Neural growth factor expression in the lateral retinaculum in painful patellofemoral malalignment

We studied 7 samples of lateral retinaculae excised at the time of surgical realignments, They were obtained from patients with isolated symptomatic p atellofemoral malalignment resistant to conservative treatment and were eva luated with immunohistochemistry and immunoblotting. We found that neural g rowth factor is higher in patients with pain than in those with instability as the main symptom. Neural growth factor is related to neural proliferati on in vessels and perivascular tissue and to the release of neuroceptive tr ansmitters, such as substance P. We postulate that both mechanisms are invo lved in the pathogenesis of pain in isolated symptomatic patellofemoral mal alignment.