The effects of femoral derotation osteotomy in children with cerebral palsy: an evaluation using energy cost and functional mobility.
BACKGROUND
The effect of femoral derotation osteotomy (FDO) in children with cerebral palsy (CP) has hitherto been examined using various outcome measures including range of motion of lower extremity joints and gait parameters. However, functional ambulation following this procedure has been scarcely investigated.


OBJECTIVE
To evaluate the effect of FDO on energy cost during stair climbing and functional mobility in children with CP.


METHOD
A prospective case series study was conducted on 18 children with CP, 11 at Gross Motor Functional Classification System (GMFCS) II and 7 with GMFCS III, aged 8.5 +/- 1.24 years (range, 6.9-11 years) who underwent FDO to correct hip internal rotation. The energy cost was measured using the heart beat cost index (HBCI) during stair climbing test, whereas functional mobility was assessed using the Gillette Functional Assessment Questionnaire (FAQ). Tests were administered before surgery (P0), 6 months (P1), and at approximately a year postoperatively (P2).


RESULTS
Compared with P0, significant changes in hip rotation were observed at P1 and P2. There was a significant improvement in HBCI from P0 to P2, whereas FAQ improved significantly from P1 to P2. A moderate correlation was found between HBCI and GMFCS at all times (r = 0.61-0.78). Negative correlations were found between the HBCI and FAQ and between GMFCS and FAQ at all times (r = -0.5).


CONCLUSION
This study indicates that children with CP may benefit functionally from FDO as judged by HBCI and functional mobility rating.