Page 1 of 6 Review Licensee OA Publishing London 2013. Creative Commons Attribution License (CC-BY) For citation purposes: Tripathy SK, Behera P, Sen RK, Goyal T. Application of stem cells in orthopaedic conditions: what is the current evidence? OA Orthopaedics 2013 May 01;1(1):3. Compeng interests: none declared. Conflict of interests: none declared. All authors contributed to concepon and design, manuscript preparaon, read and approved the final manuscript. All authors abide by the Associaon for Medical Ethics (AME) ethical rules of disclosure. Diagnosis & Treatment Application of stem cells in orthopaedic conditions: what is the current evidence? SK Tripathy 1 *, P Behera 2 , RK Sen 2 , T Goyal 1 Abstract Introduction Stem cell therapy plays an impor- tant role in orthopaedic treatment. Although some studies have shown promising results in repair of bone, tendon and cartilage, few studies have demonstrated incoherent re- sults. The bone and cartilage regen- eration ability of stem cells have been demonstrated clinically, but the tendon regeneration capabil- ity is still in the experimental stage. Various factors including the stage of the disease, processing and con- centration techniques, application and retaining methods control the disease outcome. Researchers have still not identified the best carrier of stem cells. This review focuses on basics of stem cells and their cur- rent recommendation in orthopaedic conditions. Conclusion Stem cell therapy looks to be an ap- pealing new option but many of these studies have shown failures as well as successes. Many more long-term prospective randomised human tri- als need good results before the use of these cells can be recommended. Introduction Application of ‘regenerative medi- cine’ in orthopaedic practice has aroused a new ray of hope among surgeons. Myriads of orthopaedic conditions with limited therapeutic options could be benefited with tech- nologies developed in regenerative medicine 1 . Growth factors, stem cells and products developed through genetic engineering are now being widely used for several orthopae- dic conditions. Stem cells hold great potential in repairing damaged tis- sue, but the clinical application into the target site is still a major chal- lenge. In this review, a brief descrip- tion of stem cells is provided, and the current status of stem cells in orthopaedic practice is discussed. Discussion The authors have referenced some of their own studies in this review. These referenced studies have been conducted in accordance with the Declaration of Helsinki (1964) and the protocols of these studies have been approved by the relevant ethics committees related to the institution in which they were performed. All human subjects, in these referenced studies, gave informed consent to participate in these studies. Concept of stem cells A stem cell is a cell that has two es- sential properties: self-renewal and ability to differentiate into a particu- lar cell type. Thus, a stem cell is able to maintain its own population and at the same is able to produce a par- ticular lineage of cell 2,3 . The differ- entiation a stem cell would undergo depends on the type of the stem cell and the surrounding environment. Broadly, there are two types of stem cells: embryonic and adult stem cells. Embryonic stem cells (ESCs), as the name suggests, are the cells present in the embryos, i.e. found only during the early developmental phase of an organism. These are con- sidered to be purely pluripotent and capable of indefinite self-renewal. Being pluripotent, an ESC can give rise to any type of cell of the body and hence can regenerate a part or even a complete organ 3 . Harvesting an ESC, which is found in an embryo is not only technically demanding and dif- ficult, but has many ethical and legal issues associated with it too. Induced pluripotent stem cells (iPS cells) were first reported by Takahashi and Yamanaka in 2006 4 . They prepared these cells by transfecting embryonic growth factors into somatic cells to induce de-differentiation of the so- matic cells to make them behave like ESCs. Thus, this process took away the consideration of ethics but yet the technique has not been brought into mass use, primarily because of the apprehension of the teratogenic potential of such cells 5 . The adult stem cells are multipo- tent and found more or less in every tissue. These stem cells lack the pluri- potent character of the ESCs but are capable enough to produce cells of a particular type of lineage; usually the tissue in which the stem cells reside determines the lineage. This narrows the clinical applicability of such stem cells but as the current techniques of stem cell application use autologous stem cells, it is definitely safer than the ESCs and is free from the ethical and legal considerations. Moreover, considering the cost, the application of adult stem cells would be cost ef- fective than the ESCs. Among adult stem cells, mesenchymal stem cells (MSCs) are the most studied and considered as most competent stem * Corresponding author Email: sujitortho@yahoo.co.in 1 Department of Orthopaedics, All India Institute of Medical Sciences, Bhubaneshwar, India 2 Department of Orthopaedics, Postgraduate Institute of Medical education and Research, Chandigarh, India