Currently applied sonication protocols for the detection of implant-associated infections in orthopaedics: a scoping review

Implant-associated infections, including periprosthetic joint infections (PJI) and fracture-related infections (FRI), are severe complications following orthopedic surgery. Conventional tissue cultures often yield false-negative results, especially after antibiotic initiation or in chronic biofilm-associated infections. Sonication of explanted implants enhances bacterial recovery, but heterogeneous protocols limit comparability. This scoping review maps sonication protocols currently reported in the literature. A comprehensive literature search across three databases (PubMed, Embase, and Scopus) was performed. Clinical studies that reported on sonication protocols used in the microbiological workup of PJIs and FRIs published from 2007 to October 2025 were eligible for inclusion. Eligible studies were screened for the following information: container size and material and fluids, sonication device and settings, pre- and post-sonication handling, culture conditions, reporting format, and/or diagnostic thresholds. Data were extracted and synthesized descriptively. After duplicate removal, 312 records were screened, and 146 studies were included. Reporting was incomplete for several key parameters. Container material was not specified in 43.2% of studies, container type in 30.8%, and fluid type in 31.0%. Among reported protocols, hard plastic containers (54.8%) and Ringer’s lactate or saline (40.4%) were most frequently used, with fluid volumes ranging from 50 to 800 mL. Sonication frequency was reported in 50.7% of studies, most commonly 40 kHz (28.8%). Sonication time was not reported in 34.2%, with reported durations ranging from 1 to 10 min and most frequent duration as 5 min (30.1%). Vortexing and centrifugation were applied in 55.5% and 45.9% of studies, respectively. CFU thresholds varied widely, ranging from any growth to ≥50 CFU/mL or per plate. Time-to-culture and storage conditions were rarely reported. Sonication protocols vary greatly across almost all parameters, with detailed descriptions often lacking, and certain variables rarely reported. Standardizing these protocols is essential to ensure reproducibility and to establish clinically reliable diagnostic cut-offs.

IMPORTANCE

Fracture-related infections (FRI) and periprosthetic joint infections (PJI) are serious complications associated with substantial morbidity, repeated surgeries, and a high healthcare burden. Accurate and early pathogen detection is critical for guiding targeted antimicrobial therapy and improving treatment outcomes. Sonication of explanted implants has emerged as a valuable diagnostic tool by disrupting biofilms and enhancing bacterial recovery, particularly in antibiotic-exposed patients. However, sonication protocols vary widely across studies, including differences in containers, fluids, ultrasound settings, processing steps, and colony-forming unit thresholds, with inconsistent reporting further compounding the issue. This variability directly affects diagnostic performance, complicates the distinction between true infection and contamination, and limits inter-laboratory comparability. By systematically mapping this heterogeneity across 146 studies, this scoping review provides a foundation for developing standardized protocols and consensus definitions to improve diagnostic reliability and patient care.