Negative pressure wound therapy compared with conventional wound dressings for closed incisions in orthopaedic trauma surgery: A meta-analysis.

We performed a meta-analysis to evaluate the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery. A systematic literature search up to October 2021 was done and 12 studies included 3555 subjects with closed incisions in orthopaedic trauma surgery at the start of the study: 1833 of them were provided with negative pressure wound therapy and 1722 were conventional wound dressings. They were reporting relationships about the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery. We calculated the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) to assess the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery using the dichotomous and continuous methods with a random or fixed-effect model. Negative pressure wound therapy had significantly lower deep surgical site infection (OR, 0.65; 95% CI, 0.48-0.88, P = .005), superficial surgical site infection (OR, 0.23; 95% CI, 0.11-0.49, P = .31), and wound dehiscence (OR, 0.41; 95% CI, 0.21-0.80, P = .009) compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery. However, negative pressure wound therapy had no significant effect on the length of hospital stay (MD, 0.29; 95% CI, -2.00- 2.58, P = .80) compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery. Negative pressure wound therapy had significantly lower deep surgical site infection, superficial surgical site infection, and wound dehiscence; however, negative pressure wound therapy had no beneficial effect on the length of hospital stay compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery. Further studies are required to validate these findings.

BACKGROUND

Wound complications with orthopaedic trauma surgery are a major concern. Wound healing is mainly challenging after high‐energy trauma and often contributes to postoperative wound dehiscence and deep surgical site infections. A prospective randomised clinical trial reported a frequency of nearly 19% deep surgical site infections after high‐risk lower extremity fracture surgery. Deep surgical site infections are a dangerous wound complication causing increased postoperative illness, death, length of hospital stay, and economic load. With the progress of new methods and approaches, efforts are made to handle the wound healing process, improve healing rates, and lower the frequency of infectious complications. Examples of those efforts are antibiotic prophylaxis, multiple‐dose administration of prophylaxis, less invasive surgical techniques, and prophylactic negative pressure wound therapy. Negative pressure wound therapy has three chief constituents that produce a negative pressure setting: a vacuum device, a porous dressing, and a connector that allows communication. The porous dressing located on the wound is dry, hydrophobic, reticulated polyurethane‐ether foam. The wound and porous dressing are wrapped via an occlusive adhesive dressing and connected with the vacuum device to produce a sub‐atmospheric pressure environment. Negative pressure wound therapy stimulates wound healing by providing wound coverage, decreasing dead space and minimising tension, increasing blood flow, decreasing oedema, and building an environment that stimulates tissue granulation. , It has been used effectively in open wound therapy and wound complications after orthopaedic surgery. As orthopaedists turn out to be more familiar with negative pressure wound therapy, they extended the application in different surgical operations, for example, it is now being used as a postoperative dressing for fasciotomy wounds after compartment release. Current studies have reported the application of prophylactic negative pressure wound therapy on closed incisions after high‐energy lower extremity trauma and total joint arthroplasty. , These optimistic results recommend that negative pressure wound therapy might be an assistant to decrease wound complications for primarily closed incisions in orthopaedic trauma surgery, but no clear consensus was accomplished based on existing studies. The purpose of this meta‐analysis was to evaluate the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery. The hypothesis was that negative pressure wound therapy would improve outcomes in fewer surgical site infections and wound dehiscence compared with conventional wound dressings.

METHODS

The current study was completed following a reputable protocol that was based on the meta‐analysis of studies in the epidemiology statement.

STUDY SELECTION

Comprised studies were that with statistical relationship (odds ratio [OR], mean difference [MD], frequency rate ratio, or relative risk, with 95% confidence intervals [CIs]) among the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery.

Only those human studies in any language were selected. Inclusion was not limited by study size or type. Studies excluded were review articles, commentaries, and studies that did not provide a level of association. Figure 1 shows the entire study procedure. The articles were combined into the meta‐analysis when the next inclusion criteria were met:The exclusion criteria were as follows:

FIGURE 1

Schematic illustration of the study method

The study was a randomised controlled trial, prospective study, or retrospective study.

The target population is subjects with closed incisions in orthopaedic trauma surgery

The intervention programme was negative pressure wound therapy

The study included comparisons between the negative pressure wound therapy and conventional wound dressings

Studies that did not determine the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery

Studies with subjects with dressings other than negative pressure wound therapy

Studies that did not focus on the effect of comparative results.

IDENTIFICATION

A protocol of search plans was arranged based on the PICOS principle, and we defined it as follow: P (population): subjects with closed incisions in orthopaedic trauma surgery; I (intervention/exposure): negative pressure wound therapy; C (comparison): negative pressure wound therapy and conventional wound dressings; O (outcome): deep surgical site infection, superficial surgical site infection, wound dehiscence, and length of hospital stay; and S (study design): no limit. First, we performed a systematic search of Embase, PubMed, Cochrane Library, OVID, and Google scholar till October 2021, by a blend of keywords and related words for negative pressure wound therapy, conventional wound dressing, closed incisions, orthopaedic trauma surgery, surgical site infection, wound dehiscence, and length of hospital stay as shown in Table 1. All identified studies were grouped in an EndNote file, duplicates were omitted, and the title and abstracts were reviewed to remove studies that did not show any association about the effect of negative pressure wound therapy on the outcomes of care for subjects with closed incisions in orthopaedic trauma surgery. The remaining studies were studied for associated information.

TABLE 1

Search strategy for each database

Database	Search strategy
Pubmed	#1 ‘negative pressure wound therapy’[MeSH Terms] OR ‘conventional wound dressing’[All Fields] OR ‘closed incisions’[All Fields] #2 ‘Orthopaedic trauma surgery’[MeSH Terms] OR ‘negative pressure wound therapy’[All Fields] OR ‘surgical site infection’[All Fields] OR ‘wound dehiscence’[All Fields] OR ‘length of hospital stay ’[All Fields] #3 #1 AND #2
Embase	‘negative pressure wound therapy’/exp OR ‘conventional wound dressing’/exp OR ‘closed incisions’/exp #2 ‘Orthopaedic trauma surgery’/exp OR ‘ICBG’/exp OR ‘surgical site infection’/exp OR ‘wound dehiscence’/exp OR ‘length of hospital stay’/exp #3 #1 AND #2
Cochrane library	#1 (negative pressure wound therapy):ti,ab,kw OR (conventional wound dressing):ti,ab,kw OR (closed incisions):ti,ab,kw (Word variations have been searched) #2 (Orthopaedic trauma surgery):ti,ab,kw OR (surgical site infection):ti,ab,kw OR (wound dehiscence):ti,ab,kw or (length of hospital stay):ti,ab,kw (Word variations have been searched) #3 #1 AND #2

SCREENING

Data were abbreviated based on the following: study‐related and subject‐related features onto a homogeneous form as follows: the primary author last name, study period, country, publication year, the studies region, and type of the population, design of the study; the total number of subjects, demographic data, and clinical and treatment features. In addition, the evaluation period is associated with measurement, quantitative method and qualitative method of assessment, source of information, and outcomes' assessment, and statistical analysis MD or relative risk, with 95% CI of relationship. If a study fit for inclusion based on the abovementioned principles, data were extracted separately by two authors. In case of dissimilarity, the corresponding author gives a final choice. When there were different data from one study based on the evaluation of the relationship between the effects of negative pressure wound therapy compared with conventional wound dressings on the outcomes of care for subjects with closed incisions in orthopaedic trauma surgery, we extracted them separately. The risk of bias in these studies: individual studies were appraised using two authors who separately evaluated the methodological quality of the nominated studies. The ‘risk of bias tool’ from the RoB 2: A revised Cochrane risk‐of‐bias tool for randomised trials was used to measure methodological quality. In terms of the evaluation criteria, each study was valued and consigned to one of the next three risks of bias: low: if all quality criteria were met, the study was considered to have a low risk of bias; unclear: if one or more of the quality criteria were partly met or unclear, the study was considered to have a moderate risk of bias; or high: if one or more of the criteria were not met, or not comprised, the study was considered to have a high risk of bias. Any discrepancies were addressed by reviewing the original article.

ELIGIBILITY

The chief result concentrated on the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery. An assessment of the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery was extracted, forming a summary.

INCLUSION

Sensitivity analyses were restricted only to studies showing the association of the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery. For subgroup and sensitivity analysis, we performed a comparison between the negative pressure wound therapy and conventional wound dressings.

STATISTICAL ANALYSIS

We computed the odds ratio (OR), mean difference (MD), and 95% confidence interval (CI) by the dichotomous or continuous technique with a random or fixed‐effect model. We calculated the I2 index, and the I2 index was between 0% and 100%. When the I2 index was around 0%, 25%, 50%, and 75% that identifies no, low, moderate, and high heterogeneity, respectively. If the I2 was >50%, we used the random‐effect; if it was <50%, we used the fixed‐effect. We used stratifying the original calculation per result category as defined before to do the subgroup analysis. A P value for differences among subgroups of <.05 reflected statistically significant. Studies bias was measured quantitatively using the Egger regression test (studies bias is present if P ≥ .05) and qualitatively by visual examination of funnel plots of the logarithm of odds ratios against their standard errors. The entire P values were two‐tailed. Reviewer manager version 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark) was used to perform all measurements and graphs.

RESULTS

A total of 1021 distinctive studies were found, of which 12 studies (between 2010 and 2021) satisfied the inclusion criteria and were comprised in the study. , , , , , , , , , , ,

The 12 studies included 3555 subjects with closed incisions in orthopaedic trauma surgery at the start of the study: 1833 of them were provided with negative pressure wound therapy and 1722 were conventional wound dressings. All studies evaluated the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery.

The study size ranged from 65 to 1519 subjects with closed incisions in orthopaedic trauma surgery at the beginning of the study. The information of the 12 studies is revealed in Table 2. Ten studies reported data stratified to the deep surgical site infection, seven studies reported data stratified to the superficial surgical site infection, three studies reported data stratified to wound dehiscence, and three studies reported data stratified to the length of hospital stay.

TABLE 2

Characteristics of the selected studies for the meta‐analysis

Study	Country	Total	Negative pressure wound therapy	Conventional wound dressings
Reddix Jr 9	United States	301	235	66
Stannard 2	United States	263	141	122
Crist 10	United States	91	49	42
Zhou 11	China	76	22	54
Crist 12	United States	66	33	33
Dingemans 13	Netherlands	94	47	47
Costa 14	England	1519	770	749
Canton 15	Italy	65	16	49
Gantz 16	United States	266	133	133
Mueller 17	United States	274	118	156
Masters 18	United Kingdom	432	214	218
Cai 19	China	108	55	53
	Total	3555	1833	1722

Negative pressure wound therapy had significantly lower deep surgical site infection (OR, 0.65; 95% CI, 0.48–0.88, P = .005) with low heterogeneity (I2 = 38%), superficial surgical site infection (OR, 0.23; 95% CI, 0.11–0.49, P = .31) with no heterogeneity (I2 = 0%), and wound dehiscence (OR, 0.41; 95% CI, 0.21–0.80, P = .009) with no heterogeneity (I2 = 0%) compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery as shown in Figures 2, 3, 4.

FIGURE 2

A forest plot of the deep surgical site infection in negative pressure wound therapy group compared with the conventional wound dressings group

FIGURE 3

A forest plot of the superficial surgical site infection in negative pressure wound therapy group compared with the conventional wound dressings group

FIGURE 4

A forest plot of the wound dehiscence in negative pressure wound therapy group compared with the conventional wound dressings group

However, negative pressure wound therapy had no significant effect on the length of hospital stay (MD, 0.29; 95% CI, −2.00‐ 2.58, P = .80) with high heterogeneity (I2 = 93%) compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery as shown in Figure 5.

FIGURE 5

A forest plot of the length of hospital stay in negative pressure wound therapy group compared with the conventional wound dressings group

Selected studies stratified analysis that adjusted for ethnicity, and age was not completed because no studies stated or adjusted for these influences.

Based on the visual assessment of the funnel plot as well as on quantitative measurement by the Egger regression test, there was no indication of publication bias (P = .88). Yet, the majority of the comprised studies were of low methodological quality because of their small sample size. All studies did not have selective reporting bias, and no articles had incomplete result data and selective reporting.

DISCUSSION

This meta‐analysis study based on 12 studies included 3555 subjects with closed incisions in orthopaedic trauma surgery at the start of the study: 1833 of them were provided with negative pressure wound therapy and 1722 were conventional wound dressings. , , , , , , , , , , , Negative pressure wound therapy had significantly lower deep surgical site infection, superficial surgical site infection, and wound dehiscence compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery. However, negative pressure wound therapy had no significant effect on the length of hospital stay compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery. Yet, the analysis of results must be done with attention due to the low sample size of some of the selected studies, five studies with less than 100 subjects as sample size, and the low number of studies found for the meta‐analysis, recommending the necessity for additional studies to confirm these findings or perhaps to significantly impact confidence in the effect assessment, especially the wound dehiscence and the length of hospital stay with their low number of studies found for evaluation.

The effective use of negative pressure wound therapy on open wound management causes some orthopaedists to increase the use of negative pressure wound therapy for some closed incisions. A current consensus panel suggested the application of negative pressure wound therapy on subjects who are at high risk of postoperative wound complications ; although these suggestions have been confronted by the outcomes of more recent studies in orthopaedic trauma. , , However, the previous meta‐analysis indicated that negative pressure wound therapy can decrease the risk of infection of the subjects in the management of open fractures and hasten the wound healing process. In open wounds, negative pressure wound therapy promotes wound healing by improving the removal of excess interstitial fluid, decreasing oedema, improving tissue growth and expansion. , In closed incisions, negative pressure wound therapy functions to stimulate drainage, improve lymphatic flow, reduce haematoma, and seroma formation, and it decreases relative motion at the surgical site, and reduce lateral tension across the incision line. , , Latest clinical studies recommend that negative pressure wound therapy could be prophylactic management to reduce the frequency of infection in high‐risk subjects after lower extremity fractures as well as after total joint arthroplasty. ,

The extent of negative pressure wound therapy management might also affect the hospital's length of stay. A clear and essential benefit of negative pressure wound therapy is that it requires fewer dressing changes compared with conventional wound dressings. Negative pressure wound therapy decreases the strain on physicians and nursing staff, and this is mainly noticeable in obese subjects or special wound locations, for example, the popliteal fossa, buttocks, or groin. To some extent, the use of negative pressure wound therapy is helpful in the inhibition of wound infection as each dressing change is a possible chance of wound contamination. So, negative pressure wound therapy is appropriate for the subjects sent to the intensive care unit through the immediate postoperative period. Also, subjects were satisfied with the negative pressure wound therapy as it offers a cleaner wound environment, and they did not have to take care of the surgical incision. In the present modern health care environment, it is also vital to consider the economic factors when we make management decisions. The costs of negative pressure wound therapy have been assessed to be less than 500 dollars per subject, but the health care costs related to postoperative deep surgical site infections could be huge. , Consequently, in subjects at high risk for wound complications, it would be reasonable and cost‐effective to use negative pressure wound therapy for closed incisions in orthopaedic trauma surgery. Also, the use of negative pressure wound therapy did not affect the length of hospital stay. Although the current application of negative pressure wound therapy for closed incisions in orthopaedic trauma surgery has produced some satisfactory outcomes, it does not mean that negative pressure wound therapy should be applied for all orthopaedic trauma surgeries. The rational use of negative pressure wound therapy should be based on the subject's condition and risk factors. The fractures in the present meta‐analysis are calcaneus, pilon, ankle, tibial plateau, and acetabular fractures, which are frequently supplemented with a high likelihood of extended wound drainage and postoperative wound swelling. Those subjects are at a high risk of deep surgical site infections and soft tissue healing complications after the surgeries. And this problem is further increased if the subject has related risk factors, for example, obesity, diabetes mellitus, tobacco use, and prolonged surgical time. , ,

This meta‐analysis reported the association of the effect of negative pressure wound therapy compared with conventional wound dressings on closed incisions in orthopaedic trauma surgery. However, additional studies are required to confirm these probable relationships. Also, additional studies are required to provide a clinically meaningful difference in the outcomes. This was also suggested in previous similar meta‐analysis studies, which showed a similar effect of negative pressure wound therapy and conventional wound dressings in subjects with different types of orthopaedic trauma surgery. , , , , , , , , The insignificant results of negative pressure wound therapy in the length of hospital stay also need additional study and clarification because no clear reasoning was found to clarify these outcomes. Well‐conducted studies are also required to measure these factors and the blend of different ages and ethnicity, because our meta‐analysis study could not answer whether they are related to the outcomes. Most of the selected studies evaluated were designed and accompanied before 2013 when SPIRIT Statement was started as a protocol to assist in improving the quality of clinical trial protocols. The CONSORT Statement (2010) is a 25‐item checklist and flow diagram for authors to confirm transparent reporting of randomised trials. Using the SPIRIT and CONSORT protocols and checklists when designing and reporting a randomised controlled trial will assist in confirming that all vital elements of the trial are reported. Therefore, it will reduce the risk of bias, which eventually will help increase the quality of negative pressure wound therapy randomised controlled trials. , We suggest that well‐designed, high‐quality randomised controlled trials are required to be accomplished about the effect of negative pressure wound therapy on closed incisions in orthopaedic trauma surgery. Health care providers need to confirm completed studies are published to establish and document results related to the effect of negative pressure wound therapy on closed incisions in orthopaedic trauma surgery because published evidence should be used to lead the clinical practice.

In summary, negative pressure wound therapy had significantly lower deep surgical site infection, superficial surgical site infection, and wound dehiscence compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery.

However, negative pressure wound therapy had no significant effect on the length of hospital stay compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery. Further studies are required to validate these findings.

LIMITATIONS

There might be selection bias in this study because numerous studies were excluded from our meta‐analysis. Yet, the studies excluded did not fulfil the inclusion criteria of the meta‐analysis. Also, we could not answer whether the outcomes were related to age and ethnicity or not. The study was intended to evaluate the association of the effect of negative pressure wound therapy on the outcomes of care for subjects with closed incisions in orthopaedic trauma surgery based on data from earlier studies, which may originate bias brought by incomplete information. The meta‐analysis was based on only 12 studies; 5 studies were small, ≤100; variables like wound dehiscence, and length of hospital stay were only analysed using 3 studies. Variables, for example, age, ethnicity, and nutritional condition of subjects, were also the probable bias‐inducing influences. Some unpublished articles and omitted data may cause a bias in the pooled result. Subjects were using different management programmes, doses, and health care organisations. The length of negative pressure wound therapy management of the comprised studies was inconsistent.

CONCLUSIONS

Negative pressure wound therapy had significantly lower deep surgical site infection, superficial surgical site infection, and wound dehiscence; however, negative pressure wound therapy had no significant effect on the length of hospital stay compared with conventional wound dressings in subjects with closed incisions in orthopaedic trauma surgery. Further studies are required to validate these findings. More studies are essential to confirm these outcomes. Yet, the analysis of results must be done with attention due to the low sample size of some of the selected studies and the low number of studies found in the meta‐analysis; recommending the necessity for additional studies to confirm these findings or perhaps to significantly impact confidence in the effect assessment.

CONFLICT OF INTEREST

The authors declare no potential conflict of interest.