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

Abstract

To compare the tibial tuberosity-trochlear groove (TTTG) distance in Chinese patients with or without recurrent patellar dislocation. 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. 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. 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.