Clinical Investigation Center

TransFix Study


Principal Investigator: Michael Conzemius, DVM, PhD, DAVCS

Michael Conzemius, DVM, PhD, DAVCS at 612-625-3147 or
Andrea Eckert, Research Study Technician at 612-625-3157 or

Purpose of study:

New research techniques to stabilize the knee after cruciate ligament damage are ongoing in the human and veterinary medical fields.  Previous techniques utilizing ligament replacements have been shown to be weaker than the intact cruciate ligament and have a greater incidence of failure in the dog.

A recent study by Drs. Conzemius and Biskup showed that replacing the function of a torn cranial cruciate ligament with a deep digital flexor tendon allograft utilizing the Medial Portal TransFix® surgical technique had mechanical properties similar to the cranial cruciate ligament. In a pilot clinical trial in 10 dogs, patients had outcomes at 1-year after surgery similar to dogs receiving a TPLO (tibial plateau leveling osteotomy). We now would like to examine the health of the allograft long-term (1-year after surgery) through X-ray imaging, orthopedic examination, computational gait analysis and arthroscopy.

What we need:

  • Healthy, adult dogs with torn cranial cruciate ligament
  • Body weight >25 kg
  • Adult (>10 months)
  • Palpable cranial drawer (>10mm) in the affected knee
  • No significant abnormalities on complete blood count and biochemistry profile
  • Not pregnant, no bleeding disorders, or other major health impairments

Study includes:

  • Screening visit: orthopedic exam, blood draw for complete blood count (CBC) and serum profile. X-rays of the affected knee, force plate gait analysis, and you will complete the Liverpool Osteoarthritis Assessment in Dogs (LOAD).
  • Surgery: The surgery will be performed with your pet under general anesthesia. The knee will be arthroscopically explored to evaluate for the presence of osteoarthritis, to confirm cranial cruciate rupture and to look for the presence of meniscal and other cartilage damage. Then the ligament replacement surgery will be performed. 
  • Week 2 visit: suture removal
  • Month 2 visit: orthopedic exam, complete LOAD questionnaire
  • Month 6 visit: orthopedic exam, complete LOAD questionnaire
  • Month 12 visit: orthopedic exam, complete LOAD questionnaire, radiographs, force platform gait analysis, and arthroscopy of the implanted knee

The study covers the costs of all visits above. Up to $2,000 of compensation will be provided for the treatment of study related complications if treatment is provided at the VMC, University of Minnesota, until the date of study exit. Treatment from a complication could exceed this amount. Owner is responsible for all other charge’s associated with your dog’s care.