CORR Insights®: What Are the Long-term Outcomes of Mortality, Quality of Life, and Hip Function after Prosthetic Joint Infection of the Hip? A 10-year Follow-up from Sweden

Where Are We Now?

Periprosthetic joint infection (PJI) remains one of the most common and devastating complications of total joint arthroplasty. PJI causes serious morbidity, revision surgery, and a high risk of death. The economic burden of PJI is substantial, with a projected cost to the healthcare system of USD 1.6 billion per year [2].

While we have reasonable estimates about the economic impact and mortality rates associated with PJI, we know very little about the long-term functional outcomes following its treatment. Studying patients with PJI is challenging because they often are lost to follow-up or do not want to participate in research, perhaps because of the poor results they have experienced. Furthermore, some are medically fragile and cannot travel.

The current study [4] was able to overcome many of these problems by investigating this information through the Swedish Hip Arthroplasty Registry. The study reported a high risk of death among patients who experienced PJI of the hip: 45% at 10 years [4]. They also noted that these patients experienced decreased quality of life over a sustained period of time, including impaired mobility, compared to the non-PJI cohort. In addition, the authors examined other risk factors that were associated with decreased functional outcomes, and found the direct lateral approach, gender (women), and three or more operations were associated with lower Oxford Hip Scores. While many of these findings have been reported previously at short- and mid-term follow-up, it is rare to see such a high follow-up rate of a large sample size at 10 years.

Where Do We Need To Go?

There are mainly two ways we might reduce the devasting impact of PJI, and future studies should evaluate both of them: (1) how to improve our prevention of PJI and (2) how to increase the success rate and decrease the morbidity of PJI treatment.

Researchers have made substantial improvements in the prevention of PJI with perioperative antibiotics, nasal decolonization, decreased operative times, and improving potentially modifiable risk factors. However, the latter needs further study. Indeed, many risk factors for PJI have been implicated, but surgeons generally have a poor understanding on how to mitigate these risk factors, and whether mitigation attempts even result in a reduction in the likelihood of PJI. What risk factors are actually modifiable? When should we delay surgery in favor of trying to reduce a patient’s risk?

Currently, the success rates after PJI treatment, including for one-stage, two-stage, and debridement and implant retention (DAIR), are far from desirable. As Wildeman et al. [4] demonstrated, the number of PJI surgical procedures that a patient undergoes is associated with a decrease in functional outcomes. Our current understanding of when a one-stage or a DAIR can be performed instead of a two-stage needs to be deepened.

In addition to understanding our surgical indications, we need to improve our ability to disrupt biofilm, which is often attributed to infection recurrence [3]. Finally, we may need to improve our antimicrobial treatment options. Chronic suppression has consistently demonstrated improved infection-free survivorship, but we still need to determine the best duration of the treatment, as well as to address antibiotic stewardship concerns.

How Do We Get There?

Many of the studies that we perform on PJI are of low quality and of small sample sizes. National registries like this study [4] provide answers that cannot be derived in single-institution studies.

PJI prevention needs to be a priority. The next round of studies on this first requires a thorough understanding of patient risk factors. While many risk factors have been identified, further studies need to investigate how to determine the influence of multiple risk factors on the ultimate risk. Furthermore, we need to individualize this risk though the development and validation of risk calculators. It is crucial that we improve our ability to risk stratify patients and determine which patients are at high risk.

As I mentioned, future studies need to provide guidance on how surgeons can best prepare their patients in advance of surgery for PJI; we need to refine our risk-mitigation strategies, particularly for those at high risk. Large prospective studies are often impractical given the relative rarity of PJI; thus, we often rely on large institutional or multiinstitutional studies that have instituted a protocol or specific regimen.

We could reduce the morbidity of treatment by refining our indications for single-stage procedures (like DAIR) but using two-stage revision when we need to. Future studies should identify risk factors for failure and quantify the failure rate of the respective surgeries. This would allow both surgeons and patients the ability to determine whether a more morbid surgery would result in improved PJI treatment rates.

In addition, making better choices about antimicrobial treatment seems essential to maximizing the likelihood of success when treating a patient with PJI. Studies on this topic can help if they can determine the best duration and type of antibiotic treatment including chronic suppression. Further improvements in antimicrobial treatment are especially needed in the difficult-to-treat organisms and antibiotic- resistant organisms. Developing new antibiotics or antimicrobial technologies including those that combat biofilm are likely needed.

A validated patient-reported outcome measurement tool that is specific to PJI will help fill some of the gaps in our knowledge. While we are often focused on functional outcomes, the holistic impact of PJI treatment(s) on the quality of life, independence, adverse events, and psychosocial health needs to be quantified. Surveys completed by patients who have suffered from PJI are crucial to a better understanding of the “true” burden associated with PJI. In addition to developing an outcome measure that includes a psychosocial component, further studies are needed in the validation of these measures. Studies are also needed that employ psychosocial treatment through an interdisciplinary approach, as the psychosocial distress after a PJI has been demonstrated [1] to be equivalent to that of oncologic patients.