Volume and location of bone regeneration after autologous expanded mesenchymal stromal cells in hip osteonecrosis

Abstract

Aims Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs). Methods A total of 20 patients with small and medium-size symptomatic stage II femoral head ON treated with 140 million BM-hMSCs through percutaneous forage in the EudraCT 2012-002010-39 clinical trial were retrospectively evaluated through preoperative and postoperative (three and 12 months) MRI. Then, 3D reconstruction of the original lesion and the observed postoperative residual damage after bone regeneration were analyzed and compared per group based on treatment efficacy. Results The mean preoperative lesion volume was 18.7% (SD 10.2%) of the femoral head. This reduced to 11.6% (SD 7.5%) after three months (p = 0.015) and 3.7% (SD 3%) after one year (p < 0.001). Bone regeneration in healed cases represented a mean 81.2% (SD 13.8%) of the initial lesion volume at one year. Non-healed cases (n = 1 stage progression; n = 3 THAs) still showed bone regeneration but this did not effectively decrease the ON volume. A lesion size under mean 10% (SD 6%) of the femoral head at three months predicted no ON stage progression at one year. Regeneration in the lateral femoral head (C2 under Japanese Investigation Committee (JCI) classification) and in the central and posterior regions of the head was predominant in cases without ON progression. Conclusion Bone regeneration was observed in osteonecrotic femoral heads three months after expanded autologous BM-hMSC injection, and the volume and location of regeneration indicated the success of the therapy. Cite this article: Bone Joint Res 2022;11(12):881–889.

Regenerative medicine for osteonecrosis of the femoral head

“…A recent study using autologous BMSCs reported that the mean threshold residual lesion volume for progression of collapse was 10% (standard deviation 6%) at three months after implantation. 32…”

“…A recent study using autologous BMSCs reported that the mean threshold residual lesion volume for progression of collapse was 10% (standard deviation 6%) at three months after implantation. 32 Safety is one of the critical concerns in the application of cell therapy. Key features of stem cells such as selfreplication, long lifespan, and multidifferentiation are also shared by cancer cells.…”

Osteosarcoma cells/cell lines are not appropriate for studies on bone regeneration in vitro

“…[12][13][14][15][16][17] have been applied to evaluate the efficiency of those biomaterials on osteogenesis, and MSC treatments even achieved profound success in clinical trials for bone regeneration. 18,19 Due to the accumulated studies, MSCs can now be cultured without sophisticated instruments and unique medium, and commercial MSCs are also available. 20 Thus, MSCs can be cultured and tested in most laboratories worldwide.…”