Background. Surgical treatment of AIS includes several purposes such as arrest deformity progression through a solid fusion, obtain a permanent correction of the deformity and others. Objectives. To evaluate the improvement of sagittal spinopelvic parameters and clinical outcomes in patients with adolescent idiopathic scoliosis 2 years after corrective surgery. Methods. Radiological and clinical data of 134 consecutive scoliosis patients including 11 boys and 124 girls with the average age of 15.37 years, with AIS Lenke 1, 2, 3, 4, 5 or 6 were included in this retrospective study with 2-year follow-up. Whole spine anterior/posterior and lateral Xray, CT scan and MRI were taken preoperatively, immediately after surgery, at 3 months and 2 years after corrective surgery. Radiological parameters were evaluated and compared pre and post operatively. Result. In coronal plan, significant reduction was observed in main curve, proximal curve and distal curve P<0.001, 2 years after corrective surgery. Meanwhile, the translation of apex vertebra decreased p<0.001. But sagittal profile of the patients did not show obvious changes such as LL, TK. The pelvic parameters indicated that PI was 50.6 degrees, PT was 13.8, SS was 37.0 and TPA was 47.5 degrees preoperatively. Vertebral body height increased dramatically just after surgery and showed further in the last follow up. Conclusion. The changes in coronal plan was significant 2 years after correction surgery for AIS patients and were not correlated with restoration of sagittal profile. Conflict of interest. None. Sources of funding. None

Introduction. Spatial orientation of the pelvis in the sagittal plane is a key parameter for hip function. Pelvic extension (or retroversion) and pelvic flexion(or anteversion) are currently assessed using Sacral Slope (SS) evaluation (respectively SS decrease and SS increase). Pelvic retroversion may be a risk situation for THA patients. But the magnitude of SS is dependant on the magnitude of pelvic incidence (PI) and may fail to discriminate pelvic position due to patient's anatomy and the potential adaptation mechanisms: a high PI patient has a higher SS but this situation can hide an associated pelvic extension due to compensatory mechanisms of the pelvic area. A low PI patient has a lower SS with less adaptation possibilities in case of THA especially in aging patients. The individual relative pelvic version (RPV) is defined as the difference between « measured SS » (SSm) minus the « normal SS »(SSn) described for the standard population. The aim of the study was to evaluate RPV in standing and sitting position with a special interest for high and low PI patients. Materials and Methods. 96 patients without THA (reference group) and 96 THA patients were included. Pelvic parameters (SS and PI) were measured on standing and sitting EOS images. RPV standing (SSm-SSn) was calculated using the formula SSm – (9 + 0.59 × PI) according to previous publications. SSn in sitting position was calculated according to PI using linear regression: RPV sitting was calculated using the formula RPV = SS – (3,54+ 0,38 × PI). Three subgroups were defined according to pelvic incidence (PI): low PI <45°, 45°<normal PI<65° or high PI>65°. Results. For THA patients, pelvic parameters were:. SSm standing 41° (SD 11°; 8°.73°). SSm sitting 25° (SD 12°;−3°.54°). SSm variation 16°(SD 11°; 9°.46°). RPV standing −2°(SD 9°; −27°.21°). RPV sitting 7° (SD 10; −15°.29°). For non THA patients, pelvic parameters were:. SSm standing39° (SD 10°; 13°.63°). SSm sitting 17° (SD 11°;−5°.48°). SSm variation 27°(SD 13°; −27°.46°). RPV standing −1°(SD 7°; −29°.12°). RPV sitting 0° (SD 10,5; −29.35). Standing-sitting SS variations and RPV were not correlated with PI. Low PI incidence patients had very low RPV standing and sitting. In non THA patients RPV standing and sitting were very low. In THA patients standing-sitting SS variations and RPV were higher than for non THA patients. Sitting RPV was higher than in standing position. Discussion, Conclusion. The overall analysis of SS has limitations: higher or lower SS may be linked to 2 factors: pelvic morphology (PI) and sagittal orientation of the pelvis. RPV and PI were not correlated: a higher or lower value of RPV directly represents the sagittal orientation of the pelvis. Low PI patients have a specific postural pattern with low pelvic adaptability. THA patients specificity for RPV needs further studies for understanding the impact on postoperative rebalancing and instability problems

Introduction. Understanding hip-spine relationships and accurate evaluation of the pelvis position are key- points for the optimization of total hip arthroplasty (THA). Hip surgeons know the importance of pelvic parameters and the adaptation mechanisms of pelvic and sub-pelvic areas. Literature about posture after THA remains controversial and adaptations are difficult to predict. One explanation can be the segmental analysis focused on pelvic parameters and local planning. In a significant number of patients a global analysis may be important as a cascade of compensatory mechanisms is implemented, the hip being only one of the links of this chain reaction. 3 parameters can be measured on full body images:. SVA (sagittal vertical axis) : horizontal distance between the vertical line through the center of C7 and the postero-superior edge of S1. T1 pelvic angle (TPA) : line from femoral heads to T1center and line from the femoral heads to S1center. TPA combines informations from both the sagittal vertical axis and pelvic tilt. Global Sagittal Angle (GSA) : line from the midpoint of distal femoral condyles to C7 center and line from the midpoint between distal femoral condyles to the postero-superior S1corner. The objective of this preliminary study is to report the post-operative evolution of posture after THA. Material and Method. 49 patients (28 women, 21 men, mean age 61 years) were enrolled for full-body standing EOS images before and after THA. The sterEOS software was used to measure pelvic parameters (sacral slope SS, pelvic incidence PI) and global postural parameters (TPA, GSA, SVA). Sub-analysis was made, grouping the sample by TPA (<14°, 14°–22°, >22°), by PI (<55°, 55°–65°, >65°) and by SS (<35°, 35°–45°, >45°). Paired t-test was used to compare differences between preoperative and postoperative parameters within each subgroup. Statistical significance was set at p < 0.05. Results. TPA, SVA and GSA may change independently following THA surgery. In the 2 groups with TPA< 19° and 14° <TPA< 22°, GSA and SVA decreased significantly after THA (p < 0.05). The difference was not significant in the group with TPA>22°. In the group with SS between 35° and 45°, the GSA and SVA decreased after THA (p < 0.05). In the group with SS > 45° only GSA decreased. In the group with PI < 55°, GSA and SVA decreased after THA. There was no significant change in the remaining subgroups. Discussion. This preliminary study confirms a decrease of GSA and SVA after THA. Some preoperative characteristics are observed in patients with significant global sagittal postural modifications: low to standard TPA, low PI or standard to high SS. Conclusion. Planning and prediction of sagittal postural changes after THA implantation is challenging. It is an important topic in patients with stiff and degenerative spine or in case of spinal fusion. In case of complex hipspine cases, the timing of the procedures can be a real concern. The combined analysis of SVA, TPA and GSA may open new perspectives for a more rationale planning of THA

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. Spinopelvic parameters describe the orientation, shape, and morphology of the spine and pelvis. In children without spinal deformity, these parameters change during the first 10 years of life; however, spinopelvic parameters need to be defined in children with significant early-onset scoliosis (EOS). The purpose of this study is to examine the effects of EOS on sagittal spinopelvic alignment. We hypothesise that sagittal spinopelvic parameters for patients with EOS will differ from age-matched children without spinal deformity. These values will act as a baseline for future studies and may predict postoperative complications such as proximal junctional kyphosis and implant failure in children being treated with growing systems. Methods. Standing, lateral radiographs of 82 untreated patients with EOS with Cobb angle greater than 50° were evaluated. Sagittal spine parameters (sagittal balance, thoracic kyphosis [TK], lumbar lordosis [LL]) and sagittal pelvic parameters (pelvic incidence [PI], pelvic tilt [PT], sacral slope [SS], and modified pelvic radius angle [PR]) were measured. These results were compared with those reported by Mac-Thiong and colleagues (Spine, 2004) for a group of similar aged children without spinal deformity. Results. Patients had a mean age of 5·17 years and mean Cobb angle of 73·3° (□}17·3°). Mean sagittal spine parameters were: sagittal balance (+2·4 cm [□}4·03]), TK (38·2° [□}20·8°]), and LL (47·8° [□}17·7°]). These values were similar to those reported for asymptomatic patients (table). Mean sagittal pelvic parameters were: PI (47·1° [□}15·6°]), PT (10·3° [□}10·7°]), SS (35·5° [□}12·2°]), and PR (57·1° [□}21·2°]). Although PI was similar to age-matched controls, PT was significantly higher and there was a trend for lower SS in the study population. Conclusions. Sagittal plane spine parameters in children with EOS were similar to those in children without spinal deformity. Pelvic parameters (PI, SS, PR) were similar between groups; however, children with EOS had signs of pelvic retroversion (increased pelvic tilt)

Purpose. Spinopelvic parameters describe the orientation, shape, and morphology of the spine and pelvis. In children without spinal deformity, these parameters have been shown to change during the first ten years of life; however, spinopelvic parameters have yet to be defined in children with significant Early Onset Scoliosis (EOS). The purpose of this study is to examine the effects of EOS on sagittal spinopelvic alignment. Method. Standing, lateral radiographs of 82 untreated patients with EOS greater than 50 degrees were evaluated. Sagittal spine parameters (sagittal balance, thoracic kyphosis (TK), lumbar lordosis (LL)) and sagittal pelvic parameters (pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), modified pelvic radius angle (PR)) were measured. These results were compared to those reported by Mac-Thiong et al (Spine, 2004) for a group of asymptomatic (i.e. without spinal deformity) children of similar age. Results. These patients had a mean age of 5.17 years and mean scoliosis of 73.3 17.3. Mean sagittal spine parameters were: sagittal balance (+2.4 4.03 cm), TK (38.2 20.8), and LL (47.8 17.7). These values were similar to those reported for asymptomatic subjects. Mean sagittal pelvic parameters were measured for PI (47.1 15.6), PT (10.3 10.7), SS (35.5 12.2), and PR (57.1 21.2). Although PI was similar to age-matched normals, PT was significantly higher and SS trended lower in the study population. Conclusion. Sagittal plane spine parameters in children with EOS were similar to those found in children without spinal deformity. Likewise, pelvic parameters (PI, SS, PR) were similar; however, those children with EOS signs of pelvic retroversion (increased pelvic tilt). This data may be useful as a baseline in determining prognosis for children with EOS who are treated with growing systems

Introduction. Optimal implant position is critical to hip stability after total hip arthroplasty (THA). Recent literature points out the importance of the evaluation of pelvic position to optimize cup implantation. The concept of Functional Combined Anteversion (FCA), the sum of acetabular/cup anteversion and femoral/stem neck anteversion in the horizontal plane, can be used to plan and control the setting of a THA in standing position. The main purpose of this preliminary study is to evaluate the difference between the combined anteversion before and after THA in weight-bearing standing position using EOS 3D reconstructions. A simultaneous analysis of the preoperative lumbo pelvic parameters has been performed to investigate their potential influence on the post-operative reciprocal femoro-acetabular adaptation. Material and Methods. 66 patients were enrolled (unilateral primary THAs). The same mini-invasive anterolateral approach was performed in a lateral decubitus for all cases. None of the patients had any postoperative complications. For each case, EOS full-body radiographs were performed in a standing position before and after unilateral THA. A software prototype was used to assess pelvic parameters (sacral slope, pelvic version, pelvic incidence), acetabular / cup anteversion, femoral /stem neck anteversion and combined anteversion in the patient horizontal functional plane (the frontal reference was defined as the vertical plane passing through centers of the acetabula or cups). Sub-analysis was made, grouping the sample by pelvic incidence (<55°, 55°–65°, >65°) and by pre-operative sacral slope in standing position (<35°, 35°–45°, >45°). Paired t-test was used to compare differences between preoperative and postoperative parameters within each subgroup. Statistical significance was set at p < 0.05. Results. In the full sample, mean FCA increased postoperatively by 9,3° (39,5° vs 30,2°; p<0.05). In groups with sacral slope < 35° and sacral slope > 45°, postoperative combined anteversion increased significantly by 11,7° and 12,9°, respectively. In the group with pelvic incidence > 65°, postoperative combined anteversion increased significantly by 14,4°. There was no significant change of combined anteversion in the remaining subgroups. Discussion. In this series the FCA increased after THA, particularly in patients with a low or high sacral slope on the pre-operative evaluation in standing position. This may be related to a greater difficulty for the surgeon in anticipating the postoperative standing orientation of the pelvis in these patients, as they were standardly oriented during surgery (lateral decubitus). Interestingly the combined anteversion was also increased in patients with a high pelvic incidence that is commonly associated with a high sacral slope. Conclusion. Post-operative increase of anatomical cumulative anteversion has been previously reported using anterior approach. The FCA concept based on EOS 3D reconstructions brings new informations about the reciprocal femoro-acetabular adaptation in standing position. Differences found in combined anteversion before and after the surgery show that a special interest should be given to patients with high pelvic incidence and low or high sacral slope, to optimize THA orientation in standing position

Précis: Using full length x-rays and force plate technology, the purpose was first to investigate the relationship between the gravity line and spino-pelvic parameters on asymptomatic adult volunteers and then to analyse age related changes. Trunk inclination and pelvic parameters appears as the two key-factors of the GL location; with age the GL location regarding the heels does not change but trunk global inclination shifts forward, pelvic tilt increases, and the pelvis shifts toward the heels. Introduction: Although work by several authors has placed emphasis on global balance in the setting of spinal deformity, the relationship of spino-pelvic parameters related to this concept remains poorly defined. Using the force plate device and radiographic measurement, this study aimed to define the relationship between these parameters and the location of the gravity line (GL) in asymptomatic adult population. Materials and Methods: 75 asymptomatic adult volunteers were recruited and subdivided by age (18–40, 41–60, > 61). Full-length free-standing AP and lateral radiographs were obtained with simultaneous assessment of the force plate gravity line (GL) location. The latter was projected on each x-ray to compute distance between anatomical components and GL and correlate its location with radiological parameters. Age related changes were investigated using ANOVA with Bonfer-roni-Dunn Post-Hoc test. Results: Radiographic measurements revealed strong correlations between trunk global inclination and distance from S1 to the GL (r=0.7), sacral slope and pelvic incidence (r=0.78), distance from the bi-femoral head axis to the GL and S1 to the GL (r=0.73), and sacral slope and lordosis (r=0.89). With advancing age, the GL location with respect to the heels does not change and a global spino-pelvic regulatory mechanism appears to maintain this posture: trunk global inclination shifts forward, pelvic tilt increases, and the pelvis shifts toward the heels, increasing its distance from the GL. Discussion: his study demonstrates the importance of pelvic parameters and trunk inclination in the regulation of the GL location. The relationship between the gravity line, pelvic parameters, and overall spinal alignment may emerge as essential in the evaluation of spinal deformity. Further investigation in this field may lead to a formula of balance that can assist in optimal planning of corrective procedures for spinal deformity

Introduction. A comprehensive understanding of pelvic orientation prior to total hip arthroplasty is necessary to allow proper cup positioning and mitigate the risks of complications associated with component malpositioning. Measurements using anteroposterior (AP) radiographs have been described as effective means of accurately predicting pelvic orientation. The purpose of our study was to describe the inter- and intra-observer reliability and predictive accuracy of predicting pelvic tilt using AP radiographs. Methods. Five fellowship-trained orthopaedic surgeons independently analyzed pelvic tilt, within 10 degrees, for 50 different AP pelvis radiographs. All surgeons were blinded to patient information, diagnosis, and correct measurements prior to analysis. Responses were then compared to correct measurements using sitting-standing AP and lateral stereoradiographs. Results. The average correct predictive value of pelvic tilt between all surgeons was 54%. The intra-observer accuracy of predicting pelvic tilt ranged from 48% to 64%. Discussion. Pelvic tilt cannot be accurately predicted using anteroposterior radiographs. Pre-operative evaluation of pelvic parameters requires multiple views for detailed assessment. Therefore, lateral radiographs are required for accurate prediction of pelvic tilt

Anteroposterior (AP) pelvic radiographs are the standard tool used for pre-operative planning and post-operative evaluation during total hip arthroplasty (THA). The accuracy of this imaging modality is, however, limited by errors in pelvic orientation and image distortion. Pelvic obliquity is corrected for by orienting measurements to a reference line such as the interteardrop line or the interischial line, while several methods for correcting for pelvic tilt have been suggested, with varying levels of success. To date, no reliable method for correcting for pelvic rotation on pelvic imaging is available. The purpose of this study was to evaluate a novel method for correcting pelvic rotation on a standard anteroposterior (AP) radiographs. Computed tomography (CT) scans from 10 male cadavers and 10 female THA patients were segmented using 3D Slicer and used to create 3D renderings for each pelvis. Synthetic AP radiographs were subsequently created from the 3D renderings, using XRaySim. For each pelvis, images representing pelvic rotation of 30° left to 30° right, at 5° increments were created. Four unique parameters based on pelvic landmarks were used to develop the correction method: i) the horizontal distance from the upper edge of the pubic symphysis to the sacroiliac joint midline (PSSI), ii) the ratio of the horizontal distances from the upper edge of the pubic symphysis to the outer lateral border of both obturator foramina (PSOF), iii) the width ratio of the obturator foramina (OFW) and iv) the ratio of the horizontal distance from each anterior superior iliac spine to the sacroiliac joint midline (ASISSI). The relationships between the chosen parameters and pelvic rotation were investigated using a series of 260 (13 per pelvis) synthetic AP radiographs. Male and female correction equations were generated from the observed relationships. Validation of the equations was done using a different set of 50 synthetic radiographs with known degrees of rotation. In males, the PSSI parameter was most reliable in measuring pelvic rotation. In females, PSOF was most reliable. A high correlation was noted between calculated and true rotation in both males and females (r=0.99 male, r=0.98 female). The mean difference from the male calculated rotation and true rotation value was 0.02°±1.8° while the mean difference from the female calculated rotation and true rotation value was −0.01°±1.5°. Our correction method for pelvic rotation using four pelvic parameters provides a reliable method for correcting pelvic rotation on AP radiographs. For any figures or tables, please contact authors directly

Purpose of the study: Data are scarce on the long-term outcome after anterior spinal fusion for idiopathic scoliosis in adolescents. The purpose of this study was to assess the clinical and radiological results obtained in a monocentric series using a single-phase fusion with pre-formed plates for the treatment of lumbar, thoracolum-bar and thoracic idiopathic scoliosis in adolescents. Material and method: This procedure was performed in 111 patients from 1975 to 1993. Complete clinical and radiological evaluations were available for 35 patients, 7 male and 28 female. The SRS-30 questionnaire (translated into French by the authors) and the Oswestry score were used to assess functional outcome. Radiographic data were collected by an independent observer who read the pre-, post- and last follow-up images. Full spine images were available to assess correction of the curvature, frontal and sagittal balance, pelvic parameters, and degenerative changes in the subjacent discs. Functional outcome was assessed in relation to the radiographic findings. Results: Mean follow-up was 22 years (range 16–31). Mean age at surgery was 14.5 years. At last follow-up, none of the patients were unemployed because of a spinal problem and 21 women had had one or more successful pregnancies. The mean SRS-30 score was 3.8/5 and correlated with the Oswestry score (13.8%). One patient underwent revision for disc herniation and one for posterolateral lumbosacral fusion because of persistent frontal imbalance. There as a fracture of the proximal screw in six patients with no sign of nonunion. At last follow-up, the mean Cobb angle was 14 (0–42). Frontal imbalance was noted in 18 patients, mean 12 mm. In the sagittal plane, three patients presented anterior imbalance. The pelvic parameters were within the range of the general population. Signs of L5-S1 disc degeneration were noted in ten patients, with no correlation with functional outcome. Conclusion: Anterior fusion gives good long-term functional results in the treatment of idiopathic scoliosis in adolescents. Patients can pursue a normal occupational and familial life. This technique has provided satisfactory correction in the frontal and sagittal planes

Adverse spinopelvic mobility (SPM) has been shown to increase risk of dislocation of primary total hip arthroplasty (THA). In patients undergoing THA, prevalence of adverse SPM has been shown to be as high as 41%. Stiff lumbar spine, large posterior standing pelvic tilt and severe sagittal spinal deformity have been identified as risk factors for increased hip instability. Dislocation rates for dual mobility articulations have been reported to be 0% to 1.1%. The aim of this study was to determine the early survivorship from the Australian National Joint Replacement Registry (AOANJRR) of patients with adverse SPM who received a dual mobility articulation. A multicentre study was performed using data from 229 patients undergoing primary THA, enrolled consecutively. All the patients who had one or more adverse spine or pelvic mobility parameters had a dual mobility articulation inserted at the time of their surgery. Average age was 76 (22 to 93) years and 63% were female. At a mean of 2.1 (1 – 3.3) years post-op, the AOANJRR was analysed for follow-up. Reasons for revision and types of revision were identified. The AOANJRR reported two revisions. One due to infection and the second due to femoral component loosening. No revisions for dislocation were reported. One patient died with the prosthesis in situ. Kaplan Meier survival was 99.3% (CI 98.3% − 100%) at 2 years. DM bearings reduce the risk of dislocation of primary THA in patients with adverse spine and pelvic mobility

Background. Postural change after total hip arthroplasty (THA) is still a matter of discussion. Previous studies have mainly concentrated on the pelvic motions. We report the postoperative changes of the global sagittal posture using pelvic, spinal and lower extremities parameters. Methods. 139 patients (primary THA, without previous spinal or lower extremity surgery) were included. We measured pelvic parameters [SS: Sacral Slope, PI: Pelvic Incidence, PT: Pelvic Tilt, APP angle: Anterior Pelvic Plane angle] and the global posture parameters (SVA: Sagittal Vertical Angle, GSA: Global Sagittal Angle, TPA: T1 pelvic angle). Patients were categorized into low PI group <45°, 45°< medium PI <65° and high PI >65°. Results. Mean GSA and SVA decreased postoperatively (p=0.005 and p=0.004 respectively). The TPA change was not significant (p=0.078). In low PI group, GSA (5.4 ± 5.0 to 4.3 ± 4.0, p=0.005) and SVA (5.4 ± 4.9 to 4.2 ± 4.1, p=0.038) decreased with more posterior pelvic tilt. Postoperative TPA was significantly higher (8.4 ± 10.6 to 9.8 ± 10.7; p=0.048). In medium PI group, SVA decreased (4.2 ± 4.6 to 3.6 ± 4.5, p=0.020) with more posterior pelvic tilt. In high PI group, pelvic and global posture parameters did not evolve significantly. Conclusion. PI is the key determining factor in pelvic tilt modification after THA. Patients with low PI demonstrate significant modification in spine, pelvic and lower extremities. Pelvic tilt is the main adaptation mechanism for medium incidence patients whereas pelvic tilt does not change in high PI patients after surgery

Purpose: To evaluate the indications, outcome, risk factors and complications of transpedicular osteotomy (TPO) in revision scoliosis surgery. Methods: We evaluated patients undergoing TPO for revision scoliosis surgery at our institution between 1989 and 2004 with a minimum follow up of 18 months. Demographic data, anaesthetic risk factors, peri-operative data and complications were recorded. Radiographs pre-operatively, post-operatively and at last follow up recorded sagittal balance, coronal balance, lumbar lordosis and pelvic parameters. Functional outcome was measured using the Whitecloud score. Results: 21 patients (24 TPO’s) mean age 48.7 years with mean follow up 4.4 years fulfilled criteria for study. All cases had fixed sagittal imbalance pre-operatively. Mean operative time was 4.6 hours and mean transfusion requirement was 2.3. units. A significant improvement (p< 0.03) in sagittal imbalance was gained (although in 3 cases of pseudarthroses this was partially lost) and the post-operative lumbar lordosis correlated closely significantly pelvic incidence (p< 0.03). Functional outcome was good/excellent in 67% cases. We report 28 complications. 22 early included 4 dural tears, cardiac decompensation with reduction, 5 neurological deficits including a parpaplegia secondary to haematoma which was evacuated and the patient made a good recovery at 6 months, 2 UTIs, IVI infection, superficial wound infection and extension of metalwork due to early proximal decompensation. Late complications included infection (8 years), removal of prominent metalwork, radiculopathy due to screw (6 months) and 3 pseudarthroses. There was no statistically significant correlation of complication with weight, ASA grade or smoking. Conclusion: TPO in revision scoliosis is an effective method of correcting both coronal and sagittal imbalance but is not without complication, although good functional outcome is achieved in most patients. It is important to consider pelvic parameters pre-operatively to plan the level and magnitude of TPO required

Introduction. Limb length discrepancy after THA can result in medicolegal litigation. It can create discomfort for the patient and potentially cause back pain or affect the longevity of the implant. Some patients tolerate the length inequality better compared to others despite difference in anatomical femoral length after surgery. Methods and materials. We analyzed the 3D EOS images of 75 consecutive patients who underwent primary unilateral THA (27 men, 48 women). We measured the 3D length of the femur and tibia (anatomical length), the 3D global anatomical length (the sum of femur and tibia anatomical lengths), the 3D functional length (center of the femoral head to center of the ankle), femoral neck-shaft angle, hip-knee-ankle angle, knee flexum/recurvatum angle, sacral slopes and pelvic incidence. We correlated these parameters with the patient perception of the leg length. Results. The values for leg length and pelvic parameters are shown in table 1. 37 patients had a perception of the LLD (49.3%). When the global anatomical length was shorter on the operated side, the perception of the discrepancy was observed in 56% of the cases. In case of anatomical length longer on the operated side, the perception of the discrepancy was described by the patients in 46% of the cases. The LLD perception was correlated with difference in functional length (p=0.0001), pelvic obliquity (p=0.003) and sacral slope (p=0.023). The anatomical femoral length was not correlated with the LLD perception (p=0,008). Discussion. The perception of LLD is a multifactorial complication. We found that the anatomical femoral length (that can be directly affected by the position of the stem) is not the only important factor. The functional length of the lower extremity which can also be affected by the knee deformities is better correlated with the LLD. The pelvic obliquity and version also affect the patient perception of the LLD

Aims

Symptomatic spinal stenosis is a very common problem, and decompression surgery has been shown to be superior to nonoperative treatment in selected patient groups. However, performing an instrumented fusion in addition to decompression may avoid revision and improve outcomes. The aim of the SpInOuT feasibility study was to establish whether a definitive randomized controlled trial (RCT) that accounted for the spectrum of pathology contributing to spinal stenosis, including pelvic incidence-lumbar lordosis (PI-LL) mismatch and mobile spondylolisthesis, could be conducted.

Aims

To determine the major risk factors for unplanned reoperations (UROs) following corrective surgery for adult spinal deformity (ASD) and their interactions, using machine learning-based prediction algorithms and game theory.

Aim:. To establish whether there is a direct relationship between pelvic morphology and lumbar segmental angulation in the sagittal plane. Methods:. 40 lateral whole spine radiographs with normal sagittal profiles were reviewed. Pelvic incidence (PI), Lumbar Lordosis (LL), Thoracic Kyphosis (TK) and segmental angulation at each level from L1 to the sacrum were measured (from endplate to endplate) distinguishing the vertebral body and intervertebral disc contribution. Pearson correlation coefficients were used to analyse any relationship between pelvic parameters and segmental angulation. Results:. A strong correlation was found between pelvic incidence and total lumbar lordosis and angulation at cephalad lumbar segments (L12, L23 and L34) P<0.0001 with the increased lordosis primarily (four fifths on average) found at the intervertebral disc. The proportion of total lumbar lordosis contributed at L45 and L5S1 reduced as pelvic incidence increased (P<0.0001). Discussion:. PI can predict segmental angulation. Although the majority of lumbar lordosis is produced at L45 and L5S1, cephalad-lumbar segments sequentially become increasingly important as PI increases. This describes a continuum that allows segmental abnormalities to be identified when compensation in adjacent segments maintains normal total LL. It also paves the way for anatomical reconstruction in degenerative adult deformity based on pelvic morphology. Conflict Of Interest Statement: No conflict of interest

Aims

Spinopelvic characteristics influence the hip’s biomechanical behaviour. However, to date there is little knowledge defining what ‘normal’ spinopelvic characteristics are. This study aims to determine how static spinopelvic characteristics change with age and ethnicity among asymptomatic, healthy individuals.

Aims

The risk factors for abnormal spinopelvic mobility (SPM), defined as an anterior rotation of the spinopelvic tilt (∆SPT) ≥ 20° in a flexed-seated position, have been described. The implication of pelvic incidence (PI) is unclear, and the concept of lumbar lordosis (LL) based on anatomical limits may be erroneous. The distribution of LL, including a unusual shape in patients with a high lordosis, a low pelvic incidence, and an anteverted pelvis seems more relevant.