Research shows that oral hyaluronan gel reduces swelling in joints after surgery.
Joint damage is a common cause of lameness in horses. It may be caused by physical injury, or may result from developmental abnormalities such as osteochondrosis. One of the signs of damage within the joint is effusion (an increase in synovial fluid within the joint).
Hyaluronan (HA) is a glycosaminoglycan, a large molecule that forms part of the structure of articular cartilage and is present in joint fluid. It has been used to treat joint disease by injection directly into the joint, and more recently by intravenous administration. Its use in these circumstances has been tested and found to be beneficial . For the past few years an oral preparation of HA has been available for use in horses. Although there have been anecdotal reports of its efficacy, there has been no conclusive proof of its value.
Now a study has found convincing evidence that HA administered by mouth can improve the condition of joints after arthroscopic surgery for osteochondrosis.,
The study was carried out by Dr Brady Bergin and colleagues at the Rood and Riddle Equine Hospital in Lexington Kentucky. Forty-eight Thoroughbred yearlings that had been admitted for arthroscopic surgery for osteochondritis dessicans of the hock were chosen for the study. Only those individuals with mild or no effusion before surgery were included. After surgery, half of the horses were given 100mg HA gel* daily. The others received a placebo.
All horses had two weeks box rest followed by a further two weeks box rest and hand walking. No one involved in giving the treatment or assessing the response knew which horse received the HA or the placebo until after the end of the study.
Thirty days after surgery, Dr Bergin examined the horses and assessed the treated joints. He gave each joint a score for the amount of joint effusion that was present, on a scale from 0 (no effusion) to 5 (greater than a tennis ball).
Joints treated with oral HA were significantly less swollen 30 days after surgery than were joints that had received the placebo..
A full report of the research appeared in the Equine Veterinary Journal. The work’s significance was recognised when it was presented with the Journal’s annual Clinical Evidence Award, sponsored by the Home of Rest for Horses. The award is given to the paper published in the EVJ that is judged to be of outstanding merit. To be eligible for the award, studies have to be based on naturally-occurring conditions, and provide strong clinical evidence relating to specific treatments.
* “Conquer” Kinetic Technologies, Lexington Kentucky.
For more details see:
Oral hyaluronan gel reduces post operative tarsocrural effusion in the yearling Thoroughbred.
BJ Bergin, SW Pierce, LR Bramlage, A Stromberg.
Equine Vet J (2006) 38, 375 - 378.