Outcome of Standardbred racehorses following femoropatellar arthroscopy for osteochondrosis dissecans.

OBJECTIVE

To evaluate postoperative racing performance of a population of Standardbred racehorses following arthroscopic removal of an osteochondrosis dissecans (OCD) lesion of the femoropatellar joint.

STUDY

DESIGN

Retrospective study.

SAMPLE POPULATION: A total of 45 client-owned Standardbred racehorses.

METHODS

OCD lesions were measured and graded using the length of the subchondral bone defect from preoperative radiographs. Postoperative racing results were obtained from the United States Trotting Association, and follow-up owner surveys were conducted. A control group of contemporaneous paternal siblings free of OCD lesions was selected for comparison of racing performance. Regression analysis was used to determine associations between presence or grade of OCD lesions and performance parameters with sex and gait covariates.

RESULTS

There was no significant difference in proportion of horses starting a race based on OCD lesion grade. Affected racehorses had fewer starts at 3 years of age (IRR = 0.84 [95% CI: 0.74-0.96], p = .012) but not at 2 years of age, when compared to unaffected siblings. There was also no difference in race wins or earnings between affected and unaffected horses.

CONCLUSION

Arthroscopy remains an effective treatment for OCD lesions of the femoropatellar joint in Standardbred racehorses, when performed prior to the start of intensive training, and lesions treated in this manner have no major impact on racing potential. Limitations included a small number of affected individuals especially with higher grades of OCD lesions and there was no conservative treatment group.

CLINICAL SIGNIFICANCE: OCD lesions within the femoropatellar joint in Standardbred racehorses resulted in minimal impact on postoperative racing performance when removed arthroscopically.