Nick A. Guldemond

Human periosteum-derived cells from elderly patients as a source for cartilage tissue engineering?

The aim of this study was to establish the potential of human periosteum‐derived cells from elderly patients as a cell source for cartilage tissue engineering by optimizing culture conditions for both proliferation and differentiation. Periosteum was obtained from the tibiae of nine patients. Biopsies were prepared for routine histological examination. Periosteum‐derived cells were allowed to grow out from the remaining tissue, and were expanded in minimum essential medium containing D‐valine (MEM–DV). Fetal bovine serum (FBS) or substitutes, fibroblast growth factor‐2 (FGF‐2), insulin‐like growth factor‐1 (IGF‐1) and non‐essential amino acids were added to study proliferation. For differentiation of cells, serum‐free medium was used supplemented with one or more isoforms of transforming growth factor‐β (TGFβ) and/or IGF‐1. Samples were analysed for expression of collagens type I, II and X by competitive RT–PCR, immunohistochemically, and histologically using Alcian blue staining. In all samples the cambium layer could hardly be detected. Periosteum‐derived cells proliferated in serum‐containing MEM–DV. Optimal proliferation was found when this medium was supplemented with 100 ng/ml FGF‐2 and non‐essential amino acids. Chondrogenesis was detected in 59% of micromasses that were cultured with TGFβ isomers, and in 83% of the samples cultured in media to which two TGFβ isoforms were added. Periosteum from elderly humans (mean age 66, range 41–76 years) has chondrogenic potential and remains an attractive cell source for cartilage tissue engineering. By expanding cells in MEM–DV, the selection of progenitor cells might be favoured, which would result in a higher cartilage yield for tissue engineering applications. Copyright

Prediction of peak pressure from clinical and radiological measurements in patients with diabetes.

BackgroundVarious structural and functional factors of foot function have been associated with high local plantar pressures. The therapist focuses on these features which are thought to be responsible for plantar ulceration in patients with diabetes. Risk assessment of the diabetic foot would be made easier if locally elevated plantar pressure could be indicated with a minimum set of clinical measures.MethodsNinety three patients were evaluated through vascular, orthopaedic, neurological and radiological assessment. A pressure platform was used to quantify the barefoot peak pressure for six forefoot regions: big toe (BT) and metatarsals one (MT-1) to five (MT-5). Stepwise regression modelling was performed to determine which set of the clinical and radiological measures explained most variability in local barefoot plantar peak pressure in each of the six forefoot regions. Comprehensive models were computed with independent variables from the clinical and radiological measurements. The difference between the actual plantar pressure and the predicted value was examined through Bland-Altman analysis.ResultsForefoot pressures were significant higher in patients with neuropathy, compared to patients without neuropathy for the whole forefoot, the MT-1 region and the MT-5 region (respectively 138 kPa, 173 kPa and 88 kPa higher: mean difference). The clinical models explained up to 39 percent of the variance in local peak pressures. Callus formation and toe deformity were identified as relevant clinical predictors for all forefoot regions. Regression models with radiological variables explained about 26 percent of the variance in local peak pressures. For most regions the combination of clinical and radiological variables resulted in a higher explained variance. The Bland and Altman analysis showed a major discrepancy between the predicted and the actual peak pressure values.ConclusionAt best, clinical and radiological measurements could only explain about 34 percent of the variance in local barefoot peak pressure in this population of diabetic patients. The prediction models constructed with linear regression are not useful in clinical practice because of considerable underestimation of high plantar pressure values. Identification of elevated plantar pressure without equipment for quantification of plantar pressure is inadequate. The use of quantitative plantar pressure measurement for diabetic foot screening is therefore advocated.

Pressure measurements in a new TLSO with a dynamic thoracic brace pad for idiopathic scoliosis

Results Eight girls, with a mean age of 12.7 years were asked to participate. The mean duration of brace treatment prior to participating in the present study was 7 months. The mean primary right thoracic curve was 31° and the mean secondary curve measured 23°. The mean corrective force over the lumbar brace pad in standing position was 71 N; over the thoracic brace pad it was 107 N. Van den Hout found in the Boston brace that the mean corrective force through the lumbar brace pad was larger than the mean corrective force over the thoracic brace pad. However, we found higher corrective forces in the thoracic brace pad than in the lumbar brace pad.

Developing a new brace with pressure measurements

Pressure measurements are being used to understand the working mechanism of the brace, because the forces exerted by a brace cause correction of the scoliotic curve. The aim of the study was to understand the mechanism and effectiveness of adjustments in a newly developed brace by using pressure measurements.

CURVE PATTERN CHANGES IN IDIOPATHIC SCOLIOSIS

Results Forty eight patients (11 boys and 37 girls; 13 patients younger than 10 years and 35 patients older than 10 years) were monitored for a mean follow-up of 3 to 4 years. 8 patients (17%) showed changes in curve patterns. Six of these patients were younger than 10 years, while 2 patients were older than 10 years. There was no correlation between the curve severity and the curve pattern changes. We found no significant difference between the male and female patients. Single curves changed in double curves and vice versa during growth in 70% younger than 10 years and 18% older than 10 years. Conclusion In this study, changes in curve patterns suggest that idiopathic scoliosis is not a fixed deformity, but a dynamic process especially in patients younger than 10 years.