Patella alta in southern China. A new method of measurement.

The position of the patella in the Southern Chinese population is 15 to 20% higher than in Western populations, both in controls and in disease. Those with patellar dislocation and anterior knee pain have significantly higher patellae than the controls in both population groups, and this is confirmed in the 5 methods of measurement we have studied. Patella alta is more common in our region. The patella alta index described in this paper provides a reliable and reproducible measurement of patellar height. A value of more than 3.4 is abnormal in our population.