Painful dislocation of the hip is a common and unsolved problem in children, adolescents and young adults with cerebral palsy (CP). Hip displacement, defined as a migration percentage of > 30%, occurs in one third of children with CP overall and in 90% of those who are most severely affected.1 These are the children who are unable to walk and who lack sitting balance and head control (Gross Motor Function Classification System (GMFCS) V2). Dislocation is usually painful because of hypertonia and may impair care-giving, seating, positioning and quality of life.

There are few musculoskeletal problems in cerebral palsy in which management options are so diverse and opinions are so polarised as in the prevention and treatment of hip displacement. Injections of botulinum toxin A combined with abduction bracing are popular because they are not invasive but unfortunately they are not effective in preventing further displacement.3 Adductor releases are also widely used but have a weak treatment effect in non-ambulant children.4 Reconstructive surgery may be effective but most studies report small numbers and have incomplete and short-term follow-up. Despite hip surveillance, preventive strategies and reconstructive surgery, a significant number of adolescents are troubled by painful, dislocated hips. Proximal femoral resection, sometimes combined with interposition arthroplasty, distraction arthroplasty, valgus osteotomy or replacement arthroplasty are management options with variable results.5 Resection arthroplasty is the most commonly employed intervention when the hip cannot be reconstructed and the patient is frail. The most common cause of failure is persistent or recurrent pain associated with proximal femoral migration and impingement of the femoral stump against the pelvis. This is most prevalent in patients with mixed hypertonia or dystonia. Another commonly reported problem is heterotopic ossification. One of the variables, which may affect the prevalence of proximal migration and recurrent pain, is post-operative management. Reported options include skeletal traction for up to six weeks, skin traction, articulated distraction with an external fixater, hip spica casting and early mobilisation.