title: Stability and migration across femoral varus derotation osteotomies in children with neuromuscular disorders.
abstract: Background and purpose - Studies have indicated that one-third of children with cerebral palsy (CP) develop dislocation of the hip that needs surgical intervention. When hip dislocation occurs during childhood surgical treatment consists of tenotomies, femoral varus derotation osteotomy (VDRO), and acetabuloplasty. Relapse is observed in one-fifth of cases during adolescence. In this prospective cohort study, we performed a descriptive evaluation of translation and rotation across VDROs in children with neuromuscular disorders and syndromes by radiostereometric analysis (RSA). We assessed "RSA stability" and migration across the VDROs. Patients and methods - Children with a neuromuscular disorder were set up for skeletal corrective surgery of the hip. RSA follow-ups were performed postoperatively, at 5 weeks, and 3, 6, and 12 months after surgery. Results - 27 femoral VDROs were included; 2 patients were excluded during the study period. RSA data showed stability across the VDRO in the majority of cases within the first 5 weeks. At the 1-year follow-up, the mean translations (SD) of the femoral shaft distal to the VDRO were 0.51 (1.12) mm medial, 0.69 (1.61) mm superior, and 0.21 (1.28) mm posterior. The mean rotations were 0.39° (2.90) anterior tilt, 0.02° (3.07) internal rotation, and 2.17° (2.29) varus angulation. Interpretation - The migration stagnates within the first 5 weeks, indicating stability across the VDRO in most patients.
authors.affiliation: a Department of Orthopedics , Hvidovre University Hospital , Copenhagen , Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Buxbom
authors.affiliation: a Department of Orthopedics , Hvidovre University Hospital , Copenhagen , Denmark.
authors.forename: Stig
authors.initials: S
authors.lastname: Sonne-Holm
authors.affiliation: a Department of Orthopedics , Hvidovre University Hospital , Copenhagen , Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Ellitsgaard
authors.affiliation: a Department of Orthopedics , Hvidovre University Hospital , Copenhagen , Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Wong
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000293:Adolescent; D017204:Angelman Syndrome / Q000150:complications; D002547:Cerebral Palsy / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003398:Craniosynostoses / Q000150:complications; D005260:Female; D005269:Femur / Q000601:surgery*; D006617:Hip Dislocation / Q000209:etiology / Q000601:surgery*; D006801:Humans; D008607:Intellectual Disability / Q000150:complications; D007593:Joint Instability; D008297:Male; D010027:Osteotomy / Q000379:methods*; D011446:Prospective Studies; D019651:Plastic Surgery Procedures / Q000379:methods; D015518:Rett Syndrome / Q000150:complications; D012399:Rotation; D058971:Tenotomy / Q000379:methods*; D016896:Treatment Outcome