The unstable patella in children

The authors reviewed 102 unstable patellas which had been observed and trea ted from 1964 to 1990. They were divided according to whether they suffered from traumatic dislocations, recurrent dislocations or malformative instab ility. The clinical findings were the major stage of the check up. In the f ield of imaging, standard X-rays had to be performed in all cases. MRI was of interest in the congenital dislocations, in order to thoroughly investig ate the soft tissue anomalies. Two types were described: Type 1 was observe d in children with joint laxity, but without major X-ray anomalies; Type 2, a major femoropatellar dysplasia could be formed with some bone deformity. The latter was observed in the malformative instability. Four different su rgical procedures have been used, from the release of the retinacula of pat ella to the medial displacement of the patellar tendon or the tibial tubero sity. This study emphasises the concept of a true development dysplasia of patella (DDP) which can gather the different varieties of the instability o f patella.