Arthroscopy is a testing technique used by surgeons, both human and veterinary, to evaluate and treat disease within joints. The technology has also been applied to other synovial structures within the body such as tendon sheaths (known as tenoscopy) and bursae (bursoscopy). The techniques depend on a narrow, rigid instrument called an endoscope, which acts as a sort of joint telescope with a light source that is powerful enough to illuminate the inside of the joint.
Arthroscopy vs. Arthrotomy
Prior to the use of arthroscopy, synovial conditions would be treated by an “open” technique called an arthrotomy. Arthrotomy required making large incisions into joints, tendon sheaths, or bursas. By contrast, arthroscopy utilizes smaller incisions (~5-6mm), which makes post-operative incision care easier and decreases the risk of infection. Arthroscopy also results in less lay-up time and a quicker return to work with an overall improved prognosis for athletic use.
Thanks to decreased complication rates and faster healing times, arthroscopy has become more readily available. These days, it is the treatment of choice for joint, tendon sheath, and bursae conditions. Typically, arthrotomies are not recommended for most conditions in horses anymore.
However, not all orthopedic surgeries can be done arthroscopically, and most surgery requires specialized equipment and facilities. Equine surgery should be performed by a veterinary surgeon with advanced training.
How Arthroscopy Works
The endoscope is placed through a small incision to examine the inside of a joint, tendon sheath, or bursa that has been distended with sterile, balanced electrolyte solutions. The image is then transmitted to a camera for viewing on a monitor. Specially designed surgical instruments are passed through a separate small incision, which is known as a working portal. Because of their large joints, horses are uniquely suited to benefit from this technology. Listed below are just a few applications of arthroscopy.
Removal of osteochondral fragments
This is one of the most common applications for use in the horse. Osteochondral fragments, also known as ‘chips,’ are small pieces of bone and cartilage that result from small fractures within the articular surfaces of joints. They are usually due to repetitive trauma or repetitive exercise. When these fragments are small enough, they can be removed using arthroscopy. However, some chips are big enough that they should be repaired within the joint rather than removed. In these cases, arthroscopic guidance is invaluable.
Removal of osteochondrosis dissecans
Osteochondrosis dissecans, also known as “OCD”, is a developmental disease that occurs during the formation of bones. The cause of this common disease in horses is not completely understood. OCD leads to the formation of fragments within joints and can lead to joint effusion and swelling; lameness; and arthritis. Arthroscopy is used to remove OCD fragments and evaluate the overall health of the joint.
Treatment of subchondral bone cysts
Subchondral bone cysts can also arise after a disruption in the normal development of bones and joints. These lesions are usually seen on the weight-bearing surface of bones within joints and can result in lameness and joint effusion. Arthroscopy can be used to evaluate and treat these types of lesions depending on their location within the joint.
Treatment of infections
Infections can develop within synovial structures (joints, tendon sheaths, bursae). Such infections can be due to bacterial spread from the bloodstream, can be a result of wounds or lacerations in these structures, or rarely, can result after injection of these structures. Arthroscopy, tenoscopy, and bursoscopy can be used to perform lavage or ‘flushing’ of joints, tendon sheaths, or bursae to remove bacteria, debris, and inflammatory products. These procedures can also be used to evaluate the overall health of the cartilage and other structures within the joint, tendon sheath, or bursa.
Treatment of soft tissue injuries
Injuries that can occur within joints, tendon sheaths, and bursae include tendon tears, ligament tears, meniscal tears, adhesions, and synovial masses. These can be evaluated and treated using arthroscopy, tenoscopy, or bursoscopy.
Assisting fracture repair
Arthroscopy can also be used to assist in the reduction and repair of intra-articular fractures.