Radiologic Measurement of Tibial Tuberosity-Trochlear Groove (TT-TG) Distance by Lower Extremity Rotational Profile Computed Tomography in Koreans

Background

Tibial tuberosity-trochlear groove (TT-TG) distance is important in the assessment and treatment of patellofemoral disorders. However, normal and pathological TT-TG values have not been established in Koreans. The purpose of this study was to evaluate the TT-TG distance in the Korean population using lower leg rotational profile computed tomography (CT) scans.

Methods

One hundred rotational profile CT scans were retrospectively collected from patients without knee joint problems aged between 25 to 82 years. TT-TG distances were measured, and statistical analysis was performed. Each CT scan was measured twice in a blinded, randomized manner by three reviewers. Patients with pre-existing knee joint problems were excluded from the study; hence 15 of the 100 patients were excluded because of deformity or unreadable CT scans. Thus, 85 of the 100 patients were included in the study.

Results

Interobserver and intraobserver reliability of TT-TG distance measurements was good. The median TT-TG distance for this Korean population was 11.24 mm (mean, 10.24 ± 0.8 mm). TT-TG distance measured nearly 2 mm less on rotational profile CT scans.

Conclusions

Some of the TT-TG distances on rotational profile CT scans were significantly correlated, indicating that they could be accepted. Furthermore, the values on CT scans showed good reliability. In this study, the TT-TG distance in normal Korean people was approximately 10.24 mm without significant differences in TT-TG values between genders.