Management of the Hip in Cerebral Palsy: The Role of Hip Surveillance

Stacey Miller, BSc.PT
BC Children's Hospital
Vancouver, BC

Introduction

Children with cerebral palsy (CP) have an increased risk of hip displacement. Approximately one in three will be affected1-3. Unlike developmental dysplasia of the hip, the hip joint in children with CP is normal at birth4. Delayed weight-bearing and abnormal muscle forces lead to changes in the proximal femur and gradual subluxation. Progressive displacement leads to secondary acetabular dysplasia, changes to the femoral head, and, ultimately, dislocation and degenerative arthritis (Figure 1). Displacement is often silent, with no physical signs or symptoms, until the hip is dislocated and painful.

 

MILLER_Figure_1
Figure 1: Progressive hip displacement

 

Etiology of Hip Displacement

Three population-based studies have shown a linear relationship between a child's gross motor function, as described by the child's Gross Motor Function Classification System (GMFCS) level, and risk of displacement1,2,3. The GMFCS is a five level ordinal scale for children with CP that is based on self-initiated movement5,6. Children in Level I walk without limitations but have difficulty with balance and coordination. In contrast, children in Level V require considerable assistive technology and physical assistance due to significant limitations in head and trunk control. Soo et al.2 found children at GMFCS Level I had no risk of hip displacement while those classified as GMFCS Level V had a 90% risk.

Muscle imbalance around the hip is also believed to contribute to hip displacement. Increased tone in the hip adductors and flexors overcomes the relatively weaker antagonists causing the centre of hip rotation to move away from the centre of the femoral head4,7,8. This shift in centre of rotation results in the proximal femur gradually displacing upward and outward.

Impact of Hip Displacement and Dislocation

Hip dislocations have a lifelong impact on pain and mobility. The incidence of pain in adults with CP with a dislocated hip has been reported as 50-90%9,10. A dislocated hip can cause decreased sitting, standing, and walking tolerance, decreased mobility of the hip, and difficulty with perineal hygiene9-11. The influence of hip dislocation on pelvic obliquity and scoliosis is unclear4, 8.

With increasing displacement, the complexity of surgery also increases. Salvage procedures are required when changes to the femoral head and loss of cartilage prevent reconstruction. Such procedures, most frequently consisting of a femoral head resection with a valgus osteotomy, are associated with increased morbidity, complications, and medical costs.

Hip Surveillance

There is growing evidence to support the use of hip surveillance in the identification of hip displacement in children with CP3,12-16. Hip surveillance is the process of identifying early indicators of hip displacement through systematic screening13.

Hip surveillance includes clinical and radiological review of all children with CP. Clinical assessment involves assessment of GMFCS level, hip range of motion, muscle tone, pain, and changes in functional abilities1,17. Clinical assessment alone is not sufficient to detect displacement; an anteroposterior radiograph, in a standardized position, is required to measure Reimer's migration percentage (MP)1,16. Reimers (1980)18 reported that the 90th percentile for MP for typically developing children under four years of age was 10%. A hip is considered 'at risk' for progressive displacement when the MP is greater than 30%. This is the recommended threshold for review by a paediatric orthopaedic surgeon17.

Surveillance programs in Sweden and Australia, in combination with orthopaedic management, have been effective at preventing hip dislocation12,13,15,19. Ten years after the introduction of a prevention program, Hagglund et al.12 report that none of the children monitored by the program from the time of diagnosis have developed a hip dislocation. Dobson et al.13 report an increase in the number of preventive surgeries, decrease in the number of reconstructive surgeries, and elimination of salvage surgeries in the first three years following introduction of a hip surveillance program in an Australian state. A systematic review in 2006 concluded that surveillance programs allowed for earlier identification of subluxation and reduced the need for surgery on dislocated hips14.

BC Consensus on Hip Surveillance

Prompted by a high number of children presenting with painful hips that required salvage surgery, a case for a provincial hip surveillance program was initiated in BC. In May 2011, a multi-disciplinary group, including paediatric orthopaedic surgeons, paediatricians, family physicians, physiotherapists, a radiologist, nurses, parents, and policy makers from all regions of the province, met to discuss hip surveillance. There was unanimous agreement that a hip surveillance program was required in BC. Consensus was reached on the commencement, frequency, and discharge criteria for surveillance based on current best evidence and the resources available in the province. This established the "British Columbia Consensus on Hip Surveillance for Children with Cerebral Palsy". A preferred model of implementation was subsequently developed at a follow-up meeting in January 2012.

The creation of the BC Consensus on Hip Surveillance will lead to the first formal North American hip surveillance program. Evaluation of the program will include provincial adherence to the consensus statement, incidence of hip displacement, frequency and outcomes of surgical procedures, and, most importantly, child and family outcomes including quality of life.

Conclusion

The goal when treating hip displacement in children with CP is to ensure the hip remains located, mobile, and pain free into adulthood13. Systematic hip surveillance provides the opportunity to identify children with hip displacement early and prevent hip dislocation.

References

  1. Hagglund G., Lauge-Pedersen H., Wagner P. Characteristics of children with hip displacement in cerebral palsy. BMC Musculoskelet Disord, 2007. 8: 101.
  2. Soo B., Howard J.J., Boyd R.N., Reid S.M., Lanigan A., Wolfe R., Reddihough D., Graham H.K. Hip displacement in cerebral palsy. J Bone Joint Surg Am, 2006. 88: 121-29.
  3. Connelly A., Flett P., Graham H.K., Oates J. Hip surveillance in Tasmanian children with cerebral palsy. J Paediatr Child Health, 2009. 45: 437-443.
  4. Cornell M.S. The hip in children with cerebral palsy: Predicting the outcome of soft tissue surgery. Clin Orthop, 1995. 340: 165-171.
  5. Palisano R., Rosenbaum P., Walter S., Russell D., Wood E., Galuppi B. Development and reliability of a system to classify gross motor function in children with cerebral palsy. Dev Med Child Neurol, 1997. 3: 214 - 223.
  6. Palisano R.J., Rosenbaum P., Bartlett D., Livingston M.H. Content validity of the expanded and revised Gross Motor Function Classification System. Dev Med Child Neurol, 2008. 50: 744 - 750.
  7. Letts M, Shapiro L, Mulder K, Klassen O. The windblown hip syndrome in total body cerebral palsy. J Pediatr Orthop, 1984. 4:55-6.
  8. Murray A., Robb, J.E. The hip in cerebral. Curr Orthop, 2006. 20: 286-293.
  9. Cooperman D.R., Bartucci E., Dietrick E., Millar E.A. Hip dislocation in spastic cerebral palsy: long-term consequences. J Pediatr Orthop, 1987. 7:268-76.
  10. Bagg M.R., Farber J., Miller F. Long-term follow-up of hip subluxation in cerebral palsy patients. J Pediatr Orthop, 1993. 13:32-6.
  11. Samilson R.L., Tsou P., Aamoth G., Green W.M. Dislocation and subluxation of the hip in cerebral palsy. Pathogenesis, natural history and management. J Bone Joint Surg Am, 1972. 54: 863-73.
  12. Hagglund G., Andersson S., Duppe H., Lauge-Pedersen H., Nordmark E., Westbom L. Prevention of dislocation of the hip in children with cerebral palsy. The first ten years of a population-based prevention programme. J Bone Joint Surg Br, 2005. 87: 95-101.
  13. Dobson F., Boyd R.N., Parrott J., Nattrass G.R., Graham, H.K. Hip surveillance in children with cerebral palsy. Impact on the surgical management of spastic disease. J Bone Joint Surg [Br], 2002. 85-B: 720-726.
  14. Gordon G.S., Simkiss D.E. A systematic review of the evidence for hip surveillance in children with cerebral palsy. J Bone Joint Surg Br, 2006. 88: 1492-6.
  15. Elkamil A.I., Andersen G.L., Hägglund G, Lamvik T., Skranes J., Vik, T. Prevalence of hip dislocation among children with cerebral palsy in regions with and without a surveillance programme: a cross sectional study in Sweden and Norway. BMC Musculoskeletal Disorders, 2011. 12: 284.
  16. Scrutton D., & Baird G. Surveillance measures of the hips of children with bilateral cerebral palsy. Arch Diseases Child, 1997. 76: 381-384.
  17. Wynter M., Gibson N., Kentish M., Love S., Thomason P., Graham H.K. The consensus statement on Hip Surveillance for Children with Cerebral Palsy: Australian Standards of Care. J Pediatr Rehabil Med, 2011. 4: 183-195.
  18. Reimers J. The stability of the hip in children: a radiological study of results of muscle surgery in cerebral palsy. Acta Orthop Scand, 1980. 184: 1-100.
  19. Kentish M., Wynter M., Snape N., Boyd R. Five-year outcome of state-wide hip surveillance of children and adolescents with cerebral palsy. J Pediatr Rehabil Med, 2011. 4: 205-17.

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