marr, and Anna Byström. "Study design synopsis: How to conduct, prepare, analyse and report equine biomechanical studies." Equine Veterinary Journal 53.4 (2021): 645-648.

·        Netukova, Slavka, et al. "Instrumented pig gait analysis: State-of-the-art." Journal of Veterinary Behavior 45 (2021): 51-59.

2.      The methodology section is well described and is full of details required to understand the experiment. In the statistical analysis sub-chapter, try to revise the sentences in order to express more clearly which statistical tests have been used for the analysis (repeated measure anova only for the symmetry indexes?).

3.      In my opinion, the Supplementary Figure 1 reported in the supplementary file can be added inside the text of the manuscript, in the methodology section. Improve the dimension of the writing inside the figure.

4.      Results section is well schematized and obtained data are well summed up. Please, improve the quality of figures and tables (prefer vector graphics). Axes in figures 1 and 2 must have the same full scale for corresponding parameters (for example the stride velocity graph has a different full scale in figure 1 and figure 2 and similar considerations can be made for maximum force, impulse, maximum peak pressure and asymmetry indices).

5.      Table 1 and table 2 are dense of results. It is not clear the meaning of values reported between round brackets. Moreover, these values are never discussed. If not necessary, I suggest to remove these values with the attempt to improve the reading and interpretation of tables.

6.      In the discussion and conclusion sections, the obtained data are well discussed. Nevertheless, there is no discussion about the limited number of subjects and the impossibility to group them in different groups based on weight and age. Do you expect a reduction of standard deviation of parameters in case of grouping subjects? Please, add and discuss these point in the manuscript.

Author Response

Please see the attachment. 

Author Response File: Author Response.pdf