[Critical study of patella alta. II. Patella alta and femoropatellar pathology]

Patella alta is radiologically defined by an Insall index equal to or greater than 1.3. In 50 patients suffering from pain of the femur and patella, roentgenographic studies consisting of a simple profile view and occasionally completed by a view through Smillie's angle with the knee hyperextended, revealed patella alta. The stretching of the patellar tendon is facilitated by excessive tension during growth and by excessively strenuous physical exercises; patella alta can occasionally be complicated by Osgood-Schlatter's or Sinding-Larsen Johansson's disease. Ruptured tendons have occasionally been observed. Genu recurvatum can also lead to patella alta. The joint should be routinely examined for excessive mobility. Patella alta is often associated with various affections of the extensor apparatus of the knee: pathology secondary to injury, external malposition, gonarthrosis, supratrochlear erosions of the femur. The importance of the role of this condition with respect to patellar chondromalacia has been estimated to varying degrees. The diagnosis of patella alta should be considered in all cases of knee pain.