Abstract
Introduction
Some patients with Cerebral Palsy who had a de-rotation osteotomy performed for correction of excessive anteversion had persistence of internal foot progression even after surgery. Potential causes which have been implicated include: weak hip abductors, spasticity of the anterior fibres of the gluteus medius, hip adductor spasm and persistent femoral anterversion. The aim of this study was to see if there is any relationship between significant abductor weakness [less than Grade III: MRC] and persistence of internal foot progression.
Methods
We included all ambulatory patients with cerebral palsy who had had a derotation osteotomy between the periods of 2000-2005, who had also had a pre and post operative gait analysis, assessment of anteversion [Gage Test], hip range of motion and muscle charting.
There were 12 patients [17 hips, 5 bilateral] with an average age of 13. Seven were diplegic, two hemiplegic and three had asymmetric diplegia. Data was assessed using SPSS13.0. The Spearman Co-relation Coefficient was used to test if there was any correlation.
Results
Of the 17 limbs operated, pre-operative femoral anteversion was 20-60 degrees [mean: 45] and post op femoral anteversion was 0-35 [mean: 15]. Of these, 7 hips had persistent internal rotation gait on gait analysis. None of the patients with persistent internal rotation had any hip capsular contractures, and there was no significant change in abductor power after surgery.
On testing the hypothesis it was found that there is no relationship between weak hip abductors and persistent internal rotation. [r = -0.07]
Conclusion
This study suggests that hip abductor muscle weakness may not be a cause for the persistence of the internal foot progression. Significance: Weak abductor power is not a contraindication to de-rotation osteotomies and do not affect outcome.
