METACARPOPHALANGEAL JOINT SYNOVIAL PAD FIBROTIC PROLIFERATION IN 63 HORSES

Medical records, radiographs, and sonograms of 63 horses with metacarp ophalangeal joint synovial pad proliferation were examined retrospecti vely. All horses had lameness, joint effusion, or both signs associate d with one or both metacarpophalangeal joints. Bony remodeling and con cavity of the distodorsal aspect of the third metacarpal bone (Mc3) ju st proximal to the metacarpal condyles was identified by radiography i n 71 joints (93%); 24 joints (32%) had radiographic evidence of a chip fracture located at the proximal dorsal aspect of the proximal phalan x. Fifty-four joints (71%) were examined by ultrasound. The mean +/- S D sagittal thickness of the synovial pad was 11.3 +/- 2.8 mm. Seventy- nine percent of the horses had single joint involvement with equal dis tribution between the right and left forelimbs. Sixty-eight joints in 55 horses were treated by arthroscopic surgery. Sixty joints (88%) had debridement of chondral or osteochondral fragmentation from the dorsa l surface of Mc3 beneath the synovial pad and 30 joints (44%) had a bo ne chip fracture removed from the medial or lateral proximal dorsal em inence of the proximal phalanx. Complete or partial excision of both m edial and lateral synovial pads was completed in 42 joints. Only the m edial synovial pad was excised or trimmed in 21 joints, and 5 joints h ad only the lateral pad removed. Eight joints in eight horses were tre ated by stall rest, administration of intra-articular medication and s ystemic nonsteroidal anti-inflammatory drugs. Follow-up information wa s obtained for 50 horses treated surgically and for eight horses treat ed medically. Forty-three (86%) that had surgery returned to racing; 3 4 (68%) raced at an equivalent or better level than before surgery. Th ree (38%) of the medically treated horses returned to racing, only one horse raced better than the preinjury level. Horses that returned to racing at a similar or equal level of performance were significantly y ounger in age than horses returning at a lower level or not racing (P less than or equal to .05). Overall, horses with synovial pad prolifer ation treated by arthroscopic surgery had a good prognosis for return to racing at a level equal or better than before injury. (C)Copyright 1996 by The American College of Veterinary Surgeons