Letter to the Editor: A Low Percentage of Patients Satisfy Typical Indications for Single-stage Exchange Arthroplasty for Chronic Periprosthetic Joint Infection

To the Editor,

We have read with interest the study in Clinical Orthopaedics and Related Research® by Dombrowski et al. [5]. We value this work because the authors investigated an important question, the answer to which is indeed interesting. However, we are somewhat concerned about the authors’ conclusion that only 19% of their patients with periprosthetic joint infection (PJI) matched the proposed criteria of the International Consensus Meeting (ICM) for typical candidates for one-stage exchange [5].

Concerning the second question of that study, among patients who underwent two-stage exchange, Dombrowski et al. [5] found no differences in the risk of reinfection between potential candidates for one-stage exchange and those who would not be suitable for one-stage exchange [5]. Therefore, the authors concluded that only a small proportion would benefit from one-stage exchange. We believe this may be misleading. Several limitations, including the usual problems of retrospective designs, were acknowledged by the authors. Hence, their results must be interpreted cautiously and should be considered preliminary [5].

As one of the world’s largest arthroplasty institutions with experience in the management of PJI since the 1970s, especially in patients undergoing one-stage exchange, we would like to briefly share with the authors and the readers our specific concerns about the study by Dombrowski et al. [5].

Although there were no substantial changes in the recommended indications for and contraindications to one-stage exchange from the first to the second ICM [3], Dombrowski et al. [5] cited the first ICM [7, 8] as a reference. However, the criteria they used included a combination of criteria from both consensus meetings, namely the presence of a sinus tract (from the first ICM) and immunocompetence or multiple morbidities (from the second ICM) [5].

At our arthroplasty center, we consider the presence of concurrent sepsis and failure to identify the causative pathogen preoperatively, including antibiotic susceptibility, as absolute contraindications to one-stage exchange. Otherwise, all other contraindications can be considered based on the individual situation.

These indications recommended by the first and second ICM can be considered high-selecting criteria; thus, it is logical to identify a low percentage of candidates. Limiting contraindications to one-stage exchange leads to a considerable rise in the number of patients who would be indicated to undergo this procedure.

Considering the absolute and relative contraindications at our institution, about 85% of patients are considered suitable for and undergo a one-stage exchange [6, 11]. In the current study [5], 40% of the cohort had no identified pathogen preoperatively; thus, in our opinion, 60% of the patients could be candidates for one-stage exchange. However, this proportion of patients could be reduced after considering further relative contraindications such as infections by multidrug-resistant microorganisms, extensive bone and soft-tissue infection, or immune status of the patient; each patient should be analyzed individually. Because of the great advantages of one-stage exchange, we recommend using every possible tool to identify the causative pathogen preoperatively. This could include repeat aspiration or even open biopsy.

Although there was statistically no significant difference between the groups in terms of reinfection rate (20% for potential candidates versus 32% for unsuitable candidates) [5], it would be more accurate to state that instead, there was no difference between the groups. Furthermore, we wonder whether there is a strong evidence that could support the expectation of a high reinfection risk in potential candidates if they have undergone one-stage exchange.

A reinfection rate of 29%, including failure to eradicate the infection after two-stage exchange [5], is relatively high, which was not adequately discussed by the authors. Even at long-term follow-up, at our institution, we achieved success rates of above 90% using one-stage exchange [12, 13].

There are no data about the soft-tissue envelope of the joints, including the need for coverage. Instead, the presence of a sinus tract was included [5], which has been withdrawn from the proposed contraindications of the second ICM because of evidence that sinus tracts did not affect the risk of reinfection or persistent infection after one-stage exchange [1, 3, 4].

The effort to define immunocompetence and comorbidities in this study [5] must be appreciated because this issue remains unclear. We are aware that extensive comorbidities were recommended by the second ICM [3] as a relative contraindication to one-stage exchange. However, because only one procedure is needed and because a shorter duration of antibiotic therapy is used, we believe that one-stage exchange is better than two-stage exchange for such patients whenever possible to achieve better mobility and reduce perioperative morbidity. Additionally, failure to complete reimplantation and higher mortality associated with two-stage exchange can be avoided, as reported in recent studies [2, 10].

Despite its absence among the selection criteria of both ICMs [3, 7, 8], polymicrobial infections were included in Dombrowski et al.’s study [5]. We consider that polymicrobial PJIs are challenging to treat, particularly with regard to the appropriate antibiotics, but they are not a contraindication to performing one-stage exchange.

Lastly, in our own recent analyses of the risk factors for reinfection after one-stage exchange for hip and knee PJI, we identified some independent variables, including previous one-stage or two-stage exchnage, as well as enterococcal and streptococcal PJI [1, 4]. In previous studies evaluating the results of two-stage exchange, these factors were also associated with persistent or recurrent infection after treatment [1, 4].

In conclusion, one-stage exchange can be considered for selected patients [9]. However, higher proportions of patients with PJI could be considered as suitable for this advantageous method in highly specialized hospitals where a tried, effective management protocol has been established. In addition to a meticulous surgical technique by experienced surgeons, including aggressive soft-tissue and bone débridement using a local antibiotic based on prior identification of the pathogen, a multidisciplinary approach under close observation by a designated microbiologist using appropriate antimicrobial therapy is crucial to attain a higher likelihood of infection eradication.