Changes In Pelvic Obliquity Research Articles

Distal fusion level, complications, and reoperations in individuals with cerebral palsy undergoing surgery for scoliosis.

To compare radiological outcome, complications and reoperations in individuals with cerebral palsy and scoliosis fused to the fifth lumbar vertebra (L5), the sacrum, or the ilia. 208 individuals were identified in the national quality registry Swespine. Lowest level of fusion was L5 in 58, the sacrum in 92, and the ilia in 58 individuals. A subanalysis on 58 matched pairs operated to L5 or the pelvis (sacrum = 42, ilia = 16) with similar pelvic obliquity (± 5°) was performed. The median (interquartile range) follow-up for the last radiograph was 1.7 (1.7) years and for reoperations 6.0 (5.9) years. Preoperatively, median Cobb angle of the major curve was 65° (23°) in the L5 group, 68° (28°) in the sacrum group, and 78° (25°) in the ilia group (p = 0.006). Preoperative median pelvic obliquity according to Maloney was 16° (19°), 21° (13°), and 27° (28°), respectively (p = 0.004). Immediate postoperative Cobb angles were 28° (18°), 28° (16°), and 32° (25°), respectively (p = 0.11). Immediate postoperative pelvic obliquity was 7° (10°), 7° (8°), and 8° (10°), respectively (p = 0.28). The median change in pelvic obliquity from the first to the last postoperative radiograph was - 5° (7°), - 3° (6°), - 3° (6°), respectively (p = 0.55). 7 (12%), 11 (12%), and 7 (12%) patients required at least one reoperation (p = 1.0), respectively. In the matched analysis, no significant differences in the radiological outcomes were found (all p ≥ 0.38). Maintained curve and pelvic obliquity correction with no significant difference in complication and reoperation rates were found irrespective of distal fusion level.

Manipulating post-stroke gait: Exploiting aberrant kinematics

Post-stroke individuals often exhibit abnormal kinematics, including increased pelvic obliquity and hip abduction coupled with reduced knee flexion. Prior examinations suggest these behaviors are expressions of abnormal cross-planar coupling of muscle activity. However, few studies have detailed the impact of gait-retraining paradigms on three-dimensional joint kinematics. In this study, a cross-tilt walking surface was examined as a novel gait-retraining construct. We hypothesized that relative to baseline walking kinematics, exposure to cross-tilt would generate significant changes in subsequent flat-walking joint kinematics during affected limb swing. Twelve post-stroke participants walked on a motorized treadmill platform during a flat-walking condition and during a 10-degree cross-tilt with affected limb up-slope, increasing toe clearance demand. Individuals completed 15 min of cross-tilt walking with intermittent flat-walking catch trials and a final washout period (5 min). For flat-walking conditions, we examined changes in pelvic obliquity, hip abduction/adduction and knee flexion kinematics at the spatiotemporal events of swing initiation and toe-off, and the kinematic event of maximum angle during swing. Pelvic obliquity significantly reduced at swing initiation and maximum obliquity in the final catch trial and late washout. Knee flexion significantly increased at swing initiation, toe-off, and maximum flexion across catch trials and late washout. Hip abduction/adduction was not significantly influenced following cross-tilt walking. Significant decrease in the rectus femoris and medial hamstrings muscle activity across catch trials and late washout was observed. Exploiting the abnormal features of post-stroke gait during retraining yielded desirable changes in muscular and kinematic patterns post-training.

Undetected Intraoperative Pelvic Movement Can Lead to Inaccurate Acetabular Cup Component Placement during Total Hip Arthroplasty: A Mathematical Simulation Estimating Change in Cup Position

AbstractIntraoperative patient movement is a common but underappreciated phenomenon in total hip arthroplasty (THA). Such movement can significantly affect the accuracy with which the acetabular cup component is implanted. To evaluate the effect of intraoperative movement on cup position, we performed a study using mathematical modeling to simulate intraoperative movement. Mathematical simulations were used to simulate pelvic movements during THA. Pelvic axial rotation, tilt, and obliquity were simulated, and the resulting changes in intended cup position were calculated. The rate of change of inclination and anteversion per degree of pelvic movement was calculated, establishing a ratio relating cup angle sensitivity to pelvic movement. These sensitivities were used to construct nomograms showing the per-degree effect of pelvic movement on cup position. The effect of pelvic movement on cup position was multifactorial and dependent on the intended cup orientation. For a cup intended to be inserted at 15° anteversion and 40° inclination, each degree of pelvic rotation induced changes of 0.64° and –0.20°, respectively. For this same cup orientation, each degree of pelvic tilt induced changes of 0.77° for anteversion and 0.17° for inclination. Pelvic obliquity was associated with a 1:1 ratio with inclination, with each degree of obliquity inducing 1° of change in inclination. Anteversion was unaffected by changes in pelvic obliquity. This study demonstrates the consequences of undetected pelvic movement on cup position, including the increased risk of the acetabular component being placed in an orientation that could increase wear or the likelihood of impingement and dislocation.

The effect of education for daily physical activity level recovery of osteoarthritis patients after total knee arthroplasty. A prospective randomized controlled clinical trial using accelerometry

The effect of education for daily physical activity level recovery of osteoarthritis patients after total knee arthroplasty. A prospective randomized controlled clinical trial using accelerometry

The effect of sacroiliac joint mobilization on pelvic deformation and the static balance ability of female university students with si joint dysfunction.

[Purpose] The present study aimed to determine the effect of an 8-week program of joint mobilization on changes in pelvic obliquity and pain level in seventeen female university students aged in their 20’s with sacroiliac joint dysfunction by dividing them into two groups: a joint mobilization group (MWM) and a control group. [Subjects] Seventeen subjects were selected from female university students aged in their 20’s attending N University in Cheon-An City, Korea, The subjects had sacroiliac joint syndrome, but experienced no problems with daily living and had no previous experience of joint mobilization exercise. The subjects were randomly assigned to a joint mobilization group of eight and a control group of nine who performed joint mobilization exercise. [Methods] Body fat and lean body mass were measured using InBody 7.0 (Biospace, Korea). The Direct Segmental Multi-frequency Bioelectrical Impedance Analysis Method (DSM-BIA) was used for body composition measurement. A pressure footstool (Pedoscan, DIERS, Germany) and a trunk measurement system (Formetric 4D, DIERS, Germany), a 3D image processing apparatus with high resolution for vertebrae, were used to measure 3D trunk images of the vertebrae and pelvis obliquity, as well as static balance ability. [Result] The MWM group showed a significantly better Balance than the control group. In addition, the results of the left/right and the front/rear balance abilities were significantly better than those of the control group. [Conclusion] This study proved that a combination of mobilization with movement and functional training was effective in reducing pelvis malposition and pain, and improving static stability control.

Pelvic Positioning Creates Error in CT Acetabular Measurements

CT allows for accurate measurement of acetabular orientation and shape, but malpositioning of the pelvis may lead to measurement variance. We therefore sought to determine: (1) whether acetabular anteversion measurements using the femoral head centers differed from those using the posterior ischia, and (2) the extent to which changing obliquity, rotation, and tilt of a pelvis in a CT scanner affected the measurement of acetabular variables. A radiopaque human pelvis model with articulated hips was suspended from a plastic sheet as part of an adjustable frame. Changes in the transverse and sagittal planes created rotation and tilt, while rotating the frame in the coronal plane created obliquity. CT scans were obtained, varying the combinations of obliquity, rotation, and tilt by intervals of 5°, up to 20°. Acetabular anteversion (AA), anterior acetabular sector angle (AASA), posterior acetabular sector angle (PASA), and horizontal acetabular sector angle (HASA) were measured. The two methods for measuring AA yielded values differing by 1° to 4° but correlated (r = 0.981) across the spectrum of pelvis positioning. Pelvic obliquity and tilt were linearly associated with changes in the measurements. For each 1°-increase in pelvic obliquity, AA changed -0.4°, and AASA, PASA, and HASA changed 1.93°, 0.99°, and 2.80°, respectively. For each 1°-increase in pelvic tilt, AA changed 0.8°, and AASA, PASA, and HASA changed -1.07°, 0.52°, and -0.51°, respectively. Rotation had no affect on the variables. Small changes in pelvic obliquity and tilt were associated with variances in acetabular measurements. The measured changes were directly proportional to the changes in obliquity and tilt, and were additive. Pelvic rotation created no changes in measurement.

Preswing Knee Flexion Assistance Is Coupled With Hip Abduction in People With Stiff-Knee Gait After Stroke

Stiff-knee gait is defined as reduced knee flexion during the swing phase. It is accompanied by frontal plane compensatory movements (eg, circumduction and hip hiking) typically thought to result from reduced toe clearance. As such, we examined if knee flexion assistance before foot-off would reduce exaggerated frontal plane movements in people with stiff-knee gait after stroke. We used a robotic knee orthosis to assist knee flexion torque during the preswing phase in 9 chronic stroke subjects with stiff-knee gait on a treadmill and compared peak knee flexion, hip abduction, and pelvic obliquity angles with 5 nondisabled control subjects. Maximum knee flexion angle significantly increased in both groups, but instead of reducing gait compensations, hip abduction significantly increased during assistance in stroke subjects by 2.5 degrees , whereas no change was observed in nondisabled control subjects. No change in pelvic obliquity was observed in either group. Hip abduction increased when stroke subjects received assistive knee flexion torque at foot-off. These findings are in direct contrast to the traditional belief that pelvic obliquity combined with hip abduction is a compensatory mechanism to facilitate foot clearance during swing. Because no evidence suggested a voluntary mechanism for this behavior, we argue that these results were most likely a reflection of an altered motor template occurring after stroke.

Evaluation of pelvic fixation in neuromuscular scoliosis: a retrospective study in 55 patients

The literature has described different indications for pelvic fixation in neuromuscular scoliosis. We retrospectively evaluated changes in pelvic obliquity for a minimum of two years among three groups: group I (initial pelvic obliquity >15 degrees; with pelvic fixation), group II (initial pelvic obliquity >15 degrees; without pelvic fixation), and group III (initial pelvic obliquity <15 degrees; without pelvic fixation). We used iliac screws for pelvic fixation in group I. There was significant postoperative improvement (p < 0.0001) in Cobb's angle and pelvic obliquity. There was no significant loss of correction in Cobb's angle, thoracic kyphosis, and lumbar lordosis among all three groups; however, group II showed significant correction loss in pelvic obliquity compared to groups I and III at final follow-up (p < 0.0001). Our results indicate that patients who have pelvic obliquity >15 degrees require pelvic fixation to maintain the correction and balance over time while obliquity <15 degrees does not require pelvic fixation.

Validation of postural radiographs as a way to measure change in pelvic obliquity

Fann AV. Validation of postural radiographs as a way to measure change in pelvic obliquity. Arch Phys Med Rehabil 2003;84:75-8. Objective: To evaluate the validity of using postural radiographs to assess change in pelvic obliquity. Design: Blinded comparison of reference lines and instrument development of postural radiographs. Setting: Veterans Administration hospital. Participants: Thirty-nine subjects with no history of low back pain. Intervention: Repeated postural radiographs without heel lifts and with [frac14]-in (6.35-mm) and [frac12]-in (12.7-mm) heel lifts. Main Outcome Measure: The change of pelvic obliquity as measured by the intersulcate, interalar, and sacral surface lines on postural radiographs. Results: A [frac14]-in heel lift resulted in changes of 4.6[plusmn]4.0mm, 3.6[plusmn]3.1mm, and 5.8[plusmn]3.9mm and a [frac12]-in heel lift in changes of 7.8[plusmn]4.3mm, 7.8[plusmn]4.6mm, and 5.2[plusmn]3.8mm for the intersulcate, interalar, and sacral surface lines, respectively. Pearson correlation coefficients were used to correlate the change in pelvic obliquity with the corresponding heights of heel lifts; for the [frac14]-in heel lift, they were .67, .88, and .71, and for [frac12]-in heel lift they were .73, .79, and .87 for the intersulcate, interalar, and sacral surface lines, respectively (all P[lt ].001). Conclusion: All the reference lines seem to be valid measures of change of pelvic obliquity relative to the size of the lifts (ie, the changes in pelvic obliquity seem to be causally related and correlated with the lifts). These results also suggest that postural radiographs can be used to determine the magnitude of pelvic obliquity. [copy ] 2003 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Gait analysis following varus osteotomy of the femur for hip osteoarthritis

The purpose of this study was to evaluate differences in the gait patterns of healthy and osteoarthritic hips, and changes in these patterns after intertrochanteric varus osteotomy of the femur, in relation to the strength of the muscles around the hip joint. We measured the strength ratio of hip abductor muscles, temporal and distance factors, and pelvic movement, and carried out dynamic electromyography (EMG) in 24 women who underwent unilateral varus osteotomy of the femur for hip osteoarthritis (OA), 30 non-surgically-treated women with hip OA, and 54 healthy women. The stance phase time was shorter and the strength ratio of hip abductor muscles was lower in the operated patients than these values in the other two groups, changes in pelvic obliquity and tilt were smaller, and changes in the percent maximum voluntary contraction of the gluteus medius and tensor fascia latae muscles were greater than these values in the healthy subjects. This study showed the postoperative reappearance of the simulated conditions in the hip before varus osteotomy of the femur, providing evidence that the pelvis was horizontally maintained during walking due to the decreased stance phase time and increased performance of the hip abductor muscles achieved after this procedure.

Excision of hemivertebrae and wedge resection in the treatment of congenital scoliosis.

The results of anterior and posterior excision or wedge resection of a hemivertebra and arthrodesis of the spine were reviewed retrospectively for thirty-seven patients. The degree of correction that was obtained and maintained, the balance and alignment of the trunk, changes in pelvic obliquity, and associated complications were evaluated. The average age at the time of the operation was twelve years (range, six months to forty-two years). The average duration of follow-up was six years (range, two to nineteen years). The resection was at the mid-thoracic level in six patients, at the thoracolumbar level in nine, at the mid-lumbar level in seven, and at the lumbosacral level in seventeen. (Two patients had an excision of a hemivertebra at two levels.) Instrumentation was used in twenty-eight patients. Postoperatively, all patients were managed with a body cast, with a unilateral or bilateral pantaloon extension, for four to six months. The instrumentation allowed early walking and the use of a unilateral rather than a bilateral pantaloon extension. The index curve (the curve containing the hemivertebra) averaged 54 degrees (range, 18 to 132 degrees) preoperatively, 33 degrees (range, 0 to 105 degrees) postoperatively, and 35 degrees (range, 0 to 110 degrees) at the most recent follow-up evaluation. A measurable improvement in balance was achieved and maintained in nineteen patients. Pelvic obliquity did not change appreciably, as it was related primarily to limb-length inequality in this series. Complications included a temporary nerve-root lesion in seven patients, a permanent neurological deficit involving the first sacral nerve root in one patient, a pseudarthrosis in three patients, and a wound infection in three patients. Six patients had extension of the arthrodesis to include additional vertebrae.

Surgical Correction of Myelomeningocele Scoliosis

A retrospective review of 38 patients with myelomeningocele scoliosis, focusing on the incidence of eventual fusion, curve correction, and change in pelvic obliquity, was performed. Single stage anterior or posterior fusion was compared to combined anterior and posterior spinal fusion. Single stage anterior or posterior procedures resulted in only a 50% fusion rate compared to rates of 83 to 100% for various combinations of combined anterior and posterior fusions. Similarly, average curve correction and change in pelvic obliquity were much improved with a two-stage approach. No statistical difference in fusion rate, curve correction, or change in pelvic obliquity was noted between the various combinations of two-stage anterior and posterior fusions.