Arthroscopic surgery for osteochondritis dissecans of the femoropatellar joint of the horse.

Arthroscopic surgery for the treatment of osteochondritis dissecans was undertaken on 252 femoropatellar joints in 161 horses (82 Thoroughbreds, 39 Quarter Horses, 16 Arabians, 9 Warmbloods and 15 others of various breeds). There were 53 females and 108 males. Twenty-two horses were 1 year of age at the time of surgery, 68 were yearlings, 36 were 2-year-olds, 21 were 3-year-olds, and 14 were > or = 4 years old. Ninety-one had bilateral involvement and 70 had unilateral disease. Follow-up information was obtained on 134 horses, including 79 racehorses and 55 non-racehorses: 86 (64%) of these 134 horses returned to their intended use, 9 (7%) were in training, 21 (16%) were unsuccessful and 18 (13%) were unsuccessful due to other defined reasons. Horses with Grade I lesions (< 2 cm in length) had a significantly higher success rate (78%) than did horses with Grade 2 (2-4 cm) or Grade 3 (> 4 cm) lesions (63% and 54% success rates respectively). A significantly higher success rate was also noted for horses operated on as 3-year-olds compared with the remainder of the study population. A significantly lower success rate was noted for yearlings than for the remainder of the population. There was no significant difference in outcome as related to sex of animal involved, racehorse versus non-racehorse, lesion location, unilateral versus bilateral involvement, presence or absence of patellar or trochlear groove lesions, or presence or absence of loose bodies.