Comparing sutures versus staples forskin closure after orthopaedic surgery:systematic review and meta-analysis

Rohin Krishnan, S Danielle MacNeil, Monali S Malvankar-Mehta

To cite: Krishnan R,MacNeil SD, Malvankar-Mehta MS. Comparingsutures versus staples forskin closure after orthopaedicsurgery: systematic reviewand meta-analysis. BMJ Open2016;6:e009257.doi:10.1136/bmjopen-2015-009257

▸ Prepublication historyand additional material isavailable. To view please visitthe journal (http://dx.doi.org/10.1136/bmjopen-2015-009257).

Received 29 June 2015Revised 22 September 2015Accepted 23 October 2015

Department of Epidemiologyand Biostatistics, WesternUniversity, London, Ontario,Canada

Correspondence toRohin Krishnan;rkrishn6@uwo.ca

ABSTRACTObjective: To determine whether there still remains asignificant advantage in the use of sutures to staplesfor orthopaedic skin closure in adult patients.Design: Systematic Review/ Meta-Analysis.Data sources: MEDLINE-OVID, EMBASE-OVID,CINAHL and Cochrane Library. Grey and unpublishedliterature was also explored by searching: InternationalClinical Trial Registry, Grey Matters BIOSIS Previews,Networked Digital Library of Theses and Dissertations,ClinicalTrials.gov, UK Clinical Trials Gateway, UKClinical Research Network Study Portfolio, Open Grey,Grey Literature Report, and Web of Science.Selection criteria: Articles were from any country,written in English and published after 1950. We includedall randomised control trials and observational studiescomparing adults (≥18 years) undergoing orthopaedicsurgery who either received staples or sutures for skinclosure. The primary outcome was the incidence ofsurgical site infection. Secondary outcomes includedclosure time, inflammation, length of stay, pain, abscessformation, necrosis, discharge, wound dehiscence,allergic reaction and health-related quality of life.Results: 13 studies were included in our cumulativemeta-analysis conducted using Review Manager V.5.0.The risk ratio was computed as a measure of thetreatment effect taking into account heterogeneity.Random-effect models were applied. There was nosignificant difference in infection comparing sutures tostaples. The cumulative relative risk was 1.06 (0.46 to2.44). In addition, there was no difference in infectioncomparing sutures to staples in hip and knee surgery,respectively. Lastly, except for closure time, there wasno significant difference in secondary outcomescomparing sutures to staples.Conclusions: Except for closure time, there was nosignificant difference in superficial infection andsecondary outcomes comparing sutures to staples wasfound. Given that there may in fact be no difference ineffect between the two skin closure and themethodological limitations of included studies, authorsshould begin to consider the economic and logisticimplications of using staples or sutures for skin closure.PROSPERO registration number: CRD42015017481.

INTRODUCTIONIn the context of orthopaedic surgery, surgi-cal site infection (SSI)—defined as the

occurrence of wound infection followingsurgery1 2—are frequent postoperative com-plications that represent 20% of all nosoco-mial infections. SSIs are clinically classified asthe occurrence of infection affecting eitherthe superficial or deep incision sites within30 days postoperatively or within 1 year ifan implant is left inside the patient.1

Orthopaedic SSIs are frequent postoperativecomplications that represent 20% of all noso-comial infections. In addition, orthopaedicSSIs have been shown to extend postoperativehospital stay, double hospital readmissionrates and increase annual healthcare costs upto 300%.1–4 Unfortunately, orthopaedic SSIsalso inflict a tremendous burden on thepatient, often increasing physical limitationsand reducing postoperative quality of life.4 5

In response to the critical need to reducethe incidence of SSIs, a wealth of researchhas been published identifying effective pre-operative, intraoperative and postoperativestrategies to reduce the incidence of SSIs.1

Preoperative strategies include increasinghost immune status, prophylactic antibioticadministration and proper sterilisation of thepatient and all surgical staff.6 During surgery,it is imperative that the surgical environmentis properly ventilated, all surgical equipmentare sterilised, and the use of proper surgicaltechnique is employed.6 Postoperatively,

Strengths and limitations of this study

▪ Systematic review and meta-analysis (SRMA)completed with high methodological rigour.

▪ Compared with a previous SRMA, we found nosignificant difference comparing sutures tostaples across all outcomes and subgroups.

▪ Poor quality of evidence, and significant hetero-geneity in effect across included studies.

▪ Owing to lack of data, our SRMA did not capturethe effect of suture material and/or surgeon skill,which could be a potential unmeasuredconfounder.

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incisions should be properly wrapped with sterile dress-ing and proper sterile techniques should be used duringdressing changeover.6

With the increased pressure on orthopaedic surgeonsto promote rapid wound healing, reduce postoperativelength of stay (LOS) and complications, the method ofskin closure during surgery has become increasinglyimportant.7–9 The optimal goal of skin closure, ‘is topromote rapid skin healing and an acceptable cosmeticresult while minimising the risk of dehiscence or infec-tion’.7 In orthopaedic surgery, the most common skinclosure methods are the use of staples or sutures.7 10 11

Yet, there seems to be no consensus in the literature asto which closure method is superior, with some studiesreporting no difference and others reporting a higherwound complication rate following the use ofstaples.9 12–15

A systematic review and meta-analysis (SRMA), pub-lished in 2009, compared the efficacy of sutures tostaples after orthopaedic surgery.7 They reported thatthe risk for postoperative infection was over three timesgreater in patients who receive staples for skin closure ascompared with those who receive sutures.7 Yet, due tosmall sample sizes, noticeable heterogeneity in effectsize across outcomes, and lack of methodological rigourwithin studies, called for additional research in thisarea.7–10 12 15–17

Consequently, in response to the paucity of informa-tion and continuing discrepancy of results, numerousobservational studies and RCTs have been publishedwithin the past 6 years comparing methods of skinclosure after orthopaedic surgery. Therefore, theprimary aim of our study is to perform an updatedSRMA, and to investigate whether there still remains anadvantage in the use of sutures to staples for ortho-paedic skin closure.

METHODSSearch strategyWe searched MEDLINE-OVID, EMBASE-OVID,CINAHL and Cochrane Library from 1950 to January2015 (see online supplementary appendix A for detailedsearch strategy pertaining to each databases). Grey andunpublished literature was also explored by searching:International Clinical Trial Registry, Grey Matters,BIOSIS Previews, Networked Digital Library of Thesesand Dissertations, ClinicalTrials.gov, UK Clinical TrialsGateway, UK Clinical Research Network Study Portfolio,Open Grey, Grey Literature Report, and Web of Science.The following databases were searched within the Webof Science platform: Web of Science Core Collection,BIOSIS Previews, KCI-Korean Journal Database,MEDLINE, SciELO Citation Index, and ZoologicalRecord. Conference Proceedings were indexed withinthe Web of Science Core Collection database search. Nolanguage or date of coverage restrictions was placed onall searches. Lastly, on completion of levels 1, 2 and 3

screening, forward and backward citation searches weredone to assure no studies were mistakenly omitted fromour search strategy. A review protocol was submitted andapproved with PROSPERO on 10 March 2015, andapproved on 12 March 2015 (registration number:CRD42015017481). The search strategy was designed toaccommodate for database and platform-specific termin-ology, and syntax. A detailed search strategy includingMeSH terms, keywords and Boolean operators can befound within the online supplementary appendix.

Population, Intervention, Comparator, Outcomes andStudy DesignThe Population, Intervention, Comparator, Outcomesand Study Design (PICOS) were adopted from Smithet al.7 Articles were from any country, written in Englishand published after 1950. We included all randomisedcontrol trials and observational studies (not an editorial,opinion, case report or a review article) comparingadults (≥18 years) undergoing orthopaedic surgery(trauma or elective) who either received staples orsutures (excluding skin adhesives, barbed sutures andsurgical zipper) for skin closure. The primary outcomewas the incidence of SSI after orthopaedic surgery.Secondary outcomes included closure time, inflamma-tion, LOS, patient satisfaction, pain, abscess formation,necrosis, discharge, wound dehiscence, allergic reactionand health-related quality of life (HRQoL). This studyhas been reported according to the PRISMAguidelines.18

Study selectionA total of 947 studies were identified and imported intoEPPI V.4.0 Reference Manager. As per the prespecifiedsearch strategy, 280 studies were retrieved through rele-vant database searches and an additional 667 studiesretrieved from grey literature searches and various clin-ical trial registries. After removing 216 duplicates, 731articles underwent title screening. Studies were excludedif they were not, human (n=4), not a research study(n=11), and if they did not look at orthopaedic surgery(n=84) or skin closure (n=511). On completion of level1 screening, 610 studies were excluded and 121 wereincluded for level 2 (abstract) screening. Studies wereexcluded if they did not directly compare sutures tostaples for skin closure (n=102). Nineteen studies wereeligible for full-text screening. Articles were excluded if:they were not English (n=1), the results were notpublished (n=1), the studies had not yet completed(n=2; International Clinical Trial Registry: (1)TCTR20140312001 and (2) NTR3946) and if one couldnot differentiate results from orthopaedic and non-orthopaedic groups (n=1). Contact with authors wereattempted to obtain English manuscripts, and anyunpublished results or interim data. Two independentreviewers (RK and SDM) assessed articles for eligibility;κ statistics were calculated to assess reviewer agreementon the completion of levels 1 and 2 screening.

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Additionally, all disagreements were corrected throughnegotiated consensus. The agreement between reviewersfor levels 1 and 2 screening was: 0.50 and 0.85, respect-ively. A detailed PRISMA flow chart outlining thenumber of studies screened for eligibility, and reasonsfor exclusion are provided in figure 1. Specific screeningquestions are provided in the online supplementaryappendix.

Data extractionRelevant quantitative and qualitative data necessary foradequate study comparison and analysis was abstractedby a reviewer (RK). Information on study objective,design, operation type, closure material, sample size, age(mean), sex ratio, time to removal, follow-up, infection,closure time, inflammation, LOS, patient satisfaction,pain, abscess formation, necrosis, discharge, wounddehiscence, allergic reaction and HRQoL was collected.All outcomes were prespecified within PROSPERO.

Risk of bias assessmentStudies were critically appraised for adequate randomisa-tion, allocation concealment, baseline similarity, blind-ing, follow-up completion and intention-to-treat (ITT)analysis. Subsequently, using the Grading ofRecommendations, Assessment, Development, andEvaluation (GRADE) guidelines, included articles were

used to assign an overall grade of either high, moderate,low quality of evidence for infection.19–22

Summary measures and statistical analysisStatistical analysis was conducted using Review ManagerV.5.0.23 Dichotomous outcomes were reported as riskratios and continuous outcomes as mean differences(MDs). All analyses were conducted using theMantel-Haeszel random-effects model. Heterogeneity wasassessed using the χ2 and I2. All results were reported at asignificance level of 0.05, and 95% CI was provided.Stratification of infection based on surgery type has beenprespecified, and a funnel plot was calculated to assesspublication bias. In addition, ITT analysis was performedin studies in which results were reported ‘as per protocol’.Subsequently, sensitivity analysis was performed, account-ing for studies in which there was lost to follow-up.

RESULTSStudy selectionThirteen studies were included in our cumulativemeta-analysis (table 1).8–10 12 15–17 24–29 All articles werepublished between 1990 and 2015. The cumulativesample size of all studies was 563 patients within thesuture group, and 692 patients within the staple group.Ten studies were randomised controlled trials and threewere observational studies.8 26 29

Figure 1 PRISMA flow

diagram.33

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Table 1 Baseline characteristics

Study

Study

type Date Operation Closure material

Wounds Age (mean) Sex (male) Time to

removal

Follow-up

(days)Staples Sutures Staples Sutures Staple Suture

Stockley and

Elson15RCT 1987 THR, hip and knee

ORIF, TKR

Nylon suture, skin

staples

66 63 Not provided 10–16 3|7|14|365

Clayer and

Southwood12RCT 1991 THR, hip fracture

surgery

Subcuticular

polypropylene; skin

staples

33 33 75.9 75.4 10/33 11/33 10–14 56–84

Liew and Haw24 RCT 1993 Hip, knee, ankle, arm,

back (specific details

not provided)

3/0 Nylon, skin

staples

19/23

ITT

18/23

ITT

Not provided 28 24

Graham et al25 RCT 2000 TKR 4/0 Vicryl suture, skin

staples

10 10 Not

provided

(range

61–82)

Not

provided

(range

57–83)

1/10 1/10 Not

provided

3|7

Murphy et al16 RCT 2004 Fixation of ankle, tibia,

patella, femur, forearm,

olecranon and

humerous

Nylon suture, skin

clips

31 29 Not provided 13 13

Shetty et al10

(calculations used

intention to treat)

RCT 2004 Femoral Fracture Subcuticular vicryl

suture, metallic

staples

54/55

ITT

47/55

ITT

83.5 81.7 13/54 7/47 10 10

Khan et al9 RCT 2006 TKR, THR 3.0 Subcuticular

absorbable

poliglecaprone

suture, skin staples

63 64 Not provided 30/63 33/64 10 56–84

Singh et al8 PC 2006 Femoral neck fracture

correction

Subcuticular vicryl,

skin clips

41 30 85.4 82 7/41 6/30 10 2|5|7|10|14

Eggers et al28 RCT 2011 TKR Vicryl 2.0 sutures,

stainless steal staples

19 19 71 67 Not provided 1|21|42

Newman et al26 RC 2011 TKR Subcuticular

absorbable suture,

staples

82 99 60 59 Not provided

Patel et al29 RC 2012 TKR, THR, knee and

hip hemiarthroplasty

3-0 Biosyn, staples 181 51 Not provided 14|28|56

Slade Shantz

et al17RCT 2013 Upper extremity, hip,

knee, ankle surgery

Staples, absorbable

subcuticular, and

non-absorbable

suture

79/93

(ITT)

69/97

(ITT)

52 52 Not provided 14–42

Wyles et al27 RCT 2015 TKR 3-0 Monocryl and 2-0

nylon, staples

15 30 69 70.5 5/15 10/30 14 14–84

Baseline characteristics of all included studies. All missing information are omitted in black.ITT: sample size when considering intention to treat.ORIF, fraction open reduction, internal fixation; PC, prospective cohort; RC, retrospective cohort; RCT, randomised controlled trial; THR, total hip arthroplasty; TKR, total knee arthroplasty.

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Study characteristicsSeven studies provided data on the mean age of patientswithin each group.8 10 12 17 26–28 Using sample sizeweights, the overall mean age among the staple andsuture groups were 68 and 66 years, respectively. Sixstudies provided data on the distribution of sex withineach group.8–10 12 25 27 Among the 216 patients whoreceived staples, there were 66 males and 150 females.Additionally, among the 214 patients within the suturegroup, there were 68 males and 146 females. The major-ity of studies focused on lower extremity orthopaedicoperations. Surgeries ranged from total knee arthro-plasty; total hip arthroplasty; hip fracture surgery; kneefracture surgery; and miscellaneous ankle, tibia, patella,olecranon and humerus fracture corrections. Of theseven articles that included more than one surgery type,only three studies stratified the results based on proced-ure.9 15 29 Six studies did not report suture and stapleremoval time.17 24–26 28 29 In the 12 papers that providedthe relevant data, the overall time to removal was consist-ent across all studies and ranged from 10 to 16 days.One study did not report suture and staple follow-uptime.26 Among the rest, there was considerable variationin postoperative follow-up, ranging from 3 to 365 days.

There was some variation in suture material. The mostcommon materials used were Nylon and Vicryl.A summary of all baseline characteristics abstracted fromincluded studies can be found in table 1.

Risk of bias assessmentA risk of bias assessment of all 13 studies showed consid-erable variation in study quality (table 2). Two studieswere retrospective chart reviews,26 29 1 study was aprospective cohort8 and 10 studies were randomisedcontrolled trials.9 10 12 15–17 24 25 27 28 Of the 10 RCTs, 2study did not appropriately randomise patients,12 15

5 studies did not perform or clearly report allocationconcealment,12 15 16 24 25 and 5 studies did not providebaseline characteristics10 15 16 24 25 In addition, sevenstudies did not blind patients10 12 15 16 24 25 27 and sixstudies did not perform or did not clearly report ITTanalysis.10 16 17 24 25 28 However, among all included arti-cles, only six did not complete or adequately reportfollow-up.15–17 24 25 29 Despite the low quality, all studieswere included in the analysis. Lastly, with respect to ourprimary outcome of infection, an overall grade of ‘verylow quality’ was assigned due to the considerable

Table 2 Critical appraisal of included studies

Were the patients similar at the start?

Study Randomisation Allocation concealed Baseline characteristics similar

Stockley and Elson15 X X ?

Clayer and Southwood12 X X ✓Liew and Haw24 ✓ ? ?

Graham et al25 ✓ ? ?

Murphy et al16 ✓ ? ?

Shetty et al10 ✓ ✓ ?

Khan et al9 ✓ ✓ ✓Singh et al8 X X ✓Eggers et al28 ✓ ✓ ✓Newman et al26 X X ?

Patel et al29 X X ?

Slade Shantz et al17 ✓ ✓ ✓Wyles et al27 ✓ ✓ ✓

Were the patients similar throughout?

Study Blinding Follow-up complete Intention-to-treat analysis

Stockley and Elson15 X ? ✓Clayer and Southwood12 X ✓ ✓Liew and Haw24 X X ?

Graham et al25 X ? ?

Murphy et al16 X X X

Shetty et al10 X ✓ X

Khan et al9 ✓ ✓ ✓Singh et al8 X ✓ X

Eggers et al28 ✓ ✓ ✓Newman et al26 X ✓ X

Patel et al29 X ? X

Slade Shantz et al17 ✓ X X

Wyles et al27 X ✓ ✓

Critical appraisal assessing treatment randomisation, baseline allocation concealment, baseline characteristics similarity, blinding, follow-upcompletion and intention-to-treat analysis. Checkmarks indicates the presence of each factor, X’s lack thereof, and question marks indicateunclear reporting.

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amount of imprecision, inconsistency and indirectnessamong the evidence (table 3).

Primary outcome: infectionAll studies provided information on infection amongpatients receiving sutures and staples for skin closure(table 4). Wound infection comparing sutures to stapleswas insignificant, with a cumulative relative risk (RR) of1.06 (95% CI 0.45 to 2.44); figure 2).

Secondary outcomes1. Dehiscence: Seven studies provided data on wound

dehiscence.8 10 12 16 26 28 29 The cumulative risk ratiowas insignificant, with a RR of 0.96 (0.32 to 2.84;table 4 and figure 3).

2. Inflammation, discharge, necrosis, allergic reaction abscessformation: There was no significant difference ineffect comparing sutures to staples across all of theseoutcomes (table 4).

3. Pain: Two studies measured pain.15 17 Slade Shantzet al17 assessed pain using the 100 mm pain scale,and Stockley and Elson15 noted 31 cases ofreported pain among removal of staples as com-pared to seven cases of reported pain within thesuture group. Although no inferential statistics wasused, it seems that staples may be more painful toremove than sutures.

4. Closure time: Four studies provided information onclosure time.9 17 24 28 However, only within twostudies was mean closure time provided or calcul-able.17 28 The cumulative MD was significant, with aMD of 5.84 (4.52 to 7.15) comparing suture andstaple groups. Qualitatively, Liew and Haw24 notedthat wound closure was approximately 7 times fasterwith staples compared with sutures. No inferentialstatistics was used. Lastly, Khan et al9 noted thatclosure time was faster using skin clips comparedwith sutures. Data were reported as the median and

Table 3 Grade assessment for overall quality of evidence with respect to infection

Number of participants

(studies)

Follow-up Risk of bias Inconsistency Indirectness Imprecision Publication bias

Overall

quality of

evidence

Infection (follow-up: range 365 days)

761

(10 RCTs)

Serious1–6 Not serious7 Not serious8 Serious9 Publication bias

strongly suspected10⊕◯◯◯Very low

Infection (follow-up: range 365 to)

484

(3 observational studies)

Serious1 Serious7 Not serious8 Serious9 Publication bias

strongly suspected

⊕◯◯◯Very low

GRADE evaluation for overall quality of evidence. Included studies are separated into clinical trials and observational studies. Overall,included studies are of very low quality. Explanations for risk of bias, inconsistency, indirectness, imprecision and publication bias areprovided below.1. Singh et al,8 Newman et al,26 Patel et al29 were observational studies (no randomisation, allocation concealment, blinding).2. Clayer and Southwood and Stockley et al did not truly randomise (randomised based on unit number and date of birth).3. Of the randomised trials, six studies did not report or conceal allocation.4. Of the randomised trials, seven studies did not blind (patient or assessor) to the treatment (staples or sutures).5. For seven studies, completion of follow-up for all patients was not clearly reported or did not occur.6. For two studies infection was not the primary outcome.7. I2 value <75%.8. All studies included in the meta-analysis directly compare sutures to staples.9. Very few events occurred in suture and staple treatment arms resulting in very large confidence intervals.10. One study did not publish results and was excluded from our systematic review/ meta-analysis.GRADE, Grading of Recommendations, Assessment, Development, and Evaluation; RCT, randomised controlled trial.

Table 4 Primary and secondary outcomes comparing suture to staples for skin closure after orthopaedic surgery

Incidence Heterogeneity

Outcome Sutures Staples Relative risk (95% CI p Value I2 (%) χ2 (p Value)

Infection8–10 12 15–17 24–29 17|563 21|692 1.06 (0.46 to 2.44) 0.89 18 0.27

Dehiscence8 10 12 16 26 28 29 6|308 21|441 0.96 (0.32 to 2.84) 0.94 0 0.50

Inflammation8 16 3|59 22|72 0.22 (0.00 to 12.07) 0.46 84 0.01*

Discharge8 9 16 8|123 17|135 0.66 (0.14 to 3.23) 0.61 58 0.09

Necrosis15 16 1|92 3|97 0.51 (0.07 to 3.88) 0.52 0 0.43

Allergic reaction9 15 26 2|226 1|211 1.37 (0.22, 8.60) 0.74 0 0.59

Abscess10 29 2|115 2|244 1.86 (0.22 to 15.71) 0.57 0 0.37

Mean difference (95% CI)

Closure time17 28 (min) Sutures vs staples 5.84 (4.52 to 7.15) < 0.001 0 0.55*

Primary and secondary outcomes comparing sutures to staples for skin closure after orthopaedic surgery. All outcomes (95% CI) arecalculated using the Mental-Haeszel random-effects model. Heterogeneity is calculated using the I2 statistic. χ2 significance level dictateswhether the heterogeneity between studies is significant (*p<0.05).

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IQR and thus, could not be used for the cumulativeeffect estimate.

5. Length of stay: Two studies reported LOS.9 28 However,Eggers et al28 and Khan et al9 reported LOS as mean(CI) and median (IQR) days, respectively. Normalitywas not assumed, and the data was not combined.Qualitatively, there is no noticeable difference amongpatients who receive staples or sutures.

6. HRQoL: Only one study administered the ShortForm-36, a generic HRQoL questionnaire withinsuture and staple groups.28 There was no differencein HRQoL across all subscales.

Sensitivity analysisThree randomised controlled trials reported results asper protocol. We adjusted the results according to ITTand performed a sensitivity analysis to examine theoverall RR of infection. Accounting for lost to follow-up,the RR of infection remained insignificant (table 5,figures 4 and 5).

Subgroup analysis1. Hip surgery: Six studies provided data comparing infec-

tion between patients receiving sutures to staples afterhip surgery.8–10 12 15 29 The cumulative sample sizewas 164 and 245 patients in the suture and staplegroup, respectively. The cumulative risk ratio was insig-nificant, with a RR of 0.48 (0.10 to 2.45; figure 6).

2. Knee surgery: Seven studies provided data comparinginfection between patients receiving sutures to staplesafter knee surgery.9 15 25–29 The cumulative samplesize was 239 and 263 patients in the suture and staplegroup, respectively. The cumulative risk ratio was insig-nificant, with a RR of 1.38 (0.42 to 4.52; figure 7).

Publication biasPublication bias was assessed using a funnel plot for ourprimary outcome of infection (figure 8). The funnel forstudies was not fully symmetrical. Included studies werescattered throughout the bottom and top right corner ofthe plot. Yet, there seems to be some evidence formissing studies as seen by the empty space in the top leftcorner. Nevertheless, publication bias can be suspectedbut cannot be concluded based on this plot. The reasonfor difficulty in interpretation is mainly due to the smallgroup of studies and high heterogeneity and small effectsize. In addition, publication bias can be one of manypossible explanations for our funnel plot asymmetry.

DISCUSSIONAs compared with the systematic review and meta-analysispublished in 2009,7 we found no significant difference ininfection among patients who receive staples and suturesfor skin closure. Although there was no significant

Figure 2 Forest plot of the cumulative risk ratio (95% CI) of wound infection comparing patients who received staples or sutures

for wound closure after orthopaedic surgery. Analysis conducted with Mantel-Haenzel random-effects model.

Figure 3 Forest plot of the cumulative risk ratio (95% CI) of wound dehiscence comparing patients who received staples or

sutures for wound closure after orthopaedic surgery. Analysis conducted with Mantel-Haenszel random effects model.

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heterogeneity across all studies (p>0.05), there was somenoticeable variation in magnitude and direction of effect(figure 1). In addition, our study also showed no signifi-cant difference in dehiscence, inflammation, discharge,necrosis, allergic reaction, and abscess formation. Threestudies did not report results as per ITT. Sensitivity ana-lysis was conducted following ITT analysis. Two scenarioswere created accounting for two logical extreme cases.Scenario 1 assumes all lost to follow-up within the suturegroup had infection, and patients who received staplesdeveloped no infection. Conversely, scenario 2 assumesall patients who were lost to follow-up within the staplecohort received infection and no patient experiencedinfection in the suture group. The risk of infection com-paring sutures to staples within scenarios 1 and 2 wasinsignificant, further strengthening our conclusion of nosignificant difference in infection risk between suturesand staples. However, it is important to note that themagnitude of effect was large within both scenarios(figures 4 and 5; table 5), suggesting that our sensitivityanalysis may have been underpowered to detect a signifi-cant difference.Subgroup analysis was also performed comparing the

effect of sutures and staples on infection, stratified bysurgery type. Limitations on available data allowed us toonly analyse the effect of infection comparing hip andknee surgery only. There was no significant difference inthe incidence of infection across both surgery types. Inhip surgery, the results suggested a potential protectiveeffect of the use of sutures against infection. The hetero-geneity across studies was insignificant and the majorityof studies favoured staples for skin closure (figure 6).The insignificant, large magnitude of effect suggests thatour study may have been underpowered to detect a sig-nificant difference. Nevertheless, our result lendssupport to the conclusions by Smith et al7 in which theyreported patients who undergo hip surgery and receivestaples may have a higher risk for developing post-operative infection. In contrary, within knee surgery,there was considerable variation in direction of effectacross both groups (figure 7). The use of sutures waspotentially harmful, with a RR of 1.38 (0.42 to 4.52).However, caution must be given to the interpretation ofresults in this particular group due to the significant het-erogeneity in magnitude and direction of effect betweenstudies. With respect to patient-centred outcomes, onlytwo studies measured patient-reported pain.15 17

Unfortunately, the results from both studies could notbe combined quantitatively. However, based on qualita-tive analysis, there seems to be trend that staples causemore pain on removal than sutures. This trend is consist-ent with non-orthopaedic surgeries.30–32

Given that there may be no significant difference inthe use of staples or sutures for skin closure, potentiallogistic and economic implications should also consid-ered. Within our study, four articles measured closuretime.9 17 24 28 However, only two studies could be quanti-tatively synthesised.17 28 The MD of closure time (min)

Table

5Sensitivityanalysis

Sensitivityanalysis

FollowingITTanalysis

Initially

randomised

Lostto

follow-up

Deaths

Perprotocol

sample

size

Perprotocol

Favouringsutures

(worstcasestaples)

Favouringstaples

(worstcasesutures)

Study

Sutures

Staples

Sutures

Staples

Sutures

Staples

Sutures

Staples

Relativerisk

Relativerisk(95%

CI)

Relativerisk(95%

CI)

SladeShantz

etal17

97

93

28

14

00

69

79

1.14(0.07to

17.96)

0.06(0.01to

0.47)

27.80(3.87to

200)

Liew

and

Haw24

23

23

14

21

19

18

2.85(0.12to

65.74)

0.25(0.03to

2.07)

5.0

(0.25to

98.75)

Shettyetal10

55

55

00

81

47

54

0.10(0.01to

1.84)

0.09(0.01to

1.61)(nolossto

follow-up)

Sensitivityanalysis

fortherelativeriskofinfection.Adjustedstudieswere

thosewhodid

notfollow

ITTprotocolandhadlostto

follow-up.Adjustedrelativeriskswere

calculatedfortwo

scenarios.Scenario1:alllostto

follow-uphadinfectionin

suture

group,andnonein

staple

group.Scenario2:alllostto

follow-uphadinfectionin

staple

group,andnonein

thesuture

group.

Originalrandomisedtreatm

entsizeswere

usedforadjustedrelativeriskcalculations.

ITT,intentionto

treat.

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comparing sutures to staples was 5.84 (4.52 to 7.15). Theresults do suggest that staples may be slightly faster touse compared with sutures for skin closure. Slade Shantzet al17 reported an estimated 7 min time savings with theuse of staples for skin closure. If an average orthopaedicsurgeon were to perform five surgeries per day, the useof staples could save an estimated 35 min of operativetime potentially reducing overscheduling and hospitalcosts.17 28 Liew and Haw24 also noted that the use ofstaples for skin closure was approximately 7 times fasteras compared with sutures. However, the potential utilityof staples for skin closure may still be a false economydriven by surgeon perception and bias.7 The use ofstaples has always been noted as a ‘more expensivemethod’ for skin closure as compared with usingsutures.15 16 In addition, the number dressing changesrequired for patients who undergo skin stapling is muchhigher than those who undergo suturing.7

Consequently, the savings in intraoperative costs couldbe negated by costs in dressing changes and staple/applicator costs. To our knowledge, no formal cost-benefit analysis has been done comparing the use of

sutures and staples for orthopaedic surgery. Other eco-nomical considerations include difference in LOS com-paring sutures to staples. A shorter LOS can result inshorter postoperative costs, inpatient care, physicaltherapy and pharmaceuticals.28 Additionally, Eggerset al28 noted that the level of wound cosmesis might alsoaffect LOS, such that a shorter LOS may be partly dueto a higher emotional satisfaction predicated on a morecosmetically appealing incision.In our study, there seems to be no noticeable differ-

ence in LOS comparing sutures to staples. However, it isimportant to note that only two studies analysed LOS,and our conclusions are solely speculative.A major limitation of our SRMA is the substantially

low quality of evidence and considerable heterogeneityacross studies. Of the 13 studies included, 7 studies didnot provide baseline characteristics.10 15 16 24–26 29 Thus,we could not conclusively establish that patients betweengroups were similar across all confounders for infectionsuch as age, body mass index and comorbidity burden.7

Another potential limitation is that we included twostudies in which comparing wound complications

Figure 4 Forest plot indicating the adjusted relative risk (RR; 95% CI) of infection within scenario 1: all lost to follow-up had

infection in the suture group, thus favouring staples. Original randomised treatment sizes were used for RR calculations.

Cumulative effect was calculated using the Mantel-Haenzel random-effects model.

Figure 5 Forest plot indicating the adjusted relative risk (RR; 95% CI) of infection within scenario 2: all lost to follow-up had

infection in the staple group, thus favouring sutures. Original randomised treatment sizes were used for RR calculations.

Cumulative effect was calculated using the Mantel-Haenzel random-effects model.

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between sutures and staples was not the primary object-ive.25 27 One study which was published in the year 2000was captured by the previous systematic review/meta-analysis.7 The authors noted that the study wasexcluded because comparing the incidence of woundcomplications was not the primary objective. However,for the purposes of our SRMA, the two studies wereincluded because they effectively randomised patients tosuture and staple treatments. In addition, information onpostoperative infection was reported within both studies.In addition, no information was available evaluating

specific suture techniques, or surgeon skill. Murphyet al16 suggested that poor surgical technique andaccuracy of suture or staple closure can have an effect

on wound healing. However, it is unclear whethersuturing technique is confounder with respect to post-operative wound complications.7 Second, the majorityof studies did not specify whether infections weresuperficial or deep. Superficial infections typicallyrequire the administration of antibiotics while deepinfections require more severe courses of treatment.7

The strengths of our study are twofold. First, our SRMAwas completed with high methodological rigour. All ofour outcomes and subgroup analysis were prespecifiedand our study was registered with PROSPERO prior todata extraction. Second, in contrast to Smith et al,7 wefound no significant difference comparing sutures tostaples across all post-operative complications and sub-groups; suggesting that there may be no clinically relevantdifference in effect between the two skin closure methodswithin this population.Future studies should focus on conducting high-

quality randomised control trials. Detailed baselinecharacteristics, and a detailed patient recruitment flowchart should be presented. In addition, authors shouldremove themselves from ‘as per protocol’ analysis andconvey results according to the ITT principle. Second,our study failed to capture two large randomised con-trolled trials because they had not yet been completed.Thus, future SRMAs should be conducted comparingthe use of sutures to staples for skin closure.

Acknowledgements The authors would like to thank Mr John Costella for hisdedication and guidance. Without his help, this project would not be possible.

Contributors All authors had made impactful contributions to the manuscriptsubmitted. RK is the primary author of said manuscript. He made substantialcontributions to the design of the work, acquisition of data, analysis/

Figure 7 Forest plot indicating relative risk (95% CI) within knee surgeries. Cumulative effect was calculated using the

Mantel-Haenzel random-effects model.

Figure 6 Forest plot indicating relative risk (95% CI) within hip surgeries. Cumulative effect was calculated using the

Mantel-Haenzel random-effects model.

Figure 8 Funnel plot examining potential publication bias for

incidence of wound infection after orthopaedic surgery (RR,

relative risk).

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interpretation, and writing the manuscript. SDM played an integral role inselecting included studies during the screening process. She providednecessary guidance, support and mentorship throughout the whole process.She was involved in study design, statistical analysis and revising intellectualproperty. MSM-M played an integral role for this study. She providednecessary guidance, support and mentorship throughout the whole process.She was involved in study design, statistical analysis and revising theintellectual property.

Funding This research received no specific grant from any funding agency inthe public, commercial or not-for-profit sectors.

Competing interests None declared.

Provenance and peer review Not commissioned; externally peer reviewed.

Data sharing statement No additional data are available.

Open Access This is an Open Access article distributed in accordance withthe Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license,which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, providedthe original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

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