CORR Insights^®: Stem Cells Combined With Platelet-rich Plasma Effectively Treat Corticosteroid-induced Osteonecrosis of the Hip: A Prospective Study

Where Are We Now?

There is immense professional and lay interest in restorative options for musculoskeletal conditions, most notably stem cells. Indeed, the idea that pluripotent cells could be driven to form bone, cartilage, muscle, or nerve is compelling [2].

Stem cells of various derivations can be driven to form bone, muscle, or cartilage in vivo and in vitro. For example, we know that satellite cells in skeletal muscle play a role in muscle repair and aging [4], adipose derived stem cells can form cartilage [3, 6], and marrow derived stem cells are involved in fracture healing [8]. However, it is not clear what drives the cells, how consistently they might perform a desired restorative function in certain disease states, and how the cells interact with the local environment in which they are placed.

Where Do We Need To Go?

Using stem cells to treat osteonecrosis of the femoral head is a logical clinical avenue to pursue [9]. In order to understand the role of stem cells in treating osteonecrosis, however, we need clinical and laboratory research. Research is acutely needed in this area of clinical science, as the marketing of stem cells for therapeutic purposes seems to be moving at a pace that might exceed the scientific support for its use [1].

The basic studies would shed light upon how a stem cell might restore the normal reparative process that seems absent in osteonecrosis of the femoral head [7]. The authors of the current study focused on quantifying the available cells within the injected fraction. While this particular study suggests that platelet-rich plasma (PRP) may enhance the role of stem cells, it will also be important to understand the characteristics and content of the PRP, the cellular interaction induced by PRP, and the response of the cells. How do stem cells and other proteins change the cellular activity in the local environment?

Complimentary clinical studies could extend the reach of an observational cohort such as the group that was the focus of the present analysis. On the clinical research front, osteonecrosis of the femoral head is an interesting model to study given that the response to treatment of osteonecrosis of the femoral head could be determined in a relatively short time compared to other degenerative orthopaedic conditions. Tightly structured clinical studies would be helpful to elucidate how the presence of cells might compare with other known strategies such as core decompression or grafting of the femoral head with other materials. In addition to enhancing the understanding of the cellular processes, it will be important to examine whether the stem cells actually remain physically present in the location where they are placed at the time of a surgical procedure.

Fundamental to understanding how stem cells impact the natural history of osteonecrosis is the simple question of “what problem are stem cells solving?” At the present time, clinicians and scientists have a clear understanding of the clinical course of the disease, but know relatively little about the underlying deregulation of bone remodeling that drives its course [5].

How Do We Get There?

Studying the clinical impact of therapeutic strategies is an important translational extension of scientific observations about cell and tissue behavior. Perhaps the most important clinical determinant of success in using any novel strategy to treat osteonecrosis is the effectiveness in reducing pain. While studying pain relief is important, a more detailed understanding of the impact of stem cell therapy could be derived from other investigations such as functional imaging that provides clues about bone formation, vascular in-growth patterns, or even gene expression. MRI analysis of the changes in the volume of the necrotic segment could be combined with functional imaging. Likewise, important questions about the mechanisms of action of stem cells would be further supported by basic cell and tissue level studies that focus upon the understanding of the relationship of stem cells to restoring the known pathways of bone formation and healing.