•Objective: To determine predictors of recur-rent femoral and/or tibial rotational deformity following pri- mary derotation osteotomy in children with cerebral palsy (CP).
Method: One hundred fifty-one patients with CP (GMFCS I-IV ; 61% male ; age 8.4, SD 2.4 years ; follow-up 3.8, SD 2.5 years) underwent femoral and/or tibial derotation osteo- tomy with pre- and postoperative gait analysis. Rotational problems at final follow-up and potential predictive factors were recorded retrospectively and analyzed using logistic regression.
Results : New rotational problems developed in 25% (58/234) of limbs, only in patients with bilateral invol- vement. New rotational problems were more common at GMFCS levels III/IV than levels I/II (OR 3.4, 95% CI 1.6 to 7.3,p= 0.002) and increased with more external transmalleolarangle (OR 1.04, 95% CI 1.01 to 1.07, p= 0.005). When newproblems occurred, the femur almost always ended up inter- nally rotated (34/36, 94%, p< 0.0001), and the tibia exter-nally rotated (28/34, 82%, p= 0.0002). Subsequent prob-lems occurred most commonly in limbs undergoing external femoral combined with internal tibial derotation (6/8, 75%).
Conclusions: Though typically successful, subsequent femoral/ tibial rotational abnormalities may develop after primary de- rotation osteotomy, particularly in less functional patients and those with combined internal femoral rotation and external tibial rotation. These patients may require additional surgery.
Keywords : femur ; tibia ; derotation osteotomy ; gait ; cerebralpalsy.