Bone Cysts: New Surgical Technique Described

Lameness caused by bone cysts in weight-bearing joints often results in economic losses and compromised athleticism, especially of young horses. Traditional surgical procedures designed to resolve bone cysts have variable success rates. A novel approach involving absorbable implants may provide owners a more reliable solution to managing bone cysts.

“Bone cysts are abnormal, fluid-filled cavities within a bone that are readily visible on radiographs,” explained Kathleen Crandell, Ph.D., a nutritionist at Kentucky Equine Research. Bone cysts often cause lameness, though degree of unsoundness ranges from mild to severe.

Scientists remain unsure why bone cysts develop, though genetic predisposition, trauma, nutrition, and environmental factors are thought to contribute. Rapid growth spurred by excessive caloric intake has also been implicated as a cause of bone cyst formation, Crandell explained.

Regardless of the underlying causes, prompt treatment should be instituted. Traditional management approaches include rest, intra-articular injections with anti-inflammatory drugs, regenerative therapies, and surgery (e.g., debridement, screw placement, cartilage grafting).

A new surgical technique involves filling cysts with a synthetic, absorbable material.^* These implants function as scaffolds that facilitate the natural repair of the cyst with normal bone tissues.

In a recent study, the procedure was used in 38 affected horses between 10 and 24 months of age. Results of the study proved promising:

• In total, 36 of 38 horses were no longer lame 120 days after surgery;
• Bone cyst area was reduced by an average of 77% by 120 days;
• No infection at implant sites, cosmetic defects, or reaction to the foreign material was observed;
• Twenty-seven horse raced after surgery (71%) and an additional six were actively training; and
• Twenty-one of the racehorses won prize money.

In sum, this surgical procedure “resulted in progressive healing of the lesions. The implant was well tolerated, the technique is feasible in different anatomic locations, and the implant can offer an alternative to current techniques for the management of subchondral cyst lesions in young horses,” concluded the researchers.

After surgery, supplementation with high-quality joint supplements will support affected joints to slow the onset and progression of degenerative joint changes.

“Degenerative joint disease, or osteoarthritis, begins to develop after an inflammatory event that disrupts the normal, healthy joint environment. Owners should supplement these horses with high-quality joint supplements, such as Synovate HA with hyaluronic acid, as soon as a diagnosis of bone cysts has been made.”

^*Ravanetti, P., A. Lechartier, M. Hamon, and E. Zucca. 2021. A composite absorbable implant used to treat subchondral bone cysts in 38 horses. Equine Veterinary Journal. doi:10.1111/evj.13428