Bone reconstruction: Subjective evaluation and objective analysis based on conventional digital X-rays – a retrospective evaluation

• Published in: Orthopaedics & traumatology, surgery & research surgery & research, 2021-12, Vol.107 (8), p.103081-103081, Article 103081
• Main Authors: Zak, Lukas, Tiefenboeck, Thomas M., Wozasek, Gerald E.
• Format: Article
• Language: English
• Subjects: Cohort Studies; Deformity correction; Distraction osteogenesis; External Fixators; External ring fixation; Humans; Intramedullary lengthening; Osteogenesis, Distraction; Pixel value ratio; Retrospective Studies; Tibia - diagnostic imaging; Tibia - surgery; X-Rays
• ISSN: 1877-0568; 1877-0568
• DOI: 10.1016/j.otsr.2021.103081

•Pixel Value Ratio (PVR) is a practical and straightforward tool for radiological evaluation of callus tissue development. It can help decide when to remove an external fixator, weight-bear an internal nail, or remove it.•PVR shows increasing values during the bone regeneration phases.•The X-ray Evaluation System for Distraction Osteogenesis (XESDO) is an appropriate tool for subjective callus tissue follow-up.•The PVR and the XESDO can influence decisions during all phases of distraction osteogenesis.•Bone healing was different in various regions, with slower development in the anterior area. Various approaches have been used to evaluate callus stiffness in distraction osteogenesis. This assessment becomes even more critical as inadequate corticalization and premature removal of the frame lead to bending, refracture, and loss of length. This study aimed to verify the objective Pixel Value Ratio (PVR) and define an evaluation scheme to assess callus tissue development during internal and external bone lengthening. There are no differences between subjective parameters and objective evaluation for external and internal bone lengthening. We included 24 patients in this retrospective study, treated by distraction osteogenesis of the lower limb. Ten patients were treated with external ring fixators and 14 with intramedullary lengthening devices. The minimum distraction distance was 3cm. Callus tissue was evaluated with the PVR, using digital X-rays during and after treatment. We combined this method with subjective evaluation parameters, including the continuity, signal intensity, and the regeneration tissue's homogeneity, presented in the X-ray Evaluation System for Distraction Osteogenesis (XESDO). The subjective evaluation showed an increase of continuity and signal-intensity between 4th postoperative weeks and complete healing with significant differences between the external and internal groups for homogeneity only after four weeks and for all parameters at 3C (p