In this systematic review and meta-analysis, we assessed the risk of SSI after primary wound closure with staples versus sutures in elective knee and hip arthroplasty. Our primary findings suggest that wound closure with staples carries a higher risk of SSI than sutures. Furthermore, we showed that the subgroup of patients undergoing hip arthroplasty may have a higher risk of SSI when treated with staples, but no difference was found for knee arthroplasty. However, given the low power in this meta-analysis and the heterogeneity of SSI definitions, the results remain non-definitive.
This is the first meta-analysis that focused primarily on wound closure with staples and sutures in elective hip and knee arthroplasties. Previous reviews focused on heterogeneous groups, including both trauma as well as elective patients, or focused on other closing materials such as barbed sutures [4, 18,19,20]. The strength of our study includes a large number of patients (1130 patients), a relatively sufficient number of RCTs (8 studies), and study of elective arthroplasties. Using the Cochrane risk of bias assessment tool 2.0, we assessed, in detail, the risks of bias based on the 5 different domains, and conducted a sensitivity analysis by excluding the studies with a higher risk of bias.
The major limitation of this systematic review is the lack of high-quality and adequately-powered studies in arthroplasty. Future studies should primarily focus on SSI, more clearly describe the outcomes (e.g., definitive data from Centers for Disease Control and Prevention and at least 1 year follow-up to detect all potentially serious SSI), and have definitive results based on larger sample size. Second, double blinding was largely absent in the included studies due to the nature of the interventions but should be possible for the statistician in future studies. Third, the heterogeneous population (including both knee and hip arthroplasties) and different postoperative wound managements and healing processes decrease the power of the meta-analysis, resulting in a non-definitive conclusion [5].
Joint arthroplasty remains one of the most common surgical procedures and is a significant contributor to SSI burden worldwide. It is crucial to identify the interventions to reduce the risk of SSI. When choosing a wound closure method, we should consider these factors, including availability, familiarity, affordability, cost-effectiveness, cosmetic outcome, and patient and surgeon preferences. Stapling does reduce surgical time, but is a more expensive option [17, 21, 22].
Krishnan et al. [4] performed a meta-analysis and found that stapling had a higher incidence of SSI than suturing in elective and traumatic arthroplasties, but the inclusion was not limited to studies with a low risk of bias. It is unclear whether the SSI is associated with soft tissue reaction to stainless steel and titanium of staples, wound tension, the lack of perfusion, or poor techniques [21]. Overlapping or inverted wound edges may cause persistent oozing and infection at skin entry points [5, 23]. Several studies provided a description of stapling techniques [12, 13, 17]. One of them showed that wound oxygenation is similar in skin closure when subcuticular Vicryl or staples were used [13]. Theoretically, greater space between staples may provide an advantage in terms of oxygenation. Therefore, during wound closure, (1) the assistant should help prevent overlapping or inversion of the wound edges using toothed forceps, and (2) ensure enough spacing between staples (at least 6 mm) [5, 13].
No difference between subgroups was found for continuous and interrupted sutures; however, the subgroup analysis was underpowered. Liu et al. [24] studied the differences between running absorbable and vertical mattress nonabsorbable sutures in total knee arthroplasty, and also showed no difference in infection rates. We therefore hypothesize that the suturing type may be less relevant than the ongoing debate between stapling versus suturing.
In hip arthroplasty, we found stapling was associated with an increased risk of SSI, compared to suturing. The underlying mechanism remains unclear but possibly involves a longer incision in knee arthroplasty, associated with more mobility than hip arthroplasty [15, 20]. Suturing may be a preferential option to stapling in hip arthroplasty.