Pathologic external tibial torsion as one of the causes of knee joint dysfunction and formation of pronation deformity in children with cerebral palsy

Abstract

Introduction. One of the complications of the clinical course of cerebral palsy in children is external torsion of the tibia. The issue of localization and the mechanism of its formation, as well as effective methods of its elimination, is debatable. Purpose - to study the mechanisms of the formation of pathological external torsion of the tibia in children with cerebral palsy, its effect on knee joint contracture and foot deformity, and effective methods of their correction. Materials and methods. The data obtained during the observation of 45 patients (90 cases) aged from 6 to 16 years with spastic diplegia, spastic tetraparesis and foot pronation were analyzed. To study the mechanisms of formation of external torsion of the lower leg and its correction, 2 groups of patients were selected. The Group I - 24 patients with internal rotation contractures of the hip joint (10 patients with internal rotation contractures of the hip joint; 10 patients - in combination with pathological antetorsion of the femoral neck; 4 patients - in combination with flexion contractures of the knee joints). The relationship between internal rotation contracture of the hip joint and external torsion of the tibia. The Group II consisted of 21 patients who were diagnosed with flexion contracture of the knee joints in combination with external torsion of the tibia. In order to study the effectiveness of operative treatment of knee flexion contracture and external torsion of the tibia in the Group II, 2 subgroups were distinguished: the subgroup IIA - 9 patients who underwent osteotomy of the tibial bone; the subgroup IIB - 12 patients who only underwent biceps femoris transposition. Results. Based on the study of clinical and radiological indicators, it was established that pathological torsion of the tibial bone is combined with flexion contracture of the knee joints. Proximal derotational osteotomy of the tibia has a positive effect on the results of correction of knee flexion contracture and foot position. Conclusions. The main reason for the formation of external torsion of the tibia is the imbalance of the flexor muscles of the knee joint and the supinator and pronator muscles of the foot. Proximal tibial derotation osteotomy eliminates not only pathological torsion, but also flexion contracture of the knee joints and excessive pronation of the foot. The study was conducted in accordance with the principles of the Declaration of Helsinki. The study protocol was approved by the local ethics committees of all institutions participating in the study. Informed consent of the patients was obtained for the research. No conflict of interests was declared by the authors.