[Hollow femoral trochlea and femoro-patellar osteoarthritis]

The high frequency of femoro-patellar syndrome encountered in Libreville (Gabon) and its association with shallow trochlea and important cartilaginous lesions in our surgical cases urged us to investigate the role of this dysplasia as a cause of femoro-patellar osteoarthritis.

Our study consisted of two series: a retrospective study: 50 patients operated for complications of femoro-patellar syndrome. a prospective study: we analysed the trochlea morphology of 100 healthy Gabonese.

In our operated cases, we noted a high frequency of shallow trochlea (61 per cent) with important cartilaginous lesions (64 per cent of femoro-patellar osteoarthritis). In the prospective study, we noted 89 per cent of shallow trochlea. The average trochlea angle was 126 degrees.

The review of the operated patients showed important cartilaginous lesions associated with a "closed angle trochlea", confirming the observations of Buard and coll., and showing that this dysplasia can be a cause of femoro-patellar osteoarthritis. The prospective study found 89 per cent of shallow trochlea, which is higher to that seen in Europe (19 per cent for Buard and Coll.) and may pose the problem of an anatomic predisposition of osteoarthritis in the Central African patients.

The shallow trochlea is a dysplasia often encountered in Central Africa. It is associated with important cartilaginous lesions. The shallow trochlea seems to be a favourable factor to femoro-patellar osteoarthritis.