Pelvic Motion Research Articles

Pelvic stability during simulated total hip arthroplasty motions: Comparing different hip positioners

IntroductionTotal hip arthroplasty (THA) requires forceful maneuvers that can cause the pelvis to shift from its original position. Various methods for stabilizing the pelvis in the lateral decubitus position exist, but there is limited data quantifying the relative stability of each hip positioner. We sought to quantify the pelvic movement that occurred in four commercially available hip positioners during surgeon induced motion of the hip. MethodsAn infrared marker was attached to the ilium of a cadaver secured in the lateral decubitus position. Four commercially available hip positioners were used for positioning: Beanbag, Pegboard, Stulberg, and ExactFit. Rotation and translation was captured using an infrared marker and camera system while the hip was moved through six motions (Flexion, Extension, Internal Rotation, External Rotation, Push, and Pull). ResultsThe Beanbag had the greatest amount of rotation and translation of the pelvis, with maximum hip rotation of 41.5°. The Stulberg and Pegboard positioners showed intermediate stability, with a maximum rotation of 7.8° and 17.1°, respectively. The ExactFit hip positioner resulted in the least amount of motion of the pelvis, with a maximum rotation of the pelvis of up to 3.2°. Of the simulated motions performed, internal rotation and flexion of the hip led to the greatest changes in pelvic rotation and translation. ConclusionThe ExactFit positioner was associated with the smallest amount of pelvic motion during simulated motions of hip arthroplasty, followed by the Stulberg, Pegboard, and Beanbag positioners. Further studies are required to correlate this information with clinical outcomes following total hip arthroplasty.

Validity of an artificial intelligence, human pose estimation model for measuring single-leg squat kinematics

Few studies have investigated the validity of 2D pose estimation models to evaluate kinematics throughout a motion and none have included adolescents. Adolescent athletes completed single-leg squats while 3D kinematic data and 2D sagittal and frontal plane videos were recorded. Sagittal and frontal plane joint motion throughout the single-leg squats and angles at peak knee flexion were compared among 2D pose estimation, 3D motion analysis, and traditional 2D motion analysis techniques. Statistical parametric mapping compared waveforms while Pearson’s correlation compared the relationships of joint angles at peak knee flexion among techniques, respectively. We observed significant waveform differences between 2D pose estimation and 3D motion analysis at the beginning and end of the squat for sagittal plane hip and knee motion, for most of the squat for frontal plane hip motion, and throughout the entire squat for sagittal plane ankle motion and frontal plane pelvic motion. We observed moderate-to-strong relationships (r = 0.68-0.94) for sagittal plane joint angles between 2D pose estimation and 3D techniques. We observed fair correlations (r = 0.53-0.54) for frontal plane pelvic and hip joint angles between 2D pose estimation and 3D motion analysis. We observed poor relationships for the frontal plane knee angle between 3D motion analysis with 2D pose estimation (r = 0.20) and traditional 2D motion analysis (r = 0.05), respectively, but observed a strong relationship (r = 0.95) between the 2D techniques. 2D pose estimation is a valid alternative to 3D motion analysis and traditional 2D motion analysis for evaluating most sagittal and frontal plane angles during a single-leg squatting task.

Effect of 3-Dimensional Versus Single-Plane Changes in Pelvic Dynamics on Range of Motion in Hips With Femoroacetabular Impingement: A Computer Simulation Analysis.

Background:Femoroacetabular impingement (FAI) is primarily caused by bony impingement between the acetabulum and femoral neck during hip motion. Increasing posterior pelvic tilt improves hip range of motion in patients with FAI.Purpose:To use computer simulation analysis to compare the effects of 3-dimensional (3D) changes in pelvic tilt (sagittal tilt [St], axial rotation, and coronal tilt) with changes in a single plane (St), with the aim of improving range of motion in patients with FAI.Study Design:Controlled laboratory study.Methods:We evaluated 43 patients with FAI treated by arthroscopic cam resection. A 3D simulation was used to construct the following pelvic models: a 5° and 10° increase posteriorly in St (St5° and St10°) and a combined 5° change in St, axial rotation, and coronal tilt (Complex5°) from the baseline of the anterior pelvic plane. Improvements in maximum internal rotation (MIR) at 45°, 70°, and 90° of hip flexion and improvements in maximum flexion with no internal rotation were compared among the St5°, St10°, and Complex5° models. The pelvic models of each single-plane change of 5° and 10° were evaluated in the same simulation.Results:At 90° and 70°, there was a significant difference between the Complex5° and St10° models with respect to improvement in MIR (P = .004 at 90° of flexion; P = .017 at 70° of flexion). There was no significant difference in MIR at 45° of flexion (P = .71) or in maximum flexion (P = .42).Conclusion:At 70° and 90° of hip flexion, a combined change in 3D pelvic alignment of 5° (ie, St, axial rotation, and coronal tilt) was more effective in improving hip MIR than a 10° change in St only.Clinical Relevance:Effective physical therapy for FAI should address pelvic motion in all 3 planes rather than in a single plane.

Influence of Limb Length Discrepancy and its Compensation on the Amplitude of Pelvic Motion in the Frontal Plane during Walking: a Prospective Cohort Study of 40 Children

INTRODUCTION. Biomechanical abnormalities caused by limb length discrepancy are controversial problems of pediatric orthopedics. AIM. To assess the influence of limb length discrepancy and its compensation in children on the amplitude of pelvic motion in the frontal plane during walking. MATERIAL AND METHODS. We examined the study group of 21 patients with (the average discrepancy was 2,86% (from 0,23% to 6,12%). Biomechanical examination consisted of dynamic optical computed topography. The study was carried out in standard shoes and in shoes with compensation. The average compensation was 14 mm (from 5 to 45 mm). The comparison group consisted of 19 healthy children without limb length discrepancy. The angle of frontal asymmetry of the pelvis was calculated as the absolute difference in inclination. RESULTS AND DISCUSSION. When compensation was used, the amplitude of pelvic movements changed insignificantly, by an average of 1.84°, in children with discrepancy of the lower limbs. In the comparison group (healthy children), we also did not observe any changes in frontal pelvic oscillation when imitating variability compared to tests without compensation. The most obvious explanation for this phenomenon is the formation of additional compensation mechanisms for different lengths of the lower limbs. CONCLUSION. Compensation of limb length discrepancy requires an individualized approach and additional walking examinations of the patient. Further research will expand our understanding of the role of compensation for limb length discrepancy both in conservative treatment and in planning for surgical interventions.

Effect of the Pelvic Correction Exercise with Sports Taping Treatment on Trunk Isokinetic Muscle Function and Movement and Flexibility of Female Who Have Lumbar Kyphosis

This study aimed to provide fundamental data of pelvic correction exercise with sports taping treatment (PCE and STT) on trunk isokinetic muscle function and movement and flexibility of female who have lumbar kyphosis. This study conducted from April to September 2020 on female who have lumbar kyphosis who took part in PCE and SPT program. These subjects were compared with non-exercise group (NEG). Forty-eight voluntary subjects were divided by NEG (n=12), the second group who participated in the PCE and STT program 1 - 2 times a week (DEG, n=12), and the third group who normally participated in the PCE and STT (OEG, n=12), respectively. The results of this study were as follows: First, as a result of analyzing the change of trunk isokinetic muscle function according to PCE and STT, OEG was significantly improved compared to NEG and DEG. Second, as a result of analyzing the change of pelvic movement according to PCE and STT, OEG was significantly improved compared to NEG and DEG. Third, as a result of analyzing the change of flexibility according to PCE and STT, OEG was significantly improved compared to NEG and DEG. As conclusions, these results informed that the PCE and STT for 16 weeks would provide positive effects on trunk isokinetic muscle function and movement and flexibility.

Impact of intrafraction changes in delivered dose of the day for prostate cancer patients treated with stereotactic body radiotherapy via MR-Linac.

The purpose of this study is to evaluate the impact of intrafraction pelvic motion by comparing the adapted plan dose (APD) and the computed delivered dose of the day (DDOTD) for patients with prostate cancer (PCa) treated with SBRT on the MR-Linac. Twenty patients with PCa treated with MR-guided adaptive SBRT were included. A 9-field IMRT distribution was adapted based on the anatomy of the day to deliver a total prescription dose of 3000cGy in 5 fractions to the prostate plus a 5mm isotropic margin. Prostate, bladder, and rectum were re-contoured on the MR-image acquired during treatment delivery (MRBO). DDOTD was computed by propagating the dose from the daily adapted plan generated during treatment onto the MRBO. Target coverage was met for all fractions, however, computed DDOTD was significantly less than the APD (p<0.05). During an average treatment of 53min, mean bladder volume increased by 116%, which led to a significant decrease in the DDOTD bladder D40% (p<0.001). However, DDOTD to bladder 5cc was significantly higher (p<0.001) than APD. Rectum intrafraction changes were observed based on a volume change of -20% to 83% and presence of significant dose changes from APD to DDOTD for rectum D20% (p<0.05) and D1cc (p<0.0001). Intrafraction motion observed during prostate SBRT treatment on the MR-Linac have dosimetric impacts on both the target and organs at risk. Post-treatment computation using DDOTD may inform adaptation beyond anatomic changes in subsequent treatment fractions to best capitalize on MR-Linac technology and widen the therapeutic index of SBRT for PCa.

81. Mobility parameters in two level-lumbar TDR vs hybrid construct: clinical results in 235 patients

<h3>BACKGROUND CONTEXT</h3> Lumbar total disc replacement (TDR) is a treatment option with 30 years experience and extensive publications on clinical results. However, there are few publications on mid- and long-term mobility. There is also sparse literature on the quality of mobility or the difference between L4-S1 2-level TDR vs TDR/ALIF hybrid constructs. <h3>PURPOSE</h3> To measure mobility parameters in flexion-extension for two groups (L4-S1 TDR vs hybrid); compare motion at L4–L5; participation of pelvis mobility; global lumbar motion; and flexion-extension effectiveness by measuring L1 race. Besides determining the difference of mobility between TDR and hybrid, we discussed potential compensations above and below L5-S1 fusion/L4-L5 TDR, as compared to two-level TDR. <h3>STUDY DESIGN/SETTING</h3> Retrospective clinical study. <h3>PATIENT SAMPLE</h3> This study included 235 patients, operated between 2003-2013: 170 patients received 2-level TDR (TDR group) and 65 received L4-L5 TDR and L5-S1 ALIF (hybrid group). <h3>OUTCOME MEASURES</h3> Data collected included radiographic, neurological/physical assessment, self-evaluation using the Oswestry Disability Index (ODI) and visual analog back and leg pain scores (VAS). Complication, reoperation/revision rates, and perioperative data points were also assessed. <h3>METHODS</h3> Both groups were equivalent in age, body habitus and preoperative clinical parameters (ODI, VAS). Patient selection for evaluation was based on presence of clinical success criteria and pre- and postoperative sagittal X-rays and dynamic flexion-extension films at minimum 24-month follow-up. Pelvic parameters (Incidence, Pelvic Tilt, Sacral Slope) were measured. L4-L5 and L5-S1 flexion-extension range of motion (ROM) was measured pre- and postoperatively. Pelvic motion was determined by measuring sacral slope in flexion-extension. The influence on lumbar lordosis (L1-S1) was also analyzed. To show the effect the lumbopelvic complex has on global motion, we measured L1 race (flexion-extension L1 ROM). <h3>RESULTS</h3> The absolute motion and relative gain of 2-level TDR shows its superiority over hybrid constructs in all measured parameters. When L5-S1 is fused, there is no compensation from pelvic motion to overcome the loss of mobility. TDR group shows a pelvi-femoral ROM gain of 16.77°, vs a gain of only 6.11° in the Hybrid group. L5-S1 fusion also reduces L4-L5 TDR mobility in Hybrid group, compared to 2-level TDR, and decreases flexion compared to baseline. There is a mean reduction in ROM of 1.53° in Hybrid group vs 20.02° gain in TDR group. L1 race also reflects the superiority of 2-level TDR vs hybrid with a gain of 32.58° in TDR vs 4.68° in hybrid, demonstrating that reduced global motion is principally due to loss of L5-S1 motion. <h3>CONCLUSIONS</h3> This comparison between 2-level TDR and hybrid demonstrates a lack of compensation through lumbar mobility and pelvic motion when L5-S1 is fused, and debunks these preconceived ideas. Although clinical measures of activity (ODI) and pain (VAS back and leg pain) are equivalent between the groups, functional superiority of 2-level TDR is confirmed. Two new ROM parameters introduced here—pelvic motion and L1 race—must be integrated in all ROM studies as they quantify pelvic participation in mobility and the functional effectiveness of motion preservation. In this first long-term comparison of mobility between 2-level TDR vs L4-S1 hybrid, 2-level TDR demonstrates overall superiority. Consequently, 2-level TDR must be systematically indicated whenever TDR is indicated for both levels, and accepted as the "gold standard" for reimbursement purposes. <h3>FDA DEVICE/DRUG STATUS</h3> Prodisc L 1- and 2-level (Approved for this indication), Prodisc L hybrid constructs (Not approved for this indication)

P147. Total hip arthroplasty in patients with prior lumbar spine fusion: does time between surgeries affect outcomes?

<h3>BACKGROUND CONTEXT</h3> Concurrent disease of the hip and spine is becoming increasingly common. Existing evidence suggests that prior lumbar spine fusion (LSF) predisposes patients undergoing total hip arthroplasty (THA) to increased rates of instability and revision. However, consequences from the temporal relationship between the two procedures remain largely unknown and may have implications for surgical planning. <h3>PURPOSE</h3> To evaluate the impact of timing between LSF and subsequent THA on postoperative outcomes. <h3>STUDY DESIGN/SETTING</h3> Retrospective national database analysis. <h3>PATIENT SAMPLE</h3> Patients with a prior lumbar spinal fusion undergoing total hip arthroplasty recorded in Medicare, Medicaid and commercial administrative claims databases in PearlDiver from 2007-2020. <h3>OUTCOME MEASURES</h3> Postoperative complications and revisions. <h3>METHODS</h3> Five cohorts were identified and matched by age, gender, obesity, and Charlson Comorbidity Index, according to interval time between the two procedures: LSF with subsequent THA in 2 years, as well as a control group comprising THA without previous LSF. Postoperative complications and revisions were assessed at 90 days and 2 years after primary THA. Post hoc comparisons were characterized using five-way chi-squared analysis, and threshold for significance was P < 0.05. <h3>RESULTS</h3> A total of 3,260 patients were included for analysis. At 90 days, there was a significantly increased incidence of prosthetic instability in patients undergoing THA within 6 months of a prior LSF (0.77%, P = 0.015) compared to other groups. However, this difference did not persist at long-term followup. At 2 years, the incidences of postoperative infections (4.91%, P < 0.001), cellulitis (4.75%, P = 0.003), and wound complications (1.99%, P = 0.001) were significantly greater in patients whose surgeries were separated by less than a year. Additionally, patients who underwent THA within 2 years of a prior LSF demonstrated significantly increased rates of mechanical failure (2.45%, P = 0.002). <h3>CONCLUSIONS</h3> Lumbar fusion is known to alter dynamic pelvic motion and may impair hip implant accommodation. This analysis specifically found an increased risk of early postoperative instability in patients who underwent THA within 6 months of LSF. Furthermore, patients with both surgeries in 2-year proximity sustained greater rates of long-term wound, infectious and implant complications. To mitigate these risks, surgeons should consider delaying elective THA until biologic fusion matures. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Transversal Malalignment and Proximal Involvement Play a Relevant Role in Unilateral Cerebral Palsy Regardless the Subtype.

Classification of gait disorders in cerebral palsy (CP) remains challenging. The Winters, Gage, and Hicks (WGH) is a commonly used classification system for unilateral CP regarding the gait patterns (lower limb kinematics) solely in the sagittal plane. Due to the high number of unclassified patients, this classification system might fail to depict all gait disorders accurately. As the information on trunk/pelvic movements, frontal and transverse planes, and kinetics are disregarded in WGH, 3D instrumented gait analysis (IGA) for further characterization is necessary. The objective of this study was a detailed analysis of patients with unilateral CP using IGA taking all planes/degrees of freedom into account including pelvic and trunk movements. A total of 89 individuals with unilateral CP matched the inclusion criteria and were classified by WGH. Subtype-specific differences were analyzed. The most remarkable findings, in addition to the established WGH subtype-specific deviations, were pelvic obliquity and pelvic retraction in all WGH types. Furthermore, the unclassified individuals showed altered hip rotation moments and pelvic retraction almost throughout the whole gait cycle. Transversal malalignment and proximal involvement are relevant in all individuals with unilateral CP. Further studies should focus on WGH type-specific rotational malalignment assessment (static vs. dynamic, femoral vs. tibial) including therapeutic effects and potential subtype-specific compensation mechanisms and/or tertiary deviations of the sound limb.

What are the kinematic characteristics of the world champion couple in competitive ballroom dance during the waltz's spin movement?

To evaluate competitive ballroom dancing, one of the official events of the World Games, spin movements used by advanced dancers who ranked high in actual competition may be employed. The purpose of this study was to investigate the kinematic characteristics of spin movements in competitive ballroom dancing performed by world champion couples, especially holding posture and lower limb movements. A champion couple and 13 national-level competitive ballroom dancers as the control group participated in this study. An inertial measurement unit (IMU) system (MVN Link; Xsens, Netherlands) consisting of 17 IMUs, attached to feet, shanks, thighs, pelvis, sternum, head, upper arms, forearms, and hands of the dancers, was used to obtain three-dimensional kinematic data at 240 Hz. The overall trend was that the actual and normalized stride lengths of the champion male and female dancers tended to be longer than those of the male and female dancers in the control group. Further, large differences were observed in the pelvic and rib cage segments movements, and the relative angle of the rib cage segment to the pelvic segment. The champion male dancer started to move from the pelvic segment, whereas the champion female dancer and the national-level top male and female dancers started to move from the rib cage segment. During the spin movement, the champion male dancer was in a position where the rib cage segment was rotated to the left with respect to the pelvic segment, whereas the other dancers were in a position where the rib cage segment was rotated to the right. Although limited to technical aspects, these dance kinematic characteristics of the world champion couples and their differences from those of the control group dancers, will be helpful to competitive ballroom dancers and coaches in their daily practice.

Gait biofeedback training in people with Parkinson’s disease: a pilot study

BackgroundPeople with Parkinson’s disease (PD) are at a high risk of falls, with ~ 60% experiencing a fall each year. Greater mediolateral head and pelvis motion during gait are known to increase the risk of falling in PD, however the ability to modify these aspects of gait has not been examined. Thus, this study aimed to examine whether mediolateral trunk, head and pelvis motion during walking could be successfully decreased in people with PD using real-time biofeedback.MethodsParticipants were provided with real-time biofeedback regarding their mediolateral trunk lean via a visual projection whilst walking along an 8-m indoor walkway. Using the feedback provided, they were asked to reduce the magnitude of their mediolateral trunk lean. Gait was recorded for four conditions (i) Baseline, (ii) Intervention, (iii) immediately Post-Intervention, and (iv) 1-week Follow-Up. Biomechanical variables associated with falls risk were compared between conditions, including normalised mediolateral motion, gait velocity and stride length.ResultsA reduction in mediolateral trunk lean, step length and gait velocity from Baseline to the Intervention and Post-intervention conditions was observed. Contrary to this, increased normalised ML pelvis and trunk motion was observed between the Baseline and Intervention conditions, but returned to Baseline levels in the Post-Intervention condition.ConclusionsResults from the current study suggest that real-time visual biofeedback may be effective at modifying specific gait characteristics that are associated with falls in PD. Further research is required to better understand the influence of this intervention approach on falls incidence.Trial registration Australian New Zealand Clinical Trials Registry ACTRN12620000994987. Registered 10 June 2020 - Retrospectively registered, https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=380324

Quantitative Gait Analysis Before and After a Cross-country Test in a Population of Elite Eventing Horses

Early recognition of lameness is crucial for injury prevention. Quantitative gait analysis systems can detect low-grade asymmetries better than the human eye and may be useful in early lameness recognition. The aims of this study were (1) to investigate the frequency of gait asymmetries based on head and pelvic movement in elite eventing horses using inertial mounted measurement units and (2) to assess the association between asymmetries and muscle enzymes and blood lactate (LA) levelspost-exercise. Movement asymmetry of the head, wither, and pelvis were quantified in 33 elite eventing horses prior to and one day after the cross-country test of three Concours Complet International (CCI3* and CCI4*) events held three weeks apart. The effects of LA concentration immediately after completion of the cross-country course and of serum levels of creatine kinase (CK) and aspartate amino-transferase (AST) four hours post-exercise on gait asymmetry parameters were tested with linear models. A total of 58% and 77% of the 33 horses exhibited gait asymmetries that exceeded published threshold values before and after the cross-country course, respectively. The magnitude of pre-existing gait asymmetries was not significantly increased after the cross-country test and no associations with post-exercise levels of CK, AST, or LA were detected. The stride duration was significantly shorter the day following the cross-country test and was associated with LA, the age and the weight of the horses. In conclusion, a majority of the horses studied presented gait asymmetries and strenuous exercise resulted in decreased stride duration but did not worsen gait asymmetries.

A Comprehensive, Multidisciplinary Assessment for Knee Osteoarthritis Following Traumatic Unilateral Lower Limb Loss in Service Members.

Knee osteoarthritis (KOA) is a primary source of long-term disability and decreased quality of life (QoL) in service members (SM) with lower limb loss (LL); however, it remains difficult to preemptively identify and mitigate the progression of KOA and KOA-related symptoms. The objective of this study was to explore a comprehensive cross-sectional evaluation, at the baseline of a prospective study, for characterizing KOA in SM with traumatic LL. Thirty-eight male SM with traumatic unilateral LL (23 transtibial and 15 transfemoral), 9.5 ± 5.9 years post-injury, were cross-sectionally evaluated at initial enrollment into a prospective, longitudinal study utilizing a comprehensive evaluation to characterize knee joint health, functionality, and QoL in SM with LL. Presences of medial, lateral, and/or patellofemoral articular degeneration within the contralateral knee were identified via magnetic resonance imaging(for medically eligible SM; Kellgren-Lawrence Grade [n = 32]; and Outerbridge classification [OC; n = 22]). Tri-planar trunk and pelvic motions, knee kinetics, along with temporospatial parameters, were quantified via full-body gait evaluation and inverse dynamics. Concentrations of 26 protein biomarkers of osteochondral tissue degradation and inflammatory activity were identified via serum immunoassays. Physical function, knee symptoms, and QoL were collected via several patient reported outcome measures. KOA was identified in 12 of 32 (37.5%; KL ≥ 1) SM with LL; however, 16 of 22 SM presented with patellofemoral degeneration (72.7%; OC ≥ 1). Service members with versus without KOA had a 26% reduction in the narrowest medial tibiofemoral joint space. Biomechanically, SM with versus without KOA walked with a 24% wider stride width and with a negative correlation between peak knee adduction moments and minimal medial tibiofemoral joint space. Physiologically, SM with versus without KOA exhibited elevated concentrations of pro-inflammatory biomarker interleukin-7 (+180%), collagen breakdown markers collagen II cleavage (+44%), and lower concentrations of hyaluronic acid (-73%) and bone resorption biomarker N-telopeptide of Type 1 Collagen (-49%). Lastly, there was a negative correlation between patient-reported contralateral knee pain severity and patient-reported functionality and QoL. While 37.5% of SM with LL had KOA at the tibiofemoral joint (KL ≥ 1), 72.7% of SM had the presence of patellofemoral degeneration (OC ≥ 1). These findings demonstrate that the patellofemoral joint may be more susceptible to degeneration than the medial tibiofemoral compartment following traumatic LL.

Defining "Normal" Static and Dynamic Spinopelvic Characteristics: A Cross-Sectional Study.

Background:Spinopelvic characteristics influence the hip’s biomechanical behavior. However, there is currently little knowledge regarding what “normal” characteristics are. This study aimed to determine how static and dynamic spinopelvic characteristics change with age, sex, and body mass index (BMI) among well-functioning volunteers.Methods:This was a cross-sectional cohort study of 112 asymptomatic volunteers (age, 47.4 ± 17.7 years; 50.0% female; BMI, 27.3 ± 4.9 kg/m2). All participants underwent lateral spinopelvic radiography in the standing and deep-seated positions to determine maximum hip and lumbar flexion. Lumbar flexion (change in lumbar lordosis, ∆LL), hip flexion (change in pelvic-femoral angle, ∆PFA), and pelvic movement (change in pelvic tilt, ΔPT) were determined. The hip user index, which quantifies the relative contribution of the hip to overall sagittal movement, was calculated as (∆PFA/[∆PFA + ∆LL]) × 100%.Results:There were decreases of 4.5° (9%) per decade of age in lumbar flexion (rho, −0.576; p < 0.001) and 3.6° (4%) per decade in hip flexion (rho, −0.365; p < 0.001). ∆LL could be predicted by younger age, low standing PFA, and high standing LL. Standing spinopelvic characteristics were similar between sexes. There was a trend toward men having less hip flexion (90.3° ± 16.4° versus 96.4° ± 18.1°; p = 0.065) and a lower hip user index (62.9% ± 8.2% versus 66.7% ± 8.3%; p = 0.015). BMI weakly correlated with ∆LL (rho, −0.307; p = 0.011) and ∆PFA (rho, −0.253; p = 0.039).Conclusions:Spinopelvic characteristics were found to be age, sex, and BMI-dependent. The changes in the lumbar spine during aging (loss of lumbar lordosis and flexion) were greater than the changes in the hip, and as a result, the hip’s relative contribution to overall sagittal movement increased. Men had a greater change in posterior pelvic tilt when moving from a standing to a deep-seated position in comparison with women, secondary to less hip flexion. The influence of BMI on spinopelvic parameters was low.

Compensatory Gait Strategies in Persons with Transfemoral Amputations Walking with a Locked Prosthetic Knee Joint Compared with an Unlocked Knee Joint: A Crossover Trial

ABSTRACT Introduction Individuals with transfemoral amputation walking with a locked prosthetic knee joint (LPKJ) have compromised degree of freedom in leg movement compared with walking with an unlocked prosthetic knee joint (UPKJ), thus presenting a risk for compensatory gait strategies, with risk of lower back pain. The objective was to compare gait strategies in individuals with transfemoral amputation walking with an LPKJ and a UPKJ. Materials and Methods This was a crossover trial. Nine individuals with transfemoral amputation habitually walking with a UPKJ completed an intervention of 1 to 2 weeks of walking with a UPKJ followed by 1 to 2 weeks of walking with an LPKJ. Gait strategies were analyzed after each intervention using three-dimensional gait analysis. The outcome was pelvic and lumbar spinal movement from terminal stance to initial swing in the sagittal and transversal plane. Results The maximum anterior tilt of the pelvis in the sagittal plane and the pelvic rotation shifted from preswing to initial swing in the gait cycle when walking with an LPKJ compared with the UPKJ. Conclusions A compensatory gait strategy was observed among individuals with transfemoral amputation walking with an LPKJ compared with a UPKJ. Studies should investigate the incidence of low back pain in individuals with transfemoral amputation walking with LPKJ compared with those walking with UPKJ.

Kinetic Evaluation of Pelvis during the Three Trimesters of Pregnancy and its Correlation to BMI

Background: Understanding differences in mechanics between pregnant and non-pregnant females are a first step toward identifying potential pathological mechanisms. Objectives: The objective was to investigate systematic changes in the range of motion of pelvis in all three trimesters of pregnancy and its correlation to BMI. Materials and Methods: One hundred and seventy-four primigravida pregnant females with age group of 20–30 years completed testing on three occasions (first trimester, second trimester, and third trimester) using goniometer. The patient was made comfortable and her height, weight was measured to calculate the BMI. Later with the help of goniometer range of motion of pelvis (hip and lumbar) was measured. Results: In this study, significant correlation was seen for anterior pelvic tilt, posterior pelvic tilt, and backward rotation for the first and third trimester. Very significant correlation was seen for anterior pelvic tilt, posterior pelvic tilt, lateral pelvic tilt, forward rotation, backward rotation in the second trimester, and for backward rotation in the third trimester. Extremely significant correlation was seen for posterior pelvic tilt in the first trimester, for anterior and posterior pelvic tilt in the second trimester, for posterior pelvic tilt in the third trimester. Conclusion: In this study, significant correlation was seen for the first and third trimester. Very significant correlation was seen for the second trimester and for third trimester. Extremely significant correlation was seen in the first trimester, second trimester, and third trimesters.

Changes in Dynamic Postural Stability After ACL Reconstruction: Results Over 2 Years of Follow-up.

Background:The anterior cruciate ligament (ACL) is crucial for knee proprioception and postural stability. While ACL reconstruction (ACLR) and rehabilitation improve postural stability, the timing in improvement of dynamic postural stability after ACLR remains relatively unknown.Purpose:To evaluate changes in dynamic postural stability after ACLR out to 24 months postoperatively.Study Design:Case series; Level of evidence, 4.Methods:Patients undergoing ACLR were prospectively enrolled, and dynamic postural stability was assessed within 2 days before surgery, at 3-month intervals postoperatively to 18 months, then at 24 months. Measurements were made on a multidirectional platform tracking the patient’s center of mass based on pelvic motion. The amount of time the patient was able to stay on the platform was recorded, and a dynamic motion analysis score, reflecting the patient’s ability to maintain one’s center of mass, was generated overall and in 6 independent planes of motion.Results:A total of 44 patients with a mean age of 19.7 ± 6.2 years completed the study protocol. Overall mean dynamic postural stability improved significantly at 3, 6, 9, and 12 months after surgery, with continued improvement out to 24 months. Notable improvements occurred in medial/lateral and anterior/posterior stability from baseline to 6 months postoperatively, while internal/external rotation and flexion/extension stability declined initially after surgery from baseline to 3 months postoperatively before stabilizing to the end of the study period.Conclusion:Overall dynamic postural stability significantly improved up to 12 months after ACLR. Improvement in postural stability occurred primarily in the medial/lateral and anterior/posterior planes of motion, with initial decreases in the flexion/extension and internal/external rotational planes of motion.

Lead Foot Progression Angle in Baseball Pitchers: Implications to Ball Velocity and Upper-Extremity Joint Moments.

The instant of foot contact is an important transition point during the pitch cycle between the linear portion of the pitch, as a pitcher strides down the mound and the rotational portion of the pitch. Understanding the implications of lead foot angle at foot contact is an essential information needed to assist pitching coaches in their work with individual pitchers. Therefore, the purpose of this study was to determine the association between lead foot progression angle at foot contact and ball velocity, elbow varus moment, and pelvic rotation. Kinematic and kinetic data were collected from 99 collegiate pitchers and analyzed using a random intercept, mixed-effects regression model. Significant associations were found between lead foot progression angle at foot contact and elbow varus moment (P = .004), as well as pelvic rotation throughout the pitching motion (P < .001). The data indicate that increased lead foot internal rotation at foot contact is associated with increases in the elbow varus moment but is not associated with ball velocity. This study provides scientific evidence that the rotational positioning of the lead foot can affect both pelvic motion and upper-extremity joint moments.

Effect of Age on Thoracic, Lumbar, and Pelvis Coordination During Trunk Flexion and Extension.

The purpose of this study was to investigate normative and age-related differences in trunk and pelvis kinematics and intersegmental coordination during sagittal plane flexion-extension. Trunk and pelvis kinematics were recorded while 76 participants performed a maximal range of motion task in the sagittal plane. Cross-correlation was calculated to determine the phase lag between adjacent segment motion, and coupling angles were calculated using vector coding and classified into one of 4 coordination patterns: in-phase, antiphase, superior, and inferior phase. A 2-way mixed-model multivariate analysis of variance was used to compare lumbar spine and pelvis angular kinematics, phase lags, and cross-correlation coefficients between groups. Young participants exhibited greater trunk range of motion compared with middle-aged participants. The lumbar spine and pelvis were predominantly rotating with minimum phase lag during flexion and extension movement for both age groups, and differences in coordination between the groups were seen during hyperextension and return to upright position. In conclusion, middle-aged adults displayed lower range of motion but maintained similar movement patterns to young adults, which could be attributed to protective mechanisms. Healthy lumbar and pelvis movement patterns are important to understand and need to be quantified as a baseline, which can be used to develop rehabilitation protocols for individuals with spinal ailments.

Comparison of Pelvic Rotation Angle and Electromyography Activity of the Trunk and Gluteus Maximus Muscles during Four Pilates Exercises

Background The Pilates method has recently been recommended as the best way to improve spinal stability by strengthening the trunk and gluteus maximus (GM) muscles. Purpose In this study, we compared trunk and GM muscle activities and pelvic rotation angles during four traditional Pilates exercises. Study design Cross-sectional study Methods Twenty healthy volunteers were recruited for this study. During the four exercises, the activity of the trunk and GM muscles were measured via electromyography and pelvic rotation was measured using a smart phone-based measurement tool. Results The activities of the transverse abdominis/internal oblique and external oblique muscles were highest during the leg pull front (LPF) compared to the other exercises. GM activity was significantly higher during the LPF compared to the shoulder bridge and swimming (SW), but not during the one leg kick (OLK). Multifidus (MF) activity was significantly higher during SW than during the other exercises. There were no significant differences in MF activity between the SW and OLK exercises. Pelvic rotation angle was significantly reduced during the OLK compared to the LPF (<italic>p</italic>=0.004). Conclusions We recommend the LPF exercise if the goal is increased trunk and GM muscle activity and the SW exercise if you target for increased MF activity. The OLK exercise is useful for activating the trunk and GM muscles while reducing uncontrolled pelvic movements.