Contractures of the lower extremities in spinal muscular atrophy type II. Descriptive clinical study with retrospective data collection

Early development of contractures and progressive scoliosis with pelvic obliquity are the most significant orthopaedic problems for children with the intermediate form of spinal muscular atrophy, SMA type II. This study deals with the restrictions of the passive range of motion and the development of contractures of the lower extremities in these patients.We followed up 143 patients, 74 female and 69 male, with SMA type II for an average of 5.3 years (± 4.0, 0.2 - 18.7). Their average age at the first examination was 8.4 years (± 6.6, 0.1 - 34.1) and at the last examination 12.3 years (± 6.5, 0.7 - 37.1). The passive range of joint motion was determined using a goniometer. According to Johnson et al. (1992), we calculated the relative contracture index (CI).The loss of range of motion (ROM) and the contractures of the joints of the lower extremities (hip, knee and ankle) develop early and increase progressively with age. Marked restriction of motion with severe flexion contractures in some cases was observed in the knee followed by the hip and ankle joint.The findings of this study give us more information about the development of contractures and deformities of the joints of the lower extremities and aim to help to improve the quality of orthopaedic care of patients with SMA type II.