Use of locked plates and mono-rail fixator in segmental tibial defects: A prospective interventional study

Abstract

Introduction: The management of gap non-union is a major challenge to both the clinician and the patient as it is technically difficult, time-intensive, and physically arduous for the patient along with an unpredictable result. Gap non-union can arise from extrusion of bony fragment at the time of trauma or after debridement of unhealthy bone later. Moreover, Tibia because of its subcutaneous anatomy can easily undergo bone-loss and segmental defect. Among various methods available for managing gap non-union of tibia distraction osteogenesis using either ilizarov fixator or mono-rail fixator is the most popular one. Here we present functional and bony outcomes of combined use of locking plate and Limb Reconstruction System (LRS) in tibial gap non-union and assess whether it decreases fixator time and related complications.

Patients and methods: A prospective intervention study constituting 10 patients with Paley's type B1 tibial gap non-union over a period of 22months. In first stage, debridement was done; tibial locking plate and mono-rail fixator were applied along with corticomy at proximal tibia. Distraction was started 7-14 days later. At the end of distraction phase, fixator was removed and transported segment was fixed with screws with or without bone grafting at docking site. Patients were followed up every 6 weeks for radiological and clinical assessment. Functional assessment using Application for the Study and Application of the Method of Ilizarov (ASAMI) functional score, and Musculoskeletal Tumour Society (MSTS) functional score while bone outcome was assessed with ASAMI bone score. Quality of regenerate was assessed by Fernandez-Esteve grading. Detailed scoring was done at the time of index surgery, at the time of LRS removal and at the time of consolidation phase.

Results: All the 10 patients were male with mean age of 33 years. The mean defect size was 4.94 cm after debridement. Minimum duration of follow up was 30 weeks after removal of LRS. Mean duration between trauma and inclusion in the study was 17.7 months. The median external fixator index was 15.63 days/cm. The complication rate was 1.3/patient. According to Paley's classification, there were eleven problems and two obstacles, and no true complications. Both ASAMI bone score and functional scores were excellent in three and good in six patients. The median MSTS composite score was 76.66%.

Conclusion: The integrated fixation is an effective and satisfactory method enabling early external fixator removal with low rate of complication. So, this technique can be recommended for the management of segmental tibial defects.

Level of evidence: II.

Keywords: ASAMI; LRS; Limb reconstruction system; Locking plate; Mono-rail fixator; Tibia defect.

Fig. 1

Showing procedure, (a) Transverse bone ends made at the end of first surgery; (b,c) shoing application of extra periosteal locking plate; (d) Corticotomy between the clamps of Limb reconstruction system (LRS); (e) Post-operative plain radiograph showing extra periosteal plate and LRS in-situ; (f) Plain radiograph showing regenerating phase of bone transport; (g) Radiograph at removal of LRS and final fixation with screw of transported segment.