Use of magnetic resonance imaging for identifying subchondral bone damage in horses: 11 cases (1999-2003).
OBJECTIVE
To assess the use of magnetic resonance (MR) imaging for identifying subchondral bone damage in the distal limbs of horses.


METHODS
Retrospective study.


METHODS
11 horses.


METHODS
Medical records of horses with lameness and subsequent evidence of subchondral bone damage as determined by MR imaging were reviewed. Severity and duration of lameness, results of diagnostic local anesthesia and diagnostic testing, surgical and necropsy findings, and treatment were recorded. Outcome was determined by follow-up information obtained from the owner or referring veterinarian.


RESULTS
Lameness was localized by physical examination and diagnostic local anesthesia. Lameness was localized to the metacarpophalangeal or metatarsophalangeal joint in 4 horses, distal interphalangeal joint in 5 horses, and tarsocrural joint in 2 horses. The duration of lameness ranged from 2 weeks to 20 months. Magnetic resonance imaging of the affected joints revealed abnormal fluid accumulation within the subchondral bone. None of the abnormalities observed by MR imaging were detected by radiography. Subchondral bone damage was diagnosed in all horses. Arthroscopy of the affected joint was performed in 4 horses. Communication with the articular surface of the affected bone was suspected on the basis of results of MR imaging in 4 horses and was confirmed by arthroscopy in 1 horse and by necropsy in 1 horse.


CONCLUSIONS
Magnetic resonance imaging was useful for providing a diagnosis when other imaging techniques did not definitively identify the cause of lameness. Subchondral bone damage was clearly identified by MR imaging and should be considered as a cause of lameness in horses in which radiographic findings are unremarkable.
Zubrod
Chad J
CJ
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA.
Schneider
Robert K
RK
Tucker
Russell L
RL
Gavin
Patrick R
PR
Ragle
Claude A
CA
Farnsworth
Kelly D
KD
D000818:Animals; D001182:Arthroscopy / Q000662:veterinary; D001842:Bone and Bones / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D005552:Forelimb; D006614:Hindlimb; D006734:Horse Diseases / Q000175:diagnosis* / Q000473:pathology; D006736:Horses; D007596:Joints / Q000473:pathology*; D007794:Lameness, Animal / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000662:veterinary*; D008297:Male; D012189:Retrospective Studies