Impact of Infection Timing on Outcomes: A Comparative Study of Periprosthetic Joint and Fracture-Related Infections

Implant-associated infections, including periprosthetic joint infection (PJI) and fracture-related infection (FRI), are among the most challenging complications in orthopedic surgery. Although infection timing (early, delayed, late) is recognized as an important factor in surgical success, its impact on patient-reported outcomes and length of hospital stay has rarely been compared between PJI and FRI in a single cohort. This study aimed to examine the association between infection timing and health-related quality of life (HRQoL) as well as length of hospital stay (LOS), and to explore potential differences between PJI and FRI.

We conducted a retrospective monocentric cohort study of 60 patients with microbiologically confirmed implant-associated infections treated at a German level-I trauma center between January and December 2021, with follow-up performed in 2023. Patients with PJI (n = 29) or FRI (n = 31) were stratified as early (< 3 months), delayed (3-24 months), or late (> 24 months) to enable direct comparison between infection entities. Outcomes included EQ-VAS, EQ-5D-3L mean domain scores, LOS, reinfection, revision surgery, amputation, and in-hospital mortality. Group differences were tested using independent-samples t-tests for continuous variables and chi-square or Fisher's exact tests for categorical variables, with subgroup analyses considered exploratory due to small sample sizes.

Of the 60 patients, 25 had early (PJI n = 11; FRI n = 14), 24 delayed (PJI n = 11; FRI n = 13), and 11 late infections (PJI n = 7; FRI n = 4). EQ-VAS was higher in FRI compared with PJI in early (63.4 ± 17.8, n = 13 vs. 48.3 ± 20.8, n = 9) and delayed infections (66.2 ± 16.8, n = 11 vs. 56.6 ± 13.5, n = 10), while both groups showed markedly lower EQ-VAS values in late infections (FRI: 39.7 ± 25.9, n = 3 vs. PJI: 43.3 ± 23.4, n = 6), which were analyzed descriptively due to very small subgroup sizes. The EQ-5D-3L mean domain score was lower (indicating better health status) in early FRI (1.55 ± 0.33, n = 12) than in early PJI (1.91 ± 0.39, n = 9) in unadjusted analyses. LOS increased with timing, particularly in PJI (early 39.6 ± 26.8 vs. 31.4 ± 29.0 days; delayed 100.6 ± 82.2 vs. 28.2 ± 10.2; p = 0.015). Reinfection rates increased with later timing (early: 6/11 PJI vs. 3/14 FRI; delayed: 8/11 vs. 8/13; late: 5/7 vs. 4/4). Revision surgery was more frequent in early PJI (7/11 vs. 4/14; p = 0.080) but was significantly more common in delayed FRI (12/13 vs. 6/11; p = 0.033). Amputation (≤ 9%) and in-hospital mortality (≤ 15%) were rare and showed no significant differences.

Infection timing was associated with both clinical and patient-reported outcomes in implant-associated infections. Later infections were associated with poorer HRQoL, longer hospital stays, and higher reinfection rates, based on unadjusted analyses, with distinct patterns between PJI and FRI. Early recognition and timely, stage-adapted treatment strategies may help improve patient outcomes.