Alterations of gait kinematics depend on the deformity type in the setting of adult spinal deformity

Gait Characteristics Associated with Walking Speed in Postoperative Patients with Adult Spinal Deformity Extracted by Machine Learning

PURPOSE

Patients with adult spinal deformity (ASD) are unable to walk faster even after spinal fixation. Gait rehabilitation that focuses on movements associated with reduced speed may help improve gait function. This study aimed to identify the gait characteristics associated with walking velocity in postoperative patients with ASD.

METHODS

Three-dimensional gait analysis was performed in 62 postoperative patients with ASD and 105 healthy volunteers. A dimensionality reduction method, based on data from the healthy cohort, was applied to 194 gait characteristics of the patients. Then, the Markov Chain Monte Carlo method sampled the gait characteristics related to speed, and k-means clustering categorized the gait patterns. The relationships between the extracted gait characteristics and velocity were assessed using multiple regression analysis within each cluster.

RESULTS

Hip sagittal angle and moment (β = - 0.47 to 0.42) were significantly associated with postoperative velocity in all the patients (R2 = 0.834). Two clusters were identified, and hip sagittal moments at contralateral contact and toe-off (β = - 0.58 and 0.68, respectively) were associated with velocity in the group that walked faster (R2 = 0.634). Maximum ankle plantarflexion moment and hip flexion power (β = 0.53 and 0.33, respectively) were associated with velocity in the group that walked slowly (R2 = 0.448).

CONCLUSION

Larger hip joint movement may play a crucial role in enhancing gait velocity because the spinal fixation limits spino-pelvic movement. To improve gait speed, postoperative older adults with ASD who walk slowly may require new rehabilitation strategies that exert more ankle plantarflexion moment and develop an adequate stance phase to facilitate hip extension.

Effects of spinal deformities on lower limb kinematics during walking: a systematic review and meta-analysis

Spinal deformities characterized by malalignment of the spinal column, including scoliosis, hyper kyphosis, and lordosis, can significantly impact lower limb kinematics, potentially leading to altered gait patterns. We aimed to synthesize existing literature investigating the effect of spinal deformities on lower limb kinematics during walking. We searched Four databases including PubMed, Web of Science, Scopus and Embase from their inception through 29th December 2024. The Newcastle-Ottawa Scale was applied to assess quality of included studies and the Grading of Recommendations Assessment, Development and Evaluation (GRADE system) was employed to assess the overall quality of the evidence in the meta-analysis. Mean differences and 95% confidence intervals (CI) were calculated with random effects model in RevMan version 5.4. The review included 35 studies with 1941 participants. Regarding scoliosis, strong evidence suggested a significant increase in right leg stance% and non-significant changes in left leg cadence, right and left leg speed and ankle transverse ROM in individuals with scoliosis compared to controls. Sensitivity analysis showed strong evidence of decrease in right leg stride length and ankle sagittal ROM, decrease in left leg single support and non-significant change in left leg step length. Individuals with sagittal malalignment showed strong evidence of significant reduction in velocity; moderate evidence suggested a significant increase in double support and a decrease in stride length, knee and hip sagittal ROM. Sensitivity analysis revealed strong evidence of a significant decrease in cadence during walking in individuals with sagittal trunk malalignment compared to controls. Participants with adult spinal deformity exhibited strong evidence of increased double support and decreased cadence during walking compared to controls. Spinal deformities significantly alter lower limb kinematics during gait. Our findings highlight the essential need for clinicians to take gait alterations into account when developing targeted interventions for individuals with spinal deformity.

Machine learning can predict surgical indication: new clustering model from a large adult spine deformity database

PURPOSE

The choice of the best management for Adult Spine Deformity (ASD) is challenging. Health-related quality of life (HRQoL), comorbidities, symptoms and spine geometry, along with surgical risk and potential residual disability play a role, and a definite algorithm for patient management is lacking. Machine learning allows to analyse complex settings more efficiently than other available statistical tools. Aim of this study was to develop a machine-learning algorithm that, based on baseline data, would be able to predict whether an ASD patient would undergo surgery or not.

METHODS

Retrospective evaluation of prospectively collected data. Demographic data, HRQoL and radiographic parameters were collected. Two clustering methods were performed to differentiate groups of patients with similar characteristics. Three models were then used to identify the most relevant variables for management prediction.

RESULTS

Data from 1319 patients were available. Three clusters were identified: older subjects with sagittal imbalance and high PI, younger patients with greater coronal deformity and no sagittal imbalance, older patients with moderate sagittal imbalance and lower PI. The group of younger patients showed the highest error rate for the prediction (37%), which was lower for the other two groups (20-27%). For all groups, quality of life parameters such as the ODI and the SRS 22 and the Cobb angle of the major curve were the strongest predictors of surgical indication, albeit with different odds ratios in each group.

CONCLUSION

Three clusters could be identified along with the variables that, in each, are most likely to drive the choice of management.

Preoperative Spinal Sagittal Alignment Affects Improvement of Locomotive Syndrome by Four Years After Total Hip Arthroplasty

Introduction Most patients with hip osteoarthritis requiring total hip arthroplasty suffer from locomotive syndrome stage 3, which indicates difficulty with mobility and social participation. Although total hip arthroplasty improves their locomotive syndrome stage, some patients remain at locomotive syndrome stage 3 after total hip arthroplasty, despite hip function improvement. Patients with severe hip osteoarthritis may have an abnormal spinal sagittal alignment. This study investigated the influence of preoperative spinopelvic parameters for locomotive syndrome improvement at four years after total hip arthroplasty. Methods This retrospective cohort study of a prospectively maintained database included 65 patients who had undergone total hip arthroplasty. Patients were divided into two groups based on whether they showed improvement from Locomotive Syndrome stage 3 at four years postoperatively: improved group (n = 51) and unchanged group (n = 14). Preoperative spinopelvic parameters were compared between the two groups and examined using logistic analysis to determine locomotive syndrome improvement. The cut-off values for preoperative key factors of locomotive syndrome improvement obtained using logistic analysis were determined using receiver operating characteristics analysis. Results Preoperative sagittal vertical axis was significantly larger and sacral slope was significantly smaller in the unchanged group than in the improved group. In the logistic regression analysis, preoperative sacral slope and the 25-question Geriatric Locomotive Function Scale (GLFS-25) were identified as factors associated with locomotive syndrome improvement. The receiver operating characteristic analysis showed that the cut-off values of preoperative sacral slope and GLFS-25 for locomotive syndrome improvement were 32.5° and 44.5, respectively. Conclusions Among hip osteoarthritis (OA) patients with locomotive syndrome stage 3, those who have small preoperative sacral slope and large preoperative GLFS-25 score may have difficulty improving their postoperative mobility. Therefore, it may be useful to suggest preoperatively that such patients should be prepared to use social services and other services after surgery to support their postoperative mobility.

Kinematic limitations during stair ascent and descent in patients with adult spinal deformity

Background

Adults with spinal deformity (ASD) are known to have spinal malalignment, which can impact their quality of life and their autonomy in daily life activities. Among these tasks, ascending and descending stairs is a common activity of daily life that might be affected.

Research question

What are the main kinematic alterations in ASD during stair ascent and descent?

Methods

112 primary ASD patients and 34 controls filled HRQoL questionnaires and underwent biplanar X-from which spino-pelvic radiographic parameters were calculated. Patients were divided into 3 groups: 44 with sagittal malalignment (ASD-Sag: PT > 25°, SVA>5 cm or PI-LL>10°), 42 with isolated thoracic hyperkyphosis (ASD-HyperTK: TK > 60°), 26 with isolated frontal spine deformity (ASD-Front: Cobb>20°). All participants underwent 3D motion analysis of the whole body while ascending and descending a stair step from which kinematic waveforms were extracted.

Results

During stair ascent, ASD-Sag exhibited an increased thorax flexion (20 vs 5°), a decreased lumbar lordosis L1L3-L3L5 (7 vs 14°), and an increased ROM of lumbo-pelvic joint (15 vs 10°, all p < 0.05), compared to controls. Similar compensations were shown while descending the stairstep. ASD-HyperTK had similar kinematic limitations as ASD-Sag but to a lesser extent. ASD-Front had normal kinematic patterns. PCS-SF36 correlated to thorax flexion (r = -0.45) and ODI was correlated to pelvic tilt ROM (r = 0.46).

Discussion and conclusion

ASD subjects with sagittal malalignment tend to ascend and descend stairs with increased thorax flexion, making them more prone to falls. Compensation mechanisms occur at the head and lumbo-pelvic levels to maintain balance and avoid falling forward.

Longitudinal impact of multi-segment spinal fixation surgery on mobility status and clinical outcomes in adult spinal deformity: a multicenter retrospective study

PURPOSE

To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility.

METHODS

A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2 years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility.

RESULTS

Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2 years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline.

CONCLUSION

Postoperative mobility often temporarily decreases but generally improves after 2 years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

Global Sagittal Angle and T9-tilt seem to be the most clinically and functionally relevant global alignment parameters in patients with Adult Spinal Deformity

Introduction

Radiographic analysis is necessary for the assessment and the surgical planning in adults with spinal deformity (ASD). Restoration of global alignment is key to improving patient's quality of life. However, the large number of existing global alignment parameters can be confusing for surgeons.

Research question

To determine the most clinically and functionally relevant global alignment parameters in ASD.

Material and methods

ASD and controls underwent full body biplanar X-ray to calculate global alignment parameters: odontoid to hip axis angle (OD-HA), global sagittal angle (GSA), global tilt (GT), SVA, center of auditory meatus to hip axis (CAM-HA), SSA, T1-tilt and T9-tilt. All subjects filled HRQoL questionnaires: ODI, SF-36, VAS for pain and BDI (Beck's Depression Inventory). 3D gait analysis was performed to calculate kinematic and spatio-temporal parameters. A machine learning model predicted gait parameters and HRQoL scores from global alignment parameters.

Results

124 primary ASD and 47 controls were enrolled. T9 tilt predicted the most BDI (31%), hip flexion/extension during gait (36%), and double support time (39%). GSA predicted the most ODI (26%), thorax flexion/extension during gait (33%), and cadence (36%).

Discussion and conclusion

Among all global alignment parameters, GSA, evaluating both trunk shift and knee flexion, and T9 tilt, evaluating the shift of the center of mass, were the best predictors for most of HRQoL scores and gait kinematics. Therefore, we recommend using GSA and T9 tilt in clinical practice when evaluating ASD because they represent the most quality of life and functional kinematic of these patients.

Kinematic adaptations from self-selected to fast speed walking in patients with adult spinal deformity

PURPOSE

To investigate kinematic adaptations from self-selected to fast speed walking in ASD patients.

METHODS

115 primary ASD and 66 controls underwent biplanar radiographic X-rays and 3D gait analysis to calculate trunk, segmental spine and lower limb kinematics during self-selected and fast speed walking. Kinematic adaptation was calculated as the difference (Δ) between fast and self-selected speed walking. ASD with 7 or more limited kinematic adaptation parameters were classified as ASD-limited-KA, while those with less than 7 limited kinematic adaptation parameters were classified as ASD-mild-KA.

RESULTS

25 patients were classified as ASD-limited-KA and 90 as ASD-mild-KA. ASD-limited-KA patients walked with a lesser increase of pelvic rotation (Δ = 1.7 vs 5.5°), sagittal hip movement (Δ = 3.1 vs 7.4°) and shoulder-pelvis axial rotation (Δ = 3.4 vs 6.4°) compared to controls (all p < 0.05). ASD-limited-KA had an increased SVA (60.6 vs - 5.7 mm), PT (23.7 vs 11.9°), PI-LL (9.7 vs - 11.7°), knee flexion (9.2 vs - 0.4°) and a decreased LL (44.0 vs 61.4°) compared to controls (all p < 0.05). Kinematic and radiographic alterations were less pronounced in ASD-mild-KA. The limited increase of walking speed was correlated to the deteriorated physical component summary score of SF-36 (r = 0.37).

DISCUSSION

Kinematic limitations during adaptation from self-selected to fast speed walking highlight an alteration of a daily life activity in ASD patients. ASD with limited kinematic adaptations showed more severe sagittal malalignment with an increased SVA, PT, PI-LL, and knee flexion, a decreased LL and the most deteriorated quality of life. This highlights the importance of 3D movement analysis in the evaluation of ASD.

Gait alterations in patients with adult spinal deformity

Background

Adult spinal deformity patients (ASD) experience altered spinal alignment affecting spatiotemporal parameters and joint kinematics. Differences in spinal deformity between patients with symptomatic idiopathic scoliosis (ID-ASD) and patients with "de novo" scoliosis (DN-ASD) may affect gait characteristics differently. This study aims to compare gait characteristics between ID-ASD, DN-ASD, and asymptomatic healthy matched controls.

Methods

In this observational case-control study, ID-ASD (n = 24) and DN-ASD (n = 26) patients visiting the out-patient spine clinic and scheduled for long-segment spinal fusion were included. Patients were matched, based on age, gender, leg length and BMI, with asymptomatic healthy controls. Gait was measured at comfortable walking speed on an instrumented treadmill with 3D motion capture system. Trunk, pelvic and lower extremities range of motion (ROM) and spatiotemporal parameters (SPT) are presented as median (first and thirds quartile). Independent t-test or Mann-Whitney U test was used to compare ID-ASD, DN-ASD and controls. Statistical Parametric Mapping (independent t-test) was used to compare 3D joint kinematics.

Results

DN-ASD patients walk with increased anterior trunk tilt during the whole gait cycle compared with ID-ASD patients and controls. ID-ASD walk with decreased trunk lateroflexion compared with DN-ASD and controls. DN-ASD showed decreased pelvic obliquity and -rotation, increased knee flexion, and decreased ankle plantar flexion. ID-ASD and DN-ASD displayed decreased trunk, pelvic and lower extremity ROM compared with controls, but increased pelvic tilt ROM. ID-ASD patients walked with comparable SPT to controls, whereas DN-ASD patients walked significantly slower with corresponding changes in SPT and wider steps.

Conclusions

DN-ASD patients exhibit distinct alterations in SPT and kinematic gait characteristics compared with ID-ASD and controls. These alterations seem to be predominantly influenced by sagittal spinal malalignment and kinematic findings in ASD patients should not be generalized as such, but always be interpreted with consideration for the nature of the ASD.

Cross-sectional area and fat infiltration of the lumbar spine muscles in patients with back disorders: a deep learning-based big data analysis

PURPOSE

Validated deep learning models represent a valuable option to perform large-scale research studies aiming to evaluate muscle quality and quantity of paravertebral lumbar muscles at the population level. This study aimed to assess lumbar spine muscle cross-sectional area (CSA) and fat infiltration (FI) in a large cohort of subjects with back disorders through a validated deep learning model.

METHODS

T2 axial MRI images of 4434 patients (n = 2609 females, n = 1825 males; mean age: 56.7 ± 16.8) with back disorders, such as fracture, spine surgery or herniation, were retrospectively collected from a clinical database and automatically segmented. CSA, expressed as the ratio between total muscle area (TMA) and the vertebral body area (VBA), and FI, in percentages, of psoas major, quadratus lumborum, erector spinae, and multifidus were analyzed as primary outcomes.

RESULTS

Male subjects had significantly higher CSA (6.8 ± 1.7 vs. 5.9 ± 1.5 TMA/VBA; p < 0.001) and lower FI (21.9 ± 8.3% vs. 15.0 ± 7.3%; p < 0.001) than females. Multifidus had more FI (27.2 ± 10.6%; p < 0.001) than erector spinae (22.2 ± 9.7%), quadratus lumborum (17.5 ± 7.0%) and psoas (13.7 ± 5.8%) whereas CSA was higher in erector spinae than other lumbar muscles. A high positive correlation between age and total FI was detected (rs = 0.73; p < 0.001) whereas a negligible negative correlation between total CSA and age was observed (rs =  - 0.24; p < 0.001). Subjects with fractures had lower CSA and higher FI compared to those with herniations, surgery and with no clear pathological conditions.

CONCLUSION

CSA and FI values of paravertebral muscles vary a lot in accordance with subjects' sex, age and clinical conditions. Given also the large inter-muscle differences in CSA and FI, the choice of muscles needs to be considered with attention by spine surgeons or physiotherapists when investigating changes in lumbar muscle morphology in clinical practice.

Lasso Analysis of Gait Characteristics and Correlation with Spinopelvic Parameters in Patients with Degenerative Lumbar Scoliosis

PURPOSE

This study quantifies the gait characteristics of patients with degenerative lumbar scoliosis (DLS) and patients with simple lumbar spinal stenosis (LSS) by means of a three-dimensional gait analysis system, aiming to determine the image of spinal deformity on gait and the correlation between spinal-pelvic parameters and gait characteristics in patients with DLS to assist clinical work.

METHODS

From June 2020 to December 2021, a total of 50 subjects were enrolled in this study, of whom 20 patients with DLS served as the case group and 30 middle-aged and elderly patients with LSS were selected as the control group according to the general conditions (sex, age, and BMI) of the case group. Spinal-pelvic parameters were measured by full-length frontal and lateral spine films one week before surgery, and kinematics were recorded on the same day using a gait analysis system.

RESULTS

Compared to the control group, DLS patients exhibited significantly reduced velocity and cadence; gait variability and symmetry of both lower limbs were notably better in the LSS group than in the DLS group; joint ROM (range of motion) across multiple dimensions was also lower in the DLS group; and correlation analysis revealed that patients with a larger Cobb angle, T1PA, and higher CSVA tended to walk more slowly, and those with a larger PI, PT, and LL usually had smaller stride lengths. The greater the PI-SS mismatch, the longer the patient stayed in the support phase. Furthermore, a larger Cobb angle correlated with worse coronal hip mobility.

CONCLUSIONS

DLS patients demonstrate distinctive gait abnormalities and reduced hip mobility compared to LSS patients. Significant correlations between crucial spinopelvic parameters and these gait changes underline their potential influence on gait disturbances in DLS. Our study identifies a Cobb angle cut-off of 16.1 as a key predictor for gait abnormalities. These insights can guide personalized treatment and intervention strategies, ultimately improving the quality of life for DLS patients.

Are Rotations and Translations of Head Posture Related to Gait and Jump Parameters?

This study assessed the relationship between head posture displacements and biomechanical parameters during gait and jumping. One hundred male and female students (20 ± 3 yrs) were assessed via the PostureScreen Mobile® app to quantify postural displacements of head rotations and translations including: (1) the cranio-vertebral angle (CVA) (°), (2) anterior head translation (AHT) (cm), (3) lateral head translation in the coronal plane (cm), and (4) lateral head side bending (°). Biomechanical parameters during gait and jumping were measured using the G-Walk sensor. The assessed gait spatiotemporal parameters were cadence (steps/min), speed (m/s), symmetry index, % left and right stride length (% height), and right and left propulsion index. The pelvic movement parameters were (1) tilt symmetry index, (2) tilt left and right range, (3) obliquity symmetry index, (4) obliquity left and right range, (5) rotation symmetry index, and (6) rotation left and right range. The jump parameters measured were (1) flight height (cm), (2) take off force (kN), (3) impact Force (kN), (4) take off speed (m/s), (5) peak speed (m/s), (6) average speed concentric phase (m/s), (7) maximum concentric power (kW), (8) average concentric power (kW) during the counter movement jump (CMJ), and (9) CMJ with arms thrust (CMJAT). At a significance level of p ≤ 0.001, moderate-to-high correlations (0.4 < r < 0.8) were found between CVA, AHT, lateral translation head, and all the gait and jump parameters. Weak correlations (0.2 < r < 0.4) were ascertained for lateral head bending and all the gait and jump parameters except for gait symmetry index and pelvic symmetry index, where moderate correlations were identified (0.4 < r < 0.6). The findings indicate moderate-to-high correlations between specific head posture displacements, such as CVA, lateral head translation and AHT with the various gait and jump parameters. These findings highlight the importance of considering head posture in the assessment and optimization of movement patterns during gait and jumping. Our findings contribute to the existing body of knowledge and may have implications for clinical practice and sports performance training. Further research is warranted to elucidate the underlying mechanisms and establish causality in these relationships, which could potentially lead to the development of targeted interventions for improving movement patterns and preventing injuries.

ASD with high pelvic retroversion develop changes in their acetabular orientation during walking

Introduction

It was hypothesized that pelvic retroversion in Adult Spinal Deformity (ASD) can be related to an increased hip loading explaining the occurrence of hip-spine syndrome.

Research question

How pelvic retroversion can modify acetabular orientation in ASD during walking?

Methods

89 primary ASD and 37 controls underwent 3D gait analysis and full-body biplanar X-rays. Classic spinopelvic parameters were calculated from 3D skeletal reconstructions in addition to acetabular anteversion, abduction, tilt, and coverage. Then, 3D bones were registered on each gait frame to compute the dynamic value of the radiographic parameters during walking. ASD patients having a high PT were grouped as ASD-highPT, otherwise as ASD-normPT. Control group was divided in: C-aged and C-young, age matched to ASD-hightPT and ASD-normPT respectively.

Results

25/89 patients were classified as ASD-highPT having a radiographic PT of 31° (vs 12° in other groups, p ​< ​0.001). On static radiograph, ASD-highPT showed more severe postural malalignment than the other groups: ODHA ​= ​5°, L1L5 ​= ​17°, SVA ​= ​57.4 ​mm (vs 2°, 48° and 5 ​mm resp. in other groups,all p ​< ​0.001). During gait, ASD-highPT presented a higher dynamic pelvic retroversion of 30° (vs 15° in C-aged), along with a higher acetabular anteversion of 24° (vs 20°), external coverage of 38° (vs 29°) and a lower anterior coverage of 52° (vs 58°,all p ​< ​0.05).

Conclusion

ASD patients with severe pelvic retroversion showed an increased acetabular anteversion, external coverage and lower anterior coverage during gait. These changes in acetabular orientation, computed during walking, were shown to be related to hip osteoarthritis.

Functional assessment using 3D movement analysis can better predict health-related quality of life outcomes in patients with adult spinal deformity: a machine learning approach

Introduction

Adult spinal deformity (ASD) is classically evaluated by health-related quality of life (HRQoL) questionnaires and static radiographic spino-pelvic and global alignment parameters. Recently, 3D movement analysis (3DMA) was used for functional assessment of ASD to objectively quantify patient's independence during daily life activities. The aim of this study was to determine the role of both static and functional assessments in the prediction of HRQoL outcomes using machine learning methods.

Methods

ASD patients and controls underwent full-body biplanar low-dose x-rays with 3D reconstruction of skeletal segment as well as 3DMA of gait and filled HRQoL questionnaires: SF-36 physical and mental components (PCS&MCS), Oswestry Disability Index (ODI), Beck's Depression Inventory (BDI), and visual analog scale (VAS) for pain. A random forest machine learning (ML) model was used to predict HRQoL outcomes based on three simulations: (1) radiographic, (2) kinematic, (3) both radiographic and kinematic parameters. Accuracy of prediction and RMSE of the model were evaluated using 10-fold cross validation in each simulation and compared between simulations. The model was also used to investigate the possibility of predicting HRQoL outcomes in ASD after treatment.

Results

In total, 173 primary ASD and 57 controls were enrolled; 30 ASD were followed-up after surgical or medical treatment. The first ML simulation had a median accuracy of 83.4%. The second simulation had a median accuracy of 84.7%. The third simulation had a median accuracy of 87%. Simulations 2 and 3 had comparable accuracies of prediction for all HRQoL outcomes and higher predictions compared to Simulation 1 (i.e., accuracy for PCS = 85 ± 5 vs. 88.4 ± 4 and 89.7% ± 4%, for MCS = 83.7 ± 8.3 vs. 86.3 ± 5.6 and 87.7% ± 6.8% for simulations 1, 2 and 3 resp., p < 0.05). Similar results were reported when the 3 simulations were tested on ASD after treatment.

Discussion

This study showed that kinematic parameters can better predict HRQoL outcomes than stand-alone classical radiographic parameters, not only for physical but also for mental scores. Moreover, 3DMA was shown to be a good predictive of HRQoL outcomes for ASD follow-up after medical or surgical treatment. Thus, the assessment of ASD patients should no longer rely on radiographs alone but on movement analysis as well.