Biologically Derived Therapies for Tendon and Ligament Injuries
The use of biologically derived therapies in horses is common in equine practice. The most commonly used biologic products used to treat tendon and ligament injuries are mesenchymal stem cells (MSC), platelet rich plasma (PRP) and bone marrow concentrate aspirate (BMAC). The other biologics such as autologous conditioned serum (IRAP) and autologous protein solution (Prostride) are derived for use in joints.
Stem cell therapy is commonly used for a variety of tendon and ligament injuries. Bone marrow is the common source for stem cells at this time. A core lesion of a tendon or ligament is the text book case for stem cells. The stem cells are injected via ultrasound guidance directly into the lesion. In many cases the stem cells are used in combination with other treatments or surgery such as tendon splitting, superior check ligament desmotomy or shockwave therapy. Some lesions are not amenable to intra-lesional injections and treatment is done via regional limb perfusions. Intravenous perfusions have been used most commonly but recent research indicates regional limb perfusions using the median artery in the forelimb without a tourniquet allows better distribution of cells. Horses are typically treated one to three times depending on the severity of the lesion and progress. Research has also shown that the recurrence rate of superficial digital flexor tendonitis is decreased by 50%. The tendon will heal no matter what we do but the quality of healing and the incidence of recurrence will vary significantly based upon the treatment and rehabilitation program chosen.
Platelet rich plasma (PRP) was first described in treating suspensory ligaments in Standardbreds. PRP is made up of platelets and several growth factorsthat can aid in decreasing inflammation and will promote healing. PRP is commonly used in human medicine also to treat tendon and ligament injuries. In a recent study it was shown the PRP was successful at returning 80% of horses to their previous level of work at 12 months compared to horses that were not treated. Unfortunately, only 60% of the horses were still in work at 24 months compared to 50% of the controls. There are several different PRP products available but they are not all the same. Consult your veterinarian to help chose the best product for your horse. Typically, PRP is significantly less expensive than stem cell therapy.
Bone marrow aspirate (BMAC) was the first biologic therapy used to treat tendon and ligament injuries. A bone marrow sample is easily collected, prepared and injected into a lesion. This treatment is done less frequently today with the development of stem cell therapy and PRP.
The use of biologics has significantly improved our success in treating tendon and ligament injuries. The rehabilitation program post treatment is extremely important in the success of these treatments and should not be overlooked.
By Scott Hopper, DVM, MS, Dipl. ACVS.
Dr. Hopper is an internationally-renowned veterinarian. He is currently a surgeon, shareholder at Rood & Riddle Equine Hospital and head of the RREH Stem Cell Lab.Dr. Hopper’s interests include performance and sport horse lameness. Rood & Riddle Equine Hospital