Hip Disorders in Children with Cerebral Palsy

Cerebral Palsy – Hips #1

Performing bilateral varus derotational osteotomies (VDROs) for hip subluxation in nonambulatory children with cerebral palsy prior to age 6 results in high rates of:
  1. acetabular remodeling.
  2. proximal femoral remodeling.
  3. avoidance of subsequent hip operations.
  4. improved ambulatory ability.

Preferred Answer: 2

Acetabular dysplasia is a common component of neuromuscular hip subluxation, along with proximal femoral valgus and uncovering of the femoral head (an increased Reimer’s index). VDROs alone can improve the proximal femoral angle and femoral head coverage. Following VDROs, proximal femoral valgus tends to recur over time. Though VDROs alone have been found to improve acetabular depth over time, this effect is less pronounced in nonambulatory patients. Whether residual acetabular dysplasia is clinically significant remains controversial, with some authors recommending routine combined proximal femoral and acetabular procedures, and some recommending a stepwise approach, only using actetabular procedures for selected cases. When VDROs are done in isolation, reported reoperation rates, either to perform subsequent acetabular osteotomies, or to revise the proximal femoral varus range from 7% to 74%, which likely reflects significant bias regarding the indications for subsequent surgery. Maintaining adequate femoral head coverage may help preserve motion, improve seating position, avoid pelvic obliquity, and avoid painful arthritis, but there is no evidence that it can improve ambulatory potential.
Mazur JM, Danko AM, Standard SC, Loveless EA, Cummings RJ. Remodeling of the proximal femur after varus osteotomy in children with cerebral palsy. Dev Med Child Neurol. 2004 Jun;46(6):412-5.
Schmale GA, Eilert RE, Chang F, Seidel K. High reoperation rates after early treatment of the subluxating hip in children with spastic cerebral palsy. J Pediatr Orthop. 2006 Sep-Oct;26(5):617-23.
Al-Ghadir M, Masquijo JJ, Guerra LA, Willis B. Combined femoral and pelvic osteotomies versus femoral osteotomy alone in the treatment of hip dysplasia in children with cerebral palsy. J Pediatr Orthop. 2009 Oct-Nov;29(7):779-83.
Huh K, Rethlefsen SA, Wren TA, Kay RM. Surgical management of hip subluxation and dislocation in children with cerebral palsy: isolated VDRO or combined surgery? J Pediatr Orthop. 2011 Dec;31(8):858-63.
Chang FM, Ma J, Pan Z, Ingram JD, Novais EN. Acetabular Remodeling After a Varus Derotational Osteotomy in Children with Cerebral Palsy. J Pediatr Orthop. 2016 Mar;36(2):198-204.


Cerebral Palsy – Hips #2

Compared to developmental dysplasia of the hip, hip dysplasia in patients with cerebral palsy is more likely to be:
  1. present at birth.
  2. detected by physical examination.
  3. in the anterior portion of the acetabulum.
  4. progressive.

Preferred Answer: 4

Hip dysplasia from neuromuscular (NM) causes differs in several ways compared to developmental dysplasia of the hip (DDH). In DDH, the condition is typically present at birth, and hip instability is primarily detected by physical examination. In NM hip dysplasia, the hips are typically normal at birth, and bony changes develop over time due to the pull of surrounding spastic muscles. Hip dysplasia in NM patients is not usually detected until after age 2, and then usually by radiographic screening, rather than physical examination. Abnormal muscle tone around the hip in NM patients most commonly causes deficiency of the superoposterior portion of the acetabulum. In DDH patients, the deficiency is more commonly anterior. Dysplasia in DDH patients is typically not progressive, in contrast to hip dysplasia in NM patients which, again due to abnormal muscle tone, can have increasing dysplasia and subluxations or dislocations over time.
Lonstein JE, Beck K. Hip dislocation and subluxation in cerebral palsy. J Pediatr Orthop. 1986 Sep-Oct;6(5):521-6.
Bagg MR, Farber J, Miller F. Long-term follow-up of hip subluxation in cerebral palsy patients. J Pediatr Orthop. 1993 Jan-Feb;13(1):32-6.
Flynn JM, Miller F. Management of hip disorders in patients with cerebral palsy. J Am Acad Orthop Surg. 2002 May-Jun;10(3):198-209.


Article: Risk Factors for Hip Displacement in Children with Cerebral Palsy: Systematic Review

Pruszczynski B, Sees J, Miller F. Risk Factors for Hip Displacement in Children with Cerebral Palsy: Systematic Review. J Pediatr Orthop. 2016 Dec;36(8):829-833.

Identifying patients with cerebral palsy who require screening with radiographs for neuromuscular hip subluxation, and deciding how often to screen them, have been areas of controversy in pediatric orthopedics, with most algorithms using individual surgeons’ training, experience, and judgment as guidance. This recent article, from the Nemours Alfred I. DuPont Hospital for Children in Wilmington, DE, provides both an excellent narrative about the natural history and risk factors for neuromuscular hip subluxation, and also uses a summary data review to provide an algorithm for screening. This practical article has the potential to change surgeons’ practices, and encourage standardization for screening of the hips in neuromuscular patients.

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