CORR Insights®: Are Patients Who Undergo THA for Infection at Higher Risk for 30-day Complications?

Where Are We Now?

In the current study, Boniello and colleagues [2] queried the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database for patients undergoing revision THA from 2012 to 2015 and found that patients undergoing the procedure for periprosthetic joint infection (PJI) experience major complications and undergo reoperation more frequently in the first 30 postoperative days than patients undergoing revision THA for other reasons. They also found that malnutrition was associated both with reoperation and mortality. The current study serves as a good reminder of just how serious an operation revision THA for PJI can be; alarmingly, 10% of patients developed a major complication (myocardial infarction, sepsis, septic shock, stroke, or mortality) and 4% of patients developed a deep infection in just the first 30 days after the revision procedure.

Numerous earlier studies have found that revision THA for infection is associated with more reoperations [1, 5], more complications [1] (including death [3, 9]), and poorer survivorship [5] than revision THA performed for aseptic indications [1, 5, 9]. I note that the risk of death after these revisions persists even after controlling for relevant comorbidities [3, 9] and surgical duration [3]; revision for PJI seems to be a bigger “hit” than are revisions for other indications, and we need never to forget that. What we learn from Boniello and colleagues [2] is that revision THA for PJI is independently associated with major complications and reoperation even after controlling for patient age, sex, and comorbidities.

Likewise, the association of malnutrition, obesity, and patient comorbidities in general with complications in THA and revision THA has been well established [4, 6-8]. Boniello and colleagues [2] extend what we know on these themes by demonstrating that malnutrition also increases the odds of 30-day mortality by a factor of approximately 7. This is a particularly important finding given the fact that malnutrition is a modifiable risk factor.

Where Do We Need To Go?

Several important issues still need to be clarified. First, what are the medium- and long-term outcomes of septic versus aseptic revision THA and which are the risk factors associated with complications? Second, I would be most interested to know whether the various approaches to managing PJI—such as débridement with liner exchange, one-stage exchange, and two-stage exchange (as well as different local and systemic antibiotic protocols)—differ in important ways, such as with respect to death, serious complications, and (in well-selected patients) persistence of the original infection. Finally, it is important to determine to what degree any of the risk factors associated with complications—such as obesity, malnutrition, and smoking [2, 4, 6-8]—are modifiable in advance of revision THA, especially for PJI, which is not always an easy surgery to delay for a prolonged period of time.

How Do We Get There?

In order to assess the longer-term differences between aseptic and infected revision THA in implant survivorship and patient mortality and the associated risk factors, we need retrospective studies of large numbers of patients undergoing revision THA with longer followup periods. Ideally, these studies would not be based on data from individual institutions but on existing arthroplasty registries to increase confidence in the results through higher numbers and generalizability.

Similarly, the effect of specific PJI management protocols on both short-term complications, reoperations, and mortality and on longer-term implant survivorship and patient mortality would be optimally addressed by retrospective registry studies. Potential international collaboration and aggregation of data from multiple registries will greatly enhance these research endeavors.

Regarding the potential modification of risk factors and the associated effect on shorter- and longer-term complications and mortality, we need carefully-designed prospective studies with individualized protocols developed by relevant national/international societies. These protocols should attempt to balance the feasibility and anticipated benefit of addressing risk factors with the risk of delaying the revision THA. For example, delaying surgery to address obesity in a patient requiring revision THA for PJI (or periprosthetic fracture) would not be practical—or advisable. These prospective studies, carried out at multiple institutions, would help assess first, the extent to which such risk factors can be modified in a reasonable amount of time, and second, the effect of the achieved modification on complications.

Such research efforts will hopefully clarify the aforementioned questions and help us reduce the morbidity, mortality, and socioeconomic burden of the complex clinical problem of PJI after THA.