Tibial Torsion and Knee Instability in Cerebral Palsy

Abstract

Knee problems in children with Cerebral Palsy (CP) are very common. These problems include dislocation of the patella, anterior knee pain, increased flexion or crouch gait, and lack of knee flexion in swing phase. Other knee problems which are quite common in adolescents without disabilities include meniscal tears, ligamentous instability, ruptured cruciate ligaments, and varus or valgus malalignment problems. These issues may also occur in individuals with CP but are relatively rare. The most common malalignment problem at or below the knee is tibial torsion. This may be internal tibial torsion or external tibial torsion. In children with normal motor control, internal tibial torsion may lead to knee varus and external tibial torsion may lead to knee valgus; however, this seldom occurs in children with CP. Some children with CP develop torsional laxity at the knee joint that is difficult to assess and its treatment is unclear. The common instabilities that do occur at the knee joint along with tibial torsional alignment problems often do need treatment usually with rotational osteotomies. These osteotomies may be done with internal fixation but often in children can be done with a simple osteotomy and pins and plaster immobilization. Long-term outcome is good but there is a trend toward increased external tibial torsion with growth.