Comparison of the clinical outcomes of Scarf and Chevron Osteotomy for Hallux Valgus Deformity: a meta-analysis of randomized controlled trial

Background Scarf and Chevron Osteotomy have been widely used for Hallux Valgus Deformity(HVD) to correcting hallux valgus angle (HVA) and intermetatarsal 1-2 angle (IMA), but there still have controversy which approach is the best way to repair HVD,this study aims to use meta-analysis to evaluate the clinical outcomes of Scarf and Chevron Osteotomy for Hallux Valgus Deformity.Methods Pubmed, Embase, Medline and Cochrane library databases were searched for relevant studies published before September 1, 2019. Studies clearly reporting a comparison of Scarf and Chevron Osteotomy for Hallux Valgus Deformity were selected. The Post-operative hallux valgus angle (HVA) and intermetatarsal 1-2 angle (IMA) were evaluated and also the correction of HVA and IMA. The weighted mean differences and relative risks were calculated using a xed-effects or random-effects model.Results Five studies were included in this meta-analysis,one were prospective randomized controlled trials and three were randomized control trials.A total of 434 patients (210 Scarf and 224 Chevron) were enrolled in the studies.Compare Scarf Osteotomy,Chevron Osteotomy can signicantly decreaseed Post-operative hallux valgus angle (HVA)[MD = 1.92 95% CI (1.21 to 2.63),P < 0.0001],but there have no signicantly difference between Scarf and Chevron Osteotomy groups in terms of Postoperative intermetatarsal angle (IMA),the correction of IMA and HVA(C-IMA/HVA),DMAA,AOFAS and complication incidence[MD = 0.42, 95% CI (-0.34 to 1.17),P=0.28;MD = -0.30, 95% CI (-0.72 to 0.12),P =0.16; MD = -0.88, 95% CI (-2.34 to 0.57),P =0.23;MD = -0.78, 95% CI (-2.29 to 0.72),P =0.31;MD IMA,but there previous compared Scarf Osteotomy and Chevron Osteotomy for hallux valgus deformity, we established this research to evaluated the difference of the two operations for HVD.Our results show that compared with the Scarf Osteotomy group,Chevron Osteotomy can signicantly decreaseed Post-operative HVA;in addition there have no signicantly difference between Scarf and Chevron Osteotomy groups in terms of Postoperative IMA,C-IMA/HVA,DMAA,AOFAS and complication incidence.The outcomes indicated that Chevron osteotomy could achieved better HVA degree compared Scarf osteotomy,but in some researches the results showed that scarf osteotomy was expected to correct moderate and severe hallux valgus better than chevron osteotomy. in our study only two articles different severity hallux valgus deformity,and one the into three subgroups base on the severity of hallux valgus,so we haven’t difference moderate and severe hallux valgus,but valgus future different


Background
As we all know Hallux Valgus Deformity(HVD) could be associated with persistent foot pain and result in foot dyfuction,which could increased the risk of osteoarthritis (OA) at the rst metatarsophalangeal joint,hallux valgus is a highly prevalent foot deformity estimated to affect 23% of adults and 35.7% of elderly individuals. [1][2][3][4] Numerous techniques include operation and non-operation methods have been described in the past decades to improve the patient's foot function and correct hallux valgus. 5,6 Although the selection of the method mostly depends on the severity of hallux valgus deformity,but Scarf and Chevron Osteotomy is become more and more popularised to repair HVD, a lot of previous studies have demonstrated that both Scarf and Chevron Osteotomy have positive effect on postoperative HVA and IMA. 7,8 However, there is a lack of consensus regarding which method is the better choice to repair HVD.So this study aims to use meta-analysis to evaluate the clinical outcomes of Scarf and Chevron Osteotomy in HVD surgery,in order to prevent the accuracy of the result,only randomized controlled trials(RCT) or prospective-RCT were included in nal analysis.

Search strategy
Pubmed, Embase, Medline and Cochrane library were searched independently by two investigators to retrieve relevant studies published before September 1, 2019. The search criteria "Scarf","Chevron","Osteotomy" and "Hallux Valgus Deformity"were used in key word searches. All studies selected were reviewed independently by the authors and examined for broadening the potential studies through the "related articles" function. Thus, the reference lists of the included articles were also manually checked to nd relevant studies that were not found during the database searches. (Fig 1.) Inclusion Criteria:1. Osteotomy procedure was used for hallux valgus deformity,not for other diseases.2.Study type was randomized controlled trials(RCT).3.Follow-up examination must include any one among the HVA,C-HVA,IMA,C-IMA,DMMA,AOFAS and complication outcomes.Exclusion Criteria:1.Osteotomy procedure was used for trauma or tumor diseases.2.Not Randomized controlled trials(RCT) or prospective-RCT,include retrospective trials.3.Animal or laboratory study.

Data Extraction
Each article's variables and outcomes of interest and assessment of the methodological quality were reviewed independently by two readers. If there was a difference of opinion, the problems were resolved through discussion and consensus. The methodological quality of the trials was assessed through the Cochrane Handbook for Systematic Reviews of Interventions 5.1.

Statistical Analysis
The statistical analysis was performed using Review Manager 5.1 for Windows System (Cochrane Collaboration, Nordic Cochrane Centre, Copenhagen, Denmark). Categorical dichotomous variables were analyzed with relative risks (RRs), continuous variables were assessed with the weighted mean difference, and P < 0.05 was considered statically signi cant; the 95% con dence intervals (CIs) were reported. Heterogeneity was considered signi cant if the P value was less than 0.1. The value of I 2 statistics was used to assess the degree of heterogeneity (I 2 < 25%, no heterogeneity; I 2 = 25-50%, moderate heterogeneity; I 2 > 50%, large or extreme heterogeneity); if I 2 > 50%, a xed-effects model was used. The presence of publication bias was assessed by a visual inspection of a funnel plot and the Begg and Egger tests (with P < 0.05 considered statistically signi cant).

Literature Search
The initial literature search retrieved 67 relevant articles (duplicates were discarded). After a careful screening of the titles, 25 articles were excluded for not investigating the topic of interest. After reviewing the abstracts,35 articles were excluded,leaving 7 studies for further full publication review. One study was excluded because it's retrospective article and one for the format of continuous variables outcome were not mean±SD.Therefore, ve studies matched the selection criteria and were suitable for meta-analysis. [9][10][11][12][13] They are all randomized control trials (Figure 1),a total of 434 patients (210 Scarf and 224 Chevron) were enrolled in the studies. The information of the included studies is summarized in Table 1

Discussion
In this study In order to keep the accuracy of the result,we only included randomized controlled trials(RCT) were into the nal analysis,and there have two articles described different severity of the hallux valgus deformity,but only one investigator divided the group into three subgroups base on the severity of hallux valgus and reported the outcomes data.So we haven't analysis the subgroups base on the severity of hallux valgus.Although there are a lot of studies reported Scarf Osteotomy or Chevron Osteotomy repaired hallux valgus deformity ,and both treatment have got positive effect on postoperative HVA and IMA,but there are few previous articles compared Scarf Osteotomy and Chevron Osteotomy for hallux valgus deformity, so we established this research to evaluated the difference of the two operations for HVD.Our results show that compared with the Scarf Osteotomy group,Chevron Osteotomy can signi cantly decreaseed Post-operative HVA;in addition there have no signi cantly difference between Scarf and Chevron Osteotomy groups in terms of Postoperative IMA,C-IMA/HVA,DMAA,AOFAS and complication incidence.The outcomes indicated that Chevron osteotomy could achieved better HVA degree compared Scarf osteotomy,but in some researches the results showed that scarf osteotomy was expected to correct moderate and severe hallux valgus better than chevron osteotomy. 14,15 Because in our study only two articles described different severity of the hallux valgus deformity,and one investigator divided the group into three subgroups base on the severity of hallux valgus,so we haven't evaluated the difference in moderate and severe hallux valgus,but we thought the classi cation of hallux valgus is necessary in the future researches which will indicate the effective of the different type of osteotomy procedures.
Hallux Valgus Deformity(HVD) is a common disease which could be associated with persistent foot pain and foot dyfuction,moreover it could increased the risk of others complication such as impaired gait patterns, osteoarthritis (OA) at the rst metatarsophalangeal joint (MTPJ),poor coordinated stability and increased risk of falls in older adult. 16 In order to solve these problems hundred techniques have been described for treatment of hallux valgus deformity,it is well known that quality of life (QoL) improves signi cantly following hallux valgus surgery. 17,18 And the treatment procedure chosen often depend on the severity of HVD, Kushioka et al establishied a retrospective observational of 76 rheumatoid arthritis cases (60 patients) followed for a mean of 35.3 months (range, 24to 56 months) through a modi ed Scarf osteotomy was performed,the results show that there was a signi cant improvement at nal followup, in the mean JSSF RA foot and ankle score and the mean JSSF hallux score. 19 And there have others studies considered that chevron osteotomy was also can be a safe method with good clinical outcomes and comparable to traditional open techniques for symptomatic mild-moderate hallux valgus. 20,21 So there is still remains controversial about which is the better procedure for moderate or sever hallux valgus deformity.
The most accepted method of assessing the severity of the hallux valgus deformity involves angular measurements on weight-bearing radiographs, speci cally the hallux valgus angle (HVA) and the rstsecond intermetatarsal angle (IMA). 22,23 AOFAS((American Orthopaedic Foot and Ankle Society) scores have been described in previous reports which could be an effective tool to evaluated the foot function. 24,25 In our study there have only two researches reported preoperative and postoperative AOFAS data,and the result show that there have no signi cant difference between Scarf and Chevron osteotomy,but there is need more data to support this result in the future.
According to the this meta-analysis of RCT, we were able to believe that Chevron osteotomy could achieved better HVA and C-HVA degree compared Scarf osteotomy.But there are still have some limitations in this meta-analysis. (1)The included studies are describe different severity of the hallux valgus deformity,which may cause bias to the results. (2) The Chevron and Scarf osteotomy procedure is not all the same standard by different surgeons,which affects the nal results. (3)The heterogeneity between the each study will also affect the accuracy of the nal results.(4) Lack of long-term follow-up outcomes may decrease the reliability of the results.Although this meta-analysis contains many limitations, the study is still powerful enough to guide future clinical work. Multicenter, prospective, randomized control trials with large sample sizes are needed in the future.

Conclusions
In conclusion, this meta-analysis suggests that compare Scarf osteotomy,Chevron Osteotomy can signi cantly decreaseed Post-operative hallux valgus angle (HVA) and other clinical outcomes are similar between the two treatments. Search strategy ow diagram.

Figure 2
Summarizes the methodological quality of the selected studies. All of the studies were RCT(Randomized Controlled Trails) with a high level of methodological quality. Thus, the methodological bias of this study was low.             Forest plot showing the OR difference in complication incidence between Scarf and Chevron osteotomy.

Supplementary Files
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