Hip instability in spinal muscular atrophy in the era of disease-modifying therapies –⁠ a review of current knowledge from an orthopedic surgeon’s perspective

Czech version

Authors: V. Poch; A. Stančák
Authors‘ workplace: Klinika dětské a dospělé ortopedie a traumatologie FNMH – Motol, Praha
Published in: Cesk Slov Neurol N 2026; 89(S1): 27-31
doi: https://doi.org/10.48095/cccsnn2026S27

Overview

Spinal muscular atrophy (SMA) is a genetic disorder characterized by progressive muscle weakness and is frequently associated with orthopedic complications, including hip instability. The introduction of disease-modifying therapies (DMT) has significantly altered the natural course of the disease and led to a reassessment of the clinical relevance of hip involvement. Hip instability occurs in a substantial proportion of patients with SMA, and its development is closely associated with disease severity and reduced weight-bearing of the lower extremities. The pathogenesis is primarily driven by biomechanical factors leading to the development of coxa valga and acetabular dysplasia. Despite the high prevalence of structural abnormalities, their clinical manifestation, particularly hip pain, does not directly correlate with radiographic findings. The current approach to the management of hip instability is based on proactive screening and individualized, symptom-driven treatment.

Keywords:

spinal muscular atrophy – hip instability – hip joint structural changes – hip pain, disease-modifing terapies

Sources

1. Haberlová J, Hedvičáková P, Fuchsová P et al. Spinální svalové atrofie v dětském věku –⁠ aktuální stav léčby. Neurol praxi 2022; 23 (1): 9–13. doi: 10.36290/neu.2022.014.

2. Antonaci L, Pera MC, Mercuri E. New therapies for spinal muscular atrophy: where we stand and what is next. Eur J Pediatr 2023; 182 (7): 2935–2942. doi: 10.1007/s00 431-023-04883-8.

3. Vanegas MI, Baranello G, Norman-Taylor F et al. Hip displacement management in spinal muscular atrophy in the era of disease modifying therapies: a Delphi consensus study in the UK. EClinicalMedicine 2026; 95 : 103872. doi: 10.1016/j.eclinm.2026.103872.

4. Vitale M, Roye B, Bloom Z et al. Best practices for the orthopaedic care of children with spinal muscular atrophy: a consensus statement from the european neuromuscular centre standard of care orthopaedic working group. J Pediatr Orthop Soc North Am 2022; 4 (1): 296. doi: 10.55275/JPOSNA-2022-0006.

5. Xu AL, Crawford TO, Sponseller PD. Hip pain in patients with spinal muscular atrophy: prevalence, intensity, interference, and factors associated with moderate to severe pain. J Pediatr Orthop 2022; 42 (5): 273–279. doi: 10.1097/BPO.0000000000002091.

6. Ulusaloglu AC, Asma A, Shrader MW et al. Hip displacement in spinal muscular atrophy: the influences of genetic severity, functional level, and disease-modifying treatments. J Pediatr Orthop 2024; 44 (3): e226–e231. doi: 10.1097/BPO.0000000000002595.

7. Krajewski KT, Coomer W, Gerk A et al. Hip instability in children with spinal muscular atrophy: a retrospective study. J Pediatr Orthop 2025; 45 (2): e131–e137. doi: 10.1097/BPO.0000000000002827.

8. Ulusaloglu AC, Asma A, Rogers KJ et al. The influence of tone on proximal femoral and acetabular geometry in neuromuscular hip displacement: a comparison of cerebral palsy and spinal muscular atrophy. J Child Orthop 2022; 16 (2): 121–127. doi: 10.1177/18632521221084184.

9. Almeida da Silva LC, Hori Y, Kaymaz B et al. Femoral neck-shaft angle changes based on the severity of neurologic impairment in children with cerebral palsy and spinal muscular atrophy. J Child Orthop 2024; 18 (5): 523–530. doi: 10.1177/18632521241277023.

10. Hanna RB, Nahm N, Bent MA et al. Hip pain in nonambulatory children with type-I or II spinal muscular atrophy. JB JS Open Access 2022; 7 (3): e22.00011. doi: 10.2106/JBJS.OA.22.00011.