Longtime outcome after intraosseous application of autologous mesenchymal stromal cells in pediatric patients and young adults with avascular necrosis after steroid or chemotherapy

Avascular necrosis (AVN) is a severe complication of immunosuppressant therapy or chemotherapy. A beneficial AVN therapy with core decompression (CD) and intraosseous infusion of mesenchymal stromal cells (MSCs) has been described in adult patients, but there are only few data on MSC applications in pediatric and young adult patients (PYAP). Between 2006 and 2015, 14 AVN lesions of 10 PYAP (6 females) with a median age of 16.9 years (range 8.5-25.8 years) received CD and intraosseous application of autologous MSCs. Data of these patients were analyzed regarding efficacy, safety, and feasibility of this procedure as AVN therapy and compared with a control group of 13 AVN lesions of 11 PYAP (5 females) with a median age of 17.9 years (range 13.5-27.5 years) who received CD only. During the follow-up analysis [MSC group: median 3.1 (1.6-5.8) years after CD; CD group: median 2.0 (1.5-8.5) years after CD], relative lesion sizes (as assessed by magnetic resonance imaging) compared with the initial lesion volume, were significantly lower (P < 0.05) in the MSC group (volume reduction to a median of 18.5%) when compared with the CD group (58.0%). One lesion in the MSC group comprised a complete remission. Size progression was not observed in either group. Clinical improvement (pain, mobility) was not significantly different between the two groups. None of the patients experienced treatment-related adverse effects. CD and additional MSC application was regarded safe, effective, feasible, and superior in reducing the lesion size when compared with CD only. Prospective, randomized clinical trials are needed to further evaluate these findings