ObjectiveTo evaluate chemical arthrodesis using sodium monoiodoacetate for treatment of degenerative joint disease of the tarsometatarsal and distal intertarsal joints.
DesignRetrospective clinical study.Method Horses were diagnosed with degenerative joint disease of one or more of the tarsometatarsal or distal intertarsal joints based on history, lameness examination, radiographic findings and, in some cases, response to intra-articular anaesthesia or medication. Intra-articular injections of sodium monoiodoacetate were performed using 23 gauge needles in the sedated, standing horse. Positive contrast arthrography of the distal intertarsal joint was performed in all horses to evaluate needle placement and the presence or absence of communication with other synovial structures. The mean intra-articular dose of sodium monoiodoacetate was 192 mg. Horses were subject to a graded exercise program commencing 7 to 10 days after treatment. Where possible, follow up lameness examination and radiography was performed at 3, 6, 12 and 24 months after treatment.Results At 3, 6, 12 and 24 months after treatment, respectively, 0/57, 14/55, 41/50, and 29/34 of horses were sound. At 3, 6, 12 and 24 months after treatment, respectively, 5/55, 24/38, 26/30 and 18/18 of horses had radiographic evidence of ankylosis of treated joints. Post injection pain was marked in 6.7% of horses and significant complications requiring further treatment occurred in 3.8% of horses.Conclusions Chemical arthrodesis using sodium monoiodoacetate was an effective treatment method for degenerative joint disease of the distal tarsal joints. The technique was performed in the sedated standing horse and required minimal equipment. Results were comparable to those achieved following surgical arthrodesis. The risk of significant complications was minimised through good technique using an appropriate injection volume and concentration. Aust Vet J 2004;82:38-42 bpm Beats per minute CS Comfort Score DIT Distal intertarsal IV Intravenous MIA Sodium monoiodoacetate PIT Proximal intertarsal TMT Tarsometatarsal D egenerative joint disease of the TMT and DIT joints is the most common cause of hind limb lameness in performance horses. [1][2][3][4] While medical management of degenerative joint disease of the distal tarsal joints often results in temporary improvement in lameness, approximately 50% of horses treated conservatively remain lame. [5][6][7] The aim of medical management is to ameliorate pain and allow continued exercise, promoting progressive cartilage deterioration and disruption of subchondral bone. The proposed end point of medical manage-ment is spontaneous ankylosis of affected joints and soundness, however results are variable and convalescence prolonged. 5 Drilling of the distal intertarsal joints is the currently recommended technique for surgical arthrodesis. [8][9][10][11] Complementary surgical techniques appear to offer little benefit over drilling alone. 3,10-14 Chemical arthrodesis using MIA has been described as an alternative to surgery an...