Outcome of horses following femoropatellar arthroscopy for osteochondrosis dissecans (OCD)

Rhodes, Adrienne Diane

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https://hdl.handle.net/2142/124447 Copy

Description

Title

Outcome of horses following femoropatellar arthroscopy for osteochondrosis dissecans (OCD)

Author(s)

Rhodes, Adrienne Diane

Issue Date

2024-05-03

Director of Research (if dissertation) or Advisor (if thesis)

Gutierrez-Nibeyro, Santiago D

Committee Member(s)

• McCoy, Annette M
• Stewart, Matthew C
• Couëtil, Laurent L

Department of Study

Vet Clinical Medicine

Discipline

VMS-Veterinary Clinical Medcne

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• femoropatellar
• osteochondrosis dissecans
• arthroscopy
• equine

Abstract

Developmental orthopedic diseases (DOD) in growing horses includes several disorders such as osteochondrosis (OC), subchondral bone cysts, cervical vertebral stenotic myelopathy (Wobbler disease), and angular and flexural limb deformities, among others. Osteochondrosis, a failure of endochondral ossification process, is the most common orthopedic disease identified in young horses. In OC, normal ossification of the articular-epiphyseal cartilage complex (AECC) fails, resulting in a persistent area of hypertrophied cartilage. Recent research has shown that “early regression” or failure of the cartilage canals, which provide blood supply to the AECC during normal development, plays an important role in this abnormal process. Subsequently, mechanical forces over hypertrophied cartilage may lead to development of cartilage fissures and flaps, or detachment of the necrotic cartilage, or fragmentation of cartilage and subchondral bone, referred to as osteochondrosis dissecans (OCD). These OCD lesions can be clinically diagnosed in horses with or without symptoms via digital radiography or fluoroscopy. In horses, OCD most commonly affects the tibiotarsal joint, the metacarpo-(metatarso-) phalangeal joint, and the femoropatellar joint. There is breed predilection for lesion location, with lesions of the tibiotarsal joint commonly diagnosed in Standardbreds and Warmbloods and lesions of the femoropatellar joint commonly diagnosed in Thoroughbreds. Treatment options include conservative management and arthroscopic removal, but horses intended for athletic use typically undergo surgery. Previous work has mostly described the outcomes and postoperative racing performance of Thoroughbred racehorses with OCD lesions of the femoropatellar joint managed surgically. This thesis evaluated the outcomes and postoperative racing performance for a population of primarily Standardbred racehorses with OCD lesions of the femoropatellar joint managed surgically. We hypothesized that larger OCD lesions diagnosed in the femoropatellar joints and involvement of multiple joints would result in lower postoperative racing performance (i.e., fewer starts, lower earnings, etc.). Medical records of horses subjected to unilateral or bilateral femoropatellar arthroscopy for removal of OCD lesions between January 2014 and January 2022 were reviewed. The location and length of the OCD lesions were determined via digital radiographs. Post-operative racing results were obtained for Standardbred horses, and follow-up owner surveys were conducted. Sire-matched siblings free of any OCD lesions were used as a control cohort to further evaluate racing performance of Standardbreds. There were 45 Standardbred racehorses and 7 Quarter Horses presented for arthroscopic removal of OCD lesions from the femoropatellar joint during the study period. Among the Standardbreds, there was no significant difference in proportion of race starts based on grade of the OCD lesion. Regression analyses showed that larger OCD lesions had a significant impact on fewer lifetime wins (IRR = 0.49, p = 0.002) but there was no difference in lifetime starts or lifetime earnings. Affected Standardbred racehorses had fewer starts at 3 years of age (IRR = 0.73, p <0.001), at 4 years of age (IRR = 0.60, p <0.001), and lifetime starts (IRR = 0.48, p = 0.01) when compared to unaffected siblings. Standardbred racehorses in this population that underwent surgical management for OCD lesions of the femoropatellar joint were equally likely to race postoperatively than their unaffected siblings, regardless of the grade of the OCD lesions. There were minimal postoperative complications following arthroscopy of the femoropatellar joint in this study population. We conclude that arthroscopy remains an effective treatment for femoropatellar OCD when performed prior to the start of intensive training, and that the condition has no major impact on racing potential when treated in this manner.

Graduation Semester

2024-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2024 Adrienne Diane Rhodes

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