Computed Tomography in Limb Salvage and Deformity Correction—3D Assessment, Indications, Radiation Exposure, and Safety Considerations

Abstract

Computed tomography (CT) is an essential tool in orthopedic surgery but is known to be a method with that entails radiation exposure. CT increases the risk of developing fatal cancer, which should not be underestimated. However, patients with bone defects and/or deformities must frequently undergo numerous investigations during their treatment. CT is used for surgical planning, evaluating callus maturation, alignment measurement, length measurement, torsion measurement, and angiography. This study explores the indications in CT scans for limb lengthening and deformity correction and estimates the effective radiation dose. These results should help avoid unnecessary radiation exposure by narrowing the examination field and by providing explicit scanning indications. For this study, 19 posttraumatic patients were included after the bone reconstruction of 21 lower limbs. All patients underwent CT examinations during or after treatment with an external ring fixator. The mean effective dose was 3.27 mSv, with a mean cancer risk of 1:117 014. The effective dose depended on the location and indication of measurement, with a mean dose of 0.04 mSv at the ankle up to 6.8 mSv (or higher) for vascular depictions. CT evaluation, with or without 3D reconstruction, is a crucial tool in complex bone reconstruction and deformity treatments. Therefore, strict indications are necessary to reduce radiation exposure—especially in young patients—without compromising the management of their patients.

Different per-operative techniques to evaluate limb length discrepancy in hip arthroplasty.

“…20 Various methods, including full-length hip-toankle radiographs, ultrasound approaches, and "computed tomographic scanograms", are utilized for limb length measurement. 21,22 To maintain measurement accuracy, our study excluded patients with complex hip pathology, as hip position and pelvic obliquity can influence results. Despite some studies reporting differences in dislocation rates related with specific surgical methods, none have suggested major variations in LLD or cumulative post-surgery outcomes.…”

Corrective Osteotomies in Severe Non-Idiopathic Lower Limb Alignment Disorders in the Aspect of Future Joint Endoprosthesis—A Perspective Study

“…Radiographic assessment standing X-rays allowed the following angles to be measured: for femur segment: mLPFA (mechanical lateral proximal femoral angle), mLDFA (mechanical lateral distal femoral angle), MAD (mechanical axis deviation) and CORA (center of rotation of angulation) coronal and sagittal plane; for tibia segment: mMPTA (mechanical medial proximal tibial angle), mLDTA (mechanical lateral distal tibial angle), MAD (mechanical axis deviation) and CORA (center of rotation of angulation) coronal and sagittal plane [5]. Preoperative diagnosis and planning in patients with suspected torsional disorders were guided by computed tomography (CT) images with 3D and multiplanar reconstruction (MPR) [6]. All measurements were performed, accounted for and calculated statistically, considering the lower limb axis disorders relative to the segment.…”