Anterior-posterior Displacement Research Articles

The effects of six weeks of combined balance and plyometric training on postural control performance in elite badminton players: A pilot randomized, controlled study

Background/ObjectivesThe athletic performance in badminton players largely depends on the capability of dynamic postural control to quickly restore balance when performing high-paced movements (e.g., frequent single-leg jumps). Our aim was to examine the effects of a novel intervention that combines balance training on an unstable surface and plyometric training on the performance of restoring balance after jumping, as well as related postural control in elite badminton players. MethodsSixteen elite male badminton players were randomly allocated to either a combined balance and plyometric training group (CT, n = 8) or a plyometric training group (PT, n = 8). The CT group participated in a six-week training program, which included three training sessions per week. Each session comprised 40 min of plyometric exercises and 20 min of balance training. The PT group underwent plyometric training using the identical protocol as that of the CT group. All participants underwent identical technical training in badminton throughout the duration of the study. At baseline and immediately after the intervention, participants completed a single-leg jumping test. The capacity to restore balance was evaluated using the time to stabilization (TTS) after landing; and the related center of pressure (COP) fluctuations were also recorded. The effect of intervention was examined by two-way repeated-measures of ANOVA. ResultsThe primary two-way repeated-measures ANOVA models showed no significant interactions between group and time on either the time to stability in the dominant leg (D-TTS) or the time to stability in the non-dominant leg (N-TTS) (p > 0.70). Significant main effects of time, group, and their interactions on dominant legs of the anterior-posterior displacement difference (D-COPAP) (time: p = 0.001; group: p = 0.001; interaction: p = 0.014), non-dominant legs of the anterior-posterior displacement difference (N-COPAP) (time: p < 0.001; group: p = 0.003; interaction: p = 0.021) and non-dominant legs of the medial-lateral displacement difference (N-COPML) (time: p < 0.001; group: p < 0.001; interaction: p = 0.026), that is, compared to baseline of both groups and post PT, the COP metrics were significantly reduced after CT. Secondarily, within the CT and PT group, after the intervention, the N-TTS (CT: p = 0.001, post: 0.58 ± 0.87; PT: p = 0.03, post: 0.71 ± 0.11) was significantly decreased compared to baseline (CT pre: 0.76 ± 0.16; PT pre: 0.88 ± 0.13). ConclusionThis pilot study demonstrated that, compared to PT-only, the 6-week CT which combines balance training induced comparable improvements in the capacity to restoring balance after landing from a single-leg jump, and significantly improved the postural control performance as measured by COP metrics.

Refining Operative Indications for Zygomaticomaxillary Complex Fracture Repair

Study Design Case-control. Objective Although zygomaticomaxillary complex (ZMC) fractures are among the most common facial injuries, the optimal approach to management remains controversial. This study analyzes the relationship between displacement measures derived from pre-operative CT imaging and clinical symptomatology to enhance surgeon understanding of the need for operative intervention. Methods A retrospective analysis was conducted on 95 patients with ZMC fractures seen at a single institution between 2015 and 2020. Patient demographics, CT characteristics, and symptoms prompting surgery were recorded from the medical record. Statistical analysis was conducted to determine relationships between radiographic characteristics, symptomatology, and need for operative intervention. Results Malar flattening or facial asymmetry was significantly predicted by lateral maxillary wall impaction (OR = 1.36 , P &lt; .001) and anterior-posterior displacement (OR = 1.18, P = .01). Infraorbital rim step-off was significantly associated with lateral maxillary wall impaction (OR = 1.23, P &lt; .01). Vertical displacement predicted complaint of malocclusion (OR = 1.47, P = .03). Moreover, fractures with posterior displacement greater than 2.5 mm (OR = 14.3, P &lt; .001) or lateral maxillary wall impaction greater than 4.5 mm (OR = 12.0, P &lt; .001) were significantly more likely to be considered operative. Fractures displaced less than 15 mm total in all directions (OR = 16.0, P &lt; .001) were less likely to require surgery. Conclusions CT characteristics of ZMC fractures reliably predict a patient’s likelihood of developing symptoms, indicating surgical intervention. We hope these findings will aid in surgical decision-making regarding the management of ZMC fractures.

Effect of strength training with additional acupuncture on balance, ankle sensation, and isokinetic muscle strength in chronic ankle instability among college students.

Purpose: The effects of the combination of strength training and acupuncture on chronic ankle instability have not been studied. This study examined effects of strength training combined with acupuncture on balance ability, ankle motion perception, and muscle strength in chronic ankle instability among college students. Methods: Forty-six chronic ankle instability college students were randomly categorized into the experimental group (n = 24, strength training + acupuncture) and the control group (n = 22, strength training) for an 8-week intervention. Results: For the results at 8weeks, compared with the baseline, in the experimental group, the chronic Ankle Instability Tool (CAIT) score, ankle dorsiflexion, plantar flex, eversion peak torque (60°/s), and plantar flex peak torque (180°/s) increased by 13.7%, 39.4%, 13.7%, 14.2%, and 12.3%, respectively. Dorsiflexion, plantar flexion, inversion, and eversion kinesthetic sensation test angles decreased by 17.4%, 20.6%, 15.0%, and 17.2%, respectively. Anterior-posterior and medial-lateral displacement, and anterior-posterior and medial-lateral velocity decreased by 28.9%, 31.6%, 33.3%, and 12.4%, respectively. Anterior-posterior and medial-lateral displacement, and anterior-posterior and medial-lateral mean velocity decreased by 28.9%, 31.6%, 33.3%, and 12.4%, respectively. In the control group, the Cumberland Ankle Instability Tool score and the ankle dorsiflexion peak torque (60°/s) increased by 13.8% and 17.9%, respectively. The inversion kinesthetic sensation test angle decreased by 15.2%, whereas anterior-posterior and medial-lateral displacement, and anterior-posterior and medial-lateral mean velocity decreased by 17.1%, 29.4%, 12.3%, and 16.8%, respectively. 2) For the comparison between the groups after 8weeks, the values of ankle dorsiflexion and plantar flex peak torque (60°/s) in the experimental group were greater than those in the control group. The values of ankle plantar flex kinesthetic sensation test angle, the anterior-posterior displacement, and anterior-posterior mean velocity in the experimental group were lower than those in the control group. Conclusion: Acupuncture treatment in conjunction with muscle strength training can further improve the balance ability of anterior-posterior, ankle dorsiflexion, and plantar flex strength and plantar flex motion perception in chronic ankle instability participants.

The impact of suboccipital muscle inhibition on postural stability in young individuals

Introduction. Postural stability is the result of cooperation between the musculoskeletal and nervous systems. The stability of standing posture ensures the spatial arrangement of the body, where the center of gravity falls within the center of the support base. FHT (Forward Head Posture) increases the extension in the occipito-cervical joint and upper cervical spine, deepening the flexion of the lower cervical segment, causing improper contraction of the suboccipital muscles. Disorders in the tone of the suboccipital muscles may affect the balance. Objective. The research hypothesis was made that a single 4-minute suboccipital muscle inhibition procedure influences the change in postural stability values with open and closed eyes in individuals with cranio vertebral angle (CVA) within the normal range and below. Materials and Methods. Healthy participants (10 women and 8 men) with an age of 22.7 ± 0.58. The participants took part in the study. They were classified into research groups based on the CVA angle assessment. Postural stability analysis used the Koordynacja stabilometric platform. Measurements were taken with open and closed eyes, before and immediately after suboccipital muscle inhibition. Results. The suboccipital muscle inhibition was observed to affect anterior-posterior (A-P) displacements in group A (CVA &lt; 50) p-value = 0.0168, with no significant impact in group B (CVA ≥ 50), p-value = 0.3695. Conclusion. A single 4-minute suboccipital muscle inhibition procedure does not significantly influence postural stability parameters in the examined groups, except for A-P displacements with open eyes in the CVA &lt; 50 group.

The wear and kinematics of two medially stabilised total knee replacement systems

BackgroundMedially stabilised total knee replacement systems aim to provide a more natural feeling knee replacement by providing increased stability through flexion. The aim of this study was to compare the kinematics and wear of two different medially stabilised total knee replacement systems in an experimental simulation study. The Medial Rotation Knee™ system (MRK) is an early medially stabilised knee (>20 years clinical success); the SAIPH® knee system being a more modern and refined, bone conserving evolution of the original design with a larger size range. MethodsThree SAIPH and three MRK total knee replacements (MatOrtho Ltd, UK) were investigated. The study was performed on a knee simulator with load controlled input kinematic conditions (ISO 14243–1). 6 million cycles of simulation were carried out with the wear of the UHMWPE tibial components assessed gravimetrically. The resulting anterior-posterior translation and tibial rotation position was measured throughout the study. ResultsThe mean UHMWPE wear rate was 0.57 ± 0.71 and 1.24 ± 2.0 mm3/million cycles for SAIPH and MRK total knee replacement systems respectively with no significant difference in wear (p = 0.24). Analysis of simulator output kinematics showed a larger range of anterior-posterior motion for SAIPH total knee replacements compared to MRK. The magnitude of tibial rotation was low for both knee replacement systems. ConclusionThe small magnitude of anterior-posterior displacement and tibial rotation motion demonstrates the inherent stability of this knee system design offered by the constrained medial compartment. This study shows the potential for medially stabilised knee systems as a low polyethylene surface wear solution.

Stimulated cervical afferent input increases postural instability in older people with chronic neck pain: a cross-sectional study

BackgroundSeveral potential causes can impair balance in older people. The neck torsion maneuver may be useful in demonstrating impaired balance caused by the stimulation of cervical proprioceptive input. Whereas evidence suggests impaired standing balance in older people with chronic neck pain, balance impairment during the neck torsion position and its relationship with clinical characteristics have not yet been investigated in this population. The aims of this study were to investigate whether the neck torsion position could significantly influence balance responses in older people with chronic non-specific neck pain and to determine the relationships between the balance responses and characteristics of neck pain.MethodsSixty-eight older people (34 with chronic non-specific neck pain and 34 controls) participated in the study. Balance was tested using a force plate during comfortable stance with eyes open under four conditions: neutral head on a firm surface, neutral head on a soft surface, neck torsion to left and right on a firm surface and neck torsion to left and right on a soft surface. Balance outcomes were anterior-posterior (AP) and medial-lateral (ML) displacements, sway area and velocity. Characteristics of neck pain were intensity, duration and disability.ResultsOverall, the neck pain group exhibited greater AP and ML displacements, sway area and velocity in the neck torsion position on firm and soft surfaces compared to controls (partial eta squared (η²p) = 0.06–0.15, p < 0.05). The neck pain group also had greater AP displacement, sway area and velocity in the neutral position on a soft surface compared to controls (η²p = 0.09–0.16, p < 0.05). For both groups, the neck torsion position displayed overall greater postural sway compared to the neutral position (η²p = 0.16–0.69, p < 0.05). There were no relationships between the postural sway outcomes and characteristics of neck pain (p > 0.05).ConclusionThe neck torsion maneuver, stimulating the receptors resulted in increased postural sway in older people, with a more pronounced effect in those with neck pain. The study provides evidence supporting the use of neck torsion for assessing impaired balance related to abnormal cervical input in older people with chronic non-specific neck pain.

Quantitative analysis of the impact of respiratory state on the heartbeat-induced movements of the heart and its substructures

PurposeThis study seeks to examine the influence of the heartbeat on the position, volume, and shape of the heart and its substructures during various breathing states. The findings of this study will serve as a valuable reference for dose-volume evaluation of the heart and its substructures in radiotherapy for treating thoracic tumors.MethodsTwenty-three healthy volunteers were enrolled in this study, and cine four-dimensional magnetic resonance images were acquired during periods of end-inspiration breath holding (EIBH), end-expiration breath holding (EEBH), and deep end-inspiration breath holding (DIBH). The MR images were used to delineate the heart and its substructures, including the heart, pericardium, left ventricle (LV), left ventricular myocardium, right ventricle (RV), right ventricular myocardium (RVM), ventricular septum (VS), atrial septum (AS), proximal and middle portions of the left anterior descending branch (pmLAD), and proximal portion of the left circumflex coronary branch (pLCX). The changes in each structure with heartbeat were compared among different respiratory states.ResultsCompared with EIBH, EEBH increased the volume of the heart and its substructures by 0.25–3.66%, while the average Dice similarity coefficient (DSC) increased by − 0.25 to 8.7%; however, the differences were not statistically significant. Conversely, the VS decreased by 0.89 mm in the left–right (LR) direction, and the displacement of the RV in the anterior–posterior (AP) direction significantly decreased by 0.76 mm (p < 0.05). Compared with EIBH and EEBH, the average volume of the heart and its substructures decreased by 3.08–17.57% and 4.09–20.43%, respectively, during DIBH. Accordingly, statistically significant differences (p < 0.05) were observed in the volume of the heart, pericardium, LV, RV, RVM, and AS. The average DSC increased by 0–37.04% and − 2.6 to 32.14%, respectively, with statistically significant differences (p < 0.05) found in the right ventricular myocardium and interatrial septum. Furthermore, the displacements under DIBH decreased in the three directions (i.e.,− 1.73 to 3.47 mm and − 0.36 to 2.51 mm). In this regard, the AP displacement of the heart, LV, RV, RVM, LR direction, LV, RV, and AS showed statistically significant differences (p < 0.05). The Hausdorff distance (HD) of the heart and its substructures under the three breathing states are all greater than 11 mm.ConclusionThe variations in the displacement and shape alterations of the heart and its substructures during cardiac motion under various respiratory states are significant. When assessing the dose-volume index of the heart and its substructures during radiotherapy for thoracic tumors, it is essential to account for the combined impacts of cardiac motion and respiration.

Clubfoot patients show more anterior-posterior displacement during one-leg-standing and less ankle power and plantarflexor moment during one-leg-hopping than typically developing children

BackgroundClubfoot patients show good-to-excellent foot correction after the Ponseti method. Nevertheless, underlying functional problems that limit motor abilities such as one-leg-standing and one-leg-hopping still persist. These restrictions have been proposed to arise due to problems with maintaining balance and the limited force-generating capacity of clubfoot patients. More insight is needed to understand the underlying limiting factors to improve overall motor ability in clubfoot patients. Research questionThe aim of this study was to determine the differences between clubfoot patients and typically developing children (TDC) in force and balance parameters during walking, one-leg-standing and hopping. MethodsThree-dimensional motion analysis was performed in 19 TDC and 16 idiopathic Ponseti-treated clubfoot patients between 5–9 years old. Kinematic and kinetic parameters were calculated during walking and one-leg-hopping. To describe the balance parameters, center of pressure (CoP) data was assessed during walking, one-leg-hopping and one-leg-standing. Mean group values were calculated and compared using nonparametric statistical tests. A general linear model with repeated measures was used to determine which activity showed the largest group differences. ResultsClubfoot patients showed lower peak plantarflexor moment and peak ankle power absorption and generation during one-leg-hopping compared to TDC. Furthermore, clubfoot patients showed a lower hop length and velocity than TDC. The difference in peak plantarflexor moment and ankle power between the study groups was larger during one-leg-hopping than during walking. Finally, clubfoot patients showed a higher anterior-posterior CoP range during one-leg-standing. SignificanceDeviations in force parameters seemed to limit one-leg-hopping in clubfoot patients, and impaired anterior-posterior static balance was thought to be the underlying cause of problems with one-leg-standing. Furthermore, one-leg-hopping was more sensitive to distinguish between clubfoot patients and TDC than walking. Individualized physiotherapy targeting static balance and force parameters, with extra emphasis on including eccentric contractions, might improve the overall motor abilities of clubfoot patients.

Difference in the anterior displacement of the tibial tuberosity relative to the proximal tibial fragment between opening wedge and closed wedge high tibial osteotomies.

This study aimed to investigate the anterior-posterior (AP) displacement of the tibial tuberosity (TT) and to assess the difference between closed wedge and opening wedge high tibial osteotomies (OWHTO and CWHTO). One hundred consecutive knees with osteoarthritis that underwent OWHTO (50 knees) or CWHTO (50 knees) were investigated retrospectively. The femorotibial angle (FTA) was measured on AP radiographs of the knee. AP displacement of the TT, posterior tibial slope (PTS), the modified Blackburne-Peel index (mBPI), and the modified Caton-Deschamps index (mCDI) were measured on lateral radiographs of the knee. Patients had a mean correction angle of 12.58±2.84° and 18.98±5.14° (P<0.001), with a mean AP displacement of TT of 0.84±2.66mm and 7.78±3.41mm (P<0.001) in OWHTO and CWHTO, respectively. The AP displacement of the TT per correction of 1° was significantly greater in CWHTO than in OWHTO (P<0.001). A significant correlation was found between the correction angle and AP displacement of the TT in CWHTO (r=-0.523, P<0.001), but not in OWHTO. The change of PTS per correction of 1° was significantly greater in OWHTO than in CWHTO (P<0.001). The changes of mBPI and mCDI per correction of 1° were significantly greater in CWHTO than in OWHTO (P<0.001 and P<0.001, respectively). There was greater anterior displacement of the TT in CWHTO than in OWHTO, which was correlated with the correction angle. The results suggested that CWHTO would be better than OWHTO when a concomitant anteriorization of TT is required.

Isolated meniscus allograft transplantation with soft-tissue technique effectively reduces knee laxity in the presence of previous meniscectomy: In-vivo navigation of 18 consecutive cases

ObjectivesAlthough meniscal allograft transplantation (MAT) is a well-established procedure with satisfactory clinical results, limited in vivo kinematic information exists on the effect of medial and lateral MAT performed in the clinical setting. The purpose of the present study was to evaluate the biomechanical effect of arthroscopic isolated medial and lateral MAT with a soft-tissue fixation on pre- and post-operative knee laxity using a surgical navigation system. Methods18 consecutive patients undergoing MAT (8 medial, 10 lateral) were enrolled. A surgical navigation system was used to quantify the anterior-posterior displacement at 30 and 90 degrees of knee flexion (AP30 and AP90), the varus-valgus rotation at 0 and 30 degrees of knee flexion (VV0 and VV30) and the dynamic laxity on the pivot-shift test (PS), which was determined through the anterior displacement of the lateral tibial compartment (APlat) and posterior acceleration of the lateral tibial compartment during tibial reduction (ACC). Data from laxity before and after MAT were compared through paired t-test (p ​< ​0.05). ResultsAfter medial MAT, there was a significant decrease in tibial translation of 3.1 ​mm (31%; p ​= ​0.001) for AP30 and 2.3 ​mm (27%; p ​= ​0.020) for AP90, a significant difference of 2.5° (50%; p ​= ​0.002) for VV0 and 1.7° (27%; p ​= ​0.012) for VV30. However, medial MAT did not determine any reduction in the PS kinematic data. Lateral MAT determined a significant decrease in the tibial translation of 2.5 ​mm (38%; p ​< ​0.001) for AP30 and 1.9 ​mm (34%; p ​= ​0.004) for AP90 as well as a significant difference of 3.4° (59%; p ​< ​0.001) for VV0 and of 1.7° (23%; p ​= ​0.011) for VV30. There was also a significant reduction of the PS of 4.4 ​mm (22%; p ​= ​0.028) for APlat and 384.8 ​mm/s2 (51%; p ​= ​0.005) for ACC. ConclusionMAT with soft-tissue fixation results in a significant laxity reduction in an in-vivo setting. Medial MAT improved knee kinematics by determining a significant reduction with particular emphasis on AP translation and VV manoeuvre. Conversely, Lateral MAT determined a massive reduction of the PS and a mild decrease of the AP translation and VV manoeuvre. Study designControlled laboratory study.

Effect of isokinetic muscle strength training on knee muscle strength, proprioception, and balance ability in athletes with anterior cruciate ligament reconstruction: a randomised control trial.

Objective: This study aimed to investigate the effects of regular isokinetic muscle strength training on knee muscle strength, proprioception, and balance ability in athletes after anterior cruciate ligament (ACL) reconstruction. Methods: Forty-one athletes who underwent ACL reconstruction were randomly divided into the experimental (n = 21) and control (n = 20) groups. The experimental group used an isokinetic muscle strength tester for 4weeks (five times/ week) of knee flexion and extension isokinetic muscle strength training. The control group used the knee joint trainer (pneumatic resistance) for the same exercise regimen as the experimental group. Results: 1) Four weeks when compared with the baseline. Experimental group: the knee flexion and extension PT (60°/s and 240°/s) increased by 31.7%, 40.3%, 23.4%, and 42.9% (p < 0.01), and the flexion muscular endurance increased by 21.4% and 19.7% (p < 0.01). The flexion and extension kinaesthesia and the 30° and 60° position sense decreased by 36.2%, 32.3%, 40.0%, and 18.9% (p < 0.05). The anterior-posterior and medial-lateral displacement and speed decreased by 30.2%, 44.2%, 38.4%, and 24.0% (p < 0.05). Control group: the knee peak torque (60°/s) increased by 18.8% (p < 0.01). The anterior-posterior and medial-lateral displacement and speed decreased by 14.9%, 40.0%, 26.8%, and 19.5% (p < 0.01). 2) After 4weeks, compared with the control group, the knee flexion and extension peak torque (60°/s), extension, peak torque (240°/s), and extension muscular endurance of the treatment group increased to varying degrees (p < 0.05). However, the kinaesthesia, 30° position sense, and anterior-posterior displacement decreased to varying degrees (p < 0.05). Conclusion: Adding regular isokinetic muscle strength training to rehabilitation training further improved the knee flexion and extensor strength and extensor endurance of athletes with ACL reconstruction, as well as enhanced the kinaesthesia and 30° position sense and the balance between the anterior and posterior directions. However, the treatment had limited effects on knee flexion kinaesthesia and muscle endurance.

Relationship between seminal vesicle displacement and distribution of hydrogel spacer within the perirectal space in prostate radiotherapy.

The influence of a hydrogel spacer (HS) on seminal vesicle (SV) displacement in prostate radiotherapy was examined in the present study. A total of 20 patients with prostate cancer, who received intensity-modulated radiation therapy (IMRT), were enrolled. Computed tomography and magnetic resonance imaging were performed before and after HS insertion within the peripheral space for IMRT planning. Before and after HS insertion, The SV was delineated, and the amount of SV displacement was evaluated. Large SV cranial displacements (≥0.50 cm) were observed in 25% of patients. A HS lateral distribution of ≥1.00 cm in the upper two slices (midgland + superior) influenced the SV cranial displacements (P<0.01) and was associated with large SV cranial displacements (≥0.5 cm) (P<0.01). The HS cranial distribution in the upper slices did not influence SV cranial displacements (P=0.16). In addition, any HS lateral distribution of ≥1.00 cm in all slices did not induce the SV lateral and anterior-posterior displacements (P=0.50 and 0.70, respectively). In conclusion, SV cranial displacement was influenced by HS lateral distribution of ≥1.00 cm in the upper two slices. Therefore, when the sigmoid colon or small bowel is depressed in rectovesical excavation and SV needs to be included in the target volume, HS insertion should be performed carefully.

Comparison of accuracy for hip-knee-ankle (HKA) angle by X-ray and knee motion analysis system and the relationships between HKA and gait posture

BackgroundThe lower limb mechanical axis was used to assess the severity of knee osteoarthritis (KOA) with varus/valgus deformity and the accuracy of targeted lower limb alignment correction after operation by conventional X-rays. There are lots of parameters to assess the gait in elder patients such as velocity, stride length, step width and swing/stance ratio by knee joint movement analysis system. However, the correlation between the lower limb mechanical axis and gait parameters is not clear. This study is aimed at obtaining the accuracy of the lower limb mechanical axis by the knee joint movement analysis system and the correlation between the lower limb mechanical axis and gait parameters.MethodsWe analysed 3D knee kinematics during ground gait of 99 patients with KOA and 80 patients 6 months after the operations with the vivo infrared navigation 3D portable knee joint movement analysis system (Opti-Knee®, Innomotion Inc, Shanghai, China). The HKA (Hip-Knee-Ankle) value was calculated and compared to X-ray findings.ResultsHKA absolute variation after the operation was 0.83 ± 3.76°, which is lower than that before the operation (5.41 ± 6.20°, p = 0.001) and also lower than the entire cohort (3.36 ± 5.72). Throughout the cohort, a significant correlation with low coefficients (r = -0.19, p = 0.01) between HKA value and anterior-posterior displacement was found. In comparing the HKA values measured on the full-length alignment radiographs and 3D knee joint movement analysis system (Opti-Knee), there was a significant correlation with moderate to high coefficients (r = 0.784 to 0.976). The linear correlation analysis showed that there was a significant correlation between the values of HKA measured by X-ray and movement analysis system (R2 = 0.90, p < 0.01).ConclusionsData with equivalent results as HKA, the 6DOF of the knee and ground gait data could be provided by infrared navigation based 3D portable knee joint movement analysis system comparing with the conventional X-rays. There is no significant effect of HKA on the kinematics of the partial knee joint.

(A)symmetry during gait initiation in people with Parkinson's disease: A motor and cortical activity exploratory study.

Gait asymmetry and deficits in gait initiation (GI) are among the most disabling symptoms in people with Parkinson's disease (PwPD). Understanding if PwPD with reduced asymmetry during GI have higher asymmetry in cortical activity may provide support for an adaptive mechanism to improve GI, particularly in the presence of an obstacle. This study quantified the asymmetry of anticipatory postural adjustments (APAs), stepping parameters and cortical activity during GI, and tested if the presence of an obstacle regulates asymmetry in PwPD. Sixteen PwPD and 16 control group (CG) performed 20-trials in two conditions: unobstructed and obstructed GI with right and left limbs. We measured, through symmetry index, (i) motor parameters: APAs and stepping, and (ii) cortical activity: the PSD of the frontal, sensorimotor and occipital areas during APA, STEP-I (moment of heel-off of the leading foot in the GI until the heel contact of the same foot); and STEP-II (moment of the heel-off of the trailing foot in the GI until the heel contact of the same foot) phases. Parkinson's disease showed higher asymmetry in cortical activity during APA, STEP-I and STEP-II phases and step velocity (STEP-II phase) during unobstructed GI than CG. However, unexpectedly, PwPD reduced the level of asymmetry of anterior-posterior displacement (p < 0.01) and medial-lateral velocity (p < 0.05) of the APAs. Also, when an obstacle was in place, PwPD showed higher APAs asymmetry (medial-lateral velocity: p < 0.002), with reduced and increased asymmetry of the cortical activity during APA and STEP-I phases, respectively. Parkinson's disease were not motor asymmetric during GI, indicating that higher cortical activity asymmetry can be interpreted as an adaptive behavior to reduce motor asymmetry. In addition, the presence of obstacle did not regulate motor asymmetry during GI in PwPD.

Comparison between passive knee kinematics during surgery and active knee kinematics during walking: A preliminary study.

Recovery of function is among a patient's main expectations when undergoing total knee arthroplasty (TKA). However, normal gait knee function is not always completely restored, which can affect patient satisfaction and quality of life. Computer-assisted surgery (CAS) allows surgeons to evaluate passive knee kinematics intra-operatively. Understanding associations between knee kinematics measured during surgery and during daily activities, such as walking, could help define criteria for success based on knee function and not only on the correct alignment of the implant or the leg. This preliminary study compared passive knee kinematics measured during surgery with active kinematics measured during walking. Eight patients underwent a treadmill gait analysis using the KneeKG™ system both before surgery and three months afterwards. Knee kinematics were measured during CAS both before and after TKA implantation. The anatomical axes of the KneeKG™ and CAS systems were homogenised using a two-level, multi-body kinematics optimisation with a kinematic chain based on the calibration measured during CAS. A Bland-Altman analysis was performed before and after TKA for adduction-abduction angle, internal-external rotation, and anterior-posterior displacement over the whole gait cycle, at the single stance phase and at the swing phase. Homogenising the anatomical axes between CAS and treadmill gait led to limited median bias and limits of agreement (post-surgery -0.6 ± 3.6 deg, -2.7 ± 3.6 deg, and -0.2 ± 2.4 mm for adduction-abduction, internal-external rotation and anterior-posterior displacement, respectively). At the individual level, correlations between the two systems were mostly weak (R2 < 0.3) over the whole gait cycle, indicating low kinematic consistency between the two measurements. However, correlations were better at the phase level, especially the swing phase. The multiple sources of differences did not enable us to conclude whether they came from anatomical and biomechanical differences or from measurement system errors.

Manipulations of Oblique Pulling Affect Sacroiliac Joint Displacements and Ligament Strains: A Finite Element Analysis.

Clinical studies have found that manipulation of oblique pulling has a good clinical effect on sacroiliac joint pain. However, there is no uniform standard for manipulation of oblique pulling at present. The purpose of this study was to investigate the effects of four manipulations of oblique pulling on sacroiliac joint and surrounding ligaments. A three-dimensional finite element model of the pelvis was established. Four manipulations of oblique pulling were simulated. The stresses and displacements of sacroiliac joint and the strains of surrounding ligaments were analyzed under four manipulations of oblique pulling. Manipulation of oblique pulling F2 and F3 caused the highest and lowest stress on the pelvis, at 85.0 and 52.6 MPa, respectively. Manipulation of oblique pulling F3 and F1 produced the highest and lowest stress on the left sacroiliac joint, at 6.6 and 5.6 MPa, respectively. The four manipulations of oblique pulling mainly produced anterior-posterior displacement. The maximum value was 1.21 mm, produced by manipulation of oblique pulling F2, while the minimal value was 0.96 mm, produced by manipulation of oblique pulling F3. The four manipulations of oblique pulling could all cause different degrees of ligament strain, and manipulation of oblique pulling F2 produced the greatest ligament strain. The four manipulations of oblique pulling all produced small displacements of sacroiliac joint. However, they produced different degrees of ligament strain. Manipulation of oblique pulling F2 produced the largest displacement of sacroiliac joint and the greatest ligament strain, which could provide a certain reference for physiotherapists.

Observations on the kinematic characteristics of the healthy side of the knee in stroke patients: A cross-sectional study.

The abnormal gait of stroke patients not only severely limits the recovery of their walking ability, but also seriously affects their quality of daily life. Previous observational studies have focused too much on the observation of single degree of freedom and axial knee motion angles in stroke patients. Changes in the multi-degree of freedom and multi-axial joint angles of the knee have been less frequently observed, leading to somewhat limited conclusions. Therefore, the aim of this study was to use the Opti-knee motion test to analyze in real time the motion of the knee in all directions on the healthy side of stroke patients and to compare it with normal gait to provide a clinical basis for subsequent rehabilitation. In a cross-sectional study, 120 subjects (60 stroke patients were as the observation group and 60 healthy subjects as the control group) were studied. Both groups of subjects were tested for Opti-Knee tri-axial angles of motion of the healthy side of the knee, including flexion and extension, internal and external rotation, internal and external turning, anterior and posterior displacement, superior and inferior displacement, left and right displacement, maximum extension angle and maximum flexion angle. Compared with the control group, there were significant changes in the joint angles of flexion and extension, internal and external rotation, internal and external turning, maximum extension and maximum flexion of the knee on the healthy side in the observation group, and the differences were statistically significant [95%(37.22, 45.13), P = .01], [95%(9.51,13.67), P = .018], [95%(4.82,7.57), P = .049], [95%(4.12, 8.63), P = .019], [95%(51.68, 57.28), P = .0001]. However, there was no significant change in the angle of motion of the healthy side of the knee for anterior-posterior displacement, superior-inferior displacement and internal-external displacement in either group and the differences were not statistically significant [95%(1.16, 1.78), P = .72], [95%(0.85,1.32), P = .32], [95%(0.57, 0.88), P = .36]. This study confirms the importance of changes in the angle of motion of the knee on the side of the stroke patient in maintaining the stability of the knee joint. Therefore, their bilateral lower limb symmetry training should be paid attention to in the subsequent rehabilitation treatment.

The influence of sacroiliac joint reduction quality on the clinical effect of bionic reduction and internal fixation for pelvic ring injury

Objective: To examine the influence of sacroiliac joint reduction quality on the clinical effect of bionic reduction and internal fixation for pelvic ring injury. Methods: From January 2014 to February 2019,the clinical data of 78 patients diagnosed with pelvic ring injury involving sacroiliac joints and treated with bionic reduction and internal fixation at Honghui Hospital Affiliated to Medical College of Xi'an Jiaotong University were retrospectively analyzed.There were 48 males and 30 females,aged (48.3±8.3)years (range:28 to 68 years).After bionic reduction and internal fixation,the patients were grouped according to the maximum displacement distance (d) of sacroiliac joint residual on the damaged side measured by CT examination. Patients with d≤5 mm were included in anatomical bionic reduction group,and patients with d>5 mm were included in non-anatomical bionic reduction group.In non-anatomical bionic reduction group,according to the direction of residual displacement,the patients were divided into separation displacement group and anterior-posterior displacement group. The X-ray examination was performed immediately and at the last follow-up after operation.If sacroiliac joint was relocated,or internal plant loosening,displacement,fracture and re-displacement of fracture,it was defined as internal fixation failure.Majeed pelvic fracture scoring system was used to evaluate the postoperative functional status of the two groups,and visual analogue scale (VAS) was used to evaluate the postoperative pain.Comparison between groups was performed by completely random design ANOVA,χ2 test,Fisher's exact test,Mann-Whitney U and Kruskal-Wallis H test. Results: According to the CT examination,28 cases were included in anatomical bionic reduction group,and 50 cases were included in non-anatomical bionic reduction group.In non-anatomical bionic reduction group,27 cases were divided into separation displacement group and 23 cases were in anterior-posterior displacement group.There was no significant difference in general data among anatomical bionic reduction group,separation displacement group and anterior-posterior displacement group (P>0.05). The follow-up time was (37.8±6.6) months (range:25 to 51 months). At the last follow up,the excellent and good rate of Majeed score in anatomical bionic reduction group was 96.4%(27/28),which was better than that in separation displacement group(74.1%(20/27)) and anterior-posterior displacement group (30.4%(7/23)),the difference was statistically significant (Z=-6.479,P<0.01;Z=-6.256,P<0.01); and the good rate of the separation displacement group was better than that of the anterior-posterior displacement group(Z=-3.607,P<0.01).The VAS of anatomical bionic reduction group (17 cases with 0 point, 11 cases with 1 to 3 points) were lower than that of the displacement group (6 cases with 0 point,16 cases with 1 to 3 points,5 cases with 4 to 6 points) and anterior-posterior displacement group (3 cases with 0 point,7 cases with 1 to 3 points,13 cases with 4 to 6 points),the difference was statistically significant (Z=-3.515,P<0.01;Z=-3.506,P<0.01),and there was no difference between separation displacement group and anterior-posterior displacement group.Total of 8 cases of internal fixation failure occurred,and the failure rate of anatomical bionic reduction group (0,0/28) was lower than that of the separation displacement group (11.1%,3/27) and anterior-posterior displacement group (21.7%,5/23) (P=0.111,P=0.014),and there was no difference between separation displacement group and anterior-posterior displacement group(P=0.444). Conclusions: In the bionic reduction and internal fixation of pelvic fracture involving sacroiliac joint injury,the functional status,pain and internal fixation failure rate of patients with anatomical bionic reduction of sacroiliac joint are significantly better than those in the non-anatomical bionic reduction.The functional recovery of patients with separation displacement is better than that of the patients with anterior and posterior displacement.

A multiple domain postural control assessment in people with Parkinson’s disease: traditional, non-linear, and rambling and trembling trajectories analysis

BackgroundPostural impairment is one of the most debilitating symptoms in people with Parkinson's disease (PD), which show faster and more variable oscillation during quiet stance than neurologically healthy individuals. Despite the center of pressure parameters can characterize PD’s body sway, they are limited to uncover underlying mechanisms of postural stability and instability. Research questionDo a multiple domain analysis, including postural adaptability and rambling and trembling components, explain underlying postural stability and instability mechanisms in people with PD? MethodTwenty-four individuals (12 people with PD and 12 neurologically healthy peers) performed three 60-s trials of upright quiet standing on a force platform. Traditional and non-linear parameters (Detrended Fluctuation Analysis- DFA and Multiscale Entropy- MSE) and rambling and trembling trajectories were calculated for anterior-posterior (AP) and medial-lateral (ML) directions. ResultsPDG’s postural control was worse compared to CG, displaying longer displacement, higher velocity, and RMS. Univariate analyses revealed largely longer displacement and RMS only for the AP direction and largely higher velocity for both AP and ML directions. Also, PD individuals showed lower AP complexity, higher AP and ML DFA, and increased AP and ML displacement, velocity, and RMS of rambling and trembling components compared to neurologically healthy individuals. SignificanceBased upon these results, people with PD have a lower capacity to adapt posture and impaired both rambling and trembling components compared to neurologically healthy individuals. These findings provide new insights to explain the larger, faster, and more variable sway in people with PD.

Understanding the differences in wear testing method standards for total knee replacement

Preclinical evaluation of the wear of total knee replacements (TKR) is usually undertaken using International Standards Organization (ISO) test methods. Two international standards for the preclinical wear simulation of TKRs have been developed; using either force or displacement control. In addition, based on previously published measured kinematics of healthy subjects, a gait cycle (displacement control) was also developed at the University of Leeds, which pre-dates the ISO displacement control standard. Furthermore, different test methods have adopted different approaches to defining the centres of rotation and polarity (direction of application) of motions. However, the effects of using these different control regimes and input conditions on the kinematics, contact mechanics, and wear of any one TKR have not been fully investigated previously.The current study investigated the kinematics, contact mechanics, and wear performance of a TKR when running under ISO force and displacement control test methods as well as the Leeds gait cycle inputs using experimental and computational simulation methods, with the aim of understanding the mechanical and tribological outcomes predicted by the different test method standard conditions. Three ISO wear testing standards were investigated using a mid-size Sigma curved TKR (DePuy, UK), with moderately cross-linked UHMWPE curved inserts; ISO-14243-3-2004, ISO-14243-3-2014 and ISO-14243-1-2009. In addition, the Leeds displacement control gait cycle was also investigated.According to the computational simulation predictions, reversing the anterior-posterior (AP) displacement and tibial rotation polarities in the displacement control ISO-2014 standard compared to the ISO-2004 standard resulted in high stress, of more than 65 MPa, at the posterior edge of the inserts with more than 10% increase in wear rate for this TKR design. Although Leeds gait input kinematics produced femoral rollback, it did not result in high stress edge loading on the posterior lip of the insert. This was attributed to different test input kinematics and different centres of rotation of the femoral component adopted in the displacement control standard ISO-2014 and Leeds gait test methods. The predicted AP displacement and tibial rotation from the force control ISO-2009 had different polarities and magnitudes to the corresponding displacement control profiles. In addition, the predicted wear rate, from the computational model, under the force control ISO-2009 standard was more than double that predicted under displacement control ISO standards due to the increased AP displacement and tibial rotation motions predicted under the force control standard.These major differences, in the mechanics and wear, between different test methods imply that each standard must therefore be used with its own predicate control results from a device with proven clinical history and results across different standards should never be compared, as the choice of test method standard may well be dependent on the design solution for the knee. Clinically, the kinematics in the population are extremely variable, which results in highly variable wear rates. While a standard method is necessary, on its own it is not adequate and needs to be supported by tests under a portfolio of representative conditions with different kinematic conditions, different soft tissue constraints, as well as with different alignments, so that the variability and range of wear rates expected clinically might be determined. This study enables further progress towards the definition of such a portfolio of representative conditions, by deepening the understanding of the relationships between currently used input conditions and the resulting mechanical and wear outputs.