Plantar osteochondral fragments in young Standardbreds are associated with minimal joint inflammation at the time of surgical removal

Abstract

Background: Plantar osteochondral fragments (POF) are common but their effect on joint health of young Standardbreds in race training is largely unknown. Objectives: Evaluate the inflammatory effects of POF in metatarsophalangeal joints of young Standardbreds as a step towards developing evidence-based recommendations for surgical removal. Study design: Cohort study. Methods: Forty-nine Standardbred horses (age 11-33 months) presented for surgical removal of POF from 56 metatarsophalangeal joints. Synovial tissue collected at arthroscopy was subjected to histopathology. IL-1β, TNFα, and PGE-2 were measured in synovial fluid using ELISA. Digital arthroscopy images were scored for inflammation. Racing performance data were retrieved from a public database.Results: Median time in race training prior to surgery was 8 weeks (IQR 4-12; range 0-40). There was minimal evidence of synovial inflammation as assessed by histopathology (median total score 2/20, IQR 0-2, range 0-5) or arthroscopy (median average total score 2.67/15, IQR 1.79-4, range 0-8.83). IL-1β was not detected in any sample. TNFα (median 0 pg/mL, IQR 0-0) and were measured at low levels. Weeks in training prior to surgery was associated with the number of starts in the season after surgery (incidence rate ratio 1.02, 95% CI 1.00, 1.04, P = .03). Main limitations:Small sample size from a single breed with a relatively short training time prior to surgery. Conclusions:There was minimal evidence of synovial inflammation in the metatarsophalangeal joints in this population of young Standardbred horses with POF. It is possible that POF may result in a different inflammatory response than other fragments because they are generally well-embedded in situ. These findings suggest that, in Standardbreds, race training can commence several weeks prior to surgical removal

Evaluation of cartilage injury in horses with osteochondral fragments in the metacarpo−/metatarsophalangeal joint: A study on 823 arthroscopies

“…However, this also included older horses and other breeds than Standardbred trotters. Since age was found to be associated with cartilage injury, this might explain why cartilage lesions were more commonly found in the current study than what was reported by McCoy et al 45 It has been previously reported that Warmblood stallions with OCD of the sagittal ridge of the distal MC3/MT3 will likely have poorer future jumping performance than nonaffected horses 3 . However, the prognosis for athletic function is favourable for Types II (fragment associated to OCD defect) and III (OCD defect or flattening with or without fragmentation and one or more loose fragments) lesions with timely intervention, hindlimb lesions and when no degenerative changes are present within the joint 8,46 .…”

“…In the current study, POF were also not as likely to be associated with cartilage lesions as dorsal fragments. This might be because POF, in contrast to other fragments, are often well‐embedded in the joint and more stable due to attachment of the distal sesamoidean ligaments 45 . In a recent study by McCoy et al, 45 arthroscopic images of 56 joints of 49 young Standardbred trotters with POF were retrospectively evaluated for joint abnormalities.…”

“…This might be because POF, in contrast to other fragments, are often well‐embedded in the joint and more stable due to attachment of the distal sesamoidean ligaments 45 . In a recent study by McCoy et al, 45 arthroscopic images of 56 joints of 49 young Standardbred trotters with POF were retrospectively evaluated for joint abnormalities. None of the joints had cartilage lesions and the most common finding was mild joint inflammation, suggesting that race training can start prior to surgery with minimal effects on the joint 45 .…”

“…In a recent study by McCoy et al, 45 arthroscopic images of 56 joints of 49 young Standardbred trotters with POF were retrospectively evaluated for joint abnormalities. None of the joints had cartilage lesions and the most common finding was mild joint inflammation, suggesting that race training can start prior to surgery with minimal effects on the joint 45 . Furthermore, Carmalt et al 25 found no association between race speed or career longevity and fragment removal in Standardbred trotters with POF and suggested that surgical intervention should be critically examined with these types of fragments 25 .…”

“…None of the joints had cartilage lesions and the most common finding was mild joint inflammation, suggesting that race training can start prior to surgery with minimal effects on the joint. 45 Furthermore, Carmalt et al 25 found no association between race speed or career longevity and fragment removal in Standardbred trotters with POF and suggested that surgical intervention should be critically examined with these types of fragments. 25 However, Foerner et al 12 stated that surgery seemed to be the most effective treatment for POF.…”