Innovative method to treat patella alta in a patient with spastic cerebral palsy: a case report with literature review

Abstract

Patella alta, also called the high-riding patella, is a condition in which the patella lies superior to the trochlear groove of the femur. It is often found as one of the four major factors in patellofemoral joint instability. Along with trochlear dysplasia, excessive TT-TG, and patellar tilt, it can contribute to subluxation and dislocation of the patella 1 . Patella alta is also frequently found in ambulatory patients with cerebral palsy, with a reported prevalence of 61-93% in these patients 2,3 . It is often associated with crouch gait, i.e. the pattern of walking in cerebral palsy patients where a knee flexion contracture is present during the stance phase of walking. It is considered that subsequent overloading of the knee extensors combined with spasticity of the rectus femoris muscle leads to overstretching of the patellar tendon fibres causing development of patella alta 4 . Due to patella alta, contact areas between the patella and the femoral trochlea are reduced, therefore patellofemoral joint pressure stress is increased. This leads to patellofemoral dysfunction, weakness of extensor mechanism of the knee and eventual development of articular cartilage degeneration and anterior knee pain 5 .