Normal Tibial Tubercle to Trochlear Groove Distance in an Adult Chinese Population

Objective: To define the normal tibial tubercle to trochlear groove (TT-TG) distance in an adult Chinese population and to confirm that magnetic resonance imaging (MRI) measurements of TT-TG distance are reliable and reproducible. Methods: We conducted a retrospective review of MRI scans of 100 skeletally mature knees in an adult Chinese cohort from January 2015 to January 2016. Patients with MRI or clinical evidence of previous lateral patellar dislocation were excluded. TT-TG distance in MRI scans of normal knees was measured. Intraobserver and interobserver agreement was evaluated. Results: In our study, the mean normal value of the TT-TG distance in an adult Chinese cohort was found to be 10.36 +/- 2.52 mm (men 10.92 +/- 2.59 mm and women 9.67 +/- 2.28 mm). Intraobserver and interobserver agreement regarding TT-TG distance measurement with MRI was excellent. Conclusion: This study can form the basis for future studies on the relationship between TT-TG distance and patellar instability in the adult Chinese population.