Hydrolysis of Bone-Replacing Materials Based on Polylactic Acid and Containing Hydroxyapatite in an In Vitro Experiment.

We studied the features of hydrolytic degradation of polylactic acid (PLLA) implants depending on their structural filling with hydroxyapatite (HA). The resistance to in vitro hydrolysis was tested for the following samples: PLLA without HA (control; group 1), PLLA/HA 25 wt% (group 2), and PLLA/HA 50 wt% (group 3). Samples were incubated at 37°C. In the hydrolysate, lactate, calcium ions, and inorganic phosphate were determined. Additionally, the time of appearance of visual deformation and sample disintegration was recorded. PLLA degradation was higher in samples saturated with HA. The highest resistance to deformation was noted for samples without HA. Samples with a PLLA/HA 50 wt% demonstrated the maximum degradation of PLLA in combination with lower resistance to deformation and the highest bioavailability of calcium and phosphate. Group 2 samples are most promising for clinical use.

Solution blow spinning of PLLA/hydroxyapatite composite scaffolds for bone tissue engineering.

Composite poly-L-lactide acid-based scaffolds with hydroxyapatite (HAp) content up to 75 wt.% were fabricated via solution blow spinning. The influence of HAp concentration on structure, wettability, mechanical properties and chemical and phase composition of the produced materials was examined. It was found that with an increase of HAp content the average fiber diameter was increased, the uniaxial strength and relative elongation were reduced, while the phase composition and surface wettability did not change. The performance of the scaffolds during implantation in the parietal bone of a rat skull for a period from 15 to 90 days was studied. The materials have shown high ability to integrate with both soft and hard tissues. It was found that scaffolds with 25 wt.% HAp content significantly enhance osteogenesis during scarification (damage) of the periosteum. Overall, the fabricated scaffolds proved to be highly efficient for replacing bone defects in long tubular bones.

[Economic aspects in sIngle-event multilevel orthopedic surgery in patients with cerebral palsy].

This article reports an assessment of direct expenses for surgical treatment of patients with cerebral palsy and secondary orthopedic complications, who have undergone single-event multilevel orthopedic surgeries (SEMLS). It has been demonstrated that modern approach based on SEMLS is substantiated from the medical point of view and at present it is also justified from the point of view of economic assistance for that type of treating activity of a Federal Centre specialized in trauma and orthopaedics. Organization of surgical treatment using multilevel orthopaedic interventions requires selection of implants for specific characteristics and, on expenditure side, not exceeding funding of direct expenses intended for this treating process.

Bone Formation and Adaptive Morphology of the Anterior Tibial Muscle in 3-mm Daily Lengthening Using High-Fractional Automated Distraction and Osteosynthesis with the Ilizarov Apparatus Combined with Intramedullary Hydroxyapatite-Coated Wire.

PURPOSE: We studied osteogenesis and morphofunctional features of the anterior tibial muscle using 3-mm high-frequency automated lengthening with the Ilizarov apparatus alone and in combination with intramedullary nailing. MATERIAL AND METHODS: Tibia was lengthened with a round-the-clock automated distractor at a 3-mm daily rate for 10 days in 16 mongrel dogs. In group 1 (n = 8), a 1.8-mm intramedullary titanium wire coated with hydroxyapatite was introduced into the tibial canal followed by Ilizarov frame mounting and transverse osteotomy of the diaphysis. Distraction mode was 0.025 mm x 120 increments a day. In group 2 (n = 8), distraction mode was the same but nailing was not used. Bone formation and the anterior tibial muscle were studied at two time points: (1) upon distraction completion; (2) three months after the apparatus removal. Bone formation was studied radiographically. Muscle preparations were examined histologically and stereomicroscopically. RESULTS: There was a threefold reduction in the distraction time in both groups. Consolidation took 13.83±4.02 days in group 1 and 33.7±2.4 days in group 2. Muscle macropreparations of the experimental limb in group 1 at study time points did not show significant differences from intact tissues. Muscle histostructure in both groups was characterized by activation of angiogenesis and myohistogenesis, but the volumetric density of microvessels in the lengthening phase was three times higher in group 1. CONCLUSION: Combined technology significantly reduces the total lengthening procedure and does not compromise limb functions. Intramedullary HA-coated wires promote faster bone formation. The muscle was able to exhibit structural adaptation and plasticity of a restitution type.

Flexible intramedullary nails for limb lengthening: a comprehensive comparative study of three nails types.

This study aims to investigate the comparative study of calcium phosphate coatings for flexible intramedullary nails (FINs) used to lengthen long tubular bones. The presence of a calcium phosphate coating deposited by micro-arc oxidation (MAO) or a composite coating based on a co-polymer of vinylidene fluoride with tetrafluoroethylene (VDF-TeFE) and hydroxyapatite (HA) on the surface of the FIN significantly enhanced the regeneration of bone in the area of osteotomy during limb lengthening by combined osteosynthesis. The investigation of the physico-chemical properties of the FIN coated with calcium phosphate via MAO demonstrated that the improved bone tissue formation resulted from favourable conditions for adhesion, proliferation and differentiation of multipotent stem cells into osteoblasts on the coating surface. The composite coatings only stimulated the formation of bone tissue in vivo, primarily because of the piezoelectric properties of the VDF-TeFE co-polymer.

Osteoinductive composite coatings for flexible intramedullary nails.

This work presents composite coatings based on a copolymer of vinylidene fluoride with tetrafluoroethylene (VDF-TeFE) and hydroxyapatite (HA) for flexible intramedullary nails (FIN). The effect of the proportion of VDF-TeFE (100-25% wt.) on physicochemical and biological properties of the composite coatings was investigated. It was shown that a decrease of VDF-TeFE in the coating hinders its crystallization in ß and γ forms which have piezoelectric properties. The decrease also reduces an adhesive strength to 9.9±2.4MPa and a relative elongation to 5.9±1.2%, but results in increased osteogenesis. It was demonstrated that the composite coatings with 35% VDF-TeFE has the required combination of physicochemical properties and osteogenic activity. Comparative studies of composite coatings (35% VDF-TeFE) and calcium phosphate coatings produced using micro-arc oxidation, demonstrated comparable results for strength of bonding of these FINs with trabecular bones (~530MPa). It was hypothesized that the high osteoinductive properties of the composite coatings are due to their piezoelectric properties.

[The First Russian Consensus on the Multilevel Abobotulinumtoxin A Injections in Spastic Forms of Cerebral Palsy]. / Pervyi Rossiiskii konsensus po primeneniyu mnogourovnevykh in''ektsii abobotulinumtoxin A pri lechenii spasticheskikh form detskogo tserebral'nogo paralicha.

Spasticity treatment is one of the key aspects of the contemporary cerebral palsy (CP) rehabilitation that influences on the effectiveness of other methods. The paper presents the first Russian document that unites the recommendations for the BTA treatment of CP and could be used as the guideline for the multilevel injections. The Russian consensus on the multilevel botulinum toxin A (BTA) treatment of spastic CP is based on the international data and the results of national studies. The authors describe typical CP spasticity patterns in the upper and lower extremities, give recommended intervals for the BTA (Abobotulinum toxin A) dosages for the whole injection procedure and for the separate muscles. The method of dosage calculation for functional segments is also described. Attention is paid to the frequency, optimal intervals between the repeated injections and the whole duration of BTA treatment. The authors discuss effectiveness and safety of BTA, factors that potentially influence the results of the injections, including ultrasound and electromyography control, and indications for the continuation and termination of treatment.

[GROWTH AND RESPONSE OF LEG TISSUES FOR TRANSPHYSEAL OSTEOSYNTHESIS OF TIBIAL SHAFT FRACTURE EXPERIMENTALLY].

Six (6) mongrel dogs at the age of six (6) months underwent transphyseal elastic intramedullary osteosynthesis for tibial shaft fracture. Clinical, X-ray, and physiological methods were used. As determined, the transphyseal reinforcement of the injured bone doesn't influence the lib function, but it retards the segment longitudinal growth. The eccentric arrangement of rods leads to forming angular deformity of the articular surface. Changes occur in the temperature of the covering tissues of the lateral tibial condyle. Consolidation period of the bone fragments is not increased. The union is formed through the blood flow of hypokinetic type in soft tissues. When intramedullary elastic rods being inserted the endosteal and periosteal response contributes to increasing the thickness of bone cortical plates and diameter.

[Intramedullary Elastic Transphyseal Tibial Osteosynthesis and Its Effect on Segmental Growth].

BACKGROUND: Intramedullary transphyseal elastic osteosynthesis is used in children for the diseases accompanied by the reduced strength properties of bone tissue, and primarily for osteogenesis imperfecta. OBJECTIVE: The purpose of the experimental study was to investigate tibial growth under the conditions of transphyseal counter-directed insertion of elastic rods without bone integrity breaking, under transverse fracture modeling, as well as under combining transphyseal reinforcement and subperiosteal positioning the titanium mesh with the elastic rods intervolved in it. METHODS: Non-randomized controlled trial was performed. Three series of experiments performed in 18 puppies. Counter-directed transphyseal reinforcement of tibia performed in Series I, transphyseal reinforcement combined with transverse osteotomy of leg bones--in Series II, transphyseal elastic osteosynthesis and subperiosteal positioning the titanium nickelide mesh with intervolved in it elastic rods during transverse leg bone osteotomy performed in Series III. RESULTS: Transphyseal reinforcement resulted in growth retardation of the operated tibia. The loss of residual growth was 3.8 mm (p=0.078) in series I; 7.8 mm (p=0.032)--in series II; 7.7 mm (p=0.042)--in series III. Eccentric insertion of transphyseal rods formed an angular deformity (mean value 7°; p=0.023) of the distal tibial epiphysis in the process of residual growth. Periosteal and endosteal reactions contributed to enlargement of diaphyseal diameter of 3.9 mm (series II; p=0.037) and 3.8 mm (series III; p=0.041). Any difference of diameter between operated and intact tibia was not observed in series I. CONCLUSION: Intramedullary transphyseal reinforcement retards longitudinal bone growth. The positioning of the telescopic systems should be as close as possible to the center of growth plates in order to prevent angular deformities. Subperiosteal reinforcement doesn't retard consolidation of fragments, and it can be combined with intramedullary transnhyseal osteosynthesis.

[The results of single-event multilevel orthopedic surgeries and the early rehabilitation used in complex with botulinum toxin treatment in patients with spastic forms of cerebral palsy].

OBJECTIVE: To evaluate motor possibilities of patients with children spastic palsy (CSP) one year after single-event multilevel orthopedic low extremity surgeries in combination with early rehabilitation treatment including botulinum toxin treatment. MATERIAL AND METHODS: Authors studied the results of operative orthopedic treatment in 55 patients with CSP, aged from 5 to 17 years (mean 11.9 ± 2.5 years), who underwent multilevel surgeries with early functional rehabilitation using 1.5 treatment courses with 6-8 week treatment-free periods during 9-12 months in combination with a single injection of disport in the post-operative period. We performed 74 surgeries 140 episodes of botulinum toxin treatment using average doses of Botulinum toxin 10 U per kg of body mass injected into low extremity muscles. RESULTS: In the post-operative period, authors recorded a significant reduction in pain syndrome, assessed with a pain intensity scale, from 8.6 ± 1.2 to 4.3 ± 1.1 scores (p < 0.001). An analysis of gait demonstrated an improvement of gait patterns in all patients able to move independently. An increase in motor abilities, measured with the Gillette Functional Assessment Questionnaire, by 1 level was identified in 28 (50.9%) patients, by 2 levels in 2 (3.6%) patients, no changes were observed in 25 (45.5%) patients. CONCLUSION: Single-event multilevel orthopedic surgeries in children with CSP reduce a number of repeated surgeries. The effective control over pain syndrome in patients with CSP using multilevel botulinum toxin treatment in the post-operative period promotes the functional rehabilitation, increases rates of loading during training sessions and the motivation of CSP patients to restore the lost activity.

Bone healing by using Ilizarov external fixation combined with flexible intramedullary nailing versus Ilizarov external fixation alone in the repair of tibial shaft fractures: experimental study.

PURPOSE: Our research was aimed at studying the radiographic and histological outcomes of using flexible intramedullary nailing (FIN) combined with Ilizarov external fixation (IEF) versus Ilizarov external fixation alone on a canine model of an open tibial shaft fracture. MATERIALS AND METHODS: Transverse diaphyseal tibial fractures were modelled in twenty dogs. Fractures in the dogs of group 1 (n = 10) were stabilized with the Ilizarov apparatus while it was combined with FIN in group 2 (n = 10). RESULTS: On day 14, a bone tissue envelope started developing round the FIN wires. Histologically, we revealed only endosteal bone union in group 1 while in group 2 the radiographs revealed complete bone union on day 28. At the same time-point, the areas of cancellous and mature lamellar bone tissues were observed in the intermediary area in group 2. The periosteal layers were formed of the trabeculae net of lamellar structure and united the bone fragments. The frame was removed at 30 days after the fracture in group 2 and after 45 days in group 1 according to bone regeneration. CONCLUSION: The combination of the Ilizarov apparatus and FIN accelerates bone repair and augments stabilization of tibial shaft fractures as compared with the use of the Ilizarov fixation alone.

Experimental study of progressive tibial lengthening in dogs using the Ilizarov technique. Comparison with and without associated intramedullary K-wires.

UNLABELLED: A delay in the union of bone regenerate in surgical lengthening procedures and the healing index (HI) are major factors in the quality of the results in progressive bone lengthening. Early removal of the external fixator (EF) is associated with a low rate of postoperative complications, including pin track infection, and with better muscle and joint function recovery. Addition of intramedullary wires (IMWs) to the EF led to a 9-49% decrease in the HI depending on the clinical series. We hypothesized that IMWs may accelerate the ossification process of bone regenerate and tested it in this experimental study. METHODS: Progressive tibial lengthening of 28 mm was obtained in 12 dogs operated with the classical Ilizarov technique (group I) and in 12 dogs operated with the same technique and addition of two IMWs 1.5 mm in diameter (group II). The following criteria were assessed: HI, X-ray measurements, and histological aspect of the bone regenerate and postoperative complications. RESULTS: The mean HI was 32.3% lower in group II than in group I. The radiological bone union criteria were observed on day 15 of the fixation period in group II versus day 30 in group I. Histology showed that maturation occurred earlier and bone cortices were thicker in group II than group I. Intramedullary ossification was present along the IMW in group II, whereas it was absent in group I. No clinical complications were observed in either group. DISCUSSION: The presence of the IMWs clearly contributes to stimulation of the ossification processes of the bone regenerate and to acceleration of bone union. IMWs allowed an earlier removal of the external fixator for a 32% time reduction compared to cases without IMWs. In addition, new intramedullary bone formation and presence of IMWs are expected to increase the mechanical resistance of the bone regenerate. CONCLUSION: Improvement of quantitative and qualitative criteria of bone regenerate in progressive bone lengthening with an EF combined with IMWs was demonstrated in this experimental study. SIGNIFICANCE: Favorable results encourage the authors to continue using IMWs in addition to the EF in patients treated with long-bone progressive lengthening. LEVEL OF EVIDENCE: II.

[Botulinum toxin type A (dysport) in the complex rehabilitation of children with spastic forms of cerebral palsy].

OBJECTIVE: To analyze the efficacy of repeated use of dysport in children with spastic forms of cerebral palsy (CP). MATERIAL AND METHODS: Forty-five children with CP (main group) received 8 consecutive injections of dysport in the complex treatment. A comparison group consisted of 41 children with CP who received the same complex treatment but without dysport. Disport was used intramuscular in mean dose 26±4 u/kg. RESULTS AND CONCLUSION: A significant decrease of the muscle tone was observed after each following injection of dysport. The muscle tone did not return to baseline 24 weeks after each following injection and significantly differed after the first 4 injections. After 8 repeated courses of botulinotherapy, a number of children needed the operative treatment, were significantly greater in the comparison group (71% vs 47%, p=0,041).

[The effect of tibial transphyseal reinforcement on the growth and response of leg tissues].

Transphyseal reinforcement of right intact tibia performed with thin steel rods in six mongrel dogs at the age of six months. Contralateral segment served as control. The leg growth and blood supply studied under the created conditions for the next six months. Radiographic, physiologic (surface thermometry, photoplethysmography), and statistical methods used for studying. The significant effect of transphyseally inserted rods on the leg longitudinal growth and blood supply has not been revealed. The changes in natural shape-formation oftibial proximal and distal meta-epiphyses observed influenced by the transphyseal rods in the experiment. In order to evaluate the tissue response and the degree of the functional activity of leg bone meta-epiphyseal zones the most informative areas considered to be the following: the area of medial malleolus in the early period of physiological growth completion, and the area of the tibial lateral condyle--at the late stage.

[Calculation of the main parameters of spokes for intramedullary reinforcement of tubular bones].

The goal of this work was to determine the optimal geometric parameters of plastically deformed spokes inserted into the medullary canal during intramedullary reinforcement performed as a part of perosseous distraction osteosynthesis. The results of clinical application of the suggested technique are described.

[Description of rearrangement of distraction reclaim in the extension of the lower extremities and elimination of their deformity in patients with various etiology of shortening].

The data of X-ray and computed tomographic studies of a long tube distraction reclaim were analyzed in 80 patients who had limb shortening and deformity of varying etiology. The analysis has shown that during distraction there is a positive correlation between the increase in the connective-tissue interlayer area of a distraction reclaim and the overall increase in the area of the distraction reclaim (their ratio is not greater than 30% under the optimal elongation conditions). During fixation there is a decrease in the ratio of the area of a growth zone to the total area of a reclaim and in its total density with a parallel increase in the density of cortical laminae of a newly formed bone. Complete organotypic rearrangement comes to the end in the range of 1-3 years depending on the magnitude of pathomorphological and biomechanical changes and limb function.

[Elastic stable intramedullary nailing in Ilizarov bone lengthening]. / Embrochage centro-médullaire dans les allongements osseux selon Ilizarov.

PURPOSE OF THE STUDY: Bone lengthening with the Ilizarov technique gives good results but certain disadvantages are common: possible axial deviation during lengthening, long time to bone union, risk of fracture after removal of the external fixator. Associating the Ilizarov technique with elastic stable intramedullary nailing (ESIN) commonly used in traumatology has to be evaluated. We conducted an experimental study and report results of the first clinical application. MATERIAL AND METHODS: Eleven lengthenings of the tibia were conducted in dogs aged 1 to 4 years using an Ilizarov external fixator associated with ESIN. Lengthening started on day 1 and continued for 28 days. X-rays were obtained every week during lengthening, then at 15 and 30 days during the fixation period and 30 days after removal of the fixator. In two cases, arteriography was performed. In a pilot clinical trial, fourteen patients (8 males, 6 females) were treated with this method (1 humerus, 1 forearm, 7 femurs, 5 tibias). Mean patient age was 14 years. RESULTS: In the experimental study, the x-rays showed rapid ossification of the regenerate which led to increased tibia length in 7 cases from 1.25 to 2 mm/day. Total bone union was observed in four dogs during the lengthening period. At day 15 of the fixation period, all tibia had fused with a good quality cortical bone and healing of the growth part of the regenerate. In three dogs, the external fixator was removed at day 15 of fixation and weight-bearing was total with the ESIN in place. No axial deviation and no skin problems were observed. The medullary artery was seen on the two arteriograms. In the clinical trial, bone union of the regenerate appeared earlier than in the Ilizarov series. The regenerate always displayed good density on the x-rays, proving intense bone activity. In three patients, the lengthening rate was increased to avoid premature bone fusion. The endosteal bone regenerate was obvious. Mean healing index was 18.6 days/cm (SD=6.2). Weight-bearing was allowed at six weeks. The desired correction was achieved in all patients and no complications were related to ESIN. DISCUSSION: Bone lengthening may be obtained with an intramedullary locking nail which avoids the use of an external fixator but also destroys the endomedullary circulation. Our experimental and clinical study shows that use of an ESIN does not inhibit the endosteal regenerate and seems to improve new bone formation. In many patients, the lengthening rate had to be increased to avoid premature bone fusion. When used in optimal conditions, ESIN can stimulate new endosteal and periosteal bone formation. In addition, ESIN increases shaft stability avoiding the risk of axial deviation. ESIN plays an additional role of stabilization after early removal of the external fixation.

[Dynamics of echomorphometric human crural skin characteristics during dosed stretching]. / Dinamika ékhomorfometricheskikh pokazatelei kozhi goleni cheloveka v usloviiakh dozirovannogo rastiazheniia.

The dynamics of echo-morphometric parameters of crural skin was studied in patients with congenital shortening of lower extremity in the process of its operative elongation. It is demonstrated that dosed stretch results in increased skin thickness. After the completion of distraction, the skin thickness exceed preoperation levels by 48.7% (in patients aged 5-8 years), 20.9% (in patients aged 10-14 years) and 26.7% (in adults). Skin acoustic density after distraction termination reached the preoperation level in children and adolescents, while it was increased in adults.