Magnetic resonance imaging for detection of late meniscal tears in dogs following tibial tuberosity advancement for treatment of cranial cruciate ligament injury

Objectives: To document the use of and to estimate the accuracy of magnetic resonance (MR) imaging for detection of late meniscal tears in dogs with cranial cruciate ligament injury treated with tibial tuberosity advancement (TTA). Methods: Medical records of dogs that had TTA followed by stifle MR imaging for suspected meniscal tear and subsequent arthrotomy were reviewed retrospectively. Magnetic resonance images were reviewed independently by an observer blinded to clinical information who classified menisci as torn, abnormal but intact, or normal. Magnetic resonance and surgical findings were compared. Results: Eight stifles from large breed dogs were included. Six stifles had a medial meniscal tear identified in MR images and later confirmed surgically. In the remaining two stifles, the menisci appeared intact in MR images and no tear was identified at subsequent arthrotomy. Lateral menisci in all stifles appeared intact in MR images and were considered normal at surgery. Susceptibility artefacts associated with TTA implants were present in all images but did not adversely affect interpretation of intra-articular structures. Clinical significance: Magnetic resonance; imaging appears to be accurate for diagnosis of late meniscal tears. Artefacts associated with TTA implants did not prevent evaluation of critical intra-articular structures. Further investigation with MR imaging should be considered when late meniscal tear is suspected following TTA.