The use of flexible intramedullary nails in limb lengthening

First Clinical Case of Ilizarov Femur Lengthening over a Bioactive and Degradable Intramedullary Implant

Introduction

The Ilizarov distraction osteogenesis is a recognized method of limb lengthening in orthopaedic practice. Its most challenging problems are long duration of external fixation and related pin-tract infection and joint contractures. The solution might be the use of a bioactive degradable intramedullary implant stimulating bone healing. Case Presentation. We present a case of a 14-year-old boy with 6 cm posttraumatic shortening of the femur and associated varus deformity of 20 degrees. He was treated with the Ilizarov technique of femur lengthening over an intramedullary degradable polycaprolactone (PCL) implant with hydroxyapatite (HA) filling. We faced no complications within the lengthening process. Shortening and deformity of the femur were corrected in 90 days. The index of external fixation was 15 days/cm. External fixation time was reduced almost twice comparing to the conventional method. Degradable intramedullary nails ensured the advantage of avoidance of the removal procedure. Radiography and CT confirmed faster new bone healing and remodeling.

Conclusion

The combined lengthening technique over a PCL/HA implant might be used to shorten external fixation time and to stimulate bone healing especially in patients with compromised bone. Using a bioabsorbable material presents the benefit of eliminating the need for a second surgery to remove the nail, thereby reducing soft tissue damage.

Transport over a flexible nail to treat a tibial defect caused by shelling injury: A case report of a 13-year-old child

INTRODUCTION

The care of tibial traumatic fractures brought on by shelling injuries is extremely difficult, as these fractures are frequently comminuted, leading to a bone defect, extensive soft tissue damage, and an increased risk of bacterial contamination.

CASE PRESENTATION

A 13-year-old male presented with trauma to the right leg following a shelling injury. He had a Gustilo IIIa open fracture with soft tissue destruction and a 7.5 cm bone loss in the distal region of the tibial shaft. Neurovascular exams were unremarkable. Primary treatment by external fixation, wound debridement, and simple suture closure was achieved. After the external fixator was removed, distraction osteogenesis was performed to deal with the bone loss. The surgical technique chosen was transport over a flexible intramedullary nail. By the end of both distraction and consolidation phases, the patient was healed with no complications, deformities, or length discrepancies.

DISCUSSION

The objective of treating tibial shelling wounds is to restore functionality and save the patient's life and limb. Neurovascular evaluation, early bone fixation, and wound care are the basic treatment. Many techniques of distraction osteogenesis can be used to restore bone loss. With lower external fixation time and complications, transport over a nail is an important one. However, using a rigid intramedullary nail in children is contraindicated, so a flexible one was used.

CONCLUSION

In this case report, we highlight the value of proper management of open leg fractures and the importance of restoring bone loss to improve the quality of life for war victims, particularly children.

Femoral lengthening using limb reconstruction system augmented with only one antegrade flexible nail in children: early results

Several techniques have been described for decreasing the duration of external fixator use, augmenting stability, and minimizing complications. The purpose of the present study was to evaluate the clinical results and complications of femoral lengthening procedures using the Limb Reconstruction System (LRS) in combination with a single antegrade flexible intramedullary nail (FIN). Femoral lengthening with LRS and FIN was applied to 14 patients (aged 6-16 years) between 2017 and 2021. The etiology was a congenital femoral deficiency in 12 patients and post-traumatic growth arrest in two. A single nail was inserted antegradely through the trochanteric apophysis in each patient. Radiographs and medical records of the patients were assessed retrospectively. The mean lengthening achieved was 4.8 ± 1.0 cm. The mean duration of external fixation was 181 days (range 139-248 days) and the mean healing index was 39.6 ± 12.1 days/cm. The mean values of mechanical medial proximal tibial angle, mechanical lateral distal tibial angle, mechanical lateral proximal femoral angle, and mechanical lateral distal femoral angle were within the normal range at the last follow-up. Seven of the 14 cases had a regenerate deformity that caused a displacement of more than 2 mm in the mechanical axis deviation, none of them was greater than 10 mm and considered clinically insignificant. Fracture was seen in two limbs with regenerate deformity. This study suggests that LRS in combination with only one FIN may be an effective alternative for femoral lengthening, with acceptable complication rates.

Comparison of Intramedullary Magnetic Nail, Monolateral External Distractor, and Spatial External Fixator in Femur Lengthening in Adolescents with Congenital Diseases

The aim of this study is to evaluate the course of the treatment and clinical and functional outcomes of femur lengthening in adolescents with congenital disorders by the application of different surgical methods. This retrospective study comprised 35 patients (39 procedures). A total of 11 patients underwent femur lengthening with the use of the intramedullary magnetic nail (IMN) Precise 2 (NuVasive, San Diego, CA, USA), 7 patients (11 procedures) with the use of the monolateral external distractor Modular Rail System (MRS) (Smith and Nephew, Memphis, TN, USA), and 17 with the use of the computer-assisted external fixator Taylor Spatial Frame (TSF) (Smith and Nephew, Memphis, TN, USA). The inclusion criteria were as follows: (1) congenital femoral length deficiency without any axial deformities and (2), independently of the finally applied treatment, the technical possibility of use of each of the analyzed methods. The distraction index did not differ significantly between the groups (p = 0.89). The median lengthening index was the lowest in the IMN group (24.3 d/cm; IQR 21.8–33.1) and statistically different in comparison to the MRS (44.2 d/cm; IQR 42–50.9; p < 0.001) and the TSF groups (48.4 d/cm; IQR 38.6–63.5; p < 0.001). Similarly, the consolidation index in the IMN group (12.9 d/cm; IQR 10.7–21.3) was statistically lower than that in the MRS (32.9 d/cm; IQR 30.2–37.6; p < 0.001) and the TSF (36.9 d/cm; IQR 26.6–51.5; p < 0.001) groups. This study indicates that IMN is a more valuable method of treatment for femoral length discrepancy without axial deformity than MRS and TSF in complication rate and indexes of lengthening and consolidation.

Limb Lengthening for Congenital Deficiencies Using External Fixation Combined With Flexible Intramedullary Nailing: A Multicenter Study

BACKGROUND

Hydroxyapatite (HA) coated flexible intramedullary nailing (FIN) stimulates osteogenic activity. The role of HA-coated intramedullary nails remains unclear in normal bone lengthening. The goal of this study was to quantify the influence of FIN on the External Fixation Index (EFI) in patients with congenital lower limb discrepancy.

METHODS

Patients with femoral deficiency and fibular hemimelia underwent lengthening by the combined technique of external fixation with titanium (Ti) FIN or HA coated FIN and returned for follow-up at least 12 months after frame removal.

RESULTS

Seventy patients (mean age of 12.6 y) were included: 19 monofocal femoral lengthenings, 35 tibial monofocal lengthenings, 16 tibial bifocal lengthenings. The mean EFI's for those treated with and without HA-coated nails were not significantly different. The Conover posthoc analysis did not reveal a significant influence of the type of FIN on EFI in any subgroup. However, 2-way analysis of variance revealed simultaneous effects of nail types and age on the EFI in tibial bifocal lengthening.Significant positive correlation between the ratio "nail diameter/medullary shaft diameter" and EFI in tibial bifocal non-HA-coated FIN lengthening, and a significant positive correlation between age and EFI for femoral non-HA-coated FIN lengthening, tibial monofocal and bifocal HA-coated FIN lengthening were revealed.There were 4 cases of fracture at lengthening site required unscheduled surgery. In the non-HA-coated group, there was a statistically significant negative correlation between nail diameter and fracture occurrence at the lengthening site after frame removal. A ratio of <0.15 likely does not ensure required mechanical stability and support.

CONCLUSIONS

Both Ti-nail and HA-coated nail lengthening provide good and excellent outcomes for femoral and tibial monosegmental lengthening procedures and ensure reduced EFI. In congenital disorders which were not associated with abnormal bone, there are no differences with regard to EFI using HA-coated or non-HA-coated FIN. The ratio of "elastic Ti-nail diameter/medullary canal diameter at narrowest site" <0.15 seems to be associated with higher risk of fracture at the lengthening site after frame removal.

Biodegradable magnesium combined with distraction osteogenesis synergistically stimulates bone tissue regeneration via CGRP-FAK-VEGF signaling axis

Critical size bone defects are frequently caused by accidental trauma, oncologic surgery, and infection. Distraction osteogenesis (DO) is a useful technique to promote the repair of critical size bone defects. However, DO is usually a lengthy treatment, therefore accompanied with increased risks of complications such as infections and delayed union. Here, we demonstrated that magnesium (Mg) nail implantation into the marrow cavity degraded gradually accompanied with about 4-fold increase of new bone formation and over 5-fold of new vessel formation as compared with DO alone group in the 5 mm femoral segmental defect rat model at 2 weeks after distraction. Mg nail upregulated the expression of calcitonin gene-related peptide (CGRP) in the new bone as compared with the DO alone group. We further revealed that blockade of the sensory nerve by overdose capsaicin blunted Mg nail enhanced critical size bone defect repair during the DO process. CGRP concentration-dependently promoted endothelial cell migration and tube formation. Meanwhile, CGRP promoted the phosphorylation of focal adhesion kinase (FAK) at Y397 site and elevated the expression of vascular endothelial growth factor A (VEGFA). Moreover, inhibitor/antagonist of CGRP receptor, FAK, and VEGF receptor blocked the Mg nail stimulated vessel and bone formation. We revealed, for the first time, a CGRP-FAK-VEGF signaling axis linking sensory nerve and endothelial cells, which may be the main mechanism underlying Mg-enhanced critical size bone defect repair when combined with DO, suggesting a great potential of Mg implants in reducing DO treatment time for clinical applications.

Efficacy of the "Eiffel tower" double titanium elastic nailing in combined management of congenital pseudarthrosis of the tibia: preliminary outcomes of 17 cases with review of literature

Background

Difficulty in obtaining union, recurrent fractures, and residual deformities remain the problems challenging the management of congenital pseudarthrosis of the tibia (CPT). We applied the “Eiffel Tower” double titanium elastic nails (TENs) in the existing combined approach, which takes advantages of TEN’s mechanical stability with the protection against refracture, Ilizarov’s high fusion rate with alignment control and the biologic environment provided by bone grafting for bony union. The results of this procedure are presented and discussed.

Methods

Seventeen patients with CPT treated by combined surgery including pseudarthrosis resection, the “Eiffel Tower” double TENs technique, autogenous iliac bone grafting, and Ilizarov fixation between 2013 and 2019 were retrospectively investigated. Signs of bone union, limb length discrepancy (LLD), rate of refracture, and degree of residual deformities were reviewed. The AOFAS Ankle Hindfoot scale and measurement of ankle motion were used to evaluate ankle function. The mean follow-up time was 40.5 (11 to 91) months.

Results

The mean age at index surgery was 6.2 (2.5 to 15) years. Union of the pseudarthrosis was achieved in 100% of cases. Among them, 15 (88.2%) patients obtained union of the pseudarthrosis on the first attempt (primary union). The average time to primary union was 3.8 (2 to 6) months. The rest 2 cases achieved union after additional surgeries (secondary union). In terms of complications, refracture occurred in 2 patients (11.8%) and 4 patients (23.5%) developed pin infection. The mean limb length discrepancy at the final follow up was 33.4 (6–141) mm. The average AOFAS score improved from 38.2 (27 to 51) pre-operatively to 77 (63 to 87) post-operatively (p < 0.01).

Conclusions

The “Eiffel Tower” double TENs technique is an ideal intramedullary fixation method in the surgical treatment of CPT. The combination of TENs technique with bone grafting and Ilizarov fixation has the advantages of early bone union, less injury on metaphysis, and early functional recovery.

Level of evidence

Level IV.

Overview of methods for enhancing bone regeneration in distraction osteogenesis: Potential roles of biometals

BACKGROUND

Distraction osteogenesis (DO) is a functional tissue engineering approach that applies gradual mechanical traction on the bone tissues after osteotomy to stimulate bone regeneration. However, DO still has disadvantages that limit its clinical use, including long treatment duration.

METHODS

Review the current methods of promoting bone formation and consolidation in DO with particular interest on biometal.

RESULTS

Numerous approaches, including physical therapy, gene therapy, growth factor-based therapy, stem-cell-based therapy, and improved distraction devices, have been explored to reduce the DO treatment duration with some success. Nevertheless, no approach to date is widely accepted in clinical practice due to various reasons, such as high expense, short biologic half-life, and lack of effective delivery methods. Biometals, including calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), manganese (Mn), and cobalt (Co) have attracted attention in bone regeneration attributed to their biodegradability and bioactive components released during in vivo degradation.

CONCLUSION

This review summarizes the current therapies accelerating bone formation in DO and the beneficial role of biometals in bone regeneration, particularly focusing on the use of biometal Mg and its alloy in promoting bone formation in DO. Translational potential: The potential clinical applications using Mg-based devices to accelerate DO are promising. Mg stimulates expression of multiple intrinsic biological factors and the development of Mg as an implantable component in DO may be used to argument bone formation and consolidation in DO.

Lower limb lengthening and deformity correction in polyostotic fibrous dysplasia using external fixation and flexible intramedullary nailing

The study describes preliminary experience of the use of external fixators for limb lengthening and deformity correction in combination with flexible intramedullary nailing in management of polyostotic fibrous dysplasia.

Patients and methods

The retrospective study included 8 patients (mean age 11.6 ± 3.38 years; range 7-17 years) with polyostotic fibrous dysplasia operated on using external circular frame and flexible intramedullary nailing. Mean follow-up was 2.6 years. Surgical technique consisted of percutaneous osteotomy of a segment and application of circular external frame. The intramedullary nailing was done using two bent nails. Hydroxyapatite-coated nails were applied in three patients; five patients had titanium nails. Amount of lengthening (cm and %), amount of deformity correction, duration of external fixator use, index of external fixation, "nail/medullary canal at narrowest site" ratio, "nail-medullary canal at osteotomy site" ratio were analyzed. Results and complications were assessed according to Lascombes's classification.

Results

The mean amount of lengthening was 4.5 cm (or 13.7 ± 6.0% per segment). This gave a mean external fixation index of 32.5 ± 13.97 days/cm. The mean ratio of IM nail diameter/medullary canal diameter at the narrowest site was 0.22 ± 0.07 (range, 0.125-0.3 mm). No migration of IM nails into medullary canal were noticed. But in one case there was external migration of Ti-nail. In a year after frame removal, the results of treatment were classified as grade I in 7 cases and IIb in one case.At the latest follow-up control, mechanical axis deviation was found within normal limits in six patients. Two patients had excessive MAD of 11 and 28 mm. In the first case a partial varus deformity recurrence occurred at middle shaft site where a large dysplastic zone was presented. In the second case, a specific shepherd's crook deformity developed and caused excessive MAD. Mean lower limb length discrepancy varied from 1 to 15 mm.

Conclusion

There are advantages of using elastic intramedullary nailing and external fixation in the treatment of limb length discrepancy and deformity of long bones in patients with PFD. This strategy ensures reduced external fixation time and high accuracy of alignment. Intramedullary nails left in situ, especially nails with HA-coating, seem to prevent deformity recurrence and stimulate remodeling in dysplastic fibrous zones.

Combined technique with hydroxyapatite coated intramedullary nails in treatment of anterolateral bowing of congenital pseudarthrosis of tibia

Purpose

The goal of this study is to evaluate the treatment outcomes of anterolateral bowing and residual deformities of distal tibia in patients with CPT using circular external fixation and hydroxyapatite coated flexible intramedullary nailing without excision of affected part of tibia.

Patients and methods

Six patients (4 boys and 2 girls, mean age 12.4 ± 4.1 years) were included in the study. Mean follow-up is 2.1 years. In 4 patients with early onset of disease initial surgical treatment (at age of 5-8 years) was dysplastic zone or pseudarthrosis resection with proximal metaphyseal osteotomy for bone transport. Children with unbroken bowed tibia (2 cases of type II according to Crawford classification) had no previous surgery. Neurofibromatosis type I was diagnosed in 4 cases. Surgical technique for residual deformity correction consisted of percutaneous osteotomy, application of circular external frame and composite hydroxyapatite-coated intramedullary nailing.

Results

Mean external fixation time was 95.3 ± 17.5 days. All patients never get fractured after frame removal. At the present time, they are considered to be healed, in 2.1 years, in average, without fractures or deformity recurrence. Mean lower limb length discrepancy varied from 2 to 10 mm at the latest follow-up control. After realignment procedure, patients didn't require additional surgery but one. Intramedullary nails were removed in two years after deformity correction for individual reason.

Conclusion

Correction of anterolateral bowing or residual deformity in children with CPT is indicated. Association of external fixation with intramedullary nailing/rodding left in situ after frame removal ensure stability and accuracy of deformity correction. Biological methods of stimulation of bone formation in dysplastic zone are obligatory to ensure bone union. Intramedullary nailing with composite hydroxyapatite-coated surface provides mechanical and biological advantages in patients with CPT.

Limb lengthening and deformity correction in children with abnormal bone

Flexible intramedullary nailing (FIN) provides multiple advantages in limb lengthening and progressive deformity correction in combination with external fixation. The article presents brief literature review and authors' experience in limb lengthening of abnormal bone (Ollier's disease, fibrous dysplasia, osteogenesis imperfecta). Titanium and, especially, hydroxyapatite-coated bent elastic nails in combination with external fixator are appropriate in limb lengthening of abnormal bone in children. FIN left in situ after lengthening procedure and external frame removal should be applied for long-term reinforcement of lengthened bone in patients with abnormal bone (metabolic bone disorders, skeletal dysplasias with compromised bone tissue development). The FIN respects bone biology, which is mandatory for good bone consolidation. Osteoactive properties of intramedullary elastic implants are favorable for bone formation and as well as for stable position of nails without risks of migration in long-term follow-up.

Atypical use of pediatric flexible nails in the treatment of diaphyseal fractures in adults

Background and aim of the work:

Elastic intramedullary nails are commonly used for the treatment of diaphyseal fractures in adolescents and children. The major advantages are the minimally invasive nature of the technique, the short operation time, and the preservation of the growth plate and periosteum thus allowing bone healing within a closed and intact biological environment. Elastic nails are rarely applied to the adult fractures.

Methods:

Five selected adult patients affected by diaphyseal fractures were treated using paediatric flexible nails T2 Kids (Stryker®, Mahwah, NJ, USA) as consequence of their poor clinical conditions, high risk of neurovascular injuries and skin/soft tissues problems. All patients were monthly clinically and radiographically evaluated after surgery until fracture healing.

Results:

Radiological and clinical outcomes were satisfying. All fractures healed after a mean period of 3 months. No losses of reduction as well as mobilization/breakage of implant were observed. Conclusions: Use of pediatric elastic nails is a valid surgical option in treatment of diaphyseal fractures in selected adult patients who request fast and minimally invasive surgery as consequence of precarious clinical or soft tissues conditions. (www.actabiomedica.it)

Remote-controlled internal lengthening plate for distraction osteogenesis in pediatric patients

OBJECTIVES

Limb lengthening by distraction osteogenesis is a technique widely used to treat limb length discrepancy resulting from trauma, congenital limb defects and long bone non-union. For decades, patients have resorted to the Ilizarov apparatus, prone to pin tract infections and scarring. Although implantable lengthening nails have reduced the incidence of complications, they are not applicable in pediatric patients with open growth plates. The aim of this project is to design a remote-controlled internal lengthening device suitable for implantation in children.

METHODS

The proposed device has the form of an internal remote-controlled telescopic lengthening plate, screwed to the lateral side of the bone with locking screws. This is appropriate for use with pediatric patients. It has been tested on an experimental bench which has the form of a vertically sliding platform, on which were stacked weights simulating soft-tissue resistance forces.

RESULTS

This internal lengthening plate generated distraction forces of up to 735 N on wooden and synthetic bones (Sawbones^TM). Furthermore, it maintained a constant distraction speed over the course of the procedure for a given weight.

CONCLUSIONS

This device represents a major advancement in the field of pediatric limb-lengthening, addressing a demographic gap left open by current implantable devices.

Biomechanical properties of 3D-printed bone models

Bone lesions resulting from large traumas or cancer resections can be successfully treated by directly using synthetic materials or in combination with tissue engineering methods (hybrid). Synthetic or hybrid materials combined with bone tissue's natural ability for regeneration and biological adaptation to the directions of loading, allow for full recovery of its biological functions. Increasing interest in new production methods or various types of regenerative membranes and shaped scaffolds means that methods such as additive manufacturing can significantly accelerate the preparation of constructs used in the further biological adaptation of natural tissue. The porosity that allows not only ingrowth of the natural tissue, but also the ability of the synthetic material to transfer loadings in the skeletal system during the regeneration interval, will have a significant impact on regenerative capacities. This work presents the results of preliminary analyzes of bone models in the field of mechanical strength for monotonically and cyclically loading conditions. The determined material constants, such as ultimate tensile strength, Young modulus, and toughness or fatigue life, can be used in numerical simulations of new membranes for the regeneration of damaged bone tissue.

Comparison of Mechanical Stability of Elastic Titanium, Nickel-Titanium, and Stainless Steel Nails Used in the Fixation of Diaphyseal Long Bone Fractures

Elastic nails made of the nickel-titanium shape memory alloy (Nitinol) have been reported to control bone modeling in animal studies. However, the mechanical stability of the Nitinol nail in the fixation of long bone fractures remains unclear. This study compared mechanical stability among nails made of three materials, namely Nitinol, titanium, and stainless steel, in the fixation of long bone fractures. These three materials had identical shapes (arc length: π/2 and radius: 260 mm). A cylindrical sawbone with a 10-mm gap and fixed with two C-shaped elastic nails was used to examine the stability of the nails. A finite element (FE) model was developed based on the sawbone model. The end cap for elastic nails was not used in the sawbone test but was considered based on a constraint equation in FE simulation. The results of stability tests appeared to depend on the presence or absence of the end cap. In the sawbone test, the titanium nail yielded a higher ultimate force against the applied load than did the stainless steel and Nitinol nails before the gap completely closed; the difference in linear stiffness between the nails was nonsignificant. In FE simulation, the titanium nail produced smaller gap shortening than did stainless steel and Nitinol nails without the end cap; the difference in gap shortening between the nails was minor with the end cap. The titanium elastic nail should be a better choice in managing diaphyseal long bone fractures when the end cap is not used. For Nitinol and stainless steel nails, the end cap should be used to stop the nail from dropping out and to stabilize the fractured bone.