Twenty-three patients with thirty hips of slipped capital femoral epiphysis were treated in our department, KK Women's and Children's Hospital, Singapore between 1997 and 2005. Except one patient lost of follow-up, twenty-four SCFEs with more than 2 years (25 to 73 months, average 38.5 months) follow-up were reviewed. This study is to evaluate the effectiveness and outcome of our protocol: Russell traction followed by gentle manipulative reduction with a single screw fixation & spica cast immobilization (for acute-on-chronic cases with unstable and reducible SCFE). In this series, there were 13 boys & 5 girls, mean age 12 year old ranging from 10 to 14 years. Among them 7 were Chinese, 6 Malays & 5 Indians. There were 12 unilateral cases (8 on the left & 4 right, 67%) & 6 bilateral cases (33%), including 2 patients found contralateral SCFE subsequently 1 year postoperatively. Acute-on-chronic SCFE were 16 & chronic SCFE 8. 16 were Grate I & 8 Grate II. Russell traction was on preoperatively with an average of 6 days. Gentle manipulative reduction under general anesthesia was performed in 20 SCFEs (12 GI & 8 GII) and 17 of them were successful. Fixation with a single screw was used for all cases except one hip with 2 screws. Average follow-up was 38.5 months. Good results achieved. All patient were symptom free with good function. No complications of AVN, chondrolysis, screw loosening and reslipping of the affective hips. Our protocol of management for SCFE has been largely successful in term of manipulative reduction and fixation.

The repair of cartilage defects remains a significant clinical challenge. The use of mesenchymal stem cells for cell-based tissue-engineering strategies represents a promising alternative for the repair of the defects. In this study, we investigated the TGF-bate1 dose and cellular density-dependent effect on chondrogenic differentation of human bone marrow-derived mesenchymal stem cells (MSCs) cultured in alginate beads in vitro.

Methods A volume of 6 ml bone marrow was collected from six volunteer donors respectively. MSCs were cultured in different cellular density (1×104, 1×105, 1×106 and 5×106/ml) and treated with different doses of TGF-beta1 (0, 1, 10, 50 and 100 ng/ml). Immunohistochem-istry and in situ hybridization were applied to detect the expression of collagen type II and assay proteoglycan in different time internal.

Results 95% cellss were alive after density gradient centrifugation. BMSCs had a similar spindle-like morphology. Type II collagen and proteoglycan were showed positive staining in the 10 ng/ml TGF-beta1 group, weakly positive in the 50 ng/ml and 100 ng/ml group, negative in the 0 ng/ml and 1 ng/ml group. With time, the proteoglycan quantity increased. All cell density groups except 1×104/ml showed positive expression of collagen type II and proteoglycan synthesis, and better staining with increase of cellular density. Proteoglycan synthesis did not increased until the fifth weeks.

Conclusions The chondrogenesis differentiation of human MSCs is dose-dependent. 10ng/ml TGF-beta1 is a suitable concentration for such inducing. The cellular density is also important for the differentiation of MSCs. Too small density is ineffective. The more cells, the better differentiation. And the time of in vitro culture should not be longer than 4 weeks