Although stem cell therapy continues to increase in popularity for treating horse racing injuries, its use bas been based only on experimental data regarding the treatment modality's efficacy. However, a group of researchers from Great Britain recently published a study examining the effects of stem cell therapy in superficial digital flexor tendons (SFDT, located at the back of the cannon bone, running from the knee/hock to the fetlock) of racehorses at least two years after therapy occurred.
"My research group compared the safety and reinjury rate in Thoroughbred racehorses with naturally occurring superficial digital flexor tendinopathy (disease of the tendon) who were treated with stem cells to data published on horses with the same injury but which were managed using treatments other than stem cells," explained Roger Smith, MA, VetMB, PhD, DEO, Dipl. ECVS, MRCVS, a professor of equine orthopedics at the Royal Veterinary College in the United Kingdom.
Of the 113 horses included in the study, all of which had suffered an SDFT injury and were treated with bone marrow derived-mesenchymal stem cells (i.e., stem cells recovered from bone marrow):
- 98.2% returned to racing; and
- The reinjury rate was 25.7% in National Hunt (similar to steeplechasing) horses and 50% in flat racehorses.
Smith et al. then compared the data they collected to previously published literature on similar injuries treated with traditional methods (such as stall rest, poultices, ice, and wraps).
"The reinjury rate was significantly lower in National Hunt horses than horses treated with conservative/medical management alone," said Smith (the study did not include comparative numbers for traditionally treated horses). "There were insufficient numbers of flat racehorses to make any conclusions on this class of racehorse. Group sizes in excess of about 90 horses are needed to show significance. This was achieved for the National Hunt racehorse but only eight horses were in the flat racehorse group."
Together, these results suggest that injecting bone-marrow derived stem cells into the injured tendon might be a more efficacious treatment for this condition than other treatments, however more stem cell research is needed to scientifically substantiate anecdotal experience with this regenerative therapy.
The study, "Implantation of bone marrow-derived mesenchymal stem cells demonstrates improved outcome in horses with overstrain injury of the superficial digital flexor tendon" will be published in an upcoming edition of the Equine Veterinary Journal. The abstract is currently available on PubMed.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.