Related Experiment Video
Updated: Nov 19, 2025
Author Spotlight: Repetitive Transcranial Magnetic Stimulation Combined with Movement Observation in Cerebral Palsy
Published on: August 9, 2024
Hip displacement in children with cerebral palsy
Sarah J Wordie1, Kate E Bugler2, Paul R Bessell3
1Victoria Hospital, Kirkcaldy, UK.
Insights
For children with cerebral palsy (CP), a hip migration percentage (MP) of 46% is the point of no return. Hips with MP below 46% may improve, while those at or above 46% will likely displace further without intervention.
Area of Science:
- Orthopedics
- Pediatric Medicine
- Radiology
Background:
- Hip migration percentage (MP) is a surgical criterion for dislocated or displaced hips in children with cerebral palsy (CP).
- The threshold MP for irreversible hip displacement is not clearly defined.
Purpose of the Study:
- To determine the irreversible point of hip displacement (point of no return) using migration percentage (MP) in children with cerebral palsy (CP).
Main Methods:
- A population-based study analyzed pelvic radiographs of children with CP from the Cerebral Palsy Integrated Pathway Scotland surveillance program.
- Children with MP ≥ 35% were identified, and their radiographs were reviewed from birth to determine displacement progression.
- A minimum of two radiographs post-MP ≥ 35% measurement was required for inclusion.
Main Results:
- 239 children (346 hips) were analyzed with a mean follow-up of 6.5 years.
- Hips with MP up to 46% spontaneously returned to <40% MP without intervention.
- Hips with MP ≥ 46% consistently displaced further, with 98% certainty of no spontaneous regression.
Conclusions:
- A migration percentage (MP) of 46% is identified as the threshold for irreversible hip displacement in children with cerebral palsy (CP).
- Monitoring hips with MP not exceeding 46% may be appropriate.
- This threshold aids in guiding management decisions for displacing hips.
Aims:
The migration percentage (MP) is one criterion used for surgery in dislocated or displaced hips in children with cerebral palsy (CP). The MP at which a displaced hip can no longer return to normal is unclear. The aim of this paper was to identify the point of no return of the MP through a large population-based study.
Methods:
All children registered on the Cerebral Palsy Integrated Pathway Scotland surveillance programme undergo regular pelvic radiographs. Any child who had a MP measuring over 35% since the programme's inception in 2013, in at least one hip and at one timepoint, was identified. The national radiography database was then interrogated to identify all pelvic radiographs for each of these children from birth through to the date of analysis. A minimum of a further two available radiographs following the initial measurement of MP ≥ 35% was required for inclusion.
Results:
A total of 239 children (346 hips) were identified as suitable for analysis at a mean of 6.5 years (2.0 to 14.8) follow-up. In all, 1,485 radiographs taken both prior to and after a hip had a MP ≥ 35% were examined and the MP measured to identify any progression of displacement. Interrogation of the data identified that hips with a MP up to 46% returned to a MP below 40% without intervention, and all hips with a MP equal to or greater than 46% displaced further and the MP did not return to the normal range. Statistical analysis showed the result to be 98% specific with this degree of certainty that hips reaching a MP ≥ 46% would not spontaneously regress.
Conclusion:
These findings are clinically relevant in showing that it may be reasonable to continue to monitor hips with a MP not exceeding 46%. This threshold will also guide referral for further management of a displacing hip. Cite this article: Bone Joint J 2021;103-B(2):411-414.
