Bone marrow would represent a useful source of cells for skeletal tissue engineering. Marrow mesenchymal stem cells (MSC) can generate cartilage, bone and fat. The differentiation of this multipotent population into fibroblast, chondrocytes or osteoblasts can be inducted in vitro by the addiction of growth factor like bFGF, TGFA7, BMP-2.

In order to evaluate the possibility of inducing cell differentiation by cell-matrix interaction, we studied the in vitro behaviour of human MSC cultured on various scaffolds.

Bone marrow was obtained during surgery for pelvic fractures or hip arthroplasty. MSC were isolated by cell sorting (CD45/glycophorin A micromagnetic beads), expanded and characterised by FACSCalibur flow cytometry system (CD3, CD34, CD14, CD45, CD90 and CD105). Then cells were grown for 30 days on different scaffolds: type I and type II collagen, type I collagen + hydroxyapatite. Histochemical (alcian blue, safranin O, ALP and von Kossa stains), immunohistochemical (type I e II collagen, chondroitin sulphate, osteonectin), histomorphometric (area %) and spectrophotometric (cell proliferation, PG synthesis, ALP activity) analyses were performed after 15 and 30 days of culture.

Among the scaffolds tested in the present study, we observed a great variability in terms of MSC adhesion and proliferation. MSC grown on type II collagen differentiated into cells expressing chondrocytes markers (S100, collagen II, chondroitin-S). MSC grown on type I collagen + hydroxyapatite differentiated into osteoblast-like cells.

These data evidenced that MSC-matrix interaction can influence phenotype expression, cell adhesion and growth rate.

Purpose: To elucidate the pathomorphology of the unossified clubfoot and to monitor the progressive correction of the deformity during treatment, the authors introduce a standardized sonographic assessment of the foot at birth and at the end of both conservative and surgical corrective procedures.

Methods: 42 congenital clubfeet and 42 normal newborns were documented by ultrasound using a 7,5/10 MHz linear arrays probe with direct contact. Clubfeet were documented in the position of spontaneous alignment and during passive manual correction at the admission and at the end of both conservative and surgical treatment. Five standard ultrasound planes were used: sagittal posterior, sagittal anterior, coronal lateral, transversal and coronal medial plane.

Results: On the sagittal posterior plane the progressive gain of the dorsiflexion during the different steps of the treatment was documented measuring the distance between the distal tibial metaphysis and the calcaneal apophysis. In clubfeet, looking at the ossification centre of the talus, both its forfeit of domicile in the ankle mortise and its right positioning after treatment can be showed. On the sagittal anterior plane and on the transversal plane the medial displacement of the navicular is documented. The normalisation of the anatomic alignment of the navicular is well documented by these planes after appropriate treatment. On coronal lateral plane the relationships between the os calcis and cuboid can be estimated using the calcaneal-cuboid angle. The coronal medial plane exhibited a very low reproducibility in the neonatal clubfoot and it is not reccomended

Conclusions: Ultrasonography it is a very promising technique in the monitoring of clubfoot deformity during treatment. On the sagittal posterior and on the coronal lateral planes strictly quantitative information can be easily deduced while prevalently qualitative information are deduced on the sagittal anterior and on the transversal planes. Ultrasound gives exact and reproducible information concerning the pathomorphology of the not ossified

Paediatric acute leukemia may present with various clinical mifestations that mimic different orthopaedic conditions and can produce diagnostic confusion. In a retrospective study we reviewed the cases of 129 children (average age 6.2 years) affected by acute leukemia who had been seen between 1984 and 1999 at the Paediatric Haemato-Oncology Department of the University of Padova and had complete clinical and radiographic data. Almost all the patients (93.7%) had a variety of general signs and symptoms at presentation: weakness (44.3%); anorexia (32.7%); lethargy (7.8%); fever (64.2%); pallor (79.6%); bleeding (25.3%); lymphoadenopathy (58.8%); hepatosplenomeg-aly (75.6%). Thirty-seven patients (28.6%) had complaints related to the muscoloskeletal system when they were first seen including: pain (92.7%), swelling (29,7%), joint limitation (47.8%), limping (18.8%). Skeletal surveys were made for ninety-two (71.3%) of the patients when the diagnosis of leukemia was made, while the other thirty-seven (28.6%) had radiograms of the symptomatic areas. Seventy-five patients (58.1%) presented normal radiograms and fifty-four (41.9%) showed one or more abnormalities. Osteopenia was diagnosed in eight patients; lytic lesions were see in fourteen; metaphyseal bands in ten; periosteal reactions in four; osteosclerosis in two; mixed osteoscle-rosis and osteolysis in two; permetive pattern in eight; vertebral collapse in three children. During the course of the disease two patients developed avascular necrosis of the femoral head; one reported a pathologic femoral neck fracture; three presented collapse of one or more vertebral bodies. All these findings are not pathognomonic but the clinician should always include acute leukemia in the differential diagnosis of any child with unexplained radio-grafic changes and/or persistent skeletal pain.

The changes occurring in ligamentum flavum in lumbar spine stenosis are a matter of long–standing controversy. More recently, some studies showed that the posterior spinal structures, including hypertrophied ligamentum flavum, play a major role in the pathogenesis of the lumbar stenosis.

To investigate the pathogenesis of the degenerative changes of the ligamentum flavum occurring in lumbar spine stenosis, yellow ligament cells from patients with lumbar spine stenosis were cultured for the first time and subjected to biochemical, histochemical and immunohistochemical study.

Samples of ligamentum flavum were collected from 4 patients undergoing surgery for lumbar stenosis (mean age 47.2 years). Cell cultures were obtained from each patient and maintained in Dulbecco’s modified essential medium-10% fetal calf serum. Cell characterization was histochemically (Gomori’s and von Kossa staining), immunohistochemically (anti-type I, -type II, -type III and -type X collagen, anti-S100 protein, anti-fibronectin, anti-osteonectin and anti-osteocalcin), biochemically (cAMP activity after human parathyroid hormone stimulation) assessed. Samples collected from 2 age-matched patients who underwent surgery for lumbar fractures were used as controls.

Stenotic ligamentum flavum cells expressed high levels of alkaline phosphatase activity and produced a mineralized matrix rich in type I, type III and type X collagen, fibronectin, osteonectin, and osteocalcin. Stimulation with parathyroid hormone increased intracellular cAMP concentration. These findings indicate that there was significant evidence of osteoblast-like activity in these cells. Staining for type II and type X collagen, and S-100 protein reflected the proliferation of hypertrophic chondrocyte-like cells, confirmed with the co-localization of alkaline phosphatase and collagen type II. Cultures from control patients showed nor hypertrophic chondrocytic nor osteoblastic features. Our data demonstrated the presence of hypertrophic chondrocytes with an osteoblast-like activity in human stenotic ligamentum flavum. The osteoblast-like activity could have a role in the pathophysiology of the heterotopic ossification of ligamentum flavum in lumbar spine stenosis.

We performed intra-articular reconstruction of the anterior cruciate ligament (ACL) with the semitendinosus tendon placed in 2 mm diameter tunnels in 21 skeletally immature rabbits. The operation caused 11% damage to the physis of the femur on the frontal plane and 3% of its cross-sectional area but no alteration of growth or axial deviation of the bone resulted. In the tibia, the operation caused 12% damage to the physis in the frontal plane and 4% of the cross-sectional area. Two tibiae developed valgus deformities and one was shortened. Histological examination showed no areas of epiphysiodesis. There was no abnormality of growth-plate thickness in the two cases of tibia valga. Osseous metaplasia in the grafted tendons did not occur. The results suggest the need for careful evaluation of the percentage of damage to the growth plate before using intra-articular methods for reconstruction of the anterior cruciate ligament in adolescents.

Four cases are described of solitary spinal neurofibroma, a rare tumour of the spinal cord or nerve roots. Computerised tomography provided an accurate topographical definition of the tumour. Magnetic resonance imaging showed an increased T2-weighted signal and multiple areas of decreased T1- and T2-weighted signals centrally. The MR signals matched the histological examination which showed hyperplastic interfascicular connective tissue, pleomorphic cells, and tightly packed nerve fibres compressed by the surrounding loose connective tissue. Electron microscopy showed three types of cell: Schwann cells, fibroblast-like cells, and mast cells. The histological findings suggests that solitary spinal neurofibroma is a distinct pathological entity which could be diagnosed preoperatively from the MR images.