Left Fore Limb lameness in a 7 year-old Thoroughbred

Patient had a mild lameness of the left front limb. Lameness examination included regional analgesia and distal interphalangeal joint injection six weeks prior to referral Acute, severe lameness (grade IV/V) in the same left front limb was present shortly after lameness examination and joint injection With stall rest the lameness improved, but when allowed to exercise the severity of the lameness returned

Primary Veterinarian Workup A sample of the distal interphalangeal joint fluid was obtained and was unremarkable Radiography of the distal limb was unremarkable Ultrasound of the palmar soft tissues revealed a hypoechoic area associated with the superficial digital flexor branch and scutum laterally

Advanced Imaging The patient was referred for MRI of the pastern region

MRI Left Front Pastern Region MRI Proton density (PD) transverse images shown Distal to proximal

MRI – Sagittal Plane Proton Density Sagittal plane Lateral to medial