Hip Pain in Nonambulatory Children with Type-I or II Spinal Muscular Atrophy

Area of Science:

• Pediatric Neurology
• Orthopedics
• Genetics

Background:

• Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder affecting motor neurons.
• Nonambulatory children with SMA often experience significant health complications.
• Hip pain is a reported issue, but its prevalence and characteristics in this population require further definition.

Purpose of the Study:

• To determine the prevalence of hip pain in nonambulatory children with SMA (type I or II).
• To characterize hip pain and associated interventions prior to the widespread use of disease-modifying therapies (DMTs).
• To establish a baseline for evaluating DMTs' impact on hip pathology in SMA.

Main Methods:

• Retrospective chart review of nonambulatory children diagnosed with SMA (types I or II) between 1993 and 2017.
• Analysis of subjective reports of hip pain and interventions received.
• Radiographic evaluation of hip instability and spinal deformity.

Main Results:

• Hip pain was reported by 49% of type II SMA patients versus 12% of type I (p = 0.001).
• Pain prevalence correlated with SMN2 gene copy number (2 copies: 17%, 3 copies: 53%).
• Most patients had abnormal hip radiographs, but few required invasive intervention; interventions provided limited pain relief.

Conclusions:

• Hip pain is a frequent symptom in nonambulatory children with SMA, particularly type II.
• Symptom reporting should guide clinical management over radiographic findings alone.
• This data is vital for assessing the long-term effects of DMTs on hip health in SMA.