Even though great efforts have been tried for implant salvage when faced with acute PJI, there still exists a vast difference in the reported failure rate of DAIR. The key of DAIR to control the infection is to eradicate the bacterial encapsulated within the biofilm that adheres to the interface between bone and implant and prevent the residual bacteria from comeback. Apparently, the combined use of debridement, irrigation, and antibiotics is somehow unable to guarantee a satisfactory eradication of infection according to the reported success rate of DAIR. The outcomes of vacuum sealing drainage for infected incisions are promising because of its biological effects and the application of VSD in deep portion as an adjunct to DAIR has not been reported before as far as we are concerned. Theoretically, VSD can assist in infection control and prevent the recolonization of bacteria the infection by promoting granulation tissue formation, enhancing bacterial clearance, and increasing necrotic tissue debridement., we wonder if the placement of VSD around the infected hip joint could help increase the success rate of DAIR for early postoperative and hematogenous PJI.
Decreased bacteria loading of the application of VSD in the infected sites has been shown in numerous studies. Effective bacteria clearance of VSD was first observed by Morykwas et al in an animal model[13]. Similar results were reported in clinical trials about various microorganisms including Staphylococcus aureus, Staphylococcus epidermidis, and Gram-negative bacteria[14–16]. The mechanical suction could accelerate the debridement of the necrotic tissue and stimulate angiogenesis and subsequent enhanced inflammatory responses, which might account for the decline of the bacterial load[17]. According to a previous study, the infected sites could be isolated from the external environment due to the focal closed negative pressure environment formed by VSD[18], because of which we believed there is a chance to apply VSD in deep infection as an adjunct to DAIR for better infection control as the relatively closed environment around the infected prosthesis could further prevent the invasion of additional bacteria after a thorough debridement and irrigation. Several factors are supposed to be associated with the outcome of DAIR such as type of causative organism[19, 20], duration between symptoms and surgery[21, 22], exchange of modular components[6, 23], and preoperative comorbidities[24]. Besides, the drainage in the operative area was also essential to the success rate of DAIR. There was a high risk of residual dead space because the hole of the routine drainage was frequently blocked by the necrotic tissues, which could be solved by the application of VSD. From our point of view, the reshaped VSD sponge was able to guarantee sufficient filling of the remaining space after debridement and effective drainage due to the porous design and suction environment.
Although not an emergency, DAIR is an urgent procedure as the surgery timing is considered to be a crucial factor affecting the success rate of the procedure[8]. Prompt intervention is believed to obtain a better bacterial clearance due to the immature biofilm and the susceptible organism within the early onset of the infections[25, 26]. According to the previous studies concerning biofilm biology[6, 27–29], the surgical timing of DAIR was strictly controlled in our department and we considered the duration of the symptoms within 4 weeks the suitable indication of DAIR for acute PJI. In addition, the optimal operation frequency to obtain a better outcome of DAIR is under debate. Antonios et al stated that two-stage DAIR was more cost-effective than one-stage due to the higher rate of success and presence of a more “sterile” field at the second-stage procedure despite the higher financial costs and longer hospital stays[30]. In our study, DAIR combined with VSD in deep portion was found to be effective in eradication of the focal infections as planned two-stage or even multiple-stage DAIR (4 of 12 cases underwent 4-stage procedure) for the change of VSD and thorough debridement reduced the necrotic tissue, narrowed the interstitial space and increased the formation of granulation tissue according to our intraoperative findings.