[Major dysplasia of the trochlea. Contribution to the measurement of A.T. T.G. Proposal of a x-ray computed tomographic protocol].

The A.T. T.G.'s scanographic measure sets problems in the major dysplasic trochlear groove because point G.T. is quite impossible to determine. We purpose to define it by an original procedure based on bidimensional reconstruction of A.T. T.G. system. Point G.T. is defined by extrapolation: it is situated at the junction of proximal trochlear scan section with the line representing distal trochlear groove.