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. 2021 Feb 17;16(2):e0242496. doi: 10.1371/journal.pone.0242496

Percutaneous Chevron/Akin (PECA) versus open scarf/Akin (SA) osteotomy treatment for hallux valgus: A systematic review and meta-analysis

Gabriel Ferraz Ferreira 1,#, Vinícius Quadros Borges 2,#, Leonardo Vinícius de Matos Moraes 3, Kelly Cristina Stéfani 4,*
Editor: Osama Farouk5
PMCID: PMC7888602  PMID: 33596196

Abstract

Purpose

The objective of the study is to compare the radiographic and clinical results of two techniques for the treatment of hallux valgus that have the same indication, the open scarf/Akin (SA) technique and the percutaneous Chevron/Akin (PECA).

Methods

A meta-analysis was performed with the studies found during a systematic review of articles included in electronic databases until 30 May 2020. The pooled analysis was summarized according to clinical outcomes, such as visual analog pain scale (VAS) and American Orthopaedic Foot & Ankle Society (AOFAS) score, radiographic outcomes and complications, with a 95% confidence interval.

Results

Three studies comparing the open scarf/Akin (SA) versus the PECA techniques were added to the analysis, corresponding to 235 feet, 102 in the PECA group and 133 in the SA. The final mean difference in the hallux valgus angle was 0.80 degrees and in the intermetatarsal angle 0.53, in the last radiographic evaluation. In the AOFAS score, the final mean difference was 4.97 points and in the VAS 0.14 in relation to the last clinical evaluation. Exposure to radiation during the surgical procedure was higher in the PECA group with a mean of 35.53 seconds.

Conclusions

The PECA surgical technique for the treatment of hallux valgus when compared with SA demonstrated similar radiographic correction, pain and function after six months of follow-up but with a longer radiation exposure time.

Register of systematic review (PROSPERO)

CRD42018096613.

Introduction

Hallux valgus is a widely studied deformity that affects the feet, and even though more than 130 conventional techniques have been described for its correction, the best technique has not yet been determined [1].

One of the most commonly used techniques is open scarf/Akin (SA) osteotomy, which is performed through a medial approach in the forefoot and uses screw fixation to achieve absolute stability [2]. The results described are satisfactory; however, residual complains are reported in open surgery by approximately 15% of patients and include intense postoperative pain, slow recovery and stiffness [3–6].

This result led to a search for research on alternative methods for hallux valgus correction, and the concepts of minimally invasive surgery have been employed, increasing the number of publications on the subject in recent years [7,8].

Currently, the third generation of minimally invasive surgery for hallux valgus is the percutaneous Chevron/Akin (PECA) technique, described by Vernois and Redfern [9] as MICA (minimally invasive Chevron-Akin).

The reviews published so far suggest that there is a lack of randomized clinical trials comparing the PECA technique with conventional open techniques, as only one case series with low methodological quality was found in the literature [10,11].

The objective of this study was to carry out a systematic review with the following characteristics:

  • Population: patients diagnosed with hallux valgus;

  • Intervention: PECA;

  • Control: SA;

  • Outcome: pain, function and radiographic evaluation;

  • Studies: randomized controlled trials or controlled retrospective studies;

Methods

Search strategy

A systematic review was performed by two reviewers according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines [12]. Studies were located by searching the Medline (PubMed), Cochrane Library, Scopus and Embase databases. The search was performed on 30 May 2020 with the keywords "hallux valgus AND (percutaneous OR minimally invasive)”, without any language restriction or filter. In addition, a manual search was performed of the references cited in studies, letters, reviews and foot and ankle reference textbooks. The present systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) [13]. Two reviewers retrieved the data and independently analyzed each selected study; instances of disagreement were resolved by the senior investigator.

Inclusion and exclusion criteria

The inclusion criteria were the following: (1) hallux valgus diagnosis and (2) surgical treatment by the SA and PECA technique. The exclusion criteria were the following: (1) patients with previous treatments and (2) patients with associated neuromuscular diseases. Case reports, letters to the editor, systematic reviews and opinion pieces were removed.

Data extraction

The article data were extracted by two independent researchers according to a previously established protocol. The data collected were tabulated according to the relevant data using a previously defined protocol.

Quality assessment

We used two different methods for analyzing the quality of the studies (Table 1). For the study by Lai et al. [14] and Frigg et al. [15] we used ROBINS I [16] which classified the study as having a serious risk of bias and moderate risk of bias, respectively. In turn, the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2.0) [17] was used to evaluate the study by Lee et al. [18] since it was a randomized controlled trial. The study was categorized as having a some concerns.

Table 1.

A; Summary of risk of bias assessment for randomized controlled trials. B; Summary of risk of bias assessment for non-randomized controlled trials.

A
Study Randomization process Deviations from intended Missing outcome data Measurement of the outcome Selection of the reported result Overall Bias
Lee et al Low risk Low risk Some concerns Some concerns Some concerns Some concerns
B
Study Bias due to confounding Bias in selection of participants into the study Bias in classification of interventions Bias due to deviations from intended interventions Bias due to missing data Bias in measurement of outcomes Bias in selection of the reported result Overall
Lai et al Moderate risk of bias Serious risk of bias Low risk of bias Serious risk of bias No information Serious risk of bias Moderate risk of bias Serious risk of bias
Frigg et al Low risk of bias Moderate risk of bias Low risk of bias Moderate risk of bias Moderate risk of bias Moderate risk of bias Moderate risk of bias Moderate risk of bias
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Statistical analysis

The studies included were qualitatively analyzed, and the summary of their results is reported in tables. The meta-analysis was performed through the Meta package for R. The standardized mean difference and the mean difference were used for the continuous outcome variables. The dichotomous variables were compared using relative risk. The results were described with the corresponding 95% confidence interval (95% CI). A p value < 0.05 was considered statistically significant. Heterogeneity among studies was calculated using the I2 and τ2 statistics.

Date items

The results gathered from the various databases were synthesized and categorized using EndNote X7.7.1 (Thomson Reuters, CA, USA). Duplicates were removed.

Outcomes and prioritization

The selected outcomes included visual analog scale of pain, function according to the American Orthopaedic Foot & Ankle Society Hallux Metatarsophalangeal-Interphalangeal (AOFAS Hallux MTP-IP) [19] rating system, visual analog scale of pain, radiographic evaluation, quality of life assessment (Bonney and Macnab) [20] and satisfaction with the outcome. In addition, other outcomes, such as complications, radiation exposure time and surgery time, were evaluated.

Results

Study selection

The search retrieved 691 articles: 189 from Medline (PubMed), 267 from Embase, 22 from the Cochrane Library and 213 from Scopus. After excluding duplicates and articles not relevant to the topic, 27 articles were selected for full-text review. Finally, three studies met the inclusion criteria and were included in the qualitative analysis and meta-analysis. A flowchart representing study selection is shown in Fig 1.

Fig 1. PRISMA flowchart of the literature search and study selection.

Fig 1

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Study characteristics

The most recent study was published by Frigg et al. [15] in 2019 in which the authors compared the prospective results of the treatment of hallux valgus using the PECA versus open SA technique without randomization from January 2014 to December 2017. Fifty patients were included in the open group and 48 in the percutaneous group.

The article by Lee et al. [17] was published in 2017, in which the author conducted a randomized controlled trial between April 2012 and May 2015. Fifty patients were included, 25 in the PECA group and 25 in the SA group.

The study by Lai et al. [14] was a retrospective analysis of prospective data. The PECA and SA control groups included 29 and 58 feet, respectively, in a 2:1 ratio. The surgical procedures were performed between 2013 and 2014.

All studies identified in the systematic review reported that surgical hallux valgus correction was only indicated after failure of conservative treatment. In total, 235 feet were submitted to PECA (102 feet) or SA (133 feet) surgery. The main characteristics of the three studies are shown in Table 2.

Table 2. Summary of studies included in the systematic review.

Study Year of publication Country Study design Age (mean) p PECA SA p
PECA SA Men Woman Total Men Woman Total
Lee et al 2017 Australia Cohort study 52.6 (20–76) 53.4 (25–75) 0.759 2 23 25 3 22 25 0.799
Lai et al 2017 Singapore Randomized controlled trial 54.3 ± 12.8 54.3 ± 12.7 0.986 4 25 29 6 52 58 0.725
Frigg et al 2019 Switzerland Cohort study 48.04* 48.23* 0.79 7 41 48 6 46 50 0.47
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* Median.

Preoperative and postoperative clinical evaluations were performed using a visual analog pain scale, as shown in Table 3.

Table 3. Summary of evaluations by visual analog pain scale (VAS).

Study VAS Pre △VAS Pre SA—PECA p
PECA SA
Lee et al. 7.1 ± 1.5 6.9 ± 1.7 - 0.2 0.179
Lai et al. 4.0 ± 2.9 4.9 ± 2.6 0.9 0.124
Frigg et al. 3 (3, 4)* 4 (3, 4)* 1 0.35
Study VAS 1 day (Perioperative) △VAS 1 day (Perioperative) SA—PECA p
PECA SA
Lee et al. 2.2 ± 1.2 3.9 ± 1.9 1.7 < 0.001
Lai et al 1.9 ± 0.6 3.9 ± 1.0 2 < 0.001
Frigg et al. N/S
Study VAS 2 weeks △VAS 2 weeks SA—PECA p
PECA SA
Lee et al. 1.0 ± 1.4 2.4 ± 1.7 1.4 < 0.001
Lai et al. N/S
Frigg et al. N/S
Study VAS 6 weeks △VAS 6 weeks SA—PECA p
PECA SA
Lee et al. 0.6 ± 1.8 2.1 ± 2.0 1.5 0.004
Lai et al. N/S
Frigg et al. N/S
Study VAS 6 months △VAS 6 months SA—PECA p
PECA SA
Lee et al. 0.3 ± 0.9 0.5 ± 1.1 0.2 0.160
Lai et al. 0.7 ± 1.8 0.9 ± 1.8 0.2 0.572
Frigg et al. N/S
Study VAS Last follow-up △VAS Last follow-up SA—PECA p
PECA SA
Lee et al. 0.3 ± 0.9 0.5 ± 1.1 0.2 0.160
Lai et al. 0.7 ± 1.9 0.4 ± 1.5 -0.3 0.620
Frigg et al. 0 (0, 0)* 0 (0, 0)* 0 0.39
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N / S: not specified;

* Used the median and interquartile range.

Another important clinical evaluation that was performed in all studies was the AOFAS score. This score takes into account the function, range of motion, pain and gait of the patient. The AOFAS score was applied both in the preoperative and in the immediate and late postoperative periods (Table 4).

Table 4. AOFAS score for pre- and postoperative functional evaluation.

Study AOFAS Pre △AOFAS Pre (SA—PECA) p
PECA SA
Lee et al. 61.3 ± 3.2 58.5 ± 4.3 -2.8 0.220
Lai et al. 58.6 ± 16.6 53.2 ± 14.6 -5.4 0.127
Frigg et al. 52 (47, 60)* 49 (44, 57)* -3* 0.06
Study AOFAS 6 months △AOFAS 6 months (SA—PECA) p
PECA SA
Lee et al. 88.7 ± 2.1 83.0 ± 3.5 - 5,7 0.560
Lai et al. 85.6 ± 14.9 82.7 ± 14.5 -2.9 0.183
Study AOFAS Last follow-up △AOFAS Last follow-up (SA—PECA) p
PECA SA
Lee et al. 88.7 ± 2.1 83.0 ± 3.5 - 5,7 0.560
Lai et al. 87.4 ± 17.8 88.4 ± 13.8 1.0 0.547
Frigg et al. 95 (90, 100)* 100 (86, 100)* 5* 0.60
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* Used the median and interquartile range.

Moreover, only the study by Lee et al. [17] used the Bonney and Macnab criteria to assess quality of life, while studies by Lai et al. [14] e de Frigg et al. [15] evaluated the degree of satisfaction with the procedure.

Radiographic evaluation was performed in all studies. The metatarsophalangeal angle, known as the hallux valgus angle (HVA), and the intermetatarsal angle (IMA) were measured before the procedure. The last HVA and IMA measurements were considered the postoperative outcome. A summary of the radiographic evaluation results is shown in Table 5.

Table 5. Summary of radiographic evaluations.

Study HVA Pre p HVA Last follow-up p
PECA SA PECA SA
Lee et al. 31.4 ± 2.1 31.2 ± 4.1 0.890 7.6 ± 1.2 10.1 ± 1.9 0.520
Lai et al. 29.9 ± 8.5 30.6 ± 8.4 0.702 8.8 ± 5.9 13.8 ± 7.6 0.003
Frigg et al. 25 (21, 27)* 25 (20, 30)* 0.72 7 (5, 11)* 10 (6, 14)* 0.07
Study IMA Pre p IMA Last follow-up p
PECA SA PECA SA
Lee et al. 15.6 ± 1.0 15.7 ± 1.4 0.960 6.4 ± 0.8 7.6 ± 0.9 0.270
Lai et al. 14.6 ± 3.9 14.6 ± 3.3 0.954 10.3 ± 3.1 8.8 ± 3.4 0.055
Frigg et al. 13 (11, 14)* 13 (11, 15)* 0.93 6 (5, 8)* 5 (4, 7)* 0.008
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* Used the median and interquartile range.

Other important characteristics were measured, such as radiation exposure time, surgical time, surgical scar size and complications. The PECA group presented complications only with the screws, in some cases being necessary to remove them. The SA group presented complications ranging from metatarsalgia to wounds complications.

Regarding the length of the surgical wound, it was measured by the study of Lee et al [18] with an average of 25.3mm in the PECA group and 107.1mm in the SA group, as well as in the study of Frigg study being the median of 5 cm for open surgeries and 1.2cm percutaneous (p < 0.001). In two studies there was the evaluation of radiation exposure that surgeons undergo during the procedure, being much higher in percutaneous surgeries than in open surgery. The operative time was measured only by the article by Lai et al [14], being greater in the procedures performed by the SA technique than by the PECA.

Pooled analysis

The radiographic evaluation (IMA and HVA), clinical evaluation (AOFAS and VAS), complication and radiation exposure were analyzed together.

Radiographic evaluation

The radiographic analysis of the studies was conducted based on two distinct measurements: the HVA and IMA at the last visit. Regarding the HVA found, there was a mean difference (HVA PECA—HVA SA) of -0.80 degrees in the fixed effects model (95% CI = -1.07 to -0.52, p = 0.03, I2 = 70%, τ2 = 0.14), as shown in Fig 2.

Fig 2. Forest plot of the meta-analysis of the studies evaluating the final radiographic difference in the HVA.

Fig 2

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There was a difference between the mean IMA at the last radiographic evaluation (IMA PECA—IMA SA) of -0.53 degrees in the fixed effects model (95% CI = -0.93 to -0.13, p < 0.01, I2 = 93%, τ2 = 2.37), according to the forest plot in Fig 3.

Fig 3. Forest plot of the meta-analysis of the studies evaluating the final radiographic difference in the IMA.

Fig 3

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Clinical evaluation

Functional assessment was performed using the AOFAS score determined at the last clinical evaluation. The mean difference between the groups (PECA—SA) was 4.97 points in the fixed effects model (95% CI = 3.55 to 6.39, p = 0.14, I2 = 48%, τ2 = 2.87), as shown in the forest plot in Fig 4.

Fig 4. Forest plot of the meta-analysis of the studies evaluating the difference in the AOFAS score at six months postoperatively.

Fig 4

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The visual analog pain scale was used postoperatively at two time points, the first of which was the first day after surgery, as shown in Fig 5, and the mean difference between the groups (PECA—SA) was -1.68 points in the fixed effects model (95% CI = -2.09 to -1.27, p < 0.01, I2 = 87%, τ2 = 0.60), performed only by two studies.

Fig 5. Forest plot of the meta-analysis of the studies evaluating the difference in the visual analog pain scale score at one day postoperatively.

Fig 5

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The analogue pain scale was also used at the last medical appointment, described in the three studies. The mean difference in the score between the groups (PECA—SA) was -0.14 points in the fixed effects model (95% CI = -0.49 to 0.20, p = 0.81, I2 = 0%, τ2 = 0), as shown in Fig 6.

Fig 6. Forest plot of the meta-analysis of the studies evaluating the difference in the visual analog pain scale score at the last clinical evaluation.

Fig 6

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Complications

Complications in the groups are described in Fig 7 and were evaluated using the fixed effects model with a relative risk of 1.51 (95% CI = 0.80 to 2.86, p = 0.36, I2 = 3%, τ2 = 0.01). The complication was the removal of synthesis material, metatarsalgia and problems with wound healing.

Fig 7. Forest plot of the meta-analysis of the studies evaluating the relative risk of complications.

Fig 7

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Radiation exposure

Exposure to radiation during the surgical procedure was assessed using the mean fluoroscopy duration in seconds. Fig 8 shows that the difference was 35.53 seconds between the PECA group and the SA group in the fixed effects model (95% CI = 31.75 to 35.31, p < 0.01, I2 = 87%, τ2 = 11.31).

Fig 8. Forest plot of the meta-analysis of the studies evaluating the difference in exposure to intraoperative radiation between the types of surgical procedures.

Fig 8

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Publication bias

The funnel plot and Begg’s test were not performed since the inclusion of only three studies in the meta-analysis does not allow this type of evaluation.

Discussion

Although the techniques used for hallux valgus correction have been described and are familiar to foot and ankle surgeons, comparison between studies is not easy because of the wide variations in techniques and heterogeneous samples, as described in the systematic review by Bia et al. [10], in addition to the low methodological quality of the studies without control or case series, as found in other reviews [7,11].

Therefore, our study prioritized the search for articles on specific and widely used techniques such as SA in open surgery and PECA in percutaneous surgery, thus enabling comparison between the studies and a search for the best evidence regarding the outcomes.

In open surgeries for hallux valgus correction, it makes no sense to compare the Chevron/Akin technique with Scarf/Akin. However, the Percutaneous Chevron (PECA) technique is used for moderate or severe hallux valgus cases, with a similar indication for the open Scarf/Akin technique. In the radiographic evaluation, there was a difference between the groups in the final HVA and IMA, with means derived from the meta-analysis of 0.80 and 0.53 degrees, respectively. Radiographic correction was achieved in both groups, with a small difference between the groups. Although radiographic alignment did not necessarily guarantee clinical correction, both techniques demonstrated the potential for deformity correction.

In the studies included in the meta-analysis, the AOFAS score was used to measure the postoperative outcome, as was the visual analog pain scale score. The AOFAS score was higher in the PECA group, with a small mean difference of 4.97 points. The visual analog pain scale was used at two time points: immediately postoperatively (only in two studies) and last clinical evaluation. At the first time point, there was a difference between the means of the groups, with the PECA group having a mean score that was 1.68 points lower. At last rating the difference between the groups decreased, with a mean difference of 0.14 points.

The theoretical advantages of percutaneous surgery include lower rates of morbidity and faster recovery with immediate full weight-bearing, which have led to an increased use of the technique [21]. Based on the results of the meta-analysis, the difference between the techniques favored PECA, which yielded a lower pain score in the visual analog scale. However, the result found was based on only two studies, and should be generalized with limitations. In addition, the scar size was only measured in the study of Lee et al. [17], and the mean for the PECA group (23.3 mm) was much lower than that for the SA group (107.1 mm).

Another important difference between the percutaneous surgical technique and the open technique is the radiation exposure time. Percutaneous surgery requires localization by fluoroscopy, while in the open technique, fluoroscopy is used only at the end of the procedure to check the final outcome and screw sizes. Therefore, both studies evaluated the radiation exposure time, and the mean for the PECA group was higher than that for the SA group, with a difference of 33.53 seconds. Thus, the greater use of fluoroscopy and its potential for radiation exposure can be considered negative features of the method.

The percutaneous techniques presented complications such as osteonecrosis, malunion, relapse and pseudoarthrosis [10,21]. Open surgeries also present complications similar to those of percutaneous surgeries, such as those previously described [22,23]. In our study, complications were assessed as outcomes through the relative risk, but without significance.

Although the PECA technique is minimally invasive, percutaneous surgeries present a long learning curve, with a higher risk of complications compared with that attained by more experienced surgeons, requiring training on cadavers and previous specific training [4]. Surgical time should also be taken into account. This parameter was only measured in the study by Lai et al. [14], and it was higher in the SA group (44.3 minutes) than in the PECA group (56.6 minutes).

This study has some limitations. Only three studies were included in the systematic review, two of which was retrospective. Another limitation was the short follow-up time in the studies, which could interfere with the outcome. These factors can influence the risk of bias and lead to erroneous conclusions.

Conclusion

The PECA surgical technique for the treatment of hallux valgus when compared with SA demonstrated similar radiographic correction, pain and function after six months of follow-up but with a longer radiation exposure time. Only three studies were included in the meta-analysis. A multicenter study with the same design as that of the selected studies is necessary to confirm the results obtained.

Supporting information

S1 Checklist. PRISMA 2009 checklist.

(DOC)

Click here for additional data file. (64.5KB, doc)

Data Availability

All relevant data are within the manuscript and its Supporting information files.

Funding Statement

The authors did not receive specific funding for this work.

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Decision Letter 0

Osama Farouk

1 Sep 2020

PONE-D-20-20197

Percutaneous Chevron/Akin versus open scarf/Akin osteotomy treatment for hallux valgus: a systematic review and meta-analysis

PLOS ONE

Dear Dr. Stefani,

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Osama Farouk

Academic Editor

PLOS ONE

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Reviewers' comments:

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Comments to the Author

1. 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: Partly

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. 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: No

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

**********

5. 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: Thank you for asking me to review this paper dealing with a comparison between percutaneous Chevron/Akin and traditional Scarf/Akin. The topic is definitely interesting. I think the paper will be suitable for publication after a revision by authors. The most important point will be to remodulate the conclusion, since I don’t believe that data allow to say the early postoperative pain is better for PECA. It can be said that the outcomes are comparable after 6 months, but that no analysis is possible about the early recovery based on published data.

My comments in detail are:

ABSTRACT

I would recommend to include more data in the methods section. In results, how many patients were considered in the 3 studies in total?

INTRODUCTION

Line 59 Better to say The reviews published so far…

METHODS

Line 85 I think here you may want to say ‘…treatment by the SA and PECA technique »

RESULTS

VAS at 1 day is reported only by two studies and at 1 week and 2 weeks by one study

Line 170 Is this Portuguese?

Line 171 Typo

Line 179-180 This is not clear

Line 188 -0.53 what? and in favour of what technique?

Line 193 As above. Please, be clearer when reporting differences

Line 198 As above

Line 206 As above

Line 212 As above

DISCUSSION

Line 233 0.80 what? Please revise the whole paper indicating the Units for values

Line 237-243 I think this paragraph should be remodulated. Was the difference in AOFAS statistically significant? I think you cannot draw any conclusion on the immediate postoperative pain since only one or two studies assessed it.

Line 247 Pain score at VAS cannot be judged only on one or two studies

CONCLUSION

I think that, based on your numbers, you cannot infer that PECA led to less postoperative pain. You may say that the clinical outcome is comparable at 6 and 12 months, and that early recovery cannot be assessed based on current literature.

Reviewer #2: This study addresses a common problem in foot surgery. A well-tried technique is compared with a new percutaneous technique in the context of a meta-analysis. This analysis was carried out technically flawlessly. The only problem I see is that only 3 studies could be included. However, this fact was openly presented and discussed by the authors in the discussion.

Please delete „were excluded“ in line 87

**********

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Reviewer #1: No

Reviewer #2: Yes: PD Dr. med. habil. Kajetan Klos

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PLoS One. 2021 Feb 17;16(2):e0242496. doi: 10.1371/journal.pone.0242496.r002

Author response to Decision Letter 0

16 Oct 2020

Response to Reviewers

A detailed response to the recommendations of the reviewers is provided here, including the specific revisions made to the original manuscript. A table format has been used for clarity.

Reviewer 1

COMMENT RESPONSE TEXT CHANGES

General

Thank you for asking me to review this paper dealing with a comparison between percutaneous Chevron/Akin and traditional Scarf/Akin. The topic is definitely interesting. I think the paper will be suitable for publication after a revision by authors. The most important point will be to remodulate the conclusion, since I don’t believe that data allow to say the early postoperative pain is better for PECA. It can be said that the outcomes are comparable after 6 months, but that no analysis is possible about the early recovery based on published data. Thank you for this comment. We agree that the data is not robust enough for this conclusion. We changed the conclusion of the study as suggested by the reviewer. Thank you very much.

Abstract

I would recommend to include more data in the methods section. In results, how many patients were considered in the 3 studies in total? Perfect. We added in abstract and results the total number of feet that underwent surgical treatment and the results found in the meta-analysis, valuing the data included in the three studies. The conclusion was modified according to the reviewer's suggestion. Line 14 and Line 122-123

Introduction

Line 59 Better to say The reviews published so far… The sentence really got confused. We changed it as suggested. Thank you. Line 37

Methods

Line 85 I think here you may want to say ‘…treatment by the SA and PECA technique » We agree with the comment. We changed the "or" to "and". It was much better that way. Thank you. Line 63

Results

Line 170 Is this Portuguese? Translated. This was a mistake by the translator. We apologize and appreciate the comment. Line 146

Line 171 Typo Adjusted. Line 147

Line 179-180 This is not clear The item was to be clear about subsequent analyzes. But it was loose in the text and confused. Thanks for the comment. We decided to remove.

Line 188 -0.53 what? and in favour of what technique? The grouped analysis corresponds to the difference in the averages. We standardize the calculations to be PECA minus SA, in the text is for example "(HVA PECA - HVA SA)". If the difference in the average is negative as in the case -0.53, it means that the mean of SA is greater than PECA. This comparison in means is standardized for all forest plots in the present study, as in the other values found.

Line 193 As above. Please, be clearer when reporting differences

Line 198 As above

Line 206 As above

Line 212 As above

Discussion

Line 233 0.80 what? Please revise the whole paper indicating the Units for values Thank you for the question. In this case 0.80 and 0.53 are the difference in the means of the HVA and IMA angles. “...final HVA and IMA, with means derived from ...” We added the word "degrees" in the sequence of values for easy reading. Lines: 161, 164, 169, 174, 178

Line 237-243 I think this paragraph should be remodulated. Was the difference in AOFAS statistically significant? I think you cannot draw any conclusion on the immediate postoperative pain since only one or two studies assessed it. Very good comment. We cannot affirm and conclude with absolute certainty the results, as we have points of possible bias in the study. We included in the last paragraph of the discussion: "These factors can influence the risk of bias and lead to erroneous conclusions." The result of the meta-analysis we interpret as a pooled analysis and heterogeneity (i2), and not on statistical significance. The difference in the means is a statistical synthesis that can present distortions that are demonstrated in the weak points of the study.

Line 247 Pain score at VAS cannot be judged only on one or two studies In fact, the low number of articles included in the meta-analysis can increase the risk of bias and restrict its generalization. We add in this paragraph that the result was obtained from only two studies, with this evident limitation. We appreciate the suggestion. Line 223 - 224

Conclusion

I think that, based on your numbers, you cannot infer that PECA led to less postoperative pain. You may say that the clinical outcome is comparable at 6 and 12 months, and that early recovery cannot be assessed based on current literature. The conclusion was modified according to the reviewer's suggestion, both in the abstract and in the conclusion. Line 253 – 255 and Line 19 - 21

Reviewer 2

COMMENT RESPONSE TEXT CHANGES

This study addresses a common problem in foot surgery. A well-tried technique is compared with a new percutaneous technique in the context of a meta-analysis. This analysis was carried out technically flawlessly. The only problem I see is that only 3 studies could be included. However, this fact was openly presented and discussed by the authors in the discussion. We really appreciate your time for this review. We hope that after the modifications suggested by the reviewers, the article will be suitable for publication. Thank you very much.

Please delete „were excluded“ in line 87 Thank you for the comment. The word "excluded" was really inappropriate. We changed it to "removed". Thank you. Line 65

Attachment

Submitted filename: Reviewer_Table.docx

Click here for additional data file. (20.9KB, docx)

Decision Letter 1

Osama Farouk

4 Nov 2020

Percutaneous Chevron/Akin (PECA) versus open scarf/Akin (SA) osteotomy treatment for hallux valgus: a systematic review and meta-analysis

PONE-D-20-20197R1

Dear Dr. Stefani,

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

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Osama Farouk

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

Reviewer #2: All comments have been addressed

**********

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

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: I Don't Know

**********

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

Reviewer #2: Yes

**********

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

Reviewer #2: Yes

**********

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: The authors have addresses all the concerns. I believe that the paper can be published in its current form.

Reviewer #2: (No Response)

**********

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.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

Acceptance letter

Osama Farouk

16 Dec 2020

PONE-D-20-20197R1

Percutaneous Chevron/Akin (PECA) versus open scarf/Akin (SA) osteotomy treatment for hallux valgus: a systematic review and meta-analysis

Dear Dr. Stefani:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Osama Farouk

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Checklist. PRISMA 2009 checklist.

    (DOC)

    Click here for additional data file. (64.5KB, doc)
    Attachment

    Submitted filename: Reviewer_Table.docx

    Click here for additional data file. (20.9KB, docx)

    Data Availability Statement

    All relevant data are within the manuscript and its Supporting information files.

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