Spinal Muscular Atrophy SMA Orthopaedic Care Guidance

How New Therapies Are Reshaping Orthopaedic Care for Children with Spinal Muscular Atrophy

Medical advances have changed the prognosis for children with spinal muscular atrophy (SMA). Disease-modifying therapies like nusinersen, risdiplam, and onasemnogene abeparvovec improve survival and motor function, but they create a new set of physical health challenges. A 2026 UK consensus study involving 45 clinicians from 19 centres provides the first formal guidance on managing one critical issue: hip displacement in children whose physical abilities are evolving because of these treatments.

The New Challenge: Preserving Mobility as Motor Function Improves

Spinal muscular atrophy is caused by mutations in the SMN1 gene, leading to the loss of motor neurons and progressive muscle weakness. Before disease-modifying therapies, children with the most severe form, SMA type 1, rarely survived infancy and never achieved sitting or walking. Now, these therapies promote the survival of motor neurons, allowing for unprecedented gains in head control, sitting, and even standing.

However, this new mobility exists within a musculoskeletal system that developed in the context of profound weakness. The hip joint is a ball-and-socket structure that requires balanced muscle pull to stay centered. In SMA, weaker hip muscles cannot adequately counter the pull of stronger ones. This muscle imbalance, combined with the force of new weight-bearing activities, can gradually pull the ball (femoral head) out of the socket (acetabulum), a process called hip displacement or subluxation. If untreated, it leads to painful dislocation, contractures, and difficulty sitting.

A UK Consensus Calls for Proactive, Individualized Hip Surveillance

Led by Dr. Maria I. Vanegas of Evelina London Children’s Hospital and Dr. Giovanni Baranello of Great Ormond Street Hospital, a Delphi panel sought to standardize care where evidence was scarce. The group achieved consensus on 13 statements after two rounds of voting. A central finding was the need for proactive management, especially for children with “higher motor potential” — those who, because of therapy, can sit, stand, or walk.

The panel rejected a one-size-fits-all approach. Instead, they stated care “should be individualised and based on multidisciplinary assessment.” This means a child’s neurologist, orthopaedic surgeon, and physiotherapist must collaborate to track motor milestones, muscle tone, and hip anatomy through regular imaging. The goal shifts from treating dislocation after it happens to preventing it through early intervention, which may include targeted physiotherapy, bracing, or in some cases, preventive surgery. The experts openly acknowledge this guidance is based on clinical experience, as high-quality long-term studies on hips in this treated population are still lacking.

Translating Expert Consensus into Family-Centered Care

For families, this consensus translates to a more anticipatory and coordinated care journey. From the time of SMA diagnosis, parents can expect hip health to be part of the conversation. Regular monitoring, often with simple ultrasounds or X-rays, becomes routine. Physiotherapy focuses not just on achieving motor skills but on doing so with good alignment and muscle balance to protect vulnerable joints.

This model mirrors effective strategies for other childhood conditions. For example, structured play-based health education helps children understand and engage with their own care. Furthermore, just as nutrient deficiencies require specific correction, the “mechanical deficiency” in SMA hips requires specific, planned support to optimize development.

Practical Steps for Protecting Joint Health in a Child with SMA

The consensus offers clear pathways for clinical teams, but parents and caregivers also play an essential role. First, understanding that increased movement is a positive sign that requires new safeguards is important. Communicate any signs of hip or leg pain, uneven leg movements, or difficulty with sitting posture to the care team immediately.

Second, advocate for the multidisciplinary care the consensus recommends. Ensure communication happens between specialists. Finally, integrate prescribed exercises and positioning into daily life. Consistent, gentle movement within safe limits is key; the objective is sustainable mobility, not just peak performance. Managing this complex interaction between new neurological potential and old musculoskeletal constraints is the current frontier in SMA care.

Sources:
https://pubmed.ncbi.nlm.nih.gov/42023171/
https://pubmed.ncbi.nlm.nih.gov/41988871/
https://pubmed.ncbi.nlm.nih.gov/41970266/