Tibial tuberosity-trochlear groove distance in Chinese patients with or without recurrent patellar dislocation.

ABSTRACT

PURPOSE: To compare the tibial tuberosity-trochlear groove (TTTG) distance in Chinese patients with or without recurrent patellar dislocation. METHODS: The TTTG distance of 14 knees in 5 men and 9 women aged 16 to 38 years with recurrent patellar dislocation were compared with that of 73 control knees using magnetic resonance imaging. RESULTS: The mean TTTG distance was significantly greater in patients with recurrent patellar dislocation than in controls (16.4 mm vs. 10.1 mm, p<0.001). Six (43%) knees with recurrent patellar dislocation had the TTTG distance greater than the cut-off threshold of 16.4 mm, compared to none in controls. CONCLUSION: The TTTG distance is related to height and is shorter in Chinese than Caucasian patients; the threshold for tibial tuberosity transfer should be lower in Chinese patients.