Automated measurement of fracture callus in radiographs using portable software

Abstract

The development of software applications that assist the radiographic evaluation of fracture healing could advance clinical diagnosis and expedite the identification of effective treatment strategies. A radiographic feature regularly used as an outcome measure for basic and clinical fracture healing research is new bone growth, or fracture callus. In this study, we developed OrthoRead, a portable software application that uses image-processing algorithms to detect and measure fracture callus in plain radiographs. OrthoRead utilizes an optimal boundary tracking algorithm to semi-automatically segment the cortical surface, and a novel iterative thresholding selection algorithm to then automatically segment the fracture callus. The software was validated in three steps. First, algorithm accuracy and sensitivity were analyzed using surrogate models with known callus size. Second, the callus area of distal femur fractures measured using OrthoRead was compared to callus area manually outlined by orthopaedic surgeons. Third, the callus area of ovine tibial fractures was measured using OrthoRead and compared to callus volume measured from micro-CT. The software had less than a 5% error in measuring surrogate callus, and was insensitive to changes in image resolution, image rotation, and the size of the analyzed region of interest. Strong positive correlations existed between OrthoRead and clinicians (R2 = 0.98), and between 2D callus area and 3D callus volume (R2 = 0.70). The average run time for OrthoRead was 3 s when using a 2.7 GHz processor. By being accurate, fast, and robust, OrthoRead can support prospective and retrospective clinical studies investigating implant efficacy, and can assist research on fracture healing mechanobiology.

Generation of Open Metatarsal Fracture in Rats: A Model for Secondary Fracture Healing

“…Although the aim of this study was not to keep the rats until the complete healing process has taken place, an attempt was made to assess the degree of the healing process at week seventh when animal experimentation was terminated. The histological and radiographic assessments of bone healing are among the most important qualitative and quantitative criteria used for evaluating fracture healing process as reported by Morshed, [43]; Gomez-Barrena et al [30]; Porter et al [32]. The radiological healing evaluation results of both lateral and anterior-posterior views revealed good, advance healing process with the majority of the radiological feature showed good bridging of the fracture gap.…”

“…Fracture consolidation was assessed and evaluated based on two parameters; callus index and fracture line disappearance in the course of the healing period. The callus index was measured by taking the ratio of the callus diameter against the diameter of the counter lateral normal limb (callus diameter/normal bone diameter) as described by Porter et al [32]. The callus diameter was measured under the dissecting stereo-microscope (Huvitz; HSZ-645TR, Korea) fitted with 3.1 mega pixel digital camera (VIS imaging; UC3010; Malaysia) and VIS plus ver.3.50 image analysis and measurement software; Canada.…”

Loss of scleraxis in mice leads to geometric and structural changes in cortical bone, as well as asymmetry in fracture healing

“…After death, plain radiographs were obtained (MX-20; Faxitron, Tucson, AZ, USA) to image the fracture in the sagittal plane. Digitized radiograph images at d 14 after fracture were analyzed for ventral/dorsal callus area and asymmetry using OrthoRead (Boise State University, Boise, ID, USA) (31). Asymmetry was calculated using:…”

Virtual structural analysis of tibial fracture healing from low-dose clinical CT scans

“…However, RUST scores are not objective and interpretation of the scoring criteria can be ambiguous, leading to known difficulties in inter-rater agreement (Leow et al, 2016). Some recent efforts to introduce objectivity in healing assessment have included image analysis techniques for measuring callus from 2D plain film X-rays (Porter et al, 2016), but the results from these methods are not a measure of structural mechanics at the fracture site.…”