Revision for PJI after total hip replacement: more exploration is needed

Erik Lenguerrand and colleagues

presented multiple risk factors associated with risk of revision due to prosthetic joint infection (PJI) after total hip replacement in an observational cohort study of 623 253 patients. The potential to define and modify risk factors for PJI is of great clinical significance because it remains a serious complication of total hip replacement. Some new factors identified by Lengueerand and colleagues,

including the use of lateral surgical approach and younger age, are controversial because of the paucity of data regarding the association between these factors and the risk of PJI.

First, the authors claim that the lateral approach was correlated with increased PJI risk from 3 months onwards compared with posterior or other approaches, probably due to the increased bleeding associated with the lateral approach, which was identified in a study published in 1991.

We think it would be more credible to use the raw data regarding blood loss for the total hip replacements included in this study or other more recent studies. The lateral approach might be associated with lower risk for polymicrobial and Gram-negative PJI when compared with the direct anterior approach, whereby the incision is located closer to the groin and thus is more susceptible to colonisation with bacilli.

Second, older patients are generally considered to have less competent immune systems and are more predisposed to develop PJI after total hip replacement than younger patients.

Conversely, this study had an opposite conclusion. This result should be interpreted with caution because no causative link was established, and this conclusion was inconsistent with other longitudinal studies,

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thus we speculate that it is biased.

Third, although several guidelines have been published by the Musculoskeletal Infection Society, the Infectious Disease Society of America, and the European Bone and Joint Infection Society to assist clinicians in the management of PJI, diagnosis of less commonly encountered organisms, including fungi, myco-bacteria, and Gram-negative bacilli, has not been comprehensively addressed and remains challenging. Moreover, improved clinical examination does not guarantee sensitive diagnosis of culture-negative PJI.

Furthermore, the authors declared that the diagnosis for PJI was reflective of contemporary practice during the long study period,

during which diagnostic criteria and perioperative care for PJI might have been modified, leading to underestimation or overestimation of possible cases and yielding selective bias.

Considering these issues, we believe that some findings of this study might be unreliable and careful exploration is still needed to identify the underlying cause of PJI, and ultimately guide clinical practice.

We declare no competing interests.