Chondromalacia patellae. The relation to abnormal patellofemoral joint mechanics.

Twenty-two patients treated non-operatively for chondromalacia patellae were followed up after an average of 5.7 years in order to evaluate the effect of abnormal patellofemoral biomechanics on the natural history of the symptoms. Clinical and radiological investigation revealed 15 patients with signs of malalignment, femoral trochlear dysplasia or excessive lateral pressure syndrome, 3 patients with marginal signs of malalignment and 4 patients with no demonstrable abnormalities. A statistically significant difference in the evolution of symptoms between the normal and the abnormal group is demonstrated, 14 out of 15 in the latter group having unchanged or worsened symptoms. The stage of chondromalacia change as judged arthrographically at the beginning of the observation period did not influence the clinical outcome.