Increased tibial tuberosity to trochlear groove distance (TT-TG) | Radiology Case

DISCUSSION: This is a limited study to measure the distance from tibial tuberosity (TT) to trochlear groove (TG). Measurements are typically performed using superimposition (combined slice technique) to accurately align the trochlear groove and tibial tuberosity.

In this case, the TT–TG distance is increased bilaterally, measuring 19 mm on the right and 18 mm on the left. These values fall within the borderline range, with the right side nearing abnormal values, suggested to patellar instability.

No acute fracture is identified. There are bilaterally associated mild osseous deformity.

Range:

normal : <15 mm

borderline : 15-20 mm

abnormal : >20 mm

Acknowledgement: Dr. Mokhtar Al-Molik, Consultant of orthopedic and pelvic surgery