A reference method for the evaluation of femoral head joint center location technique based on external markers

Accurate localization of joint centers is essential in movement analysis. However, joint centers cannot be directly palpated and alternative methods must be used. To assess the relative merits of these methods, a medical image based reference should be used. The EOS1 system, a new low dose bi-planar X-rays imaging technique may be considered. The aim of this study was to evaluate the accuracy of hip joint center (HJC) localization using the EOS1 system. Seventeen healthy young adults participated in the study. Femoral heads and pelvic external markers were localized using the EOS1 system and the HJCs were expressed in the movement analysis coordinate system. Results showed that external marker localization was reliable within 0.15 mm for trained assessors. Mean accuracy for HJC localization was 2.9 mm (SD: 1.3, max: 6.2). The EOS based method therefore appeared reliable and may be used for femoral head localization or as a reference to assess the accuracy of other methods for HJC localization.The authors are grateful to VICON (OMG-UK) for the loan of a motion capture system necessary for the overall study

Vertebral Augmentation: State of the Art

Osteoporotic vertebral compression fractures (OVF) are an increasing public health problem. Cement augmentation (vertebroplasty of kyphoplasty) helps stabilize painful OVF refractory to medical treatment. This stabilization is thought to improve pain and functional outcome. Vertebroplasty consists of injecting cement into a fractured vertebra using a percutaneous transpedicular approach. Balloon kyphoplasty uses an inflatable balloon prior to injecting the cement. Although kyphoplasty is associated with significant improvement of local kyphosis and less cement leakage, this does not result in long-term clinical and functional improvement. Moreover, vertebroplasty is favored by some due to the high cost of kyphoplasty. The injection of cement increases the stiffness of the fracture vertebrae. This can lead, in theory, to adjacent OVF. However, many studies found no increase of subsequent fracture when comparing medical treatment to cement augmentation. Kyphoplasty can have a protective effect due to restoration of sagittal balance

Spinopelvic Adaptations in Standing and Sitting Positions in Patients With Adult Spinal Deformity

Purpose To describe spinopelvic adaptations in the standing and sitting positions in patients with adult spinal deformity (ASD). Methods Ninety-five patients with ASD and 32 controls completed health-related quality of life (HRQOL) questionnaires: short form 36 (SF36), Oswestry Disability Index (ODI), and visual analog scale (VAS) for pain. They underwent biplanar radiography in both standing and sitting positions. Patients with ASD were divided into ASD-front (frontal deformity Cobb > 20°, n = 24), ASD-sag (sagittal vertical axis (SVA) > 50 mm, pelvic tilt (PT) > 25°, or pelvic incidence (PI)-lumbar lordosis (LL) > 10°, n = 40), and ASD-hyper thoracic kyphosis (TK >60°, n = 31) groups. Flexibility was defined as the difference (Δ) in radiographic parameters between the standing and sitting positions. The radiographic parameters were compared between the groups. Correlations between HRQOL scores were evaluated. Results All participants increased their SVA from standing to sitting (ΔSVA<0), except for patients with ASD-sag, who tended to decrease their SVA (78-62 mm) and maximize their pelvic retroversion (27-40° vs 10-34° in controls, p<0.001). They also showed reduced thoracic and lumbar flexibility (ΔLL = 3.4 vs 37.1°; ΔTK = −1.7 vs 9.4° in controls, p<0.001). ASD-hyperTK showed a decreased PT while sitting (28.9 vs 34.4° in controls, p<0.001); they tended to decrease their LL and TK but could not reach values for controls (ΔLL = 22.8 vs 37.1° and ΔTK = 5.2 vs 9.4°, p<0.001). The ASD-front had normal standing and sitting postures. ΔSVA and ΔLL were negatively correlated with the physical component scale (PCS of SF36) and ODI (r = −0.39 and r = −0.46, respectively). Conclusion Patients with ASD present with different spinopelvic postures and adaptations from standing to sitting positions, with those having sagittal malalignment most affected. In addition, changes in standing and sitting postures were related to HRQOL outcomes. Therefore, surgeons should consider patient sitting adaptations in surgical planning and spinal fusion. Future studies on ASD should evaluate whether physical therapy or spinal surgery can improve sitting posture and QOL, especially for those with high SVA or PT

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

IntroductionAdult 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.MethodsASD 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&amp;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.ResultsIn 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 &lt; 0.05). Similar results were reported when the 3 simulations were tested on ASD after treatment.DiscussionThis 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

Is visual estimation of passive range of motion in the pediatric lower limb valid and reliable

<p>Abstract</p> <p>Background</p> <p>Visual estimation (VE) is an essential tool for evaluation of range of motion. Few papers discussed its validity in children orthopedics' practice. The purpose of our study was to assess validity and reliability of VE for passive range of motions (PROMs) of children's lower limbs.</p> <p>Methods</p> <p>Fifty typically developing children (100 lower limbs) were examined. Visual estimations for PROMs of hip (flexion, adduction, abduction, internal and external rotations), knee (flexion and popliteal angle) and ankle (dorsiflexion and plantarflexion) were made by a pediatric orthopaedic surgeon (POS) and a 5^thyear resident in orthopaedics. A last year medical student did goniometric measurements. Three weeks later, same measurements were performed to assess reliability of visual estimation for each examiner.</p> <p>Results</p> <p>Visual estimations of the POS were highly reliable for hip flexion, hip rotations and popliteal angle (ρ_c≥ 0.8). Reliability was good for hip abduction, knee flexion, ankle dorsiflexion and plantarflexion (ρ_c≥ 0.7) but poor for hip adduction (ρ_c= 0.5). Reproducibility for all PROMs was verified. Resident's VE showed high reliability (ρ_c≥ 0.8) for hip flexion and popliteal angle. Good correlation was found for hip rotations and knee flexion (ρ_c≥ 0.7). Poor results were obtained for ankle PROMs (ρ_c< 0.6) as well as hip adduction and abduction, the results of which not being reproducible. Influence of experience was clearly demonstrated for PROMs of hip rotations, adduction and abduction as well as ankle plantarflexion.</p> <p>Conclusion</p> <p>Accuracy of VE of passive hip flexion and knee PROMs is high regardless of the examiner's experience. Same accuracy can be found for hip rotations and abduction whenever VE is performed by an experienced examiner. Goniometric evaluation is recommended for passive hip adduction and for ankle PROMs.</p

Spinopelvic Adaptations in Standing and Sitting Positions in Patients With Adult Spinal Deformity

International audiencePurposeTo describe spinopelvic adaptations in the standing and sitting positions in patients with adult spinal deformity (ASD).MethodsNinety-five patients with ASD and 32 controls completed health-related quality of life (HRQOL) questionnaires: short form 36 (SF36), Oswestry Disability Index (ODI), and visual analog scale (VAS) for pain. They underwent biplanar radiography in both standing and sitting positions. Patients with ASD were divided into ASD-front (frontal deformity Cobb > 20°, n = 24), ASD-sag (sagittal vertical axis (SVA) > 50 mm, pelvic tilt (PT) > 25°, or pelvic incidence (PI)-lumbar lordosis (LL) > 10°, n = 40), and ASD-hyper thoracic kyphosis (TK >60°, n = 31) groups. Flexibility was defined as the difference (Δ) in radiographic parameters between the standing and sitting positions. The radiographic parameters were compared between the groups. Correlations between HRQOL scores were evaluated.ResultsAll participants increased their SVA from standing to sitting (ΔSVA<0), except for patients with ASD-sag, who tended to decrease their SVA (78-62 mm) and maximize their pelvic retroversion (27-40° vs 10-34° in controls, p<0.001). They also showed reduced thoracic and lumbar flexibility (ΔLL = 3.4 vs 37.1°; ΔTK = −1.7 vs 9.4° in controls, p<0.001). ASD-hyperTK showed a decreased PT while sitting (28.9 vs 34.4° in controls, p<0.001); they tended to decrease their LL and TK but could not reach values for controls (ΔLL = 22.8 vs 37.1° and ΔTK = 5.2 vs 9.4°, p<0.001). The ASD-front had normal standing and sitting postures. ΔSVA and ΔLL were negatively correlated with the physical component scale (PCS of SF36) and ODI (r = −0.39 and r = −0.46, respectively).ConclusionPatients with ASD present with different spinopelvic postures and adaptations from standing to sitting positions, with those having sagittal malalignment most affected. In addition, changes in standing and sitting postures were related to HRQOL outcomes. Therefore, surgeons should consider patient sitting adaptations in surgical planning and spinal fusion. Future studies on ASD should evaluate whether physical therapy or spinal surgery can improve sitting posture and QOL, especially for those with high SVA or PT

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