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

Abstract. Introduction. Recent reports show that spinopelvic mobility influences outcome following total hip arthroplasty. This scoping review investigates the relationship between spinopelvic parameters (SPPs) and symptomatic femoroacetabular impingement (FAI). Methods. A systematic search of EMBASE, PubMed and Cochrane for literature related to SPPs and FAI was undertaken as per PRISMA guidelines. Clinical outcome studies and prospective/retrospective studies investigating the role of SPPs in symptomatic FAI were included. Review articles, case reports and book chapters were excluded. Information extracted pertained to symptomatic cam deformities, pelvic tilt, acetabular version, biomechanics of dynamic movements and radiological FAI signs. Results. The search identified 42 papers for final analysis out of 1168 articles investigating the link between SPPs and pathological processes characteristic of FAI. Only one (2.4%) study was of level 1 evidence, five (11.9%) studies) were level 2, 17 (40.5%) were level 3 and 19 (45.2%) were level 4. Three studies associated FAI pathology with a greater pelvic incidence (PI), while four associated it with a smaller PI. Anterior pelvic tilt was associated with radiographic overcoverage parameters of FAI. In dynamic movements, decreased posterior pelvic tilt was a common feature in symptomatic FAI patients at increased hip flexion angles. FAI patients additionally demonstrated reduced sagittal pelvic ROM during dynamic hip flexion. Six studies found kinematic links between sagittal spinopelvic movement and sagittal and transverse plane hip movements. Conclusions. Our study shows that spinopelvic parameters can influence radiological and clinical manifestations of FAI, with pelvic incidence, acetabular version and muscular imbalances being aetiologically implicated. These factors may be amenable to non-surgical therapy. Individual spinopelvic mechanics may predispose to the development of FAI. If FAI pathoanatomy already exists, sagittal pelvic parameters can influence whether FAI symptoms develop and is an area of further research interest

Introduction. A deep squat (DS) is a challenging motion at the level of the hip joint generating substantial reaction forces (HJRF). During DS, the hip flexion angle approximates the functional range of hip motion. In some hip morphologies this femoroacetabular conflict has been shown to occur as early as 80° of hip flexion. So far in-vivo HJRF measurements have been limited to instrumented hip implants in a limited number of older patients performing incomplete squats (< 50° hip flexion and < 80° knee flexion). Clearly, young adults have a different kinetical profile with hip and knee flexion ranges going well over 100 degrees. Since hip loading data on this subgroup of the population is lacking and performing invasive measurements would be unfeasible, this study aimed to report a personalised numerical model solution based on inverse dynamics to calculate realistic in silico HJRF values during DS. M&M. Fifty athletic males (18–25 years old) were prospectively recruited for motion and morphological analysis. DS motion capture (MoCap) acquisitions and MRI scans of the lower extremities with gait lab marker positions were obtained. The AnyBody Modelling System (v6.1.1) was used to implement a novel personalisation workflow of the AnyMoCap template model. Bone geometries, semi-automatically segmented from MRI, and corresponding markers were incorporated into the template human model by an automated nonlinear morphing. Furthermore, a state-of-the-art TLEM 2.0 dataset, included in the Anybody Managed Model Repository (v2.0), was used in the template model. The subject-specific MoCap trials were processed to compute squat motion by resolving an overdeterminate kinematics problem. Inverse dynamics analyses were carried out to compute muscle and joint reaction forces in the entire body. Resulting hip joint loads were validated with measured in-vivo data from Knee bend trials in the OrthoLoad library. Additionally, anterior pelvic tilt, hip and knee joint angles were computed. Results. A preliminary set of results (20 out of 50 subjects) was analysed. The average HJRF was 3.42 times bodyweight at the peak of DS (95% confidence interval: 2.99 – 3.85%BW). Maximal hip and knee flexion angles were 113° (109.7°–116.8°) and 116° (109.4 – 123.0°) respectively. The anterior pelvic tilt demonstrated a biphasic profile with peak value of 33° (28.1° – 38.4°). Discussion. A non-invasive and highly personalised alternative for determining hip loading was presented. Consistently higher HJR forces during DS in young adults were demonstrated as opposed to the Orthoload dataset. Similarly, knee and hip flexion angles were much higher, which could support the increase in HJRF. We can conclude that DS hip kinetics in young adults clearly differ from the typical total hip arthroplasty population