Arnold Popkov

Flexible Intramedullary Nail Use in Limb Lengthening

Background The aim of this study is to evaluate the influence of the external fixation associated with flexible intramedullary nailing (FIN) on the healing index (HI) in limb lengthening. Methods We compared the healing index between 2 groups of children undergone the lengthening of upper and lower limbs carried out with the Ilizarov external fixator alone (group I, 194 cases of lengthening) or with the combination of the Ilizarov external fixator and intramedullary nailing (group II, 92 cases). Two nails of the diameter from 1.5 to 2.0 mm with the ray of curvature about 40 degrees to 50 degrees were used for the intramedullary nailing. Results The HI was less in every subgroup of Group II compared with Group I. A significant difference was noted in congenital pathologies: monofocal monosegmental lengthening at the level of femur and forearm, bifocal lengthening of the tibia, polysegmental lengthening; and in acquired discrepancy: monofocal tibial lengthening, bifocal femoral lengthening, and the forearm lengthening. The reduction of HI was between 60% and 85% in congenital pathologies: monosegmental femur and forearm, bifocal femur and tibia lengthening; and in acquired discrepancy: femur, tibia, humerus and forearm monosegmental lengthening, humerus and tibia bifocal lengthening, and polysegmental in upper and lower limbs. This difference varies from 1.9 days/cm to 19.1 days/cm. That means that the duration of the external fixator was decreased of 20% to 33% of the number of days between the Group I and the Group II. Maximum diminution of HI was noted for monofocal acquired forearm cases (51.3%) and bifocal acquired femoral lengthening cases which (59.9%). Conclusions The flexible intramedullary nailing allows adding multiple advantages to the method of limb lengthening with the external fixator. Correctly applied the FIN indeed respects the bone biology that is essential during the limb lengthening. The major effect of application of the combination of Ilizarov frame fixation with FIN is a significant decrease of duration of the external osteosynthesis. Level of Evidence II.

Elastic intramedullary nailing as a complement to Ilizarov's method for forearm lengthening: A comparative pediatric prospective study

PURPOSE Most of the techniques for forearm lengthening involve external fixation to achieve stability and provide progressive distraction. We introduce the use of elastic stable intramedullar nailing (ESIN) in combination with external circular assembly for the procedure. The purpose of this prospective study was to compare Ilizarovs classical technique with this combined technique. METHODS Fifty-seven patients, with forearm length discrepancies or deformities either congenital or acquired, were prospectively followed-up. Patients were divided in two groups: 35 had only external fixation, and 22 had external fixation-ESIN combined techniques. Patients were assessed for clinical and radiographic outcome with a mean follow-up of 21 months after external device removal. RESULTS Overall lengthening was 45.0mm. Healing index (HI) was 22.2d/cm with the combined technique, and 32.0 d/cm with external fixation. HI was 30% better when ESIN was used, for congenital and for overall cases. Combined technique has a lower complication rate. CONCLUSION Although forearm lengthening still remains a time-consuming procedure, ESIN can shorten external fixator wearing time. No additional complication occurred and bony complications seem to be limited by the nails. We recommend this technique, which we now use for most of our patients undergoing limb lengthening. LEVEL OF EVIDENCE Level IV.

Ollier's disease limb lenghtening: Should intramedullary nailing be combined with circular external fixation?

INTRODUCTION During progressive lower limb lengthening in the management of Olliers disease, the mean bone-healing index usually reported in the literature stands around 35 days/cm. One of the therapeutic objectives is to reduce the duration of the external fixation. HYPOTHESIS The use of an elastic stable intramedullary nailing system (ESIN) combined with a circular external fixator significantly reduces the healing index. MATERIAL AND METHODS Two groups of patients were compared. In group I, seven patients were operated on for progressive limb lengthening using a circular external fixator associated with an ESIN system: four monosegmental femoral lengthenings, one monosegmental tibial lengthening and two polysegmental femorotibial lengthenings. Nailing was performed via two intramedullary nails already used in traumatology. The date of external fixator removal coincided with that of radiographic healing. The nails were left in place. Group II included 37 patients who underwent limb lengthening by means of an external fixator only. The healing index was calculated and complications were analysed in both groups. RESULTS The mean healing index (HI) values were: in group I: 23.3 days/cm for the femur, 22.4 days/cm for the tibia and 11.6 days/cm for polysegmental lengthenings ; in group II: 31.6 days/cm for the femur, 35.7 days/cm for the tibia and 19.9 days/cm for polysegmental lengthenings. Group I demonstrated a statistically significant decrease in the HI for monosegmental femoral lengthenings. CONCLUSION A substantially reduced duration of external fixation, limited postoperative complications and prevention of later pathologic fractures are the reported advantages of the associated use of a circular external fixator with an ESIN system in the management of Olliers disease. LEVEL OF EVIDENCE Level III, comparative retrospective study.

Analysis of segmental residual growth after progressive bone lengthening in congenital lower limb deformity

INTRODUCTION The issue of prognosis in limb length discrepancy in children affected by congenital abnormality remains a subject of concern. Therapeutic strategy must take length prediction into account, to adapt equalization techniques and the timing of treatment. Initial prognosis, however, may need revising after completion of one or several surgical interventions on the pathologic limb. The aim of this study was to determine the different types of growth response that a bone segment can present after progressive lengthening in case of congenital limb length discrepancy. MATERIALS AND METHODS A series of 114 bone lengthenings with external fixator, performed in 36 girls and 50 boys with congenital lower limb length discrepancy, was retrospectively analyzed. Bone segment growth rates were measured before lengthening, during the first year after frame removal and finally over long-term follow-up, calculating the ratios of radiological bone length to the number of months between two measurements. Mean follow-up was 4.54±0.2 years. RESULTS Changes in short- and long-term growth rate distinguished five patterns of bone behavior after lengthening, ranging from growth acceleration to total inhibition. DISCUSSION These five residual growth patterns depended on certain factors causing acceleration or, on the contrary, slowing down of growth: age at the lengthening operation, percentage lengthening, and minimal period between two lengthenings. These criteria help optimize conditions for resumed growth after progressive segmental lengthening, avoiding conditions liable to induce slowing down or inhibition, and providing a planning aid in multi-step lengthening programs. LEVEL OF EVIDENCE Level IV. Retrospective study.

Current approaches to flexible intramedullary nailing for bone lengthening in children

Limb-length discrepancies and extremity deformities are among the most common non-traumatic orthopaedic conditions for which children are hospitalised. There is a need to develop new treatment options for lower-limb length discrepancy in order to ameliorate treatment outcomes, avoid or reduce rates of complication and provide early rehabilitation. The authors report on the basic principles, experimental and clinical data, advantages, problems and complications of a combined technique associating the Ilizarov method and flexible intramedullary nailing (FIN) in limb lengthening and deformity correction in children. They describe features of the use of hydroxyapatite-coated intramedullary nails in patients with certain metabolic bone disorders and in cases where bone consolidation has been compromised. The advantages of bone lengthening using a combined technique (circular fixator plus FIN) are a lower healing index, quicker distraction-consolidation, a reduced rate of septic and bone complications, the ability to correct deformities gradually and the increased stability of bone fragments during the external fixation period and after frame removal.

BIOLOGICAL ACTIVITY OF THE IMPLANT FOR INTERNAL FIXATION

Early treatment of bone fractures was performed using implants, which are often used in the form of plates of various types, which are fixed on the bone surface (extracellular fixation) and nails that are located in the medullary canal (intracerebral fixation). The goal of this study was to investigate the features of osseointegration of implants for internal fixation (intramedullary or extramedullary) with various bioactive coating techniques. During experimental study on 20 mongrel dogs, the implant model in the form of 1.0‐mm plate made of titanium alloy (Ti6Al 4V) was placed in the medullary canal (first series) or under the periosteum (second series): the plates had bioactive coating (hydroxyapatite) produced using the technology of magnetron sputtering (six animals), plasma electrolytic oxidation or microarc oxidation technology (PEO; eight animals), and composite technology (six dogs). Anatomic and histological studies have shown that the process of active osseointegration of porous implants with bioactive coating begins after 7 days: at first, granulation tissue – and then fibrous connective tissue – is formed; after 14 days, the osteogenic substrate can be found, and after 28 days, the entire implant area is covered by the lamellar bone tissue, which creates single implant–bone block. The most active formation of bone tissue is observed around implants with bioactive coating produced using the last two technologies. Low traumatic placement of porous implants with bioactive coating in the medullary canal or subperiosteally provides the stimulation of reparative osteogenesis and rapid (especially with PEO technique) osseointegration of the implant.

The use of flexible intramedullary nails in limb lengthening

ABSTRACT Introduction: Lower and upper limb length discrepancy and deformity, congenital or acquired, are amongst the most common conditions in children for orthopaedic referral. Over the last twenty years, surgical techniques have evolved in an attempt to decrease Healing Index and minimise these complications. Areas covered: The flexible intramedullary nailing (FIN) is a minimally invasive intramedullary osteosynthesis. In combination with an external fixator, it is appropriated for pediatric bone lengthenings and lengthening of bones of small diameter in adults. In the study the Scopus and/or PubMed indexed publications about this combined technique were analyzed. Expert commentary: The use of titanium or stainless steel or hydroxyapatite-coated bent elastic nails is appropriate in limb lengthening for congenital and acquired limb length discrepancy. Hydroxyapatite-coated FIN should be applied for long-term reinforcement of lengthened bone in patients with metabolic bone disorders, skeletal dysplasias with compromised bone formation. Osteoinductive surface of nails is favorable for bone formation and as well as for stable position of nails without risks of migration in long-term follow-up. The FIN is an unique intramedullary fixation which respects the bone biology which is mandatory for a good bone consolidation.

Osseointegration of A Bioactive Implant in Extramedullary Osteosynthesis

The purpose of the study is providing rationale for the optimal type and structure of an extramedullary implant to achieve its rapid osseointegration and, consequently, to reduce the time required for bone fracture union. In an experimental study on 10 mongrel dogs, extramedullary osteosynthesis of tibia was done with 1.0 mm thick titanium alloy (Ti6Al 4V) plates having either solid or perforated structure, and the osseointegration process was compared in animals with an implant with no bioactive coating with those with hydroxyapatite (HA) on the implant surface. The plates were fixed to the tibia under the periosteum. Radiological, anatomical and histological studies demonstrated that the process of osseointegration of a perforated implant with a bioactive coating actively begins at Days 7-14 first with formation of granulation tissue and then followed by formation of fibrous connective tissue, so by Day 28 the entire implant area is covered with tissue substrate, having the signs of osteogenesis, which connects an extramedullary implant and bone surface into a single implant-tissue segment. Fixation of perforated implants with a bioactive coating under the periosteum stimulates reparative osteogenesis and rapid implant osseointegration to achieve consolidation of bone fragments based on the principle of the primary bone union.