Modification of elastic stable intramedullary nailing with a 3rd nail in a femoral spiral fracture model – results of biomechanical testing and a prospective clinical study

Abstract

BackgroundElastic stable intramedullary nailing (ESIN) is the standard treatment for displaced diaphyseal femoral fractures in children. However, high complication rates (10-50%) are reported in complex fractures. This biomechanical study compares the stiffness with a 3rd nail implanted to that in the classical 2C-shaped configuration and presents the application into clinical practice.MethodsFor each of the 3 configurations of ESIN-osteosynthesis with titanium nails eight composite femoral grafts (Sawbones®) with an identical spiral fracture were used: 2C configuration (2C-shaped nails, 2 × 3.5 mm), 3CM configuration (3rd nail from medial) and 3CL configuration (3rd nail from lateral). Each group underwent biomechanical testing in 4-point bending, internal/external rotation and axial compression.Results2C and 3CM configurations showed no significant differences in this spiroid type fracture model. 3CL had a significantly higher stiffness during anterior-posterior bending, internal rotation and 9° compression than 2C, and was stiffer in the lateral-medial direction than 3CM. The 3CL was less stable during p-a bending and external rotation than both the others. As biomechanical testing showed a higher stability for the 3CL configuration in two (a-p corresponding to recurvation and 9° compression to shortening) of three directions associated with the most important clinical problems, we added a 3rd nail in ESIN-osteosynthesis for femoral fractures. 11 boys and 6 girls (2.5-15 years) were treated with modified ESIN of whom 12 were ‘3CL’; due to the individual character of the fractures 4 patients were treated with ‘3CM’ (third nail from medial) and as an exception 1 adolescent with 4 nails and one boy with plate osteosynthesis. No additional stabilizations or re-operations were necessary. All patients achieved full points in the Harris-Score at follow-up; no limb length discrepancy occurred.ConclusionThe 3CL configuration provided a significantly higher stiffness than 2C and 3CM configurations in this biomechanical model. These results were successfully transmitted into clinical practice. All children, treated by 3CL or 3CM according to the individual character of each fracture, needed no additional stabilization and had no Re-Do operations. As a consequence, at our hospital all children with femoral diaphyseal fractures with open physis are treated with this modified ESIN-technique.

Quadruple ESIN (Elastic Stable Intramedullary Nailing): Modified Treatment in Pediatric Distal Tibial Fractures

“…18 In our department additional nails are inserted if the ESIN osteosynthesis does not provide enough stability in complex fracture types or in patients weighing >50 kg. 18 In our department additional nails are inserted if the ESIN osteosynthesis does not provide enough stability in complex fracture types or in patients weighing >50 kg.…”

Leg Length Discrepancy Due to Loss of Femoral Antecurvatum After Elastic Stable Intramedullary Nailing of Diaphyseal Fractures of the Femur in Children

“…Elastic stable intramedullary nailing (ESIN) using a pair of titanium nails is a widely accepted method of treatment of long bone diaphyseal fractures in children, leading to fast recovery, short hospital stay, and fewer complications compared with other methods of treatment [1][2][3][4]. Opposite to typical rigid intramedullary nailing for fractures of the femur, ESIN enters the femoral diaphysis not through, but between the growth plates of the long bone, thus avoiding potential growth disturbance secondary to physis injury and avascular necrosis of the femoral head secondary of injury of the nutrient vessels of the femoral head [1,5]. Unfortunately, this is accomplished in expense of fracture stability and less control on the mechanical and torsional profile of the affected limb.…”

“…The main indication of ESIN is a transverse or short oblique long bone diaphyseal fracture of the growing skeleton in children between the ages of five and 12 years and weighing less than 50 kg [6]. Due to the simple operative technique and the rapid healing potential of the growing skeleton of the child, surgeons increasingly use this technique even in oblique or comminuted fractures [1,5,7]. 1 2 3…”

“…Complications such as skin problems due to prominent hardware, infection, fracture nonunion, hardware failure (bending, breakage) and complications during hardware removal may be observed in children treated with the ESIN technique [2,8]. The complications rate is higher in more complex fractures and in children weighing more than 40 kg [5,9].…”

“…Until callus consolidation is complete, ESIN allows some movement (telescoping, bending, translation, torsion) at the fracture site. This may result in loss of longitudinal, torsional and angular alignment of the fracture and to subsequent malalignment and limb length discrepancy (LLD) [4][5].…”