Roussouly's sagittal spino-pelvic morphotypes as determinants of gait in asymptomatic adult subjects.

Sagittal alignment is known to greatly vary between asymptomatic adult subjects; however, there are no studies on the possible effect of these differences on gait. The aim of this study is to investigate whether asymptomatic adults with different Roussouly sagittal alignment morphotypes walk differently. Ninety-one asymptomatic young adults (46M & 45W), aged 21.6±2.2years underwent 3D gait analysis and full body biplanar X-rays with three-dimensional (3D) reconstructions of their spines and pelvises and generation of sagittal alignment parameters. Subjects were divided according to Roussouly's sagittal alignment classification. Sagittal alignment and kinematic parameters were compared between Roussouly types. 17 subjects were classified as type 2, 47 as type 3, 26 as type 4 but only 1 as type 1. Type 2 subjects had significantly more mean pelvic retroversion (less mean pelvic tilt) during gait compared to type 3 and 4 subjects (type 2: 8.2°; type 3:11.2°, type 4: 11.3°) and significantly larger ROM pelvic obliquity compared to type 4 subjects (type 2: 11.0°; type 4: 9.1°). Type 2 subjects also had significantly larger maximal hip extension during stance compared to subjects of types 3 and 4 (type 2: -11.9°; type 3: -8.8°; type 4: -7.9°) and a larger ROM of ankle plantar/dorsiflexion compared to type 4 subjects (type 2: 31.1°; type 4: 27.9°). Subjects with type 2 sagittal alignment were shown to have a gait pattern involving both increased hip extension and pelvic retroversion which could predispose to posterior femoroacetabular impingement and consequently osteoarthritis.This study was supported by the research council of the University of Saint-Joseph (grant number: FM189). The study sponsors were involved in neither the study design, collection, analysis and interpretation of data nor in the writing of the manuscript; nor in the decision to submit the manuscript for publication

How the type of sagittal alignment defined by Roussouly determines the gait of asymptomatic adult subject

While curvatures of the sagittal spine are known to greatly differ among asymptomatic adult subjects, there are no studies that determine whether this heterogeneous normality affects gait. This study aimed to elucidate the relationships between normal sagittal spine profiles and gait in asymptomatic adult subjects. Ninety-one asymptomatic adult subjects (age = 21.6 ±2.2, 47 M & 44F) with no prior orthopedic treatment underwent full body biplanar X rays with 3D reconstruction of the spine and pelvis. The following sagittal spino-pelvic parameters were generated from the 3D reconstructions: pelvic incidence, sacral slope, pelvic tilt, L1L5 lordosis, L1-S1 lordosis, T1-T12 kyphosis and T4-T2 kyphosis. Lower limb kinematics was assessed using 3D gait analysis. Each subject was classified into one of the 4 types of normal sagittal alignment previously described by Roussouly. Kruskal-Wallis test was used to evaluate the differences in gait and spino-pelvic parameters between the Roussouly types

Influence of patient rotational malpositioning on pelvic parameters assessed on lateral radiographs

Aim: To estimate the effect of patients' axial rotation (AR) during pelvic radiograph acquisition, on the reliability and validity of sagittal pelvic parameters. Materials and methods: Lateral digitally reconstructed radiographs (LDRRs) were obtained from the pelvic computed tomography (CT) scans of eight children and nine adults. Then, the AR of the pelvis was simulated and the corresponding LDRRs were reconstructed at 5°, 10°, 15°, and 20° of the AR. Pelvic parameters were measured digitally on each radiograph. Intra- and interobserver variability were evaluated at each AR position (three operators repeated the measurements three times each). The bias on each clinical parameter, in each AR position, was calculated relatively to the 0° position. Results: Interobserver variability increased similarly in children and adults with AR. It reached 4.4° for pelvic incidence and 4.7° for the sacral slope at 20° of AR. Biases on radiological parameters increased with AR and exceeded the acceptable threshold of errors when AR reached 10°. A linear regression was established (R2=0.834, p<0.0001) in order to estimate the AR of a patient on a lateral pelvic radiograph based on the measurement of the bifemoral distance normalized to the sagittal pelvic thickness. Conclusions: AR of patients during radiograph acquisition can be estimated in clinical practice, which would allow physicians to discard any radiographs where the calculated AR exceeded 10°

Validity and reliability of different techniques of neck–shaft angle measurement

AIM: To determine a valid and reliable neck-shaft angle (NSA) measurement method while rotating the pelvises in increments of 5° in order to simulate patient malpositioning. MATERIALS AND METHODS: CT images of 17 patients were used to produce digitally reconstructed radiographs in frontal and lateral views and three-dimensional (3D)-reconstructions of the femurs, considered to be the reference standard. Malpositioning was simulated by axially rotating the frontal radiographs from 0° to 20°. Three operators measured in two-dimensions the NSA using four different methods, three times each, at each axial rotation (AR) position. Method 1 (femoral neck axis drawn by joining the centre of the femoral head (CFH) to the median of the femoral neck base; femoral diaphysis axis drawn by joining the median of two lines passing through the medial and lateral edges of the femoral axis below the lesser trochanter) and method 2 (femoral axis taken as the median of a triangle passing through base of femoral neck and medial and lateral head-neck junction; femoral diaphysis as previous) were described for the first time; method 3 was based on a previous study; method 4 was a free-hand technique. Reliability, validity, and global uncertainty were assessed. RESULTS: Method 1 showed the best reliability and validity. The global uncertainty also showed minimal values for method 1, ranging from 7.4° to 14.3° across AR positions. CONCLUSION: Method 1, based on locating the CFH, was the most reliable and valid method and should be considered as a standardised two-dimensional NSA measurement method for clinical application

How the type of sagittal alignment dfined by Roussouly determines the gait of asymptomatic adult subject

International audienceWhile curvatures of the sagittal spine are known to greatly differ among asymptomatic adult subjects, there are no studies that determine whether this heterogeneous normality affects gait. This study aimed to elucidate the relationships between normal sagittal spine profiles and gait in symptomatic adult subjects. Ninety-one asymptomatic adult subjects (age = 21.6 ±2.2, 47 M & 44F) with no prior orthopedic treatment underwent full body biplanar X rays with 3D reconstruction of the spine and pelvis. The following sagittal spino-pelvic parameters were generated from the 3D reconstructions: pelvic incidence, sacral slope, pelvic tilt, L1L5 lordosis, L1-S1 lordosis, T1-T12 kyphosis and T4-T2 kyphosis. Lower limb kinematics was assessed using 3D gait analysis. Each subject was classified into one of the 4 types of normal sagittal alignment previously described by Roussouly. Kruskal-Wallis test was used to evaluate the differences in gait and spino-pelvic parameters between the Roussouly types.While curvatures of the sagittal spine are known to greatly differ among asymptomatic adult subjects, there are no studies that determine whether this heterogeneous normality affects gait. This study aimed to elucidate the relationships between normal sagittal spine profiles and gait in asymptomatic adult subjects. Ninety-one asymptomatic adult subjects (age = 21.6 ±2.2, 47 M & 44F) with no prior orthopedic treatment underwent full body biplanar X rays with 3D reconstruction of the spine and pelvis. The following sagittal spino-pelvic parameters were generated from the 3D reconstructions: pelvic incidence, sacral slope, pelvic tilt, L1L5 lordosis, L1-S1 lordosis, T1-T12 kyphosis and T4-T2 kyphosis. Lower limb kinematics was assessed using 3D gait analysis. Each subject was classified into one of the 4 types of normal sagittal alignment previously described by Roussouly. Kruskal-Wallis test was used to evaluate the differences in gait and spino-pelvic parameters between the Roussouly types

Is posterior vertebral arthrodesis at the end of the electromagnetic rod lengthening program necessary for all patients? Comparative analysis of sixty six patients who underwent definitive spinal arthrodesis and twenty four patients with in situ lengthening rods

International audiencePurpose: Magnetically controlled growing rods (MCGR) should be removed or changed at most two years after their implantation in the treatment of patients with early-onset scoliosis (EOS) (Safety notice July 2021). However, in the face of patients at high risk of intraoperative complications and relying on the principle of auto-fusion of the spine, some surgeons would prefer a more wait-and-see attitude. The aim of this study was to report on patients who did not undergo final fusion at the end of the lengthening program with MCGR and to compare them with those who did.Methods: This was a multicenter study with ten centres. We collected all graduate patients with EOS who had received MCGR between 2011 and 2022.Results: A total of 66 patients had final fusion at the end of the lengthening program and 24 patients kept MCGRs in situ. The mean total follow-up time was 66 months (range, 25.3-109), and the mean follow-up time after final lengthening was 24.9 months (range, 3-67.7). Regarding the main curve and thoracic height, there was no significant difference in the percentage of correction over the whole follow-up between the two groups (p = 0.099, p = 0.176) although there was a significant difference between the end of lengthening and the last follow-up (p < 0.001). After completion of the lengthening program, 18 patients who had final fusion developed 24 of the 26 recorded complications (92.3%).Conclusion: Contrary to the manufacturer's published safety notice, not all patients systematically benefited from the removal of the MCGRs. Although arthrodesis significantly improved the scoliotic deformity, no significant difference was found in terms of radiographic outcome between patients who underwent spinal fusion and those who kept the MCGRs in situ

Clinical and radiographic evolution of graduate patients treated with magnetically controlled growing rods: results of a French multicentre study of 90 patients

International audiencePurpose: The purpose of this study was to investigate patients with early-onset scoliosis (EOS) who completed their electromagnetic lengthening rod program to assess the demographics of this population and to analyze the evolution of clinical and radiological parameters and the occurrence of complications. Methods: This was a multicenter study with 10 French centers. We collected all patients with EOS who had undergone electromagnetic lengthening between 2011 and 2022. They had to have reached the end of the procedure (graduate). Results: A total of 90 graduate patients were included. The mean follow-up time over the entire period was 66 months (25.3-109). Of these, only 66 patients (73.3%) underwent definitive spinal arthrodesis at the end of the lengthening phase, whereas 24 patients (26.7%) kept their hardware in situ with a mean follow-up time from the last lengthening of 25 months (3-68). Patients had an average of 2.6 surgeries (1-5) over the entire follow-up. Patients had an average of 7.9 lengthenings for a mean total lengthening of 26.9 mm (4-75). Analysis of the radiological parameters showed a percentage reduction in the main curve of 12 to 40%, depending on the etiology, with an average reduction of 73-44°, and an average thoracic height of 210 mm (171-214) for an average improvement of 31 mm (23-43). There was no significant difference in the sagittal parameters. During the lengthening phase, there were a total of 56 complications in 43 patients (43.9%; n = 56/98), of which 39 in 28 patients (28.6%) resulted in unplanned surgery. In the graduate patients, there were a total of 26 complications in 20 patients (22.2%), all of which resulted in unscheduled surgery. Conclusion: MCGR, allow to decrease the number of surgeries, to progressively improve the scoliotic deformity and to reach a satisfactory thoracic height at the price of an important complication rate linked in particular to the complexity of the management of patients with an EOS