Accuracy of Rotational Correction in Femoral Rotational Osteotomies Performed in the Prone and Supine Positions

Internal rotation gait (IRG), typically caused by increased femoral anteversion, is a leading cause of lever-arm dysfunction in patients with cerebral palsy (CP). The well-accepted corrective surgery is a Varus Rotational Osteotomy (VRO), either in the prone or supine position. The aim of this study was to compare the accuracy of VRO in the both positions.

Children with CP, (ages 5 to 18; GMFCS levels I-III), who underwent VRO and had pre and post-op motion analysis were included. Group 1 included 36 patients (72 limbs) operated in the prone position between 1990-1995. Group 2 included 26 patients (47 limbs) operated in the supine position between 2005-2015. The primary outcome was hip rotation (°) during stance. Secondary outcomes included passive range of motion (PROM), temporal-spatial parameters, average hip abduction and maximum hip and knee extension in stance. Statistical analysis was performed using Chi-square and Fisher exact tests for categorical parameters; t-test and Mann-Whitney U tests for continuous variables.

The groups were matched for sex and age. There were more diplegics in group 1 (100%) than group 2 (73%). GMFCS level varied with group 2 having more severely involved patients, having more concomitant procedures. Both groups had significantly improved stance hip rotation (p<0.001). There was no difference between the prone and supine groups in post-op stance hip rotation (p=0.066). Group 1 showed improved hip IR PROM (p<0.001) and IR/ER difference (p=0.002), and in maximum hip extension, pelvic tilt, velocity and cadence (p<0.001) post-op.

There was no difference in the primary outcome between the groups. Many surgeons advocate prone positioning during VRO based upon the presumption it allows more accurate assessment of the rotational correction. However, supine positioning may be more convenient when additional procedures are required. Based on our findings, either approach is acceptable; the approach choice should be surgeon-dependent.