Retrospective study links SMA type 1 to higher hip instability prevalence in children

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Frontiers in Medicine Published April 23, 2026 Medically reviewed May 25, 2026 DOI ↗ By Dr. Sofia Müller, MD · Lifespan & Whole-Person Care

Key Takeaway

Consider screening for hip instability in type 1 SMA patients based on this observational data.

This retrospective cross-sectional study included 54 children with a genetic diagnosis of spinal muscular atrophy. The setting was a single tertiary care center in the United Arab Emirates. Researchers examined associations between SMA type, motor status, SMN2 copies, and disease modifying therapies. Comparator groups included SMA types (1-3) and motor status groups.

Hip dislocation or subluxation was most prevalent in type 1 SMA patients, with p = 0.046. Patients with fewer SMN2 copies were more likely to have scoliosis, showing p = 0.023. However, no significant correlation existed between hip subluxation or dislocation and scoliosis. Absolute numbers for scoliosis were not reported.

Associations of hip abnormalities with gender, age, motor status, and scoliosis showed no statistically significant association. Adverse events, serious adverse events, and discontinuations were not reported. Tolerability information was not reported. No significant correlation was found between hip instability and scoliosis.

The retrospective cross-sectional design limits causal inference, noting that associations are reported rather than causation. Follow-up duration was not reported. Findings can aid the development of hip instability screening programs in SMA patients, enabling early intervention. Certainty is limited by the retrospective cross-sectional design.

Study Details

Study typeCohort

EvidenceLevel 3

PublishedApr 2026

View Original Abstract ↓

IntroductionHip instability is an important complication of spinal muscular atrophy (SMA), which leads to various functional impairments, including mobility challenges and difficulties with daily care. The primary objective of this study is to determine the prevalence and severity of hip instability in a cohort of SMA patients managed at a tertiary care center. The prevalence of scoliosis and its association with hip instability in children with SMA were also assessed.MethodsThis is a retrospective cross-sectional study including children with a genetic diagnosis of SMA and available hip x-rays, conducted between 2018 and 2023. Patients were grouped based on SMA type and motor status (non-sitters, sitters, or walkers). Relevant parameters were collected including hip subluxation/dislocation, presence of scoliosis, number of SMN2 copies and disease modifying therapies (DMTs) received.ResultsFifty-four children with types 1–3 SMA were included in this study. Hip dislocation/subluxation in both hips was most prevalent in type 1 SMA patients [Fisher's Exact Test (FET): p = 0.046]. There was no significant correlation between the presence of hip subluxation or dislocation and scoliosis, but patients with fewer SMN2 copies were more likely to have scoliosis (p = 0.023). Several factors, including gender, age, motor status and presence of scoliosis were analysed, but none showed a statistically significant association with hip abnormalities.DiscussionTo the best of our knowledge, this is the first study in the Middle East on hip instability and scoliosis in a cohort of children with SMA. Hip dislocation and/or subluxation is most common and most severe in type 1 SMA. The study's findings can aid the development of hip instability screening programs in SMA patients, enabling early intervention.