High-speed fluoroscopic imaging for investigation of three-dimensional knee kinematics before and after marathon running

BackgroundKnee injuries often occur during or shortly after marathon running, and are linked to altered knee kinematics.Research questionThe kinematics of healthy knees during pre- and post-marathon running have not been examined with high-speed fluoroscopy. This study aimed to evaluate the effects of marathon running on knee kinematics during walking and running by using a combined high-speed fluoroscopy and MRI technique.MethodsTen healthy runners underwent knee MRI within 24 h before marathon running to construct three-dimensional (3D) knee models. Knee kinematics during treadmill walking and running were evaluated using high-speed fluoroscopy (200hz) within 24 h before and as soon as possible (within 5 h) after marathon running. All pre- and post-marathon measurements were compared.Results(1) For post-marathon walking, posterior femoral translation increased 1.4 mm at initial contact (p = 0.015); proximal-distal distance of tibia and femur decreased 0.7 mm and 0.8 mm at initial contact and after contact, respectively (p = 0.039, p = 0.046); and valgus femur rotation increased 1.2° after contact (p = 0.027). (2) For post-marathon running, proximal-distal distance decreased 0.7 mm and 1.0 mm at initial contact and after contact (p = 0.011, p = 0.003) respectively; knee flexion decreased 4.3° before contact (p = 0.007); knee flexion increased 1.8° and 2.6° at initial contact and after contact, respectively (p = 0.038, p = 0.011); external femoral rotation increased 1.2° and 1.8° at initial contact and after contact, respectively (p = 0.012, p = 0.037). Valgus femoral rotation after contact increased 2.3° (p = 0.001).SignificancePost-marathon changes in valgus and external femoral rotation, knee flexion, posterior femoral translation, and proximal-distal distance may increase the risk of knee injury. This study provides information to better understand the response of the knee to marathon running.     

Comparison of instantaneous knee kinematics during walking and running

BackgroundAccurate measurements of in-vivo knee joint kinematics are essential to elucidate healthy knee motion and the changes that accompany injury and repair. Although numerous experimental measurements have been reported, the accurate non-invasive analysis of in-vivo knee kinematics remains a challenge in biomechanics.Research questionThe study objective was to investigate in-vivo knee kinematics before, at, and after contact during walking and running using a combined high-speed dual fluoroscopic imaging system (DFIS) and magnetic resonance (MR) imaging technique.MethodsThree-dimensional (3D) knee models of ten participants were created using MR images. Knee kinematics during walking and running were determined using high-speed DFIS. The 3D knee models were then related to fluoroscopic images to obtain in-vivo six-degrees-of-freedom knee kinematics.ResultsBefore contact knee flexion, external femoral rotation, and proximal-distal distance were 11.9°, 3.4°, and 1.0 mm greater during running compared to walking, respectively. Similar differences were observed at initial contact (9.9°, 7.9°, and 0.9 mm, respectively) and after contact (6.4°, 2.2°, and 0.8 mm, respectively). Posterior femoral translation at initial contact was also increased during running compared to walking.SignificanceThis study demonstrated accurate instantaneous in-vivo knee kinematic characteristics that may further the understanding of the intrinsic biomechanics of the knee during gait.     

Longitudinal study of the morphological and T2* changes of knee cartilages of marathon runners using prototype software for automatic cartilage segmentation

Objective:To study the effect of long-distance running on the morphological and T2* assessment of knee cartilage.Methods:3D-DESS and T2* mapping was performed in 12 amateur marathon runners (age: between 21 and 37 years) without obvious morphological cartilage damage. MRI was performed three times: within 24 h before the marathon, within 12 h after the marathon, and after a period of convalescence of two months. An automatic cartilage segmentation method was used to quantitatively assessed the morphological and T2* of knee cartilage pre- and post-marathon. The cartilage thickness, volume, and T2* values of 21 sub-regions were quantitatively assessed, respectively.Results:The femoral lateral central (FLC) cartilage thickness was increased when 12-h post-marathon compared with pre-marathon. The tibial medial anterior (TMA) cartilage thickness was decreased when 2 months post-marathon compared with pre-marathon. The tibial lateral posterior (TLP) cartilage volume was increased when 12-h post-marathon compared with pre-marathon. The cartilage T2* value in most sub-regions had the upward trend when 12-h post-marathon and restored trend when 2 months post-marathon, compared with pre-marathon. The femoral lateral anterior (FLA) and TMA cartilage volumes were decreased 2 months post-marathon compared with pre-marathon.Conclusions:The marathon had some effects on the thickness, volume, and T2* value of the knee cartilages. The thickness and volume of knee cartilage in most sub-regions were without significantly changes post-marathon compared with pre-marathon. T2* value of knee cartilage in most sub-regions was increased right after marathon and recovered 2 months later. The TLP and TMA subregions needed follow-up after marathon.Advances in knowledge:The morphological and T2* changes of knee cartilage after marathon were evaluated by MRI and automatic segmentation software. This study was the first to use cartilage automatic segmentation software to evaluate the effects of marathon on the morphology and biochemical components of articular cartilage, and to predict the most vulnerable articular cartilage subregions, for the convenience of future exercise adjustment and the avoidance of sports cartilage injury.     

Influence of hamstring flexibility on running kinematics in adolescent long-distance runners

BackgroundStudies have found no or minimal differences in running kinematics between flexible and inflexible adult runners. The interaction between hamstring flexibility and running kinematics has not been reported in adolescent long-distance runners.Research questionDoes hamstring flexibility influence running kinematics in adolescent long-distance runners?MethodsAdolescent long-distance runners (n = 140, ages 9–19) were enrolled in our cross-sectional study. Hamstring flexibility was assessed with the forward bending Beighton task. Runners were categorized if they tested positive or negative on the forward bending task. Participants ran at a comfortable self-selected speed on a treadmill. Runners who tested positive on the forward bending task (n = 17) were matched with runners who tested negative on the task (n = 17) according to sex, physical maturation, and running speed. Statistical parametric mapping compared trunk, pelvis, hip, and knee kinematic waveforms throughout the gait cycle and independent sample t tests compared temporal-spatial parameters between the groups.ResultsRunners who tested positive on the forward bending task demonstrated significantly greater anterior pelvic tilt during stance (average difference = 4.8° ± 0.4°, p < .001) and swing (average difference = 4.3° ± 0.2°, p < .01) compared to runners who tested negative on the forward bending task. No significant differences were found between groups for the remaining kinematic waveforms or for any temporal-spatial parameters (p > .05).SignificanceThis is the first study to report the interaction between hamstring flexibility and running kinematics in adolescent long-distance runners. The greater anterior pelvic tilt demonstrated by runners with greater hamstring flexibility may place more eccentric demands on the hamstring musculature. However, as there were no other differences in joint kinematics or temporal-spatial parameters between groups, greater hamstring flexibility does not appear to have a significant interaction with running kinematics when running at sub-maximal speeds. Our results suggest hamstring flexibility does not predispose adolescent long-distance runners to sub-optimal segment positions associated with running-related injuries.     

Test-retest reliability of two-dimensional video analysis during running

ObjectivesTo examine test-retest reliability of two-dimensional measured frontal and sagittal plane kinematics during running, and to determine how many steps to include to reach and maintain a stable mean.DesignReliability study.SettingResearch laboratory.ParticipantsTwenty-one recreational runners.Main outcome measuresLateral trunk position, contralateral pelvic drop, femoral adduction, hip adduction, knee flexion and ankle dorsiflexion during midstance, and foot and tibia inclination at initial contact were measured with two-dimensional video analysis during running for 10 consecutive steps for both legs. All participants were tested twice one week apart. A sequential estimation method was used to determine the number of steps needed to reach a stable mean. Intraclass correlation coefficients (ICC) and smallest detectable differences (SDD) were calculated.ResultsThe minimal number of steps was 6.3 ± 0.3. Lateral trunk position, femoral adduction and foot inclination showed excellent reliability (ICC 0.90–0.99; SDD 1.3°–2.3°). Tibia inclination and ankle dorsiflexion showed good to excellent reliability (ICC 0.73–0.92; SDD 2.2°–4.8°). Hip adduction and knee flexion showed good reliability (ICC 0.82–0.89; SDD 2.3°–3.8°). Contralateral pelvic drop showed moderate to good reliability (ICC 0.59–0.77; SDD 2.7°–2.8°).ConclusionTwo-dimensional video analysis is reliable to assess running kinematics on different days. The mean of at least 7 steps should be included.     

The 6DOF knee kinematics of healthy subjects during sloped walking compared to level walking

BackgroundLevel Walking is a frequent functional movement during daily life. However, sloped walking is also common. Exploring 6DOF knee kinematics during sloped walking is important. It provides a reference for the rehabilitation, safety, and knee health of patients with knee diseases walking on sloped surfaces.Research questionThe study aimed to explore 6DOF knee kinematics characteristics during sloped walking compared to level walking. We hypothesized that tibial anteroposterior translation and flexion angle (the sagittal plane) were significantly different from those of level walking.MethodsOne hundred young, healthy adults (50 males and 50 females) were recruited for this study. A three-dimensional gait analysis system was used to collect 6DOF knee kinematics during level and sloped walking. The slope was set to ± 15% when the sloped walking was performed.ResultsSloped walking mainly increased knee flexion angle (upslope, 2.5–26.2°, 1–100% gait cycle (GC), p < 0.05; downslope, 1.7–11.9°, 15–95% GC, p < 0.05) and anterior tibial translation (upslope, 0.7–4.1 mm, 3–54% GC & 0.6–2.1 mm, 80–94% GC; downslope, 1.0–2.2 mm, 21–69% GC) in the participants’ knees. However, participants' other 4DOF knee kinematics during sloped walking were significantly different from those during level walking (p < 0.05). Participants had ‘drastically changeable’ knee kinematic alterations in the transverse and coronal plane (the other 4DOF knee kinematics) during sloped walking compared to level walking.SignificanceOur results confirmed the hypothesis. Sloped walking significantly increased anterior tibial translation (in most GC) and flexion angle. These kinematic changes in healthy subjects should be evaluated and further explored for patients with knee diseases, such as anterior cruciate ligament deficiency. Our findings are meaningful for their rehabilitation or safety or knee health while walking on sloped surfaces. Our study may provide a pilot reference for the 6DOF knee kinematic exploration of sloped walking.     

The effects of downhill slope on kinematics and kinetics of the lower extremity joints during running

BackgroundThe purpose of this study was to investigate how lower extremity kinematics and kinetics change when running downhill.MethodsFifteen male recreational runners ran on an instrumented treadmill with three different slope conditions [level (0°), moderate (−6°), and steep (−9°)] at a controlled speed of 3.2 m/s. Ten consecutive steps were selected for analysis for each of the slope conditions and the order of slope conditions was randomized. Synchonized motion analysis and force plate were used to determine joint kinematics and kinetics.ResultsCompared to level running, participants demonstrated significantly larger knee flexion but smaller ankle plantar-flexion and hip flexion during downhill running (Ps < 0.05). Significantly smaller peak propulsive ground reaction forces and posterior impulses were found during downhill running (Ps < 0.05). Furthermore, participants experienced significantly larger extension moment and negative joint power at the knee (Ps < 0.05) but smaller plantar-flexion moment and negative joint power at the ankle during downhill running (Ps < 0.05). Negative net joint work increased for all joints with increased declinations and the knee joint showed the greatest increase in negative net joint work amongst the three joints (Ps < 0.05).SignificanceThese findings indicate that runners modify their running mechanics resulting in greater kinetic demand on the knee during downhill running. Differences in lower extremity injury mechanisms with different running slopes may be linked to the changes in loading at the knee but further investigation using clinical trials is needed to support the potential relationship.     

The effect of changing mediolateral center of pressure on rearfoot eversion during treadmill running

IntroductionAtypical rearfoot eversion is an important kinematic risk factor in running-related injuries. Prominent interventions for atypical rearfoot eversion include foot orthoses, footwear, and taping, yet a running gait retraining is lacking. Therefore, the aim was to investigate the effects of changing mediolateral center of pressure (COP) on rearfoot eversion, subtalar pronation, medial longitudinal arch angle (MLAA), hip kinematics and vertical ground reaction force (vGRF).MethodsFifteen healthy female runners underwent gait retraining under three conditions. Participants were instructed to run normally, on the lateral (COP lateral) and medial (COP medial) side of the foot. Foot progression angle (FPA) was controlled using real-time visual feedback. 3D measurements of rearfoot eversion, subtalar pronation, MLAA, FPA, hip kinematics, vGRF and COP were analyzed. A repeated-measures ANOVA followed by pairwise comparisons was used to analyze changes in outcome between three conditions. Data were also analyzed using statistic parameter mapping.ResultsRunning on the lateral side of the foot compared to normal running and running on the medial side of the foot reduced peak rearfoot eversion (mean difference (MD) with normal 3.3°, p < 0.001, MD with COP medial 6°, p < 0.001), peak pronation (MD with normal 5°, p < 0.001, MD with COP medial 9.6°, p=<0.001), peak MLAA (MD with normal 2.3°, p < 0.001, MD with COP medial 4.1°, p < 0.001), peak hip internal rotation (MD with normal 1.8°, p < 0.001), and peak hip adduction (MD with normal running 1°, p = 0.011). Running on the medial side of the foot significantly increased peak rearfoot eversion, pronation and MLAA compared to normal running.SignificanceThis study demonstrated that COP translation along the mediolateral foot axis significantly influences rearfoot eversion, MLAA, and subtalar pronation during running. Running with either more lateral or medial COP reduced or increased peak rearfoot eversion, peak subtalar pronation, and peak MLAA, respectively, compared to normal running. These results might use as a basis to help clinicians and researchers prescribe running gait retraining by changing mediolateral COP for runners with atypical rearfoot eversion or MLAA.     

Fatigue matters: An intense 10 km run alters frontal and transverse plane joint kinematics in competitive and recreational adult runners

BackgroundFatigue is an essential component of distance running. Still, little is known about the effects of running induced fatigue on three-dimensional lower extremity joint movement, in particular in the frontal and transverse planes of motion.Research questionHow are non-sagittal plane lower extremity joint kinematics of runners altered during a 10 km treadmill run with near-maximum effort?MethodsIn a cross-sectional study design, we captured three-dimensional kinematics and kinetics at regular intervals throughout a 10 km treadmill run in 24 male participants (subdivided into a competitive and recreational runner group) at a speed corresponding to 105 % of their season-best time. We calculated average and peak joint angles at the hip, knee and ankle during the stance phase.ResultsWe observed peak deviations of 3.5°, 3° and 5° for the hip (more adduction), knee (more abduction) and ankle (more eversion) in the frontal plane when comparing the final (10 km) with the first (0 km) measurement. At the end of the run peak knee internal rotation angles increased significantly (up to 3° difference). Running with a more abducted knee joint and with a higher demand for hip abductor muscles in the unfatigued state was related to greater fatigue-induced changes of joint kinematics at the knee and hip.SignificanceThe fatigue related change of non-sagittal joint kinematics needs to be considered when addressing risk factors for running-related injuries, when designing shoe interventions as well as strengthening and gait retraining protocols for runners. We speculate that strengthening ankle invertors and hip abductors and monitoring the dynamic leg axis during running appear to be promising in preventing fatigue induced alterations of non-sagittal joint kinematics.     

Multi-segment spine range of motion in dancers with and without recent low back pain

BackgroundAltered spine kinematics are a common in people with LBP. This may be especially true for populations such as dancers, who are required to perform repetitive movements of the spine, although this remains unclear.Research questionDo dancers with recent LBP display altered spine kinematics compared to their asymptomatic counterparts?MethodsA cross-sectional study of multi-segment spine kinematics was performed. Forty-seven pre-professional and professional female dancers either with LBP in the past two months (n = 26) or no LBP in the past 12 months (n = 21) participated. Range of motion (ROM) during standing side bending, seated rotation, and walking gait were compared.ResultsFemale dancers with LBP displayed reduced upper lumbar transverse plane ROM in seated rotation (Effect Size (ES)= −0.61, 95% Confidence Interval (CI): −1.20, 0.02, p = 0.04), as well as reduced lower lumbar transverse plane ROM (ES=−0.65, 95% CI: −1.24, −0.06, p = 0.03) in gait. However, there was increased lower thoracic transverse plane ROM (ES = 0.62, 95% CI: 0.04, 1.21, p = 0.04) during gait. No differences in the frontal plane were observed.SignificanceAltered transverse plane spine kinematics were evident in dancers with recent LBP for select segments and tasks. This may reflect a protective movement strategy. However, as the effect sizes of observed differences were moderate, and the total number of differences between groups was small, collectively, it seems only subtle differences in spine kinematics differentiate dancers with LBP to dancers without.     

MRI study of changes in knee bone marrow edema-like signal in asymptomatic amateur marathon runners before and after half-marathon running

ObjectiveTo evaluate the incidence of knee bone marrow edema-like signal and its changes before and after running a half marathon running in asymptomatic amateur marathon runners to explore the impact of the half marathon on knee bone marrow edema-like signal.Methods50 asymptomatic amateur marathon runners (30 males, 20 females) were recruited. T1-weighted imaging (T1WI), fat-suppressed protein density weighted imaging (fs-PDWI) and three-dimensional double-echo steady-state (3D-DESS) sequence on the right knee were performed before and within 3 h after a half-marathon running. 20 healthy volunteers were recruited as control. According to the whole-organ magnetic resonance imaging score (WORMS) system, the involvement of bone marrow edema-like signal in 15 regions of knee was graded from 0 to 3. The results were classified and Mann Whitney U test was used for comparison between groups.ResultsThe total incidence of bone marrow edema-like signal in amateur marathon group was 62%. Among them, the incidence of grade 1–3 was 48% (24/50), 12% (6/50), 2% (1/50), respectively, which was statistically significant compared with the controls (P = 0.007). There was no significant difference between gender before running (P = 0.172) and after running (P = 0.162). There was no significant difference before and after running (P > 0.05). However, 3 subjects showed new lesions, 8 subjects showed progression and 4 subjects showed decreased signal.ConclusionThe occurrence of knee bone marrow edema-like signal in amateur marathon runners is more common. The lesions of bone marrow edema-like signal will show aggravation or improvement in a certain extent after the half marathon.     

Maintaining motivation and health among recreational runners: Panel study of factors associated with self-rated performance outcomes at competitions

ObjectivesTo investigate health-related factors associated with self-rated race performance outcomes among recreational long-distance runners.DesignPanel study.MethodsData were collected from runners one month before and after a community-level race event including distances from 8 to 42.2 km. The primary outcome measure was self-rated race performance outcome. The explanatory variables represented health complaints suffered during the build-up year, the pre-race month, and the race and among full marathon runners predicted objective performance outcome (mean pace equal to training pace or faster). Multiple logistic regression was used to determine factors associated with the self-rated performance outcome.ResultsTwo-hundred forty-five runners (29%) provided complete data sets. Seventy-four percent of the runners reached their desired race performance outcome. Achievement of the performance outcome was more likely when having avoided illness during the build-up and pre-race periods (OR = 3.8; 95% CI:1.8–8.0, p < 0.001), having avoided per-race injury (OR=3.0; 95% CI:1.2–7.4, p = 0.02) and avoided per-race illness (OR = 4.1; 95% CI:1.3–15, p = 0.020). Having obtained the self-rated performance outcome was also associated with running a shorter distance (OR=3.6; 95% CI: 1.7–8.0, p = 0.001) and being younger than 50 years of age (OR = 2.4; 95% CI:1.1–5.3–8.3, p = 0.03). Having met the predicted objective performance outcome predisposed marathon runners to also obtain the self-rated performance outcome (OR = 4.7, 95% CI: 1.5–16, p < 0.01).ConclusionsHaving avoided illness during build-up and pre-race was positively associated with self-rated race performance outcome among recreational runners. Adjusting the desired performance outcomes with regard to recent illness and age may help recreational runners to more often achieve their goals and thereby prevent them from leaving the sport.     

The effect of tibiotalar alignment on coronal plane mechanics following total ankle replacement

BackgroundGait mechanics following total ankle replacement (TAR) have reported improved ankle motion following surgery. However, no studies have addressed the impact of preoperative radiographic tibiotalar alignment on post-TAR gait mechanics. We therefore investigated whether preoperative tibiotalar alignment (varus, valgus, or neutral) resulted in significantly different coronal plane mechanics or ground reaction forces post-TAR.MethodsWe conducted a non-randomized study of 93 consecutive end-stage ankle arthritis patients. Standard weight-bearing radiographs were obtained preoperatively to categorize patients as having neutral (±4°), varus (≥5° of varus), or valgus (≥5° of valgus) coronal plane tibiotalar alignment. All patients underwent a standard walking assessment including three-dimensional lower extremity kinetics and kinematics preoperatively, 12 and 24 months postoperatively.ResultsA significant group by time interaction was observed for the propulsive vertical ground reaction force (vGRF), coronal plane hip range of motion (ROM) and the peak hip abduction moment. The valgus group demonstrated an increase in the peak knee adduction angle and knee adduction angle at heel strike when compared to the other groups. Coronal plane ankle ROM, knee and hip angles at heel strike, and the peak hip angle exhibited significant increases across time. Peak ankle inversion moment, peak knee abduction moment and the weight acceptance vGRF also exhibited significant increases across time. Neutral ankle alignment was achieved for all patients by 2 years following TAR.ConclusionsRestoration of neutral ankle alignment at the time of TAR in patients with preoperative varus or valgus tibiotalar alignment resulted in biomechanics similar to those of patients with neutral preoperative tibiotalar alignment by 24-month follow-up.     

Is there a dose-response of medial wedge insoles on lower limb biomechanics in people with pronated feet during walking and running?

BackgroundAlthough the effects of medial wedge insoles on lower limb biomechanics have been investigated, information about the effects of different magnitudes of medial posting is still lacking.Research questionWhat are the dose-response effects of medial wedge insoles with postings varying between 0 °, 3 °, 6 °, and 9 ° of inclination on the lower limb biomechanics during walking and running in individuals with pronated feet?MethodsSixteen participants with an FPI ≥ 6 were recruited. Four arch-supported insole conditions with varying degrees of medial heel wedge were tested (0°, 3°, 6°, and 9°). A 3D motion analysis system with force plates was used to obtain the kinetics and kinematics of walking and running at self-selected speeds. To compare the ankle, knee, and hip angles and moments among conditions, a time series analysis was performed using Statistical Parametric Mapping (SPM).ResultsA reduction in ankle eversion angle was observed during walking for all insoles. For running, the 6° and 9° insoles decreased the ankle eversion angle during early stance and increased this angle during the propulsive phase. A decrease in ankle eversion moment was observed in walking and running for 6° and 9° insoles. An increase in knee adduction moment occurred in walking and running for all insoles. For hip, the 6° and 9° insoles showed, during walking, a decrease in hip adduction angle and an increase in hip adduction and external rotation moments. For most variables, statistical differences were found for a greater period across the stance phase as the medial wedge increased, except for ankle eversion moment and hip external rotation moment during walking.SignificanceThe biomechanical effects over the time series for many of the parameters increased with the addition of insole inclination, showing a dose-response effect of medial wedge insoles on the lower limb biomechanics during walking and running in adults with excessive foot pronation.     

Posterior-stabilized inserts are preferable to cruciate-substituting ultracongruent inserts due to more favourable kinematics and stability

Purpose

It is unknown whether the conforming superiority of ultracongruent (UC) inserts over posterior stabilized (PS) inserts, due to an increased anterior lip for prevention of anterior displacement of the condyles during knee flexion, leads to better knee scores or greater knee stability in arthroplasty patients. This meta-analysis compared clinical outcomes, intraoperative kinematics, sagittal stability, and range of motion (ROM) between groups with either UC or PS inserts in primary total knee arthroplasty (TKA).

Methods

Studies that recorded clinical outcomes, intraoperative kinematics, sagittal stability, and ROM in patients who underwent primary TKA with UC or PS inserts were included in the meta-analysis. Subgroup analyses based on differences in flexion angles were performed for intraoperative kinematics.

Results

Thirteen studies met the criteria for inclusion in the meta-analysis. The UC and PS insert groups reported similar pain scores (95% CI ??0.15 to 0.16; n.s.) and function scores (95% CI ??0.30 to 0.14; n.s.). In contrast, femoral rotation during flexion (95% CI ??0.06 to 6.35; p?=?0.05), posterior femoral translation during flexion (95% CI ??2.74 to ??0.15; p?=?0.03), tibial sagittal laxity at 90° (95% CI 2.91 to 7.72; p?<?0.0001), and ROM (95% CI ??4.84 to ??1.53; p?=?0.0002) differed significantly between the groups. Subgroup analyses revealed that the pooled data for femoral rotation were significantly different between groups: 60°, 4.09 (p?<?0.00001); 90°, 7.94 (p?<?0.00001); and 120°, 8.16 (p?<?0.00001). Furthermore, pooled data for posterior femoral translation were significantly different between groups: 90°, ??3.70 (p?<?0.00001); and 120°, ??3.96 (p?<?0.00001).

Conclusions

There were no significant differences in clinical outcomes between the groups with UC and PS inserts. However, the UC insert group showed significantly greater external femoral rotation, less posterior femoral translation, greater tibial laxity in the sagittal plane, and less ROM than the PS insert group. Based on the results of the current meta-analysis, in substituting the PCL, PS inserts are preferable to UC inserts due to more favourable kinematics and stability, even though both inserts have equivalent clinical outcomes.

Level of evidence

Therapeutic study, Level II.

     

Reasons and predictors of discontinuation of running after a running program for novice runners

Objectives

To determine the proportion of participants of a running program for novice runners that discontinued running and investigate the main reasons to discontinue and characteristics associated with discontinuation.

In vivo kinematics of the ACL-deficient limb during running and cutting

Anterior cruciate ligament-deficient (ACLD) knee kinematics during high-demand activities are poorly understood. We have devised a new method, using gait analysis, to more accurately assess 3-D in vivo kinematics of the knee. This has enabled us to report on how knee kinematics are altered after ACL rupture, during running and cutting. Fifteen unilaterally ACLD subjects were assessed using a 12-camera 100 Hz VICON motion analysis system. Simultaneous electromyographical (EMG) recordings were used to assess the role of the sensorimotor system in knee joint stability. All subjects were able to perform demanding cutting activities without experiencing symptoms of instability. We found that running produces fundamentally different kinematic patterns to those seen during walking. Tibiofemoral translation in the anteroposterior plane is controlled to within normal limits. Conversely, coronal translation and rotation are poorly controlled. We found that the injured leg was maintained in greater extension during the stance phase of all running activities studied and that the quadriceps muscle was active for longer during this period. We believe that low-demand activities, such as walking, do not reproduce kinematics relevant to ACLD instability and that future investigations into functional instability in the ACLD knee should focus on coronal and rotational displacements.     

Frontal plane kinematics predict three-dimensional hip adduction during running

ObjectivesTo investigate if frontal plane kinematics are predictive of three dimensional (3D) hip adduction and hip internal rotation during running.Study designCross-sectional.SettingBiomechanics laboratory.ParticipantsThirty healthy male runners aged 18–45 years.Main outcome measuresTwo dimensional (2D) angles in the frontal plane (peak pelvic obliquity, peak hip adduction, peak femoral valgus, peak knee valgus and peak tibial valgus) and 3D hip adduction and hip internal rotation during stance phase of running were obtained.ResultsLinear regression modelling revealed that peak 2D pelvic obliquity (a drop towards the contralateral leg) and peak femoral valgus significantly predicted 88% of the variance in peak 3D hip adduction (p < 0.001). Frontal plane kinematics however, were not predictive of peak hip internal rotation in 3D (p > 0.05).ConclusionsFrontal plane kinematics, specifically contralateral pelvic drop and femoral valgus, predicted the vast majority of the variance in 3D hip adduction during the stance phase of running. This indicates that 2D video may have potential as a clinically feasible proxy for measurement of peak 3D hip adduction – a risk factor for patellofemoral pain.     

Effects of medially wedged insoles on the biomechanics of the lower limbs of runners with excessive foot pronation and foot varus alignment

BackgroundExcessive foot pronation during running in individuals with foot varus alignment may be reduced by medially wedged insoles.Research questionThis study investigated the effects of a medially wedged insole at the forefoot and at the rearfoot on the lower limbs angles and internal moments of runners with excessive foot pronation and foot varus alignment.MethodsKinematic and kinetic data of 19 runners (11 females and 8 males) were collected while they ran wearing flat (control condition) and medially wedged insoles (insole condition). Both insoles had arch support. We used principal component analysis for data reduction and dependent t-test to compare differences between conditions.ResultsThe insole condition reduced ankle eversion (p = 0.003; effect size = 0.63); reduced knee range of motion in the transverse plane (p = 0.012; effect size = 0.55); increased knee range of motion in the frontal plane in early stance and had earlier knee adduction peak (p = 0.018; effect size = 0.52); reduced hip range of motion in the transverse plane (p = 0.031; effect size = 0.48); reduced hip adduction (p = 0.024; effect size = 0.50); reduced ankle inversion moment (p = 0.012; effect size = 0.55); and increased the difference between the knee internal rotation moment in early stance and midstance (p = 0.012; effect size = 0.55).SignificanceInsoles with 7˚ medial wedges at the forefoot and rearfoot are able to modify motion and moments patterns that are related to lower limb injuries in runners with increased foot pronation and foot varus alignment with some non-desired effects on the knee motion in the frontal plane.     

Mechanical effects of medial and lateral wedged orthoses during running

ObjectiveThe aim of the current investigation was to examine the effects of orthoses with 5° medial and lateral wedges on knee joint kinetics during the stance phase of running.DesignRepeated measures.SettingLaboratory.ParticipantsTwelve recreational runners.Outcome measurementsTwelve male participants ran over a force platform at 4.0 m/s in three different conditions (medial orthotic, lateral orthotic and no-orthotic). Lower limb kinematics were collected using an 8-camera motion capture system allowing knee kinetics to be quantified using a musculoskeletal modelling approach. Differences in knee joint kinetics between orthotic conditions were examined using one-way repeated measures ANOVA.ResultsThe results showed that peak patellofemoral force was significantly increased in the medial (31.81 N/kg) and lateral (31.29 N/kg) wedged orthoses, in comparison to the no-orthotic (29.61 N/kg) condition. In addition, the peak knee adduction moment was significantly increased in the medial (1.10 Nm/kg) orthoses, in comparison to the lateral (0.87 Nm/kg) condition.ConclusionsThe results from this study indicate that lateral orthoses may be effective in attenuating runners risk from medial tibiofemoral compartment OA, but that wedged orthoses may enhance their risk from patellofemoral pain.