Many studies describe the use of the Ilizarov ring fixator for lower limb lengthening and for the management of the 3-dimensional lower limb deformities in achondroplasia, and most confirm the efficacy of this technique. However, long term follow up of these achondroplastic patients is lacking. Most studies have focused on magnitude of lengthening, treatment time required and complications, but no study has analyzed the long term postoperative condition of these patients using an objective, functional method such as gait analysis. Nineteen (19) achondroplastic patients, 12 males and 7 females, aged 19–38 years (mean 27.3 y) who have undergone tibia and femur lengthening, using the Ilizarov method, at the age of 9–19 years (mean 12.6 y), were evaluated 5–19 years (mean 10.1 y) after their last surgery, using 3-dimensional gait analysis. Nineteen (19) normal, height-matched subjects were used as controls. The VICON Nexus 8 Camera System was used to accurately measure spatiotemporal characteristics (walking velocity, stride length, step length, cadence) and kinematics (range of motion) of lower limb joints. Statistical comparison of deformity parameters between achondroplastic patients and normal population was done using the student t- test. A level of p<0.05 was considered statistically significant. Walking velocity, step length and stride length were statistically significantly decreased (p<0.05) in achondroplastic patients compared to normal population values. The achondroplastic group presented with excessive anterior pelvic tilt (mean 21.9. o. ± 7.3), excessive pelvic rotation (range 28.7. o. ±7.8), decreased hip extension (mean 1.8. o. ±10.1) and decreased plantar flexion (mean 17.1. o. ±5.1) when compared to normal controls. There was no statistically significant difference in the knee kinematics between the operated achondroplastic patients and normal controls. The achondroplastic patients present decreased values in their spatiotemporal characteristics compared to the normal subjects because, despite the height gain, their lower limbs remain shorter. Their excessive anterior pelvic tilt is attributed to their lordosis. Their excessive forward pelvic rotation is an attempt to increase stride and step length. The decreased hip extension is due to their anterior pelvic tilt. The correction of these patients genu varum restored knee kinematics to normal. In order to address the hip and pelvis deformities a proximal femoral osteotomy should be considered. The Ilizarov method provides functional height gain and substantially corrects the three-dimensional lower limb deformities of achondroplastic patients especially around the knee joint but more planning needs to be implemented when the system is applied to correct the disease specific deformities of the hip and pelvis. Gait analysis is an objective tool that can be used to address these design issues

We noted, in the immature ankle, a discrepancy between the alignment of the distal tibial physis, the distal tibial articular surface and the talar dome in the coronal plane. This led to variability in the orientation of wires and half pins used for limb reconstruction depending on which landmark was used. We aimed to investigate the variability in normal ankle joints to determine which is the most reliable landmark to use for correct wire or pin insertion. Radiographs of the ankle of 98 children were analysed. A variety of angular measurements were made with respect to the axis of the tibia and classified according to methods described by Shapiro & Mulhotra. We investigated the inter- and intra-observer variation in these measurements and classifications. Using the Bland-Altman method we found that the talar plafond angle (TPA) showed less variation than the lateral distal tibial angle (LDTA) with narrower limits of agreement and coefficients of repeatability. This was the same across the age and gender groups studied. The Shapiro classification of distal tibial epiphyseal shape did not appear to correlate with age or gender, but showed more inter- and intra-rater variation using weighted Kappa analysis. This study suggests that when measuring the orientation of the ankle joint from plain radiographs that the TPA is a more reliable measurement than the LDTA and this should be taken into consideration during decision making and pre-operative planning of lower limb deformity correction