Arthroscopy in Equine Lameness
Arthroscopy is the accepted way to perform joint surgery in horses and is a valuable tool in the diagnosis of joint disease. Arthroscopic surgery can be used to remove bone and cartilage fragments, debride damaged ligaments and menisci, assist the repair of articular fractures with internal fixation, debride or inject subchondral bone cysts, repair cartilage, and debride and flush contaminated or septic synovial cavities. Arthroscopy is a valuable method to evaluate intrasynovial structures and is particularly useful to evaluate soft-tissue structures such as ligaments, cartilage, menisci, and synovial membranes. It should be used in concert with other diagnostic methods, including high-quality radiographs, ultrasonography, and CT and MRI when available. Diagnostic arthroscopy is the most sensitive and specific tool for intra-articular evaluation in horses. Athroscopes of 2.5–5 mm diameter can be placed in all joints of the equine limbs; however, not all areas of every joint can be examined. The arthroscope has also been used to examine, diagnose, and perform surgery on structures within the digital, carpal, and tarsal tendon sheaths (tenoscopy) and in the navicular, calcaneal, and bicipital bursas (bursoscopy).
Advantages of arthroscopy compared with standard surgical procedures include the use of small stab incisions for placement of the arthroscope and instruments, the ability to view numerous areas of the joint, easy operations on more than one joint during the same surgical procedure, less trauma to periarticular soft tissues, less pain, reduced convalescent times, and reduced complications.
Diagnostic and surgical arthroscopy is technically demanding, and extensive experience is necessary to become proficient. Good knowledge of joint anatomy and good hand-eye coordination and spatial awareness are essential characteristics of successful surgeons.
Most arthroscopic procedures are performed with the horse under general anesthesia. Many surgeons prefer dorsal recumbency to allow surgical access to all sides of the joint, to allow surgery on multiple joints and limbs, and to control hemorrhage. Routine aseptic surgical preparation and draping is necessary. Basic equipment required for arthroscopy includes an arthroscope and insertion sleeve, light source and cable, fluid pump for joint distention, egress cannula, and an assortment of hand instruments for intra-articular procedures. A video camera and video screen are highly recommended to decrease the risk of contamination, to improve visualization and depth perception, and to allow capture of images and videos. Triangulation techniques are used to optimize manipulation of intra-articular instruments.
Arthroscopy, bursoscopy, and tenoscopy are often used to evaluate and treat contaminated synovial cavities. The techniques facilitate wound debridement, removal of fibrin and foreign debris, and copious flushing of the cavities without inducing more trauma from a major incision. The normal intrasynovial environment can recover quickly. Bursoscopy of the navicular bursa has greatly reduced the need for the streetnail procedure to treat punctures of the navicular bursa and has reduced the morbidity of calcaneal infections after injury to the hock. Tenoscopy has improved the recovery rate of septic tenosynovitis in horses.