Lameness is not infrequently caused by damage to joints. This may be damage to the cartilage, which lines the joint, to the fibrous capsule that surrounds a joint (the synovium) or may include a chip fracture of the underlying bone. Which joint is damaged can be determined by clinical examination, regional nerve blocks (numbing the area responsible for the lameness), and then by intra articular nerve blocks (injection of local anaesthetic into the suspect joint) to make the horse sound. The next stage is usually radiography. Colin is shown below checking a radiograph of a horse's foot. This horse had been lame for six weeks. The lameness had been shown to be in the coffin joint (joint between the short pastern and the pedal bone) by intra articular anaesthesia of the joint. There were no abnormalities on X - ray, so damage to the cartilage was suspected and the joint was medicated with a drug called 'Hyonate', which acts to protect and repair damaged areas of cartilage. Unfortunately no progress was made suggesting that cartilage damage not visible on the radiograph could be present.
Radiographs are examined carefully before surgery.
The decision was taken to call in our visiting consultant orthopaedic surgeon Dr. David Platt to evaluate the joint by means of 'key hole surgery' this is more properly known as 'arthroscopy'. Strict hygiene (asepsis) is required during this surgery. A small hole is made surgically into the joint (this is known as a portal). A small fibreoptic instrument (the arthroscope) is introduced through this portal, and a second portal created through which various instruments can be introduced. The inside of the joint is displayed on a large television set, so that they surgeon can manipulate the instruments within the joint to help repair the damaged area.
Dr. Platt at work, investigating a problem coffin joint.
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| A large flap of loose cartilage could be seen within the joint. This was carefully removed and the underlying bone smoothed off. |
Arthroscopy can take up to an hour and a half, careful monitoring of the horse whilst it is anaesthetised is essential. Ian is checking the horses pulse in the illustration above. He also monitors the E.C.G. (a measure of electrical activity in the heart), the level of oxygen in the blood stream, and the average arterial blood pressure.
On this occasion extensive cartilage damage was found. As well as enabling direct treatment of the damaged area at surgery, a course of intra articular medication will be given to aid healing.
Equine Services
