ZnO-mesoporous glass scaffolds loaded with osteostatin and mesenchymal cells improve bone healing in a rabbit bone defect.

The use of 3D scaffolds based on mesoporous bioactive glasses (MBG) enhanced with therapeutic ions, biomolecules and cells is emerging as a strategy to improve bone healing. In this paper, the osteogenic capability of ZnO-enriched MBG scaffolds loaded or not with osteostatin (OST) and human mesenchymal stem cells (MSC) was evaluated after implantation in New Zealand rabbits. Cylindrical meso-macroporous scaffolds with composition (mol %) 82.2SiO2-10.3CaO-3.3P2O5-4.2ZnO (4ZN) were obtained by rapid prototyping and then, coated with gelatin for easy handling and potentiating the release of inorganic ions and OST. Bone defects (7.5 mm diameter, 12 mm depth) were drilled in the distal femoral epiphysis and filled with 4ZN, 4ZN + MSC, 4ZN + OST or 4ZN + MSC + OST materials to evaluate and compare their osteogenic features. Rabbits were sacrificed at 3 months extracting the distal third of bone specimens for necropsy, histological, and microtomography (µCT) evaluations. Systems investigated exhibited bone regeneration capability. Thus, trabecular bone volume density (BV/TV) values obtained from µCT showed that the good bone healing capability of 4ZN was significantly improved by the scaffolds coated with OST and MSC. Our findings in vivo suggest the interest of these MBG complete systems to improve bone repair in the clinical practice.

A predictive mechanical model for evaluating vertebral fracture probability in lumbar spine under different osteoporotic drug therapies.

Osteoporotic vertebral fractures represent a major cause of disability, loss of quality of life and even mortality among the elderly population. Decisions on drug therapy are based on the assessment of risk factors for fracture from bone mineral density (BMD) measurements. A previously developed model, based on the Damage and Fracture Mechanics, was applied for the evaluation of the mechanical magnitudes involved in the fracture process from clinical BMD measurements. BMD evolution in untreated patients and in patients with seven different treatments was analyzed from clinical studies in order to compare the variation in the risk of fracture. The predictive model was applied in a finite element simulation of the whole lumbar spine, obtaining detailed maps of damage and fracture probability, identifying high-risk local zones at vertebral body. For every vertebra, strontium ranelate exhibits the highest decrease, whereas minimum decrease is achieved with oral ibandronate. All the treatments manifest similar trends for every vertebra. Conversely, for the natural BMD evolution, as bone stiffness decreases, the mechanical damage and fracture probability show a significant increase (as it occurs in the natural history of BMD). Vertebral walls and external areas of vertebral end plates are the zones at greatest risk, in coincidence with the typical locations of osteoporotic fractures, characterized by a vertebral crushing due to the collapse of vertebral walls. This methodology could be applied for an individual patient, in order to obtain the trends corresponding to different treatments, in identifying at-risk individuals in early stages of osteoporosis and might be helpful for treatment decisions.

Lymphocyte response to polymethylmethacrylate in loose total hip prostheses.

We investigated the lymphocyte-mediated immune response to polymethylmethacrylate bone cement in 26 patients who had revision surgery for aseptic loosening of cemented total hip arthroplasties, at a mean time of seven years after the first replacement. We studied eight patients with cemented total hip arthroplasties which were not loose as controls. Patch tests to polymethylmethacrylate bone cement were positive in 13 patients with loosening, and these patients had higher lymphoblast transformation values against polymethylmethacrylate bone cement patients with a negative skin reaction (p < 0.01) or those in the control group (p < 0.001). Specific monoclonal antibodies were used to assess the percentage of certain cells of the immune system according to their cluster of differentiation (CD). There was a higher number of total T and B lymphocytes (CD2 and CD22) and interleukin-2 receptor-positive lymphocytes (activated cells, CD25) in patients with loose prostheses. More CD25 lymphocytes were found in patients with positive patch tests. The activation of the lymphocyte-mediated immune response was not related to the presence or absence of aggressive granulomatous lesions at the cement-bone interface.

Soft tissue behavior during limb lengthening: an experimental study in lambs.

The effect of femoral elongation on skeletal muscle, nerves, and vessels was studied. Three groups of five lambs were used. After the intervention, the animals were killed at 2, 3, and 4 months. A left femoral elongation of 6 cm was practiced on all of them by means of callotasis, with a distraction rate of 0.5 mm every 12 hours. The femoral elongation process was evaluated by monthly x-ray films. The nucleic acid and protein levels in the muscular tissue were quantified at the level of the elongation focus and in the control extremity. The motor conduction velocity of the sciatic nerve was measured in both posterior limbs before the intervention and immediately before the lambs were killed. The arterial blood flow of both subsequent extremities was measured at the moment of death. A histological study of quadriceps muscle, sciatic nerves, artery, and subsequent femoral vein were examined histologically at the level of the elongation focus of both extremities. After elongation, no significant differences were observed in the muscle protein and nucleic acid levels with respect to the control extremity. No significant changes of the nerve conduction velocity were observed in any animal among the different groups. The arterial blood flow of the elongated extremity showed a progressive increase, reaching its maximum value 1 month after the distraction had terminated, with subsequent normalization. This increase of the blood flow was also observed in the control extremity, suggesting a possible systemic effect. The histological study revealed a comparative thickening of the endomysium and perimysium in the elongated muscle tissue, present at the end of the distraction and which was later normalized. No histological changes of the nerve stems undergoing distraction were observed either. During elongation, the arteries showed minimal histological changes. On the other hand, the veins showed areas of endothelial damage accompanied by thrombosis phenomena, especially at the end of the distraction period. The vascular morphology presented progressive normalization after the distraction phase.

Results in displaced radial neck fractures in children. Metaizeau technique versus arthrotomy.

The aim of the present article is to ascertain the differences between two surgical treatments commonly used in displaced radial neck fractures in children. We report the retrospective results of 20 displaced radial neck fractures with > 30 degrees of tilt (Judet grades 3-4) in children aged between 7 and 14 years treated with closed intramedullary pinning according to the Metaizeau technique (6 cases) or with arthrotomy and pinning (14 cases). Sex distribution was 14 girls and 6 boy. The average follow-up was 43 months. We found no relationship between delay in the surgical treatment and functional results. On the other hand, a relationship between residual final tilt and poorer functional results appears. The Metaizeau technique produced better results and fewer complications than arthrotomy and pinning, and, in our opinion, is the treatment of choice in this type of fracture.

[Simple bone cysts in childhood. Retrospective study of 15 cases and review of literature]. / El quiste óseo esencial en la infancia. Estudio retrospectivo de 15 casos y revisión de la literatura.

We present a review of 15 cases of simple bone cyst treated by curettage and bone grafting or intralesional steroids injection. We analysed the localisation, cyst activity, the number of cavities and the occupied area, valuing the results according to the Neer and Chigira classification. We have noticed a higher rate' of cure with curettage and bone grafting than with steroids injection (p: 0.01). The activity of the cyst, the uni-multilocutarity and the area related to a greater index of recurrence and failure in the cases treated by steroids injection, although this is statistically non significant.

Management of sternoclavicular dislocation in young children: considerations about diagnosis and treatment of four cases.

The records of 4 children of under 14 years of age treated at our institution for traumatic sternoclavicular dislocation (SCJ) were reviewed. Closed reduction in posterior SCJ after computed tomography (CT) was successful as immediate procedure. For anterior SCJ instability, open reduction and SCJ reconstruction obtained satisfactory results. Conservative treatment of SCJ subluxation for asymptomatic children was sufficient. Radiographs in "serendipity view" were useful for confirming reduction and stability in children. No postoperative CT was needed for this purpose. Closed reduction in posterior SCJ dislocation and surgical treatment in anterior SCJ dislocation in young children can provide stability and a satisfactory return to a normal function, but with some limitation when intense or competitive shoulder motion is required during sport. Young children and parents should be aware about this possibility. Conservative treatment of SCJ subluxation for asymptomatic children is useful. Reflection is required regarding the correct imaging examination after treatment to check stable reduction in a SCJ injury.

In vivo osteointegration of three-dimensional crosslinked gelatin-coated hydroxyapatite foams.

The main requirement of bone regenerative scaffolds is to enhance the chemical reactions leading to the formation of new bone while providing a proper surface for tissue in-growth as well as a suitable degradation rate. Calcium phosphate ceramics are conformed by different shaping methods. One requirement is to design implants and scaffolds with suitable shapes and sizes, but also with interconnected porosity to ensure bone oxygenation and angiogenesis. In this work we present the in vivo performance of hierarchically arranged glutaraldehyde crosslinked, gelatin-coated nanocrystalline hydroxyapatite (HABP) scaffolds (1-400 µm), with high potential as bone regenerators and excellent osteointegration performance, as well as an appropriate bioresorption rate. 6×10 mm bone defects were made in the lateral aspect of both distal femoral epiphysis of 15 mature (9 months old) male New Zealand rabbits. The bone defect in the left femur was then filled by using HABP foam cylinders, allowing the surgeon to carve the appropriate shape for a particular bone defect with high stability intra-operatively. The foam becomes swollen with body fluid and fills the cavity, ensuring good fixation without the need for a cement. Histological and radiographical studies after 4 months implantation showed healing of all treated bone defects, with bone integration of the HABP foam cylinders and bone conduction over the surface. This in vivo behaviour offers promising results as a scaffold for clinical applications, mainly in orthopaedics and dentistry.

Osteoblastoma causing rigidity of the elbow. Case report.

A 21-year-old man complained of pain and rigidity of the elbow with a flexion contracture of 100 degrees. A radiographic examination revealed an 1.5-cm osteolytic injury in the center of a sclerotic lesion in the distal humerus. The diagnosis of an osteoblastoma was later confirmed histologically. Once the tumor had been excised, the pain disappeared and functional mobility was reestablished.

Lengthening of the first metatarsal bone. A case of congenital shortening.

A 14-year-old boy had a congenital shortening of the first right metatarsal bone, with overloading of the central metatarsals and medial deviation of the second toe. A percutaneous osteotomy and slow distraction by an external fixator for 10 weeks lengthened the bone from 32 mm to 60 mm. After the distraction, a bone graft was performed, and tenotomies and a capsulotomy corrected a threatening subluxation. Consolidation of the lengthening focus required 16 weeks.

Delayed distraction in bone lengthening. Improved healing in lambs.

We compared delayed distraction (DD) with immediate distraction (ID) in bone-lengthening. Open femoral diaphyseal osteotomy was performed on 24 three-month-old lambs, and external distractor fixators were applied. In the ID group (n 12), distraction commenced on the first postoperative day; in the DD group (n 12), distraction was delayed until the tenth day after surgery. In all the animals, the femur was lengthened by 2 cm at the rate of 1 mm/day. The animals were killed 1, 2, and 3 months postoperatively. Radiography and densitometry of the lengthened callus showed that DD, compared with ID, improved the quality of the callus with quicker, denser, and more homogeneous bone formation.

Tenosynovial chondromatosis of the third finger.

Synovial chondromatosis is an uncommon lesion, characterised by cartilaginous and osseous metaplasia of the joint synovium. It usually involves a large joint and rarely occurs in the hand. A case of tenosynovial chondromatosis of the third finger is reported.

[A case of multiple malignant schwannoma as the only disease in a 40-year-old patient: is this a new type of neurofibromatosis?]. / A propósito de un caso de schwannoma maligno múltiple como única patología en un paciente de 40 años: un nuevo tipo de neurofibromatosis?

We present the case of a 40-year-old man that presented a fast growing tumour on the external side of the left elbow. The tumour was extirpated by means of marginal exerectomy. The microscopic study corresponded to epithelioid malignant schwannoma, and the patient received radiotherapy and adjuvant chemotherapy. During the following years two local recidives and two new malignant schwannomas, one in the left sciatic common trunk and another paraspinal one, appeared and were extirpated. Radiotherapy and chemotherapy were again administered. In the last year, four new tumours have appeared: in the supraclavicular space, right posterior costofrenic, left costovertebral, and in the inferior abdominal wall, none of them has been extirpated or has hystologic diagnosis at the moment, however radiologic findings suggest malignant schwannomas. In this moment there is no neurologic deficiency except for the secondary ones to surgical procedures, and no neurofibromatosis types I to VII signs have been observed. So, the possibility of a new neurofibromatosis type is appointed.

Absorbable screws through the greater trochanter do not disturb physeal growth: rabbit experiments.

We studied the effect of implantation of self-reinforced polyglycolic acid (SR-PGA) screws through the greater trochanter in rabbits. 15 rabbits aged 10 weeks had an SR-PGA screw inserted through the left trochanter physis. A similar drilling was made through the right greater trochanter without screw implantation. The animals were assigned to 3 groups of 5, and were killed after 1, 2 or 3 months. Radiographs of both femurs were obtained monthly and the articulo-trochanteric distance and the neck-shaft angle were measured. After killing the animals, a histological study was performed. The drilling on the right trochanter generated a bony bridge in all the animals. The SR-PGA screws did not give rise to an epiphysiodesis. The progressive peripheral degradation of the implants gave rise to the formation of only modest bridges, which were smaller in size than those observed in the control trochanter. Our findings suggest that absorbable PGA screws implanted through a growth plate cause only minor bone formation and no epiphyseodesis.