How Much Does Prosthetic Joint Infection and Its Successful Treatment Affect Patient-reported Quality of Life?

Background: Uncomplicated joint replacement improves pain and other patient-reported outcome measures (PROMs) such as joint function scores and quality-of-life measures. However, the overall impact of periprosthetic joint infection (PJI) and its successful treatment on PROMs is poorly defined. In this study, we describe quality-of-life scores using the 12-item Short Form survey, version 2 (SF-12v2), collected as part of a large, prospective, observational study of PJI.

Questions/purposes: (1) Do patients with newly diagnosed PJI have lower quality-of-life scores than the general age-matched population? (2) Are lower quality-of-life scores for patients with PJI sustained for ≥ 12 months? (3) What factors are associated with a good functional outcome at 12 months, defined by achieving a physical component summary (PCS) score of > 50 on the SF-12v2 (that is, above the age-adjusted population mean) or an increase of > 8.9 or more from baseline?

Methods: The PIANO (Prosthetic joint Infection in Australia and New Zealand, Observational study) cohort was a prospective, longitudinal, multicenter cohort study of 783 patients with newly diagnosed PJI recruited across 27 centers between July 2014 and December 2017. All participants were followed for 2 years. SF-12v2 scores were collected at diagnosis (baseline) and 3, 12, and 24 months after diagnosis. Treatment success was defined as being alive with no clinical or microbiological evidence of infection and no ongoing use of antibiotics for the index joint.

Results: After exclusion of 6.6% (52) who had died, 4.2% (33) with PJI of joints other than hips and knees, and those with incomplete data sets (200 [25.5%]), 498 patients had complete SF-12v2 data sets available. At baseline, the median (IQR) PCS score was 37 (30 to 46), which increased to 41 (34 to 49; p < 0.001) at 12 months. Both measures were lower than those for the general age-matched population norm. There was no further improvement in PCS scores between 12 and 24 months. By contrast, the median (IQR) mental component summary score of the SF-12v2 was similar to age-adjusted population norms (48 [37 to 57]) at baseline. Only 40% of patients with PJI achieved a good functional outcome at 12 months. After adjustment for other factors, treatment success of PJI increased the odds of a good functional outcome by 67% (95% CI 11% to 154%; p = 0.02).

Conclusion: PJIs have a large effect on the PCS score of the SF-12v2 quality-of-life measure at baseline, which is sustained for at least 2 years. Successful treatment of PJI increases the likelihood of a good functional outcome. These data can be used to set expectations for patients presenting with PJI and can be used to inform future clinical studies in which quality-of-life measures are incorporated into clinical endpoints.

Level of evidence: Level II, therapeutic study.