Tibial rotation outcomes following hamstring lengthening as part of single event multilevel surgery in children with cerebral palsy

•First paper on tibial rotation outcomes following hamstring lengthening.•Guidelines for which hamstrings to lengthen are unclear.•Medial only or combined medial and lateral are comparable post operatively.•Control group shows similar changes in tibial rotation due to natural progression. Hamstring lengthening remains the most common surgical procedure in the treatment of crouch gait for children with cerebral palsy (CP). While sagittal plane knee kinematics have been shown to improve post-surgery, the effects on transverse plane kinematics have not been reported. Given the differing actions of the medial and lateral hamstring muscles there is potential for change in tibial rotation post hamstring lengthening. What is the effect of medial only versus combined medial and lateral hamstring lengthening on tibial rotation during gait in children with CP? A retrospective analysis of children with a diagnosis of CP who underwent a hamstring lengthening procedure. These children were divided into 2 groups: G1 (n = 18) had isolated medial hamstring lengthening while G2 (n = 30) had combined medial and lateral hamstring lengthening. A matched non-surgical control group (n = 15) was also included. Kinematic data were analysed pre and post-operatively. Pre-operative to post-operative outcomes for G1 and G2, a comparison at baseline for both groups and the difference in outcomes between the groups were analysed. Baseline to follow-up outcomes for the control group were also analysed. External tibial rotation increased significantly within groups (G1: −10°, p < 0.01; G2: −11°, p < 0.001, control: −7.7, p < 0.01), with no significant difference in the change between the intervention groups. Foot progression angles became more external in both intervention groups (G1: −15°, p < 0.001; G2: −15°, p < 0.0001) and did not change in the control group. Results demonstrated similar increases in external tibial rotation, regardless of whether an isolated medial or combined medial and lateral surgery was performed. The control group demonstrated a similar change in external tibial rotation suggesting that hamstring lengthening surgery does not contribute to increased external tibial rotation in children with CP compared to what would be expected due to natural progression.