Stem cells and growth factors in orthopedics

By Dr. Corrado Bait - Specialist in Orthopedics and Traumatology

They sound a bit like a magic formula, "stem cells and growth factors" and, without even knowing what it is all about, the miracle is expected: cartilages that regenerate, ligaments and tendons that reconstitute, joints that return to work without problems. However effective and promising, these treatments are not able to solve everything. And first of all, they are not the same thing.

The stem cells used in orthopedics are the mesenchymal ones (MSC is the abbreviation that defines them) and are usually derived from the iliac crest, the highest part of the pelvic bones. "Stem cells are multipotent undifferentiated cells - explains Corrado Bait, head of the Operative Unit of Knee Surgery and Traumatology of Sport at the Istituto Clinico Humanitas and member of the specialized Physioclinic center in Milan -. Their destiny is not yet decided and therefore, through a process of differentiation, they can give rise to different cells. In orthopedics they are mainly used for chondral lesions, ie those of the cartilage, a problem with a strong social impact given the high number of subjects affected, with pain and joint dysfunctions that limit everyday life, even work ». But what are the advantages of using mesenchymal stem cells in cartilage lesions? The first is above all the possibility of performing a "one step" intervention. In fact, in a single surgical session, the stem cells are taken and transferred to the joint to be treated. "It is a great step forward compared to the previous technique - says Bait - which involved a small cartilage removal from the patient, about 200 mg, and then in vitro cultivation for a period of 3-4 weeks". At the end of this period, with a new intervention, the suspension thus obtained was transferred to the point to be reconstructed, although in vitro cultivation was not always successful and produced the desired results.

"The treatment with stem cells is shorter, cheaper and above all more effective - explains Bait -, because unlike what happens with in vitro cultivation and replanting, with this technique it can be reconstructed, at least in part and with the necessary precautions, also the underlying bone tissue ». The cells, however, need to be "conveyed" to the area to be treated through a solid support that acts as a frame (scaffold) for growth. After MSC treatment, the patient is immediately moved to model the obtained scaffold and reduce the chances of intra-articular adhesions. In any case, however, the times are not short: low-impact sporting activity can be resumed after about 4 months, while for running, soccer and tennis you have to wait almost a year.

The possibility of using platelet growth factors, the so-called PRP, derived from the patient's own blood, is less striking but wider. Platelets are in fact obtained from autologous donations (in practice the patient donates blood to himself) and concentrated through low-speed centrifugation methods. "Growth factors - explains Bait - intervene in stimulating the regeneration of injured tissues. As the name suggests, they are more than one and each growth factor intervenes on a specific cell line, producing an anti-inflammatory and reparative process in the tissue metabolism. For this reason, growth factors are used in cartilage lesions, in tendon lesions, ligaments and muscles ". After concentrating the platelets, they are injected into the affected area of the body. There are usually three infiltrations, 15 days apart, but the overall situation has already improved considerably since the second.

Naturally these methods are strongly conditioned by the biology of the patient, in fact age plays a fundamental role in the ability of cells to implement reparative processes. We cannot expect the same results at 20 and 40 years, as always the correct indications are always the best cure.