Purpose. Patients with acetabular dysplasia demonstrate altered biomechanics during gate and other activities. We hypothesized that these patients exhibit a compensatory increase in the anterior pelvic tilt during gait. Materials & Methods. Twelve patients were included in this prospective radiographic and gait analysis study prior to the PAO. All were women. The mean age was 27 years (+/− 8 yrs). Tonnis grade was zero in nine, and one in three hips. All patients performed multiple one-minute walking trials on the level, the incline, and the decline treadmill surfaces in an optical motion capture lab. Anterior pelvic tilt is reported in (+), while the posterior pelvic tilt is reported in (–) values. Results. Radiographic Data. : The mean alpha angle measured from the Dunn and the frog lateral images was 63.0º±17.4, and 54.7º±16.4, respectively. The mean LCEA was 14.9°±6.1, and the mean anterior center edge angle was 18.3°±8.9. the mean acetabular version at 1, 2, and 3 o'clock were 12.1°±11.6, 29.2°±9.9, and 23.3°±7.4, respectively. Intra-class correlation coefficient (ICC) for these measurements were 0.934, 0.895, and 0.971, respectively. The mean femoral anteversion, as measured on the 3D CT scan was 21.3°±16.1. The mean hip flexion range was 107.1°± 7.2. The mean pelvic tilt was 88.7 mm ± 14.4 using the PS-SI distance with an ICC of 0.998. Gait Data. : Baseline measurements were done in the standing position. On the leveled surface, 5 patients had anterior (+) while 7 had posterior (−) pelvic tilt. The mean posterior pelvic tilt was 1.0° with the range of −2.8° to +0.67°. On the inclined surface, all patients had posterior (−) pelvic tilt. The mean pelvic tilt was −4.9° with the range of −6.4° to −3.1°. On the declined surface, 8 patients had anterior (+) while 4 patients had posterior (−) pelvic tilt. The mean pelvic tilt was −0.39° with the range of −1.9° to +1.0°. The pelvic tilt was negatively correlated with the PS-SI distance on all three surfaces with the Spearman coefficients of −0.27, −0.04, and −0.18 on the 3 different surfaces, respectively. Conclusion. Our results demonstrated that the patients with hip dysplasia exhibit variable degrees of the pelvic tilt while walking on different surface inclinations. Weak negative correlation with the standing pelvic tilt measurements from the radiographs suggests that those patients with more anterior standing pelvic tilt tend to have greater compensatory posterior tilt during gait

Variation in pelvic tilt during postural changes may affect functional alignment. The primary objective of this study was to quantify the changes in lumbo-pelvic-femoral alignment from sitting to standing in patients undergoing THA. 144 patients were enrolled. Standing and sitting radiographs using the EOS imaging system were analyzed preoperatively and 1-year postoperatively. Pelvic incidence (PI), lumbar lordosis (LL), sacral slope (SS), proximal femoral angle (PFA) and spine/femoroacetabular flexion were determined. 38 patients had multilevel DDD (26%). Following THA, patients sat with increased anterior pelvic tilt demonstrated by a significant increase in sitting lumbar lordosis (28° preop vs 35° postop; p<0.01) and sacral slope (18° vs 23°; p<0.01). Following THA, patients flexed less through their spines (preop 26° vs postop 19°; p<0.01) and more through their hips (femoroacetabular flexion) (preop 60° vs postop 67°; p<0.01) to achieve sitting position. Patients with multilevel DDD sat with less spine flexion (normal 22° vs spine 13°; p<0.01), less change in sacral slope (more relative anterior tilt) (17° vs 9°; p<0.01), and more femoroacetabular flexion (64° vs 71°; p<0.01). For the majority of patients after THA, a larger proportion of lumbo-pelvic-femoral flexion necessary to achieve a sitting position is derived from femoroacetabular flexion with an associated increase in anterior pelvic tilt and a decrease in lumbar spine flexion. These changes are more pronounced among patients with multilevel DDD. Surgeons may consider orienting the acetabular component with greater anteversion and inclination in patients identified preoperatively to have anterior pelvic tilt or significant DDD

Osteochondroplasty procedure for cam deformity provides excellent outcomes on alleviating pain, improving quality of life and clinical function in femoroacetabular impingement syndrome (FAIS) patients. Although medium-term outcomes on gait biomechanics have been reported, it is unclear how it would translate to better hip muscle forces and joint loading in high range of motion tasks. The purpose of this study was to compare the muscle forces and hip joint contact forces (HCF) during a squat task in individuals before and after cam-FAIS surgical correction. Ten cam-FAIS patients prior and 2-years after osteochondroplasty, and 10 BMI- age- and sex-matched healthy control participants (CTRL) underwent 3D motion and ground reaction forces capture while performing a deep squatting task. Muscle and HCF were estimated using musculoskeletal modeling and comparisons were done using statistical parametric mapping (SPM). Postoperatives squatted down with a higher anterior pelvic tilt and higher hip flexion compared with the preoperatives. Preoperative semimembranosus generated lower forces than the two other groups on the squat ascending, with no differences detected between post-ops and CTRLs. Preoperatives also showed reduced forces for the distal, ischial and medial portions of the adductor magnus relative to the CTRLs, which although reduced, still presented differences postoperatively. Preoperative anterior and medial contact forces were significantly lower than the CTRL group during both phases of the squat. Postoperative vertical and medial forces were also lower compared to the CTRLs. However, with higher vertical forces during the ascent phase of the squat compared to the preoperative, the postoperative group, significantly increased its HCF magnitude. A higher anterior pelvic tilt was associated with an innate restoration of the pelvis position, once the cam deformity no longer existed. The increased force of the semimembranosus muscle while ascending the squat generated higher vertical HCF, which also influenced the increased HCF total magnitude. For any tables or figures, please contact the authors directly

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

We studied the results of multi-level surgical intervention for children with cerebral palsy. Thirty patients, aged 7–16 years, with spastic diplegia (n=20), or spastic hemiplegia (n=10) were studied prospectively by gait analysis. Multilevel surgery included a combination of psoas lengthening, medial hamstring lengthening, rectus femoris transfer and gastrocnemius lengthening +/− foot surgery or femoral derotation osteotomies. Gait analyses were carried out pre-op and at 6 and 24 months post-op. Children with spastic diplegia increased their walking velocity by an average of 20% at two years (p< 0.05). Mean stride length increased from 89cm pre-op to 102cm at two years (p< 0.05) with similar improvements in both groups of children. Maximum knee extension in stance improved from an average 17.5 degrees flexion pre-operatively to an average 5 degrees flexion postoperatively (p< 0.05). Peak knee flexion in swing was maintained and the timing improved. Peak ankle dorsiflexion in stance was unchanged following surgery but the timing of peak ankle dorsiflexion was normalised to late stance (from 24% of cycle pre-operatively to 48% of cycle post-operatively (norm = 48%). Average maximum hip extension in stance did not change. The mean anterior pelvic tilt did not change post-operatively. However, a number of children with spastic diplegia had increased anterior pelvic tilt post-operatively. These results are similar to those reported internationally, with most improvement seen distally at the knee and ankle and less improvement at the hip. Increased anterior pelvic tilt was seen as a consequence of hamstring lengthening in some more involved patients

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

Objectives. The spinopelvic relationship (including pelvic incidence) has been shown to influence pelvic orientation, but its potential association with femoroacetabular impingement has not been thoroughly explored. The purpose of this study was to prove the hypothesis that decreasing pelvic incidence is associated with increased risk of cam morphology. Methods. Two matching cohorts were created from a collection of cadaveric specimens with known pelvic incidences: 50 subjects with the highest pelvic incidence (all subjects > 60°) and 50 subjects with the lowest pelvic incidence (all subjects < 35°). Femoral version, acetabular version, and alpha angles were directly measured from each specimen bilaterally. Cam morphology was defined as alpha angle > 55°. Differences between the two cohorts were analysed with a Student’s t-test and the difference in incidence of cam morphology was assessed using a chi-squared test. The significance level for all tests was set at p < 0.05. Results. Cam morphology was identified in 47/100 (47%) femurs in the cohort with pelvic incidence < 35° and in only 25/100 (25%) femurs in the cohort with pelvic incidence > 60° (p = 0.002). The mean alpha angle was also greater in the cohort with pelvic incidence < 35° (mean 53.7°, . sd. 10.7° versus mean 49.7°, . sd. 10.6°; p = 0.008). Conclusions. Decreased pelvic incidence is associated with development of cam morphology. We propose a novel theory wherein subjects with decreased pelvic incidence compensate during gait (to maintain optimal sagittal balance) through anterior pelvic tilt, creating artificial anterior acetabular overcoverage and recurrent impingement that increases risk for cam morphology. Cite this article: W. Z. Morris, C. A. Fowers, R. T. Yuh, J. J. Gebhart, M. J. Salata, R. W. Liu. Decreasing pelvic incidence is associated with greater risk of cam morphology. Bone Joint Res 2016;5:387–392. DOI: 10.1302/2046-3758.59.BJR-2016-0028.R1

Aims. The aims of the study were to determine the differences in spinopelvic mobility between a cohort of hip OA patients and a control group for the 1) standing to relaxed-seated and 2) standing to deep-seated task. Methods. A cohort of 40 patients with end-stage hip OA and a control group of 40 subjects, matched for age, gender and BMI were prospectively studied. Clinical data and lateral view radiographs in different positions were assessed. Sagittal spinopelvic mobility was calculated as the change when moving from the standing to relaxed-seated and standing to deep-seated positions for the lumbar lordosis angle, pelvic tilt and pelvic-femoral angle. Results. When moving from the standing to sitting position, hip OA patients demonstrated less hip flexion (52±18 vs. 69±11, p<0.001), an increased posterior pelvic tilt (23±13 vs. 12±9, p<0.001) and more flexion of the lumbar spine (22±15 vs. 14±11, p=0.01). Similarly, when moving from the standing to deep-seated position, hip OA patients demonstrated also less hip flexion (64±21 vs. 84±18, p<0.001), accompanied by a posterior and not an anterior pelvic tilt as in the control group (10±16 vs. −3±17, p<0.001). No difference could be found for lumbar spine flexion (40±15 vs. 43±13, p=0.28). The percentage of subjects with stiff spinopelvic mobility was significantly lower in the patient group (15% vs 48%; p=0.002) and there was a trend towards a higher percentage in spinopelvic hypermobility in patients (20% vs 2%; p=0.08). Conclusions. Decreased hip flexion due to OA leads to an increased posterior pelvic tilt when taking a relaxed-seated position. Less than 10° of posterior pelvic tilt from the standing to relaxed seated position (spinopelvic ‘stiffness’) is more frequent in controls without hip OA and results from hip mobility and not from stiffness of the lumbar spine

Aim. The aim of the study was to characterise gait in patients with achondroplasia post lengthening. Patients/Materials and Methods. Full kinematic and kinetic lower limb gait analysis was performed at the Sheffield Children's Hospital gait laboratory, Sheffield, using a Vicon system (6 cameras working at 50Hz) and processed using Plug In Gait modelling software. The lengthened Achondroplasia group (n=11, mean age = 24.5 ± 6.1) had previously undergone surgical lengthening of the legs. The lengthened Achondroplasia group was compared to a control group of 11 adult normal subjects. Results. Averaged sagittal plane kinematics are shown in Figure 1. The key sagittal plane characteristics we found were increased anterior pelvic tilt (Achondroplasia mean = 22.2 ± 7.1°, normal mean = 14.2 ± 5.3°), decreased peak hip extension (Achondroplasia = 10.5 ± 11.2°, normal = −5.8 ± 5.3°), increased peak hip flexion (Achondroplasia = 49.3 ± 9.8°, normal = 40.0 ± 5.2°), and reduced knee extension in midstance (Achondroplasia = 14.0 ± 8.5°, normal = 4.4 ± 8.5°) At the ankle the mean of the lengthened Achondroplasia group lies within one standard deviation of the normal dataset throughout the gait cycle. Summary and Conclusions. Three dimensional gait analysis of people with Achondroplasia following lower limb-lengthening surgery showed characteristic Achondroplasic gait, that is: increased anterior pelvic tilt, reduced hip extension and increased hip flexion. The group of lengthened Achondroplasia participants also failed to extend the knees fully in midstance. At the ankle the sagittal plane kinematics were within one standard deviation of the normal dataset

Purpose: The aim of this study was to see if there is any relationship between a positive hamstring shift test, which is a measure of knee flexion deformity after eliminating pelvic tilt with anterior pelvic tilt during the gait cycle. Methods: We included all patients with cerebral palsy who had a gait analysis and a full physical assessment including measurement of the popliteal angle and hamstring shift test between August and December 05. The difference in measurement of knee flexion between the popliteal angle at 90 degrees and the hamstring shift test was termed hamstring length (HL). There were 33 patients of which 9 [18 limbs] were selected who fulfilled the criteria of a significant positive hamstring shift [> 10 degrees difference]. Maximum dynamic hip extension and average pelvic tilt were estimated from the gait analysis graph. SPSS13.0 was used to analyse the data. Results: Mean HL was found to be 15.28 degrees. 6 (33.3%) patients had average pelvic tilt < 5 degrees, 8 (44.4%) was between 5–10 degrees and 4 (22.2%) patients had pelvic tilt of more than 10 degrees. The data had a normal distribution. There was no co relation between HL and pelvis tilt [p value:0.363 and r= −0.228.] or between average anterior pelvic tilt and the hip fixed flexion deformity. (p=0.361). However, it was found that maximum dynamic hip extension had strong negative association with average pelvic tilt (p=0.05, r = −0.455). Conclusion: This study suggests that hamstring shift test does not have any correlation with pelvic tilt. In patients with a positive hamstring shift test, correcting the pelvic tilt will not correct the flexion deformities of the knee

Introduction. The direct anterior approach (DAA) for total hip arthroplasty continues to gain popularity. Consequently, more procedures are being performed with the patient supine. The approach often utilizes a special leg positioner to assist with femoral exposure. Although the supine position may seem to allow for a more reproducible pelvic position at the time of cup implantation, there is limited evidence as to the effects on pelvic tilt with such leg positioners. Furthermore, the DAA has led to increased popularity of specific softwares, ie. Radlink or JointPoint, that facilitate the intra-op analysis of component position from fluoroscopy images. The aim of this study was to assess the difference in cup orientation measurements between intra-op fluoroscopy and post-op CT. Methods. A consecutive series of 48 DAA THAs were performed by a single surgeon in June/July 2018. All patients received OPS. TM. pre-operative planning (Corin, UK), and the cases were performed with the patient supine on the operating table with the PURIST leg positioning system (IOT, Texas, USA). To account for variation in pelvic tilt on the table, a fluoroscopy image of the hemi-pelvis was taken prior to cup impaction, and the c-arm rotated to match the shape of the obturator foramen on the supine AP Xray. The final cup was then imaged using fluoroscopy, and the radiographic cup orientation measured manually using Radlink GPS software (Radlink, California, USA). Post-operatively, each patient received a low dose CT scan to measure the radiographic cup orientation in reference to the supine coronal plane. Results. Mean cup orientation from intra-op fluoro was 38° inclination (32° to 43°) and 24° anteversion (20° to 28°). Mean cup orientation from post-op CT was 40° inclination (29° to 47°) and 30° anteversion (22° to 38°). Cups were, on average, 6° more anteverted and 2° more inclined on post-op CT than intra-op. These differences were statistically significant, p<0.001. All 48 cups were more anteverted on CT than intra-op. There was no statistical difference between pre- and post-op supine pelvic tilt (4.1° and 5.1° respectively, p = 0.41). Discussion. We found significant differences in cup orientation measurements performed from intra-op fluoro to those from post-op CT. This is an important finding given the attempts to adjust for pelvic tilt during the procedure. We theorise two sources of error contributing to the measurement differences. Firstly, the under-compensation for the anterior pelvic tilt on the table. Although the c-arm was rotated to match the obturator foramen from the pre-op imaging, we believe the manual matching technique utilised in the Radlink software carries large potential errors. This would have consistently led to an under-appreciation of the adjustment angle required. Secondly, the manual nature of defining the cup ellipse on the fluoro image has previously been shown to underestimate the degree of cup anteversion. These combined errors would have consistently led to the under-measurement of cup anteversion seen intra-operatively. In conclusion, we highlight the risk of over-anteversion of the acetabular cup when using 2D measurements, given the manual inputs required to determine a result

Introduction. Early hip OA may be attributed to smaller coverage of the femoral head leading to higher loads per unit area. We hypothesize that tight hamstrings may contribute to increased loads per unit area on the femoral head during gait. When a patient has tight hamstrings they cannot flex their pelvis in a normal fashion which may result in smaller coverage of the femoral head (Figure 1). This study aimed to determine if subjects with tight hamstrings can improve femoral head coverage during gait after a stretching intervention. Methods. Nine healthy subjects with tight hamstrings (popliteal angle>25°) were recruited and consented for this IRB approved study. Gait analysis with 58 reflective markers were placed by palpation on anatomical landmarks of the torso and lower extremities. Ten optoelectronic cameras (Qualisys, Gothenburg, Sweden) and three force plates (AMTI, Watertown, MA) were used to track marker position and measure foot strike forces. Subjects walked at a self-selected speed across the force plates until ten clean trials were performed and then were scanned with the reflective markers on the spine using an EOS (EOS Imaging, France) bi-planar x-ray system. Following testing participants completed a six week stretching program to increase hamstring length. Pelvic tilt (PT) was measured at heel strike for each trial and averaged. Using EOS scans the femoral head radius was measured using three points that best fit the load bearing surface on the sagittal view from the anterior acetabular rim to a point on the posterior acetabulum 45 degrees from vertical. The radius of femoral head and angle of acetabular coverage were used to calculate the load bearing surface area of femoral head. Load on the femur was calculated using an Anybody lower body model (Anybody Technology, Aalborg, Denmark) and load per unit area change was compared. Results. Nine participants completed the stretching program and post intervention testing. PA increased in all subjects (mean ± SD) 18.8° ± 11° (p<.01). Eight of nine subjects had an increase in anterior PT at heel strike resulting in a mean change of 2.1° ± 2.9° (p<.05). The change in PT resulted in a mean surface area change of 0.63cm. 2. ± 0.77 cm. 2. (p<.05), which resulted in a mean pressure change of −57.9MPa ± 55.7MPa. Removing the one subject who decreased in anterior pelvic tilt resulted in a mean change in PT of 2.9° ± 1.2°, a mean change in surface area of 0.85cm. 2. ± 0.46 cm. 2. , and a mean pressure change of −74.4 MPa ± 27.2 MPa. (Table 1). Discussion/Conclusion. This study verified the hypothesis that functional PT is influenced significantly by tight hamstrings. Using a stretching intervention program small changes in functional PT can be elicited that may significantly decrease the force per unit area on the femoral head and possibly the risk for developing degeneration joint disease. Although our study is limited by the small number of participants it does lend one significant benefit to intervene in patients who have chronically tight hamstrings. For figures/tables, please contact authors directly.

Introduction. Pelvic and acetabular injuries are relatively rare and surgical reconstruction usually occurs only in specialist centres. As part of their work up there is a local protocol for radiological investigations including Judet oblique views for acetabular fractures, pelvic inlet and outlet for pelvic ring fractures and urethrograms for sustaining anterior pelvic injury. The aim of this service evaluation was to assess whether patients had these radiological investigations prior to transfer. Methods. The last 50 patients transferred for surgery were evaluated (41 male, 9 female), average age 48 (range 17–86). Four were excluded as original radiology not available and one due to non-acute presentation. Regional PACS systems were accessed and radiological investigations recorded. Results. Transfers were from 17 different hospitals including 27 acetabular fractures, 17 pelvic ring fractures and one patient with both. 22 patients sustained isolated injuries. 16 patients were investigated radiologically asstipulated in the protocol. No inlet/outlet views were performed for 10 of the ring fractures, and no Judet views for eight of the acetabular fractures. An antero-posterior pelvic radiograph was not performed on one patient. No urethro/cystogram was performed for 10 pelvic ring fractures. Average time to transfer 5.4 days (range 0–22). Discussion. A significant proportion of patients are not assessed as per protocol prior to transfer. This can lead to undetected injuries, delays to diagnosis or definitive management and increased morbidity/mortality. The reasons for not being able to perform these investigations need to be understood

Introduction. Acetabular cup orientation has been shown to be a factor in edge-loading of a ceramic-on-ceramic THR bearing. Currently all recommended guidelines for cup orientation are defined from static measurements with the patient positioned supine. The objectives of this study are to investigate functional cup orientation and the incidence of edge-loading in ceramic hips using commercially available, dynamic musculoskeletal modelling software that simulates each patient performing activities associated with edge-loading. Methodology. Eighteen patients with reproducible squeaking in their ceramic-on-ceramic total hip arthroplasties were recruited from a previous study investigating the incidence of noise in large-diameter ceramic bearings. All 18 patients had a Delta Motion acetabular component, with head sizes ranging from 40 – 48mm. All had a reproducible squeak during a deep flexion activity. A control group of thirty-six patients with Delta Motion bearings who had never experienced a squeak were recruited from the silent cohort of the same original study. They were matched to the squeaking group for implant type, acetabular cup orientation, ligament laxity, maximum hip flexion and BMI. All 54 patients were modelled performing two functional activities using the Optimized Ortho Postoperative Kinematics Simulation software. The software uses standard medical imaging to produce a patient-specific rigid body dynamics analysis of the subject performing a sit-to-stand task and a step-up with the contralateral leg, Fig 1. The software calculates the dynamic force at the replaced hip throughout the two activities and plots the bearing contact patch, using a Hertzian contact algorithm, as it traces across the articulating surface, Fig 2. As all the squeaking hips did so during deep flexion, the minimum posterior Contact Patch to Rim Distance (CPRD) can then be determined by calculating the smallest distance between the edge of the contact patch and the true rim of the ceramic liner, Fig 2. A negative posterior CPRD indicates posterior edge-loading. Results. The mean CPRD was significantly less in the squeaking group than the control group, −2.5mm and 2.9mm respectively, (p < 0.001), Fig 3. The mean pelvic tilt in the flexed seated position was 12.6° (range −13.5° to 30.3°) for the squeaking group and 5.1° (−9.8° to 26.4°) for the control group. Consequently, the mean functional cup anteversion at seat-off was significantly less in the squeaking group than the control group, 8.1° (−10.5° to 36.0°) and 21.1° (−1.9° to 38.4°) respectively (p < 0.001), Fig 3. There were 67% (12) of patients in the squeaking group that showed posterior edge-loading in the simulation compared to only 28% (10) in the control group that exhibited posterior edge-loading in the simulation. Conclusions. Acetabular cup orientation during activities associated with edge-loading are likely very different from those measured when supine. Patients with large anterior pelvic tilts during deep flexion activities might be more susceptible to posterior edge-loading and squeaking in ceramic-on-ceramic bearings, as a consequence of a significant decrease in cup anteversion. If these patients can be identified preoperatively, cup orientation and bearing choice could be customised accordingly to accommodate these individual motion patterns

Aims

The aim of this study was to investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies. We asked: is there a difference in APP-PT between young symptomatic patients being evaluated for joint preservation surgery and an asymptomatic control group? Does APP-PT vary among distinct acetabular and femoral pathomorphologies? And does APP-PT differ in symptomatic hips based on demographic factors?

A 10° deviation from the ideal cup orientation in Metal on Metal (MoM) bearing couples leads to increased wear and the subsequent risk of early revision surgery. We assessed the accuracy of orthopaedic trainees and consultants in achieving optimal acetabular cup orientation. 49 trainees and 18 consultants were asked to orientate an acetabular component to 40° inclination and 20° anteversion in 3 consecutive pelvic models:. osteoarthritic (OA),. OA with anterior pelvic tilt,. OA with soft tissue cladding, the task most realistic of a surgical scenario. The trainee group experience in performing hip arthroplasty procedures ranged from novice to expert (> 100 procedures performed). Performance was measured using an image based navigation system. Average angular error in all tasks was less than 10°, but the range in anteversion or inclination was up to 65°. Eighteen percent of trainees were +/− 10° of the target orientation in Station A, 29% in B and 2% in C. Forty four percent of consultants achieved the safe zone in A, 16% in B and 0% in C. There was no significant difference in accuracy between the two groups in any of the tasks (p> 0.01). There was no correlation between experience and angular accuracy. We have been unable to demonstrate trainees have the ability to achieve the optimal cup orientation in a clinically relevant safe zone. A similar range of error is found in experienced surgeons. Focused training or intra-operative computer assistance may provide the solution to improving accuracy in this core orthopaedic skill

Introduction: Fibular hemimelia (FH) is a congenital limb reduction deficiency characterised by partial or complete absence of the fibula and a spectrum of associated anomalies. For children with a major anticipated limb length discrepancy and severe foot deformity, management (amputation or limb reconstruction) is controversial. Materials and Methods: 8 children who are now adults (average age 28 years) underwent limb reconstruction as children in one of two UK centres for severe fibular hemimelia. All 8 participants were recalled to our institution for instrumented gait analysis. The SF-36 and lower limb domains of the Toronto Extremity Salvage Score (TESS) questionnaires were also administered. Results: Partcipants scored well for general health but had functional limitations reflected in lower TESS scores. Kinematic analysis revealed decreased sagittal knee motion and valgus knee alignment. Also ubiquitous were anterior pelvic tilt and obliquity with incomplete hip extension and reduced range of hip abduction. Kinetic analysis showed reduced peak plantar flexion moment with reduced push-off power and an internal hip adduction moment in late stance. These parameters are compared to control data for below knee amputees. Discussion and conclusions: Although the number of participants is small, this is the first study to use instrumented gait analysis for severe fibular hemimelia managed with limb reconstruction. The results add objective data to the debate over limb reconstruction or amputation in this group of children

Aims

Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients.

Introduction: During the last decade the Ilizarov method of limb lengthening has provided a solution for many patients with short stature, suffering not just from cosmetic problems, but having functional disability as well. The aim of this presentation is to discuss our experience of physiotherapy at all stages of treatment, from pre-operative evaluation to the final adaptation of the patient to his new limb condition and the problems that evolved and our solution to them. Patients and Methods: Over the past six years, five patients underwent limb lengthening. Two had achrondoplasia, one had proximal focal femoral dysplasia and two had metaphysical dysplasia. Physiotherapy was given to prevent pulmonary complications, maintain joint mobility and muscle strength, stretch the soft tissue, encourage weight bearing and improve gait. The main complications that occurred were short quadriceps tendon, short Achilles tendon causing equines, excessive anterior pelvic tilt, restriction of the knee joint due to tightness of the iliotibial band and non-compliance of the patient. Results: After the completion of treatment all patients walked independently and returned at least to their pre-operative functional level. Their posture and self-confidence were improved. Average lengthening of the lower limb was 28 cm. Discussion: Careful selection of patients, maintenance of maximal range of motion of all joints involved at every stage of the treatment and long term physiotherapy after the removal of the external fixators are essential for success. It may be important to halt the lengthening process if adequate joint motion is not achieved. It can be concluded that despite the fact that this is a lengthy and painful procedure, the end results make it worthwhile