The Hip in Spinal Muscular Atrophy

The musculoskeletal burden of spinal muscular atrophy (SMA) primarily involves the hip and spine. The incidence of hip instability is 30–40% and neuromuscular scoliosis is 60–90% in non-ambulatory SMA patients. The intrinsic relationship between hip and spinal deformity often requires concomitant management of the hip and spine to maximize functional and clinical outcomes. This chapter summarizes the non-operative and operative treatments for hip instability and spinal deformity in the SMA population. While hip subluxation/dislocation has traditionally been treated non-operatively in non-ambulatory SMA patients, the intra-thecal administration of Nusinersen has changed the functional and ambulatory prognosis of patients with SMA. Thus, orthopedic surgeons should consider treating hip instability with operative hip reconstruction as the surgical complication and recurrence rate is similar to that in other neuromuscular conditions.