Hip Kinematics Research Articles

Trunk flexion during walking in people with knee osteoarthritis

BackgroundOver 50% of the body’s mass is concentrated within the head, arms and trunk. Thus, small deviations in the orientation of the trunk, during normal walking, could influence the position of the centre of mass relative to the lower limb joint centres and impact on lower limb biomechanics. However, there are minimal data available on sagittal kinematics of the trunk in people with knee osteoarthritis (OA) during walking. Research questionDo people with knee OA have altered kinematic patterns of the trunk, pelvis or hip compared with healthy control participants during walking? MethodsStatistical parametric mapping was used to compare sagittal and frontal plane kinematic patterns, during walking, between a healthy group and cohort of people with knee OA. ResultsIndividuals with knee OA walked with a mean increase in trunk flexion of 2.6°. Although this difference was more pronounced during early stance, it was maintained across the whole of stance phase. There were no differences, between the groups, in sagittal plane pelvic or hip kinematics. There were also no differences in trunk, pelvic or hip kinematics in the frontal plane. SignificanceMost previous gait research investigating trunk motion in people with knee OA has focused on the frontal plane. However, our data suggest that an increase in sagittal trunk flexion may be a clinical hallmark of people with this disease. Altered trunk flexion could affect joint moments and muscle patterns and therefore our results motivate further research in this area.

In vivo kinematic analysis of replaced hip during stationary cycling and computer simulation of optimal cup positioning against prosthetic impingement

BackgroundDynamic hip kinematics during stationary cycling after total hip arthroplasty (THA) have been unclear. Furthermore, no computer simulation of optimal cup position based on in vivo kinematics has yet been assessed. MethodsThis study consisted of 7 patients who underwent unilateral primary THA for symptomatic osteoarthritis. Using a flat-panel X-ray detector, continuous radiographs were obtained during stationary cycling. We analyzed the three-dimensional replaced hip kinematics from the top to the bottom position of the crank using image-matching techniques and quantified minimum liner-to-stem neck distance. Simulation analyses with in vivo kinematics were performed to examine patient-specific optimal cup placement against prosthetic impingement. FindingsDuring stationary cycling, pelvis showed 27.1° of posterior tilt on average without significant change. Hip flexed by 59.4° and 19.3° on average at the top and bottom positions, respectively. Minimum liner-to-neck distance was 8.8 mm on average at the bottom position. Liner-to-neck, bone-to-bone, or bone-to-component impingement was not observed at any positions in any hips. Simulation analysis of cup placement showed that larger cup anteversion, inclination, and use of elevated liner significantly decreased the minimum distance between posterior liner and stem neck. Cup anteversion of more than 30° with elevated liner could cause posterior liner-to-neck impingement at bottom position. InterpretationStationary cycling after THA provides no excessive hip range of motion or liner-to-neck contact. Cup placement and use of elevated liner significantly influence the minimum liner-to-neck distance, in some cases simulating posterior prosthetic impingement.

Hip and knee kinematics of the forward lunge one year after unicondylar and total knee arthroplasty

Patients with unicondylar knee arthroplasty (UKA) report higher functionality compared to those with total knee arthroplasty (TKA). However, these patients should also be assessed during more demanding tasks in order to appreciate their true functionality. The forward lunge (FL) is a motor task commonly used in clinics to evaluate functional recovery after knee replacement surgery. Unfortunately, clear evidence comparing FL kinematics between patients with UKA and TKA is still missing. The purpose of this study was to compare hip and knee joint kinematics during the FL between patients with UKA, TKA and controls. Twenty subjects (8 TKA, 6 UKA, 6 controls) underwent 3D motion analysis during a FL. Differences in hip and knee kinematics between groups were identified using statistical parametric mapping. We concluded that patients with TKA demonstrated reduced knee and hip flexion angles during the loaded phase of the FL, which could have been an attempt to unload the knee joint. This is in contrast to patients with UKA, who showed similar knee and hip joint kinematics compared to controls throughout the entire FL. It seems that retaining the cruciate ligaments is beneficial for the execution of a complex motor task such as the FL.

Effect of a Combined Stretching and Strength Training Program on Gait Function in Children with Cerebral Palsy, GMFCS Level I & II: A Randomized Controlled Trial.

Background and objectives: Ambulant children with cerebral palsy (CP) often develop impaired gait, and reduced active knee extension is often a part of the problem. This study aimed to evaluate the effect of a combined intervention program including stretching and progressive resistance exercise (PRE) targeting active knee extension on gait function, in children with spastic CP. Materials and methods: Thirty-seven children (21 boys, 16 girls, mean age 10.2 (±2.3) years), classified by Gross Motor Function Classification System I–III, were randomized to an intervention (n = 17) and a comparison group (n = 20). The intervention group received a 16-week combined exercise program (3 sessions per week) including stretching of hamstrings and PRE targeting the lower extremities, followed by a 16-week maintenance program (1 session per week). The comparison group received care as usual. Gait function was evaluated by three-dimensional gait analysis (3DGA); knee, hip and pelvic kinematics in the sagittal plane, step length and speed, Gait Deviation Index (GDI), and Six-Minute Walk test (6MWT) at 0, 16, and 32 weeks. Results: There were no statistically significant differences between the intervention group and the comparison group for any of the gait parameters measured at 16 and 32 weeks. There was a significant increase in gait distance measured by 6MWT within both groups; however, no differences between the groups were found. Conclusion: A 16-week combined stretching and PRE program followed by a 16-week maintenance program did not improve gait function in ambulant children with CP.

In vivo kinematics, component alignment and hardware variables influence on the liner-to-neck clearance during chair-rising after total hip arthroplasty

BackgroundThere is an interest in quantifying dynamic hip kinematics before and after total hip arthroplasty (THA) during chair-rising: one of daily life activities. MethodsThe study consisted of 21 patients who underwent unilateral total hip arthroplasty for symptomatic osteoarthritis. We obtained continuous radiographs using a flat-panel X-ray detector while the participants rose from chair. We assessed the pre and postoperative hip joint's movements using three-dimensional-to-two-dimensional model-to-image registration techniques. We also measured minimum liner-to-neck distances at maximum hip flexion and extension as anterior and posterior liner-to-neck distances, respectively. Multivariate analyses were applied to determine which factors were associated with liner-to-neck distances. ResultsThe cup inclination, cup anteversion, and stem anteversion averaged 37.4°, 23.1°, and 30.1°, respectively. Significantly larger maximum hip flexion angle (72°) was found during chair-rising after THA compared to that before THA (63°, P < 0.01). The anterior pelvic tilt at the maximum hip flexion after THA (3° of anterior tilt) was significantly (P < 0.05) anterior compared to that before THA (1° of posterior tilt). The anterior and posterior liner-to-neck distances averaged 12.3 mm and 8.1 mm, respectively, with a significant difference (P < 0.01). No liner-to-neck contact was found in any hips. In multivariate analysis, the hip flexion angle, cup inclination, stem anteversion and head diameter were significantly associated with the anterior liner-to-neck distance (P < 0.05), the hip extension angle, cup anteversion, neck length and with or without elevated rim were significantly associated with the posterior liner-to-neck distance (P < 0.05, 0.01, 0.05, 0.01, respectively). ConclusionThis study indicates that well-positioned THA provide increased range of hip flexion with sufficient anterior liner-to-neck clearance during chair-rising. Dynamic hip kinematics, component position, and hardware variables significantly influenced on the liner-to-neck clearance under weight-bearing conditions.

Modified gait patterns due to cam FAI syndrome remain unchanged after surgery

BackgroundIn order to reduce the development of hip osteoarthritis related to cam-type femoroacetabular impingement syndrome (FAIS), corrective surgery has evolved to become a safe and effective treatment. Although corrective surgery produces high level of patient satisfaction, it is still unclear how it affects muscle and hip contact forces during level walking. Research questionThe purpose was to compare the muscle force contributions and hip contact forces in patients before and after surgical correction for cam FAIS with healthy control (CTRL) individuals during level walking. MethodsEleven male patients with symptomatic cam-type morphology, who underwent hip osteochondroplasty, had their level walking recorded pre- and at 2-year postoperatively. The patients were sex-, age-, BMI-matched to 11 CTRL individuals. Sagittal and frontal hip kinematics and kinetics were computed and, subsequently, muscle and hip contact forces were estimated using musculoskeletal modelling and static optimization. ResultsPatient-reported outcomes improved postoperatively. The pre- and postoperative FAIS walked slower and with shorter steps than the CTRL. Postoperative biceps femoris (CTRL: 0.35 ± 0.13 N/BW; pre-op: 0.28 ± 0.11 N/BW; post-op: 0.20 ± 0.07 N/BW) and semimembranosus forces (CTRL: 0.77 ± 0.24 N/BW; pre-op: 0.66 ± 0.24 N/BW; post-op: 0.41 ± 0.14 N/BW) were lower at ipsilateral foot-strike. Postoperative rectus femoris force (CTRL: 1.73 ± 0.35 N/BW; pre-op: 1.44 ± 0.24 N/BW; post-op: 1.18 ± 0.23 N/BW) was lower than the other two groups, and the pre- and postoperative FAIS had lower iliacus (CTRL: 1.17 ± 0.18 N/BW; pre-op: 0.93 ± 0.16 N/BW; post-op: 0.94 ± 0.21 N/BW) and psoas (CTRL: 1.55 ± 0.24 N/BW; pre-op: 1.14 ± 0.38 N/BW; post-op: 1.10 ± 0.46 N/BW) muscle forces at contralateral foot-strike compared with the CTRL. Pre- and postoperative FAIS demonstrated lower peak hip contact loading resultant than the CTRL. SignificanceThe altered gait parameters observed in the preoperative FAIS was not restored after surgery, and was still away from the CTRL. It is possible that the reduced dynamic muscle forces of the biceps femoris, semimembranosus and rectus femoris postoperatively were associated with the protected mechanism that involved the iliopsoas preoperatively. This is an indication that the gait adaptations affected by the FAIS do not restore to normal after surgical correction at the 2-years follow-up.

Lower limb biomechanics during low- and high-impact functional tasks differ between men and women with hip-related groin pain

BackgroundThe effect of pain on lower limb biomechanics during walking has been found to be sex specific for certain joint diseases. However, it is not known if sex is an effect-modifier in people with hip pain. Therefore, the aim of the study was to determine the differences in lower limb biomechanics between men and women with hip-related groin pain during functional tasks. Methods65 male and 23 female football players with hip-related groin pain were recruited. Biomechanical data were recorded during walking and the single-leg drop jump. Hip, knee and ankle joint kinematics and kinetics were calculated. Differences between men and women were assessed using statistical parametric mapping. FindingsWalking: Men with hip-related groin pain walked with lower hip flexion and internal rotation angles during stance compared to women. During different sections of stance, men also displayed a lower hip adduction angle and ‘external’ adduction moment, a lower knee flexion angle and ‘external’ flexion moment, as well as greater ‘external’ dorsi-flexion moment and impulse.Single-leg drop jump: Men with hip-related groin pain displayed a lower hip flexion angle during early stance, and greater ‘external’ knee flexion and ankle dorsi-flexion moments. The impulse of the ‘external’ dorsi-flexion moment was also greater for men compared to women. InterpretationMen and women with hip-related groin pain display differing lower limb biomechanics in both low and high impact tasks. Sex may therefore be a potential effect modifier in people with hip-related groin pain. Future research in this area should incorporate sex-specific analyses. Trial registration numberNA.

Predictors of Walking Efficiency in Children With Cerebral Palsy: Lower-Body Joint Angles, Moments, and Power.

People with cerebral palsy (CP) experience increased muscle stiffness, muscle weakness, and reduced joint range of motion. This can lead to an abnormal pattern of gait, which can increase the energy cost of walking and contribute to reduced participation in physical activity. The aim of the study was to examine associations between lower-body joint angles, moments, power, and walking efficiency in adolescents with CP. This was a cross-sectional study. Sixty-four adolescents aged 10 to 19 years with CP were recruited. Walking efficiency was measured as the net nondimensional oxygen cost (NNcost) during 6 minutes of overground walking at self-selected speed. Lower-body kinematics and kinetics during walking were collected with 3-dimensional motion analysis, synchronized with a treadmill with integrated force plates. The associations between the kinematics, kinetics, and NNcost were examined with multivariable linear regression. After adjusting for age, sex, and Gross Motor Function Classification System level, maximum knee extension angle (β=-0.006), hip angle at midstance (β=-0.007), and maximum hip extension (β=-0.008) were associated with NNcost. Age was a significant modifier of the association between the NNcost and a number of kinematic variables. This study examined kinetic and kinematic variables in the sagittal plane only. A high interindividual variation in gait pattern could have influenced the results. Reduced knee and hip joint extension are associated with gait inefficiency in adolescents with CP. Age is a significant factor influencing associations between ankle, knee, and hip joint kinematics and gait efficiency. Therapeutic interventions should investigate ways to increase knee and hip joint extension in adolescents with CP.

Influence of Testing Position on Hip Torque and Relationships with Frontal Plane Kinematics in Females

The relationship between hip extension, abduction, and external rotation torque has been correlated to frontal plane biomechanics during functional tasks like the single leg squat. Altering testing position has been identified to influence torque output for hip extension, abduction, and external rotation. However, comparing the relationship between hip torque at different testing positions and frontal plane hip and knee squatting kinematics has yet to be evaluated. PURPOSE: To assess the influence of testing position on hip extension, abduction, and external rotation torque in females and relationships to frontal plane squatting kinematics. METHODS: Isometric hip torque was assessed in 19 college aged females at varying degrees of hip flexion. Torque was assessed with hand-held dynamometry for hip extension (0, 45, and 90 degrees of hip flexion); hip abduction (-5, 0, and 45 degrees of hip flexion); and hip external rotation (0, 45 and 90 degrees of hip flexion). Five single leg squats were also completed for 2-dimensional analysis of frontal plane hip and knee kinematics. Repeated measures ANOVAs were used to evaluate differences in hip torque across testing positions. Relationships between hip torque and frontal plane hip and knee kinematics during a single leg squat were explored with correlations. Significance was set at p<.05. RESULT: Greater torque was seen during hip extension at 90 degrees of hip flexion (0.74±0.25Nm/kg*m) compared to both 0 (0.43±0.14Nm/kg*m) and 45 (0.50±0.19Nm/kg*m) degrees of flexion (p<.001). A significant decrease in hip abduction torque was seen at 45 degrees of hip flexion (0.44±0.15Nm/kg*m) compared to both -5 (0.58±0.21Nm/kg*m) and 0 (0.63±0.24Nm/kg*m) degree testing position (p<.001). No differences in torque were seen for hip external rotation. Significant, positive, and moderate correlations were seen with hip extension torque and hip adduction kinematics at 90 degrees of hip flexion (r=.544, p=.016) compared to 0 (r=.490, p=.033) and 45 (r=.477, p=.039) degrees of hip flexion. No significant correlations were seen between squatting kinematics and hip abduction or external rotation torque. CONCLUSION: Testing position alters hip torque in healthy aged females but does not influence the relationship between torque and lower extremity kinematics of a single leg squat.

Effect of Sex on Linear and Nonlinear Kinematic Variability during a Stop Jump

Women are 4 to 6 times more likely to sustain a non-contact ACL injury compared to men. Sex differences in lower extremity landing mechanics are believed to be associated with this increased risk. However, no previous studies have examined sex-specific differences in the variability of lower extremity mechanics during a landing. Variability may provide unique information regarding movement control which pertains to injury risk. PURPOSE: To compare variability in hip and knee kinematics during a stop jump between men and women. METHODS: 22 male and 20 female healthy uninjured individuals completed seven bilateral stop jumps while lower extremity kinematics and kinetics were collected. Hip and knee joint 3D kinematics were calculated from initial contact to toe off of the first landing and time normalized using Visual 3D. Linear variability was quantified as the standard deviation of peak knee flexion and peak knee ab/adduction across the seven trials, then as the average standard deviation during ground contact. Joint couples were created between knee flexion and knee abduction, hip flexion and knee abduction, hip rotation and knee abduction, knee flexion and knee flexion velocity, and knee abduction and knee abduction velocity, all isolated to the landing phase. Vector coding variability and divergence of nearest neighboring trajectories was quantified for each couple and divergence was quantified for knee flexion and knee abduction angle time series. All variability outcome measures were compared between sex for the dominant limb only using independent t-tests. RESULTS: There were no sex-based differences when looking at any linear variability measures. Women had increased vector coding variability for the knee abduction/knee abduction velocity coupling (F: 36°±12°, M: 29°±7°, p=0.025). Women had increased trajectory divergence of knee abduction angles (F: 1.3°/s ±.4°/s, M: 1.0°/s ±.3°/s, p=0.009) and of the knee abduction/knee abduction velocity coupling (F: 1.4°/s±.4°/s, M: 1.1°/s ±.3°/s, p=0.013). No other sex-specific differences were observed. CONCLUSION: Women have increased knee kinematic variability during landing then men, particularly when looking at knee abduction. Linear methods of quantifying variability may be insensitive for identifying sex differences in landing variability.

Altered movement strategies during jump landing/cutting in patients with chronic ankle instability.

Centrally mediated changes in sensorimotor function have been reported in patients with chronic ankle instability (CAI). However, little is known regarding supraspinal/spinal adaptations during lower-extremity dynamic movement during a multiplanar, single-leg landing/cutting task. The purpose of this study was to investigate the effect of CAI on landing/cutting neuromechanics, including lower-extremity kinematic, electromyography (EMG) activation, and ground reaction force (GRF) characteristics. One hundred CAI patients and 100 matched healthy controls performed five trials of a jump landing/cutting task. Sagittal- and frontal-plane ankle, knee and hip kinematics, EMG activation in eight lower-extremity muscles, and 3D GRF were collected during jump landing/cutting. Functional analyses of variance (FANOVA) were used to evaluate between-group differences for dependent variables throughout the entire ground contact of the task. Relative to the control group, the CAI group revealed (a) reduced dorsiflexion, increased knee and hip flexion angles, (b) increased inversion and hip adduction angles, (c) increased EMG activation of medial gastrocnemius, peroneus longus, adductor longus, vastus lateralis, gluteus medius, and gluteus maximus, and (d) increased posterior and vertical GRF during initial landing, and reduced medial, posterior, and vertical GRF during mid-landing and mid-cutting. CAI patients demonstrated alterations in landing/cutting movement strategies as demonstrated by a higher susceptibility of foot placement for lateral ankle sprains, and more flexed positions of the knee and hip with higher EMG activation of knee and hip extensors to modulate GRF to compensate for the unstable ankle. This apparent compensation may be due to mechanical (limited dorsiflexion angle) and/or sensorimotor deficits in the ankle.

Kinematic and spatiotemporal gait characteristics in pregnant women with pelvic girdle pain, asymptomatic pregnant and non-pregnant women

BackgroundWalking difficulties are common among pregnant women with pelvic girdle pain. This cross-sectional study investigated the influence of pelvic girdle pain, pregnancy and speed on spatiotemporal and trunk, pelvic and hip kinematics during gait in the 2nd trimester of pregnancy. MethodsThree-dimensional gait analysis at self-selected speed was performed in 25 pregnant women with pelvic girdle pain, 24 asymptomatic pregnant and 24 non-pregnant women. Linear mixed models were used to investigate between-group differences in gait variables. Adjustment for gait speed was included in the analysis. Correlations between speed and fear of movement, disability and pain were examined using Spearman correlation coefficient (rs). FindingsPregnant women with pelvic girdle pain walked 18% slower (estimated marginal means (95% confidence intervals) 1.18 (1.22, 1.24) meter/s) compared to asymptomatic pregnant women (1.44 (1.38, 1.50) meter/s) (P < 0.001). Moreover, with longer double limb support (5%, P = 0.04), shorter contralateral step length (3%, P = 0.03) and more restricted pelvic and hip kinematics (0.001 ≤ P ≤ 0.01) adjusted for speed. Only stance, double limb support and thoracic rotation (0.001 ≤ P ≤ 0.04) differed between asymptomatic pregnant and non-pregnant women. Speed was negatively correlated with fear of movement (rs = −0.63, P = 0.01) and disability (rs = −0.46, P = 0.03) in the pelvic girdle pain group. InterpretationGait is primarily influenced by pelvic girdle pain and less by pregnancy. Pregnant women with pelvic girdle pain walked slower and with a more rigid gait pattern compared to asymptomatic pregnant women, presumably related to altered load transfer. Our results may assist clinical evaluation of pelvic girdle pain, as well as direct future research.

Gait Mechanics in Women of the ACL-SPORTS Randomized Control Trial: Interlimb Symmetry Improves Over Time Regardless of Treatment Group.

Women after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) are more likely than men to exhibit asymmetric movement patterns, which are associated with post-traumatic osteoarthritis. We developed the ACL specialized post-operative return-to-sports (ACL-SPORTS) randomized control trial to test the effect of strength, agility, plyometric, and secondary prevention (SAPP) training with and without perturbation training (SAPP + PERT) on gait mechanics in women after ACLR. We hypothesized that movement symmetry would improve over time across both groups but more so among the SAPP + PERT group. Thirty-nine female athletes 3-9 months after primary ACLR were randomized to SAPP or SAPP + PERT training. Biomechanical testing during overground walking occurred before (Pre-training) and after (Post-training) training and one and 2 years post-operatively. Hip and knee kinematic and kinetic variables were compared using repeated measures analysis of variance with Bonferroni corrections for post hoc comparisons (α = 0.05). There was a time by limb interaction effect (p = 0.028) for peak knee flexion angle (PKFA), the primary outcome which powered the study, characterized by smaller PKFA in the involved compared to uninvolved limbs across treatment groups at Pre-training, Post-training, and 1 year, but not 2 years. Similar findings occurred across sagittal plane knee excursions and kinetics and hip extension excursion at midstance. There were no meaningful interactions involving group. Neither SAPP nor SAPP + PERT training improved walking mechanics, which persisted 1 but not 2 years after ACLR. Statement of clinical significance: Asymmetrical movement patterns persisted long after participants achieved symmetrical strength and functional performance, suggesting more time is needed to recover fully after ACLR. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1743-1753, 2019.

Similarities and Differences of Gait Patterns in Women and Men With Parkinson Disease With Mild Disability

ObjectiveThis study aimed to quantitatively investigate the existence of differences in spatiotemporal and kinematic parameters of gait in men and women with Parkinson disease (PD) using computerized 3-dimensional gait analysis. DesignRetrospective cohort study. SettingLaboratory of Biomechanics. ParticipantsIndividuals with PD (N=35; 17 female, 18 male) of mean age 70.7 years characterized by mild disability (Hoehn and Yahr ≤2.5) who were tested in On medication state approximately 60 to 90 minutes after intake of the usual morning Levodopa dose. InterventionNot applicable. Main Outcome MeasuresSpatiotemporal parameters of gait (speed, stride length, cadence, step width, duration of stance, swing, double support phases) and kinematics of hip, knee, and ankle joints in the sagittal plane. ResultsMen and women exhibit similar spatiotemporal parameters, except for step width (wider in men). In contrast, relevant differences were found in terms of ankle kinematics. In particular, women presented increased ankle dorsiflexion through all the stance phase and mid to late swing phase, and reduced plantarflexion at the stance-swing phase transition. ConclusionsGait patterns of men and women with PD with mild disability are similar in terms of spatiotemporal parameters but characterized by marked differences regarding the ankle kinematics on the sagittal plane. The findings of the present study support the concept that investigations seeking to clarify the complex pathophysiology of PD-related gait disturbances should consider the role played by an individual's sex, thereby achieving more effective designing of physical and rehabilitative treatments.

Pelvic Drop Changes due to Proximal Muscle Strengthening Depend on Foot-Ankle Varus Alignment.

Background Strengthening of hip and trunk muscles can modify pelvis and hip movements. However, the varus alignment of the foot-ankle complex (FAC) may influence the effects of muscle strengthening, due to the relationship of FAC alignment with pelvic and hip kinematics. This study evaluated the effects of hip and trunk muscle strengthening on pelvis and hip kinematics during walking, in subgroups with larger and smaller values of FAC varus alignment. In addition, this study evaluated the effects of hip and trunk muscle strengthening on hip passive and active properties, in the same subgroups. Methods Fifty-three women, who were divided into intervention and control groups, participated in this nonrandomized controlled trial. Each group was split into two subgroups with larger and smaller values of FAC varus alignment. Hip and trunk muscle strengthening was performed three times a week for two months, with a load of 70% to 80% of one repetition maximum. Before and after strengthening, we evaluated (1) pelvis and hip excursions in the frontal and transverse planes during walking, (2) isokinetic hip passive external rotator torque, and (3) isokinetic concentric and eccentric peak torques of the hip external rotator muscles. Mixed analyses of variance (ANOVAs) were carried out for each dependent variable related to walking kinematics and isokinetic measurements (α = 0.05). Results The subgroup with smaller varus alignment, of the intervention group, presented a reduction in pelvic drop after strengthening (P = 0.03). The subgroup with larger varus alignment increased pelvic drop after strengthening, with a marginal significance (P = 0.06). The other kinematic excursions did not change (pelvic anterior rotation P = 0.30, hip internal rotation P = 0.54, and hip adduction P = 0.43). The intervention group showed increases in passive torque (P = 0.002), peak concentric torque (P < 0.001), and peak eccentric torque (P < 0.001), independently of FAC alignment. These results suggest that FAC varus alignment influences the effects of strengthening and should be considered when hip and trunk muscle strengthening is used to reduce pelvic drop during walking.

Individuals with mild-to-moderate hip osteoarthritis exhibit altered pelvis and hip kinematics during sit-to-stand

BackgroundPerformance of the sit-to-stand (STS) task is compromised in individuals with advanced hip osteoarthritis (OA). Understanding how STS performance is altered in individuals with mild-to-moderate hip OA may inform interventions to improve function and slow disease progression. Research questionDo trunk, pelvis, and hip biomechanics differ during a STS task between individuals with mild-to-moderate hip OA and a healthy, age-matched control group? MethodsThirteen individuals with mild-to-moderate symptomatic and radiographic hip OA and seventeen healthy, age-matched controls performed a standardized STS task. Data were acquired using a three-dimensional motion capture system. The primary outcome measures were task duration, sagittal and frontal plane trunk, pelvis, and hip joint angles, and sagittal and frontal plane trunk and hip joint moments. Comparisons of lower-limb measures were between the most affected side in the hip OA group and a randomly chosen limb for the control group, termed the index limb, prior to and following lift-off from the chair. ResultsParticipants with mild-to-moderate hip OA took longer to perform the STS task compared to controls. Prior to lift-off, the hip OA group exhibited greater posterior pelvic tilt, greater pelvic rise on the index side and less hip joint flexion relative to controls. Following lift-off, the hip OA group exhibited greater pelvic rise on the index side compared to controls. SignificanceIndividuals with mild-to-moderate hip OA exhibit subtle alterations in movement strategy compared to healthy controls when completing a STS task similar, to a small extent, to adaptations reported in advanced stages of the disease. Interventions to target these features and prevent further decline in physical function may be warranted in the management of mild-to-moderate hip OA while the opportunity remains.

Characteristics of frontal plane lower limb movement during walking in patients with knee osteoarthritis of varying severity.

This study aimed to investigate the effect of knee joint structural destruction on frontal plane hip and ankle joint kinematics and kinetics during the stance phase of walking in patients with differing severities of knee osteoarthritis (KOA). An early KOA group consisted of eight subjects with bilateral knee Kellgren-Lawrence (KL) scale scores of 1 or 2. An established KOA group comprised nine subjects (18 knees) with KL scores of 3 or 4. To measure walking, the data were obtained using the motion analysis system and force plates. From the ground reaction force data, the stance phase of gait was divided into five periods. In the established KOA group, the hip joint was significantly abducted, and the knee joint had significantly greater varus positioning during the stance phase. In addition, in the established KOA group, a significant knee abductor moment was observed during the stance phase. In contrast, in the early KOA group, the ankle joint showed a significant inversion moment during the stance phase, but in the established KOA group, the ankle joint moment was very small. The structural destruction of the knee joint in the frontal plane in patients with the established KOA changes the movement of the hip and the moment of the ankle.

Classification of gait patterns in patients with unilateral anterior cruciate ligament deficiency based on phase space reconstruction, Euclidean distance and neural networks

The anterior cruciate ligament (ACL) is one of the most important structures of the knee joint which plays a significant role in controlling knee joint stability. Patients with unilateral ACL deficiency often show alterations of their gait patterns in the deficient side in comparison with the unaffected contralateral side. Gait analysis is widely used to detect biomechanical changes in the lower limbs, aiming at diagnosing ACL injury, establishing physical therapy treatments or surgery, monitoring the progression of ACL deficiency over time. This paper proposes new combined methods to classify gait patterns between ACL deficient (ACL-D) knee and contralateral ACL-intact (ACL-I) knee in patients with unilateral ACL deficiency by using phase space reconstruction (PSR), Euclidean distance (ED) and neural networks. First knee, hip and ankle kinematic parameters are extracted and phase space has been reconstructed. The properties associated with the gait system dynamics are preserved in the reconstructed phase space. For the purpose of classification of ACL-D and ACL-I knee gait patterns, three-dimensional (3D) PSR together with EDs has been used. These measured parameters show significant difference in gait dynamics between the two groups and have been utilized to form the feature set. Neural networks are then used as the classifier to distinguish between ACL-D and ACL-I knee gait patterns based on the difference of gait dynamics between the two groups. Finally, experiments are carried out on forty-three patients to assess the effectiveness of the proposed method. By using the leave-one-out cross-validation style under normal and fast walking speed conditions, the correct classification rates for discriminating between ACL-D and ACL-I knees are reported to be $$95.4\%$$ and $$93.3\%$$, respectively. Compared with other state-of-the-art methods, the results demonstrate superior performance and support the validity of the proposed method.

Landing Kinematics and Isometric Hip Strength of Individuals With Chronic Ankle Instability.

Chronic ankle instability (CAI) is associated with hip strength deficits and altered movement in the lower extremity. However, it remains unclear how hip strength deficits contribute to lateral ankle sprain (LAS) mechanisms. We aimed to compare lower extremity landing kinematics and isometric hip strength between individuals with and without CAI and examine associations between hip kinematics and strength. Seventy-six individuals completed 5 single-leg landings, during which we collected three-dimensional ankle, knee, and hip kinematics from 200 milliseconds pre-initial contact to 50 milliseconds post-initial contact. We calculated average peak torque (Nm/kg) from 3 trials of isometric hip extension, abduction, and external rotation strength testing. One-way analyses of variance assessed group differences (CAI, LAS coper, and control) in hip strength and kinematics. Pearson product moment correlations assessed associations between hip kinematics and strength. We adjusted the kinematic group comparisons and correlation analyses for multiple comparisons using the Benjamini-Hochberg method. The CAI group exhibited less hip abduction during landing than LAS copers and controls. The CAI group had lower hip external rotation strength than LAS copers (P = .04, d = 0.62 [0.05, 1.17]) and controls (P < .01, d = 0.87 [0.28, 1.43]). Effect sizes suggest that the CAI group had deficits in EXT compared with controls (d = 0.63 [0.06, 1.19]). Hip strength was not associated with hip landing kinematics for any group. Altered landing mechanics displayed by the CAI group may promote mechanisms of LAS, but they are not associated with isometric hip strength. However, hip strength deficits may negatively impact other functional tasks, and they should still be considered during rehabilitation. Level III, case-control study.

Hip Injuries in Ice Hockey Goaltenders

Hip and groin injuries are among the most common locations for sports-related injuries in ice hockey players due to the specialized movements and physical nature of the sport. Goaltenders are at particular risk for hip injuries due to the unique demands of their position, particularly with the widespread use of the “butterfly style” technique, placement of the hip in extremes of motion during play, and the emphasis on repetition of skills. Hip injuries in ice hockey goalies are mainly attributed to overuse, traumatic contact injuries, or a developmental process. These injuries can be acute or chronic and involve the intra-articular joint and/or extra-articular structures including core muscles, adductors, or hip flexors. They can be treated either conservatively or operatively, depending on the player's goals and level of play. A more complicated picture arises when intra- and extra-articular hip pathologies coexist, presenting challenges in diagnosis and treatment. Fundamental understanding of goaltenders’ hip kinematics, diagnostic physical exam maneuvers, and operative indications is crucial to accurately diagnosing, treating, and preventing hip-related injuries in goalies.