gms | German Medical Science

Objectives: Periprosthetic joint infection (PJI) is a devestating but rare complication in any case of total joint arthroplasty, but infection rates appear to be much higher in megaprosthesis (15–43%). Revision of megaprosthesis is a highly complex procedure associated with massive bone loss, so that implant retention occurs as a viable initial therapy option. Unfortunately, literature regarding therapy strategies and outcome reports for PJI in megaprosthesis are scarce. The aim of this study is to report the infect eradication in relation to surgical therapy and type of infection.

Methods: All PJI in megaprosthesis caused by gram-negative pathogens or enterococcus species between March 2012 and April 2022 at an academic tertiary referral center were retrospectively analysed. 14 cases were identified. 2 were lost-to-follow-up. The nonparametric Pearson’s chi squared and Fisher’s exact test were applied for comparisons between groups. Survival analysis was evaluated using the Kaplan-Meier survival curve with 95% confidence interval. Statistical significance was defined as p < 0.05.

Results and conclusion: 3 acute and 9 chronic PJI were included. The infection-free survival for cases treated with debridement, antibiotics and implant retention (DAIR) (n = 8), two-stage revision (n = 1) and multi-stage revision (n = 3) was 25%, 100% and 67% after a mean follow-up of 12.9 (1; 101) months, respectively. 88% of treatment failures occurred within one year. Amputation as a definitive treatment was necessary in four cases.

DAIR was associated with low success rates in acute and chronic PJI (80%; 50%).

There were no statistically significant differences with respect to either type of intervention (p = 0.37) nor type of infection (p = 0.84).

Infection with gram-negative pathogens or enterococcus species appears to be a main cause of chronic PJI.

Implant retention for PJI in megaprosthesis with those pathogens is associated with high failure rates regardless of acute or chronic infections. Two-stage and multi-stage revision were associated with the best infect eradication in this study taking into account the low case numbers. Despite those findings, PJI of megaprosthesis remains a complex problem since the potential risks and consequences of an implant removal are high.