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.

Use of sliding transphyseal flexible intramedullary nailing in pediatric osteogenesis imperfecta patients.

In our country, the sliding Flexible Intramedullary Nailing is used alone or in combination with Ilizarov frame in children with osteogenesis imperfecta. The study assesses the results of sliding intramedullary nailing in deformity correction in severe types of osteogenesis imperfecta. We retrospectively reviewed 17 consecutive cases (mean age 5.2 y.o.) of types III, IV and VII of osteogenesis imperfecta. In group I (9 patients) the transphyseal FIN was performed using titanium nails. Sliding flexible intramedullary nailing was associated with Ilizarov frame in group II in 8 children. Patients in group I had overall complication rate of 88.9%: proximal nail migration (3), early secondary torsional displacement (4), non-telescoping (12), angular deformity (2), delayed or non-union (2). The reoperation rate was 100%. In group II we observed complications in 6 patients: nail migration (2), bowing of femur (2), non-telescoping (3). The reoperation rate was 87.5%. Flexible intramedullary nailing allows realignment and good functional outcomes. Its major disadvantage is an important complication rate and related reoperation rate. The use of Ilizarov frame provides additional stability and allows early weight-bearing.

Progressive lengthening of short congenital forearm stump in children for prosthetic fitting.

PURPOSE: The sufficient length of congenital forearm stump is essential for prosthetic fitting. In our study we reviewed the results of a series of forearm stump lengthening, observed complications and their outcomes. We evaluated possibilities of combined technique to reduce or avoid problems and complications in forearm stump lengthening. METHODS: We retrospectively reviewed 18 children who have undergone forearm stump lengthening. In all patients the forearm lengthening was performed by means of Ilizarov frame. Additional flexible intramedullary nailing (FIN) was applied in two cases. RESULTS: The mean lengthening gain was 4.6 cm. The planned lengthening gain was obtained in all cases. The mean healing index (HI) was 34.1 days/cm. The most reduced HI was observed in two cases of combined technique (Ilizarov frame with FIN): 25.4 and 27.0 days/cm. Considering complications and outcomes the results were classified according to Lascombes: grade I--5 cases, IIa--10 cases, IIb--2 cases, IIIa--1 case. In the long term follow-up all patients used their prostheses fixed at the forearm stump with natural function of elbow joint. CONCLUSION: Forearm progressive lengthening in children with congenital transverse deficiency of the forearm is justified in order to facilitate prosthetic procedures and to preserve natural function of elbow joint. Sufficient lengthening can be achieved within one operation with a low rate of major complications. In our experience a repeated lengthening of forearm stump is not mandatory.

The normal radiological anteroposterior alignment of the lower limb in children.

INTRODUCTION: The development of reconstructive surgery of the lower limbs aimed at multilevel correction demands a precise knowledge of the physiological variations in general radiological parameters of the lower limbs in children of various age groups. It is crucial in systemic skeletal diseases, when deformities affect limbs and the surgeon does not have an intact limb as a reference. The aim of this retrospective study was to establish the normal radiological values of lower limb parameters used in the surgical correction of deformities in children of various age groups. MATERIAL AND METHODS: Teleradiographs of the lower limbs taken in children with unilateral congenital or posttraumatic deformity were retrospectively reviewed. Weight-bearing full-length anteroposterior radiographs of the entire lower extremities were taken in a standing position. The study involved 215 extremities of 208 children (93 girls and 115 boys); the ages ranged from 2 years 1 month to 15 years 11 months old. Key variables included the anatomic medial proximal femoral angle (aMPFA), anatomic lateral distal femoral angle (aLDFA), anatomic medial proximal tibial angle (aMPTA), anatomic lateral distal tibial angle (aLDTA), mechanical axis deviation (MAD), the angle formed by the femoral anatomical axis and the mechanical axis of the lower limb. RESULTS: The means and dynamics of variations, standard deviations (SD) and 95% confidence intervals of each parameter were calculated for each age and gender group. Simple regression analysis was performed to determine the relationship between the patient's age and the magnitude of aMPFA, aLDFA, aMPTA and aLDTA. Simple regression analysis showed a significant inverse correlation between patient age and the magnitude of aMPFA: the correlation coefficient was -0.77. A statistically significant inverse correlation between the MAD and the angle between the anatomic femoral axis and mechanical limb axis was found: the correlation coefficient was -0.53. CONCLUSION: In general, the received values were concordant to results of other studies. It concerned the MAD, aLDFA, aMPTA and angle between the mechanical limb axis and anatomic femoral axis. This is the first chronological evaluation of aMPFA and aLDTA from a relavively large series of patients. These normative data should be taken into consideration when evaluating lower limb alignment in children or applied in practice for planning and evaluation of the quality of surgical correction of complex deformities.

Prevention of recurrence of tibia and ankle deformities after bone lengthening in children with type II fibular hemimelia.

PURPOSE: This study aimed to evaluate development of the tibia after Ilizarov lengthening and deformity correction depending on whether or not the simultaneous resection of fibular anlage was performed in children with fibular aplasia type II, who did not undergo early surgery. METHODS: The study analyses results of reconstructive treatment in 38 children at the age of over four years. Two groups of children are compared: bifocal tibial lengthening with the Ilizarov device (group I) and bifocal lengthening associated with resection of the fibular anlage (group II). The results were estimated at 12 months and in the long-term exceeding three years. RESULTS: Radiological data of measurement of the anatomical lateral distal tibial angle (aLDTA) show surgical correction of deformities achieved in both groups. During the further limb growth a tendency to normalisation of the aLDTA was observed only in the group II. Quick relapse of the angular deformities of the tibial shaft in the first group occurred mainly during further growth of the limb regardless of complete correction at the time of treatment. On the other hand, there were no recurrences of diaphyseal deformities in the group II. CONCLUSIONS: In children with congenital fibular deficiency of type II at the age of four years, the bone lengthening and deformity correction should be associated with fibular anlage resection. That approach improves conditions for distal tibia development and prevents or decreases significantly the recurrence of deformities of the tibia and ankle joint in long-term follow-up.

Results of deformity correction in children with X-linked hereditary hypophosphatemic rickets by external fixation or combined technique.

BACKGROUND: The operative procedures to correct multiplanar bone deformities may be indicated for prevention of secondary orthopaedic complications in children with X-linked hereditary hypophosphatemic rickets (XHPR). Different problems related to surgical correction were reported: increased rate of non-union, delayed union, recurrent deformity, deep intramedullary infection, refracture, nerve palsy, and pin tract infection. The aim of this retrospective study was comparison of results of correction in children with XHPR who underwent the treatment with either the Ilizarov device alone or a combined technique: the Ilizarov fixator with flexible intramedullary nailing (FIN) with hydroxyapatite bioactive coating and FIN. MATERIAL AND METHODS: We retrospectively analysed 47 cases (children of age under 14 years) affected by XHPR. Simultaneous deformity correction in femur and tibia was performed with the Ilizarov device (group I) or the combined method (group II). This article is based on the results of a historical comparative retrospective study from the same institution. RESULTS: The duration of external fixation is noted to be shorter applying the combined technique: 124.7 days (group I) vs 87.4 days (group II). In both groups deformity correction was achieved with a proper alignment. Nevertheless, while a child continues to grow during long-term follow-up, deviations of the mechanic axis from the centre of the knee joint have been developing again and values of mLDFA, mMPTA have become pathologic in the most of the cases. In group I location of a newly developed deformity resembled a pre-operative one, whereby both diaphyseal and metaphyseal parts were deformed. In group II in all the cases an apex of deformity was located in distal metadiaphyseal zone of the femur and proximal metadiaphyseal zone of the tibia. It is important to note that all of those in group II were out of the zone of the intramedullary nail. CONCLUSION: Simultaneous correction of femoral and tibial deformities by means of circular external fixators is preferable. Application of a combined osteosynthesis allows to considerably reduce the duration of external fixation and decrease the number of complications. There were no recurrent deformities in parts of bone reinforced by intramedullary nails.

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.

Preliminary Results of Bone Lengthening over Telescopic Titanium Intramedullary Rod.

Background: Limb lengthening and deformity correction in patients with abnormal bone associating fragility often require an approach combining methods of external and internal fixation. This study demonstrates results of simultaneous application of external fixator, and telescopic rod for femoral lengthening and deformity correction in three children with osteogenesis imperfecta or severe form of Ollier's disease. Materials and Methods: Three patients (two boys with Ollier's disease and a girl with osteogenesis imperfecta, type I) were operated on for femoral lengthening with combined technique associating Ilizarov frame and titanium telescopic intramedullary rodding. Results: Planned amount of lengthening and deformity correction were achieved for all patients. We found neither rod bending nor pull out of threaded tips. There was no difficulty of expanding of telescopic intramedullary rods made of titanium alloy during distraction phase of lengthening procedure. Conclusion: This short series proved feasibility of performing one-stage surgery with external frame and telescopic rodding in limb lengthening. The technique of telescopic rods in lengthening procedure is promising method requiring meticulous insertion of rod in centralized positioning in epiphysis. Acute alignment of the segment been elongating should be achieved at surgery. No any progressive angular deformity correction in postoperative period is authorized in order to avoid bending of telescopic rod. This combined approach does not affect bone healing.

Impact of telescopic intramedullary rodding on the growth of tibia: Comparative experimental study in dogs.

INTRODUCTION: The most commonly accepted method of long bone deformity correction in children with osteogenesis imperfecta is surgical realignment with transphyseal telescopic intramedullary rodding. This approach ensures reinforcement of the bone throughout the growth period. Although longitudinal growth does occur with these implants there has been very little work carried out to calculate the effect of such factors as rod position or implant material on growth. We carried out a prospective comparative study on 12 puppies using titanium alloy telescopic tibial rods with and without hydroxyl-apatite coating. The aim of this non-randomized controlled experimental study was to assess the impact of telescopic intramedullary rodding on spontaneous growth of the tibia. MATERIAL AND METHODS: Twelve mongrel puppies aged of 5 months underwent intramedullary transphyseal rodding of the right tibia. In group I (6 dogs) a titanium telescopic rod was used, in group II (6 dogs) a titanium rod with hydroxyapatite (HA)-coated threaded end was used. The following radiological criteria were assessed before surgery and every month until age of 12 months (natural fusion of physes in dogs): length of tibia, amount of superposition of inner (male) rod into external (female) rod; alteration of anatomy in terms of joint angles (mMPTA, mLDTA, mPPTA, mADTA); positioning of threaded ends in proximal and distal epiphyses and evidence of premature growth arrest. Parameters were compared with left tibia serving as control segment. The null hypothesis was that neither rod position nor implant material altered growth. RESULTS: The transphyseal rods did not lead to irreversible epiphysiodesis in either group. In group II (HA-coated) some loss of residual length was found in all six dogs, over 7mm (5.9%) in comparison to left intact tibia. In contrast to that, in group I (titanium nail) only one animal (16.7%) demonstrated a tibia length discrepancy of 8mm (4.8%). Eccentric ( posterior) positioning of the rod in the distal epiphysis resulted in a procurvatum deformity (increased anterior distal tibial angle) in both groups. We found no failure of telescoping and no loss of fixation of threaded parts in either epiphyses. DISCUSSION: The presence of telescopic rods with HA-coated threads parts clearly contributes to inhibition of spontaneous longitudinal growth. We hypothesize that HA stimulates maturation of chondrocytes of growth plate. Our findings regarding the potential adverse effect of thread position in the distal physis demonstrate the importance of attempting to place the rod as central as possible. CONCLUSION: Titanium alloy telescopic rods did not reveal significant effect on physeal growth in puppies in comparison to HA-coated implants. Transphyseal HA-coated implants did however inhibit growth plate function with mean loss of length of 5.2% compared to the other side. Eccentric positioning of rods relative to center of physis resulted in angular deformity due to irregular growth. There were no cases of mechanical failure or loss of telescopic function with either group of titanium implant. LEVEL OF EVIDENCE: II; prospective comparative experimental study.

Combined lengthening for acquired leg length discrepancy: Are there advantages of hydroxyapatite-coated intramedullary nails?

INTRODUCTION: The aim of this multicenter prospective study was to analyze the outcomes of bone lengthening by external fixator associated with flexible intramedullary nailing (FIN) in acquired limb length discrepancy (LLD). HYPOTHESIS: Hydroxyapatite (HA)-coated FIN enables reduced External Fixation Index in limb lengthening for acquired leg length discrepancies in comparison to non-HA-coated FIN. MATERIAL AND METHODS: This study included 54 patients (mean age, 17.9 years) operated on for femoral or tibial lengthening by combined technique (External fixator with FIN) for acquired length discrepancy. Titanium non-HA-coated FIN (29 cases) or HA-coated FIN (25 cases) were used. The factors that might influence external fixation index, complication occurrence and outcome were analyzed: age, amount of lengthening, nail diameter, HA-coating vs. non-HA-coated nails. RESULTS: The mean External Fixation Indexes (EFI) of groups compared for non-HA-coated nails vs. HA-coated nails were not significantly different: 26.5 d/cm and 27.2 d/cm in femoral lengthening and 34.9 d/cm and 31.7 d/cm in tibial lengthening. Positive correlation between the "nail diameter/inner distance between cortices at osteotomy site" ratio and EFI in tibial lengthening was revealed (p=0.034). The nail types and the "nail diameter/medullary canal diameter" ratio interact and have significant simultaneous effect on EFI in femoral lengthening (p=0.021). DISCUSSION: The results of this study revealed no differences with regards to EFI using HA-coated or non-HA-coated titanium FIN in lengthening for acquired leg-length discrepancies. Combined technique allowed reduced EFI and avoided major complications. Both non-HA-nail and HA-coated nail lengthening provided good and excellent outcomes. LEVEL OF EVIDENCE: III; (controlled trial without randomization) prospective comparative study.

Long Bone Defect Filling with Bioactive Degradable 3D-Implant: Experimental Study.

Previously, 3D-printed bone grafts made of titanium alloy with bioactive coating has shown great potential for the restoration of bone defects. Implanted into a medullary canal titanium graft with cellular structure demonstrated stimulation of the reparative osteogenesis and successful osseointegration of the graft into a single bone-implant block. The purpose of this study was to investigate osseointegration of a 3D-printed degradable polymeric implant with cellular structure as preclinical testing of a new technique for bone defect restoration. During an experimental study in sheep, a 20 mm-long segmental tibial defect was filled with an original cylindrical implant with cellular structure made of polycaprolactone coated with hydroxyapatite. X-ray radiographs demonstrated reparative bone regeneration from the periosteum lying on the periphery of cylindrical implant to its center in a week after the surgery. Cellular structure of the implant was fully filled with newly-formed bone tissue on the 4th week after the surgery. The bone tissue regeneration from the proximal and distal bone fragments was evident on 3rd week. This provides insight into the use of bioactive degradable implants for the restoration of segmental bone defects. Degradable implant with bioactive coating implanted into a long bone segmental defect provides stimulation of reparative osteogenesis and osseointegration into the single implant-bone block.

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.

Osteointegration technology in long bone defect reconstruction: experimental study.

PURPOSE: The purpose of this experimental study was to evaluate the osteointegration of a bioactive 3D-cylindrical titanium-alloy implant (bone-graft substitute) for tibial shaft defect reconstruction. METHODS: An experimental study was done in 7 mongrel dogs. Tibial shaft defect was repaired using an original titanium-alloy (Ti6Al4V) cellular cylindrical implant. with a bioactive layer of hydroxyapatite by anode microarc oxidation. Histological study (hematoxylin-eosin stain and immunohistological reaction using ostepontin polyclonal antibodies) and scanning electron microscopy (electron probe X-ray microanalysis for calcium and phosphorus saturation in the tissue matrix) were applied to assess bone tissue regeneration. RESULTS: Experimental study revealed osteoconduction starting from the endosteum of bone fragments adjacent to the bone defect and developed to the central part of the implant. In 4 weeks, graft osteointegration was achieved in all animals. Implant cells were filled with spongy bone tissue and the graft external surface was covered with a connective tissue structures similar to the periosteum ones. CONCLUSIONS: Cellular titanium bone-graft substitute with bioactive coatings placed into bone defect stimulates reparative osteogenesis and graft osteointegration.

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 ±â€¯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 ±â€¯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.

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.

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.

Impact of Transphyseal Elastic Nailing On the Histostructure of the Tibia in Growing Animals (Non-Randomized Controlled Experimental Study).

BACKGROUND: The use of intramedullary elastic nailing is a method of choice for prevention of complications in children with osteogenesis imperfecta. However, the morphology of the growing long bones in the conditions created was not investigated. AIM: The purpose of our experiment was to study the impact of elastic intramedullary nailing on the histostructure of long bones in their physiological growth. METHODS: Six mongrel dogs underwent intramedullary elastic transphyseal nailing of the intact tibia with two titanium wires. Six months after nailing, a light-optical microscopic and histomorphometric study of the operated and contralateral tibiae was performed. RESULTS: It was found that asymmetric lesion of the distal physis induces a decrease in the height of the distal epimetaphysis. Adaptive changes in the hyaline cartilage of both articular ends were revealed corresponding to the initial stage of chondropathy. Intramedullary nailing promotes an increase in the thickness of the compact bone and the volume of the trabecular bone. CONCLUSIONS: Elastic transphyseal nailing of the intact tibia has a shaping effect which is expressed by an increase in the volume of spongy and compact bone, adaptive changes in the hyaline cartilage. Asymmetric damage to growth zones should be avoided to prevent deformities.

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.

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.

Bioactivity and osteointegration of hydroxyapatite-coated stainless steel and titanium wires used for intramedullary osteosynthesis.

A lot of research was conducted on the use of various biomaterials in orthopedic surgery. Our study investigated the effects of nanostructured calcium-phosphate coating on metallic implants introduced into the bone marrow canal. Stainless steel or titanium 2-mm wires (groups 1 and 2, respectively), and hydroxyapatite-coated stainless steel or titanium wires of the same diameter (groups 3 and 4, respectively) were introduced into the tibial bone marrow canal of 20 dogs (each group = 5 dogs). Hydroxyapatite coating was deposited on the wires with the method of microarc oxidation. Light microscopy to study histological diaphyseal transverse sections, scanning electron microscopy to study the bone marrow area around the implant and an X-ray electron probe analyzer to study the content of calcium and phosphorus were used to investigate bioactivity and osteointegration after a four weeks period. Osteointegration was also assessed by measuring wires' pull-off strength with a sensor dynamometer. Bone formation was observed round the wires in the bone marrow canal in all the groups. Its intensity depended upon the features of wire surfaces and implant materials. Maximum percentage volume of trabecular bone was present in the bone marrow canals of group 4 dogs that corresponded to a mean of 27.1 ± 0.14%, while it was only 6.7% in group 1. The coating in groups 3 and 4 provided better bioactivity and osteointegration. Hydroxyapatite-coated titanium wires showed the highest degree of bone formation around them and greater pull-off strength. Nanostructured hydroxyapatite coating of metallic wires induces an expressed bone formation and provides osteointegration. Hydroxyapatite-coated wires could be used along with external fixation for bone repair enhancement in diaphyseal fractures, management of osteogenesis imperfecta and correction of bone deformities in phosphate diabetes.