Prostride clinical trial

This study, “Evaluation of autologous protein solution as an anti-inflammatory therapeutic for adult horses with naturally occurring lameness isolated to the medial femorotibial joint,” is sponsored by Zoetis, LLC, and is facilitated by the Orthopaedic Research Center and equine sports medicine service at the Johnson Family Equine Hospital.

Purpose of the study

To evaluate the use of autologous protein solution [APS (Prostride)] compared to corticosteroid and HA as an anti-inflammatory therapeutic for adult horses with naturally-occurring lameness isolated to the medial femorotibial joint.

Study protocol

  • Lameness examination, radiographs and ultrasound will be performed at the start of the study,
  • Horses will be randomly assigned to receive either an APS injection or a corticosteroid+HA injection into the affected stifle. Veterinarians and owners will be blinded to the treatment.
  • Horses will undergo lameness examinations at week 0, 2, 6, 12, 14, 18 and 24. Repeat radiographs and ultrasound will be performed at weeks 12 and 24.
  • At the 12-week time point, horses that remain ≥ grade 1.5 of 5 lame are eligible to switch treatment groups.

Owner responsibilities

  • You are responsible for the initial testing to determine study eligibility and any other tests recommended by your horse’s veterinarian
  • You are expected to make and keep all appointments associated with the study.
  • You are responsible for transporting the horse to the Johnson Family Equine Hospital for the week 0-, 12- and 24-week timepoints. There is a cash incentive for completing the 12- and 24-week appointments at Johnson Family Equine Hospital. The interim lameness examinations may be able to be performed at your horse’s barn depending on the location.
  • Owners will be contacted 18 months after the final recheck to obtain follow-up information.



eligibility information

  • Horses aged 3 to 16 years of age
  • Lameness (graded ≥1.5 and ≤ 4 out of 5) isolated to the medial femorotibial joint of the stifle
  • No lameness in other limbs graded greater than 1 of 5
  • No new joint supplements or other intra-articular medications throughout the 6-month study period
  • No confirmed or suspected endocrine disorders such as Cushing’s or equine metabolic syndrome

Enrollment Deadline

Enrollment ends December 31, 2024

contact information

If interested in enrolling, please contact Dr. Erin Contino at