Validation of the use of radiographic fracture-healing scores in a small animal model

Precise assessment of fracture-healing is vital in both clinical and research settings, where therapies are typically assessed using animal models with union as the study end point. Radiographic scoring systems have been developed for clinical use; however have not been validated in pre-clinical models. Thirty sets of radiographs of rat tibial shaft fractures, treated with external fixation were reviewed by six observers using the Radiographic Union in Tibia (RUST) scale, the Lane 0.58; 95%CI (0.49–0.65) and 0.66 (0.43–0.89), respectively]. Inter-observer and intra-observer agreement were excellent using both the RUST score ICC; 0.81 (0.72–0.89) and 0.86 (0.74–0.93), respectively, and Lane 0.88 (0.81–0.93) and 0.90 (0.81–0.95), respectively]. Employing a defined scoring system enhances both the reproducibility and repeatability of bone healing assessment in a small animal model. Routine reporting of fracture scoring methodology should be encouraged to enrich results and facilitate data synthesis across studies. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1117–1119, 2014.