Higher Knee Flexion Research Articles

Tunnel Convergence Rate in Combined Anteromedial Portal Anterior Cruciate Ligament and Anterolateral Structure Reconstructions Is Influenced by Anterior Cruciate Ligament Knee Flexion Angle, Tunnel Position, and Direction

The goal of the present study was to evaluate a potential tunnel convergence in combined anterior cruciate ligament (ACL) reconstruction using the anteromedial portal technique and lateral extra-articular tenodesis (LET). Ten fresh frozen femora were dissected and a K-wires were inserted into the middle of the ACL stump, according to an ACL reconstruction at 110° and 140° knee flexion. ACL reconstruction at 120° and 130° was simulated. Seven K-wires with different femoral insertion sites and angulations were drilled into the lateral femoral condyle relative to the lateral epicondyle (E3: 8 mm proximal and 4 mm posterior; E1: 5 mm proximal and 5 mm anterior and E2: over-the-top position). Tunnel conflict rate was evaluated using a measuring arm and a metrology software. Drilling the femoral ACL tunnel in low knee flexion (110°-120°) significantly (P < .001) reduced the tunnel conflict rate compared to the ACL drilled in high knee flexion (130°-140°). Changing the insertion point from proximal and posterior (E3) to proximal and anterior (E1) showed a reduced tunnel conflict rate from 40 ± 21.2% to 15 ± 26% and no tunnel conflict for an ACL drilled at 110°-130° knee flexion. A possible tunnel conflict in simultaneous ACL reconstruction using the AMP technique and LET was dependent on ACL knee flexion angle, LET insertion site, and angulation. This posed the dilemma that no generally applicable LET configuration could be recommended to avoid a tunnel conflict. However, it appears that an insertion point located proximal and anterior to the lateral epicondyle results in less tunnel conflicts than an insertion point located proximal and posterior. An insertion point located proximal and anterior to the lateral epicondyle with a 30° proximal and 30° anterior angulation could reliably avoid a tunnel conflict when the ACL was drilled between 110 and 130° using a low anteromedial portal.

Limited trunk motion and posterior pelvic tilting in ambulatory children treated with bilateral rib to pelvis implants for spinal deformity control.

In young children, growth-friendly spinal implants with bilateral rib to pelvis fixation are used to control progressive spinal deformity. Whereas curve progression, complications and side-effects have been extensively studied in this patient population, no data are available on gait pattern changes and postural body adjustments. Our study evaluates whether gait pattern changed for ambulatory children treated with bilateral rib to pelvis implants compared to age-matched healthy children. In this small cohort study, gait analysis was performed using spatiotemporal and kinematic parameters of four ambulatory children with severe scoliosis and growth-friendly spinal implants using the bilateral rib to pelvis fixation. Data were statistically analyzed and compared to seven healthy age-matched children. Between both groups, no differences were seen in walking speed, cadence and stride length. The treated patients showed a lower range of motion of the pelvic obliquity and of the trunk obliquity and rotation, but a higher knee flexion. Growth-friendly spinal implants with bilateral rib to pelvis fixation are commonly used in wheelchair children and rarely indicated in ambulatory patients. The presented data show reduced trunk and pelvis motion using this implant construct. These findings help to understand body postural adjustments and add valuable information for families and care providers when considering this surgery. Level of evidence: Therapeutic level IV.

Classification of high knee flexion postures using EMG signals.

High knee flexion postures are often adopted in occupational settings and may lead to increased risk of knee osteoarthritis. Pattern recognition algorithms using wireless electromyographic (EMG) signals may be capable of detecting and quantifying occupational exposures throughout a working day. To develop a k-Nearest Neighbor (kNN) algorithm for the classification of eight high knee flexion activities frequently observed in childcare. EMG signals from eight lower limb muscles were recorded for 30 participants, signals were decomposed into time- and frequency-domain features, and used to develop a kNN classification algorithm. Features were reduced to a combination of ten time-domain features from 8 muscles using neighborhood component analysis, in order to most effectively identify the postures of interest. The final classifier was capable of accurately identifying 80.1%of high knee flexion postures based on novel data from participants included in the training dataset, yet only achieved 18.4%accuracy when predicting postures based on novel subject data. EMG based classification of high flexion postures may be possible within occupational settings when the model is first trained on sample data from a given individual. The developed algorithm may provide quantitative measures leading to a greater understanding of occupation specific postural requirements.

Classification of Whole-Body Postural Discomfort Using Cluster Analysis.

The objectives of this study were to evaluate the effect of gender and postures of the neck, trunk, and knee on overall postural discomfort, and to classify combined postures into different postural discomfort groups. A total of 95 participants (42 males and 53 females) performed 45 different static postures, which were a combination of 3 neck angles, 5 trunk angles, and 3 knee angles, and rated the perceived postural discomfort. Non-hierarchical K-means cluster analysis was employed to classify the 45 different combined postures into several postural discomfort groups. Postural discomfort was significantly affected by gender and postures of the neck, trunk, and knee (p < 0.001). Three clusters (high, medium, and low discomfort) were identified and the postural discomfort was significantly different between clusters (p < 0.001). The high discomfort group consisted of mostly males with high knee and trunk flexion angles and a moderate neck flexion angle. The low discomfort group was female-dominant with low neck and trunk flexion angles and a moderate knee flexion angle. The different flexibility (stiffness) of the joint motions between genders may affect the gender difference in postural discomfort. The knee and trunk postures were critical to the postural balance, which may affect the perception of whole-body discomfort. This result will be useful for developing and improving postural observation tools.

Kinematic changes in severe hip osteoarthritis measured at matched gait speeds.

Kinematic differences between patients with osteoarthritis (OA) and control participants have been reported to be influenced by gait speed. The purpose of this study was to experimentally detect the effect of walking speed on differences in spatiotemporal parameters and kinematic trajectories between patients with hip OA and age-matched asymptomatic participants using wearable sensors and statistical parametric mapping (SPM). Twenty-four patients with severe unilateral hip OA and 48 control participants were included in this study. Patients walked at a self-selected normal speed and control participants at self-selected normal and slow speeds. Spatiotemporal parameters and kinematic trajectories were measured with the inertial sensor system Rehagait®. Gait parameters were compared between patients with hip OA and control participants for normal and matched speed using SPM with independent sample t-tests. At self-selected normal speed, the patient group walked slower (-0.20 m/s, p < .001) and at lower cadence (-5.0 steps/minute, p < .001) as well as with smaller hip flexion (-7.4°, p < .001) and extension (-4.1°, p = .001), higher knee flexion during terminal stance (+8.0°, p < .001) and higher ankle dorsiflexion and plantarflexion (+7.1°, p < .001). While differences in spatiotemporal parameters and the ankle trajectory disappeared at matched speed, some clinically relevant and statistically significant differences in hip and knee trajectories remained. Most differences in sagittal plane gait kinematics between patients with hip OA and control participants were present for matched speed, and therefore appear to be associated with a disease rather than gait speed. Nevertheless, studies investigating hip kinematics in patients with hip OA should involve trials at matched speeds.

Children’s Single-Leg Landing Movement Capability Analysis According to the Type of Sport Practiced

(1) Background: Understanding children’s motor patterns in landing is important not only for sport performance but also to prevent lower limb injury. The purpose of this study was to analyze children’s lower limb joint angles and impact force during single-leg landings (SLL) in different types of jumping sports using statistical parametric mapping (SPM). (2) Methods: Thirty children (53.33% girls, M = 10.16 years-old, standard deviation (SD) = 1.52) divided into three groups (gymnastics, volleyball and control) participated in the study. The participants were asked to do SLLs with the dominant lower limb (barefoot) on a force plate from a height of 25 cm. The vertical ground reaction force (GRF) and lower limb joint angles were assessed. SPM{F} one-way analysis of variance (ANOVA) and SPM{t} unpaired t-tests were performed during the landing and stability phases. (3) Results: A significant main effect was found in the landing phase of jumping sport practice in GRF and joint angles. During the stability phase, this effect was exhibited in ankle and knee joint angles. (4) Conclusions: Evidence was obtained of the influence of practicing a specific sport in childhood. Child volleyball players performed SLL with lower impact force and higher knee flexion than child gymnasts. Training in specific jumping sports (i.e., volleyball and gymnastics) could affect the individual capacity to adapt SLL execution.

A musculoskeletal model to perform high knee flexion tasks: Application to ACL injury prevention

A musculoskeletal model to perform high knee flexion tasks: Application to ACL injury prevention

Development of a Full Flexion 3D Musculoskeletal Model of the Knee Considering Intersegmental Contact During High Knee Flexion Movements.

A musculoskeletal model of the right lower limb was developed to estimate 3D tibial contact forces in high knee flexion postures. This model determined the effect of intersegmental contact between thigh-calf and heel-gluteal structures on tibial contact forces. This model includes direct tracking and 3D orientation of intersegmental contact force, femoral translations from in vivo studies, wrapping of knee extensor musculature, and a novel optimization constraint for multielement muscle groups. Model verification consisted of calculating the error between estimated tibial compressive forces and direct measurements from the Grand Knee Challenge during movements to ∼120° of knee flexion as no high knee flexion data are available. Tibial compression estimates strongly fit implant data during walking (R2 = .83) and squatting (R2 = .93) with a root mean squared difference of .47 and .16 body weight, respectively. Incorporating intersegmental contact significantly reduced model estimates of peak tibial anterior-posterior shear and increased peak medial-lateral shear during the static phase of high knee flexion movements by an average of .33 and .07 body weight, respectively. This model supports prior work in that intersegmental contact is a critical parameter when estimating tibial contact forces in high knee flexion movements across a range of culturally and occupationally relevant postures.

Prevention and treatment of bearing dislocation of mobile-bearing unicompartmental knee arthroplasty

Bearing dislocation is a special complication of mobile-bearing unicompartmental arthroplasty, caused by many factors, such as imbalance of the flexion and extension gap, malposition of components, impingement by the remaining osteophytes and cement, damage or delayed chronic laxity of medial collateral ligament, traumatic accident and habitual high knee flexion. It can be reduced by strictly controlling the operation indications before operation, osteotomy and implanting the prosthesis accurately while protecting the medial collateral ligament during operation, actively guiding the appropriate rehabilitation actions and activity intensity of patients after operation. Treatment should be individualized according to the causes and individual conditions of patients.

Interobserver agreement of sensor-derived compartmental pressure measurements in computer-assisted total knee arthroplasty

BackgroundSensor-guided compartmental pressure measurements are becoming increasingly utilized in total knee arthroplasty (TKA) to objectively confirm intraoperative knee balance. We aimed to determine agreement of pressure measurements between two observers when performing sensor-guided TKA with the use of computer-assisted surgery (CAS). MethodsOne-hundred and eighteen consecutive patients undergoing 130 TKAs were analysed. Femoral and tibial trial implants were inserted prior to performing knee balancing. We compared the reliability of sensor pressure compartmental measurements between two observers at 10, 45 and 90° of flexion using intraclass correlation coefficient (ICC) estimates and the 95% limits of agreement (Bland–Altman plots). ResultsThe interobserver agreement between sensor pressure measurements was excellent at 10° of knee flexion, with ICCs of 0.93 and 0.91 in the medial and lateral compartments, respectively (P < 0.001). At 45°, medial and lateral compartment ICCs were 0.91 and 0.76, respectively (P < 0.001). At 90°, the ICC was 0.88 medially and 0.76 laterally (P < 0.001). Although the agreement decreased at higher knee flexion, it remained good to excellent. The 95% limits of agreement at each angle were all within 20 psi and 11 psi for the medial and lateral compartments, respectively. ConclusionsThere was excellent interobserver agreement of sensor pressure measurements at 10° of knee flexion with computer-assisted TKA. Interobserver agreement decreased slightly as knee flexion angles increased, particularly in the lateral compartment. It is likely that interobserver agreement and hence reliability of sensor pressure measurements in TKA has some dependence on accurate angular positioning of the knee.

Weight-bearing status affects in vivo kinematics following mobile-bearing unicompartmental knee arthroplasty.

The effects of weight bearing (WB) on knee kinematics following mobile-bearing unicompartmental knee arthroplasty (UKA) remain unknown. The purpose of this study was to clarify the effects of WB on in vivo kinematics of mobile-bearing UKA during high knee flexion activities. The kinematics of UKA were evaluated under fluoroscopy during squatting (WB) and active-assisted knee flexion (non-weight bearing, NWB). Range of motion, femoral axis rotation relative to the tibia, anteroposterior (AP) translation of the medial and lateral sides, and kinematic pathway were measured. There were no differences in knee flexion range and external rotation of the femur in each flexion angle between the WB conditions. The amount of femoral external rotation between minimum flexion and 60° of flexion during WB was significantly larger than that during NWB, and that between 60° and 130° of flexion during NWB was significantly larger than that during WB. There were no differences in medial AP translation of the femur in each flexion angle between the WB conditions. However, on the lateral side, posterior translation of 52.9 ± 12.7% was observed between minimum flexion and 130° of flexion during WB. During NWB, there was no significant translation between minimum flexion and 60° of flexion; beyond 60° of flexion, posterior translation was 41.6 ± 8.7%. Between 20° and 80° of flexion, the lateral side in WB was located more posteriorly than in NWB (p < 0.05). Mobile-bearing UKA has good anterior stability throughout the range of knee flexion. WB status affects the in vivo kinematics following mobile-bearing UKA. III.

A comparison of knee joint moments during high flexion squatting and kneeling postures in healthy individuals.

Deep knee bending has been reported as an occupational hazard to workers who have to adopt such postures. High knee joint moments have been associated with knee osteoarthritis initiation and progression. This study aimed to compare four high knee flexion postures (dorsiflexed and plantarflexed kneeling, and flat-foot and heels-up squatting) to determine which one results in lower knee joint flexion and ab/adduction moments. Forty-three participants performed five trials of each posture. Peak (for descent/ascent) and mean (for the static hold) external knee flexion and ab/adduction moments were analyzed for each posture using 2-way ANOVAs and post-hoc pairwise comparisons. It was observed that the flat-foot squat resulted in significantly lower knee flexion moment compared to the other three postures (4.63±0.99 % BW·H during the static phase, and 5.83±1.24 % BW·H and 5.94±1.24 % BW·H during descent and ascent phases, respectively). During ascent phase, significant differences was indicated in peak adduction moments for the flat-foot squat in comparison to both styles of kneeling. When high knee flexion is required but posture is not dictated, flat-foot squat will reduce exposures to high knee moments.

Kinetic and Kinematic Changes in Vertical Jump in Prepubescent Girls After 10 Weeks of Plyometric Training.

To examine the effect of a 10-week plyometric training (PT) on the kinematic and kinetic properties of prepubescent girls during squat jump, countermovement jump, and drop jumps. Twenty-four untrained girls (aged 9-11y) were assigned to a training group (TG) and a control group. The TG followed twice a week PT for 10 weeks. Squat jump, countermovement jump, and drop jumps performed from heights of 20, 35, and 50cm were tested before and after PT. Jump height, kinematic, and kinetic parameters were evaluated using a motion analysis system and a force plate. Jumping height in all jump types increased significantly after PT for the TG (P < .001). After training, the TG presented increased power (P < .001) and knee angular velocity (P < .001), higher knee flexion at the deepest point during the braking phase (P < .001), longer contact time (P < .001), and unchanged stiffness and reaction strength index (P > .05). No differences were observed in the control group (P > .05). These findings indicate that a 10-week PT positively affected jumping performance in prepubescent girls who improved their drop jump performance after training not by adopting a stiff/bouncing jumping style of short contact time and increased stiffness, but a compliant/absorbing style of prolonged contact time.

Patellar instability

Lateral patellar dislocation (PD) has multifactorial origin. Its treatment will depend on the physical demands of the patient, triggering event and injury mechanism of PD, number of dislocation episodes, patellofemoral joint morphology, and concomitant injuries. After primary PD, despite the risk of recurrence being 33-77%, first treatment option is mostly conservative, except if an osteochondral fragment needs to be refixed or removed. This practice has been questioned lately by the Patella Instability Severity Score that determines the risk for recurrent PD in function of age, bilaterality, and anatomical risk factors. Risk behavior in relation to sports activity seems to be an additional risk factor. The treatment of recurrent PD is surgical with only low recurrent rate (2-4%). Medial patellofemoral ligament (MPFL) reconstruction is the most widely used technique. The ideal candidates are subjects with painless intervals between PD and without major trochlear dysplasia (TD) or patella alta. However, postoperative pain and loss of flexion might be observed if the graft is overtensioned or its fixation point malpositioned. Trochleoplasty is the only technique that aims at improving containment with the risk to increase peak forces due to incongruence. Due to the demanding technique its superiority over isolated MPFL reconstruction has been described only in grotesque TD and PD in higher knee flexion (&gt;60°). Tibial tubercle osteotomy can be distalized in case of patella alta or medialized in case of lateralized tibial tubercle. Indication should be considered carefully, since patellar tracking will be influenced almost throughout the full range of motion and might therefore induce discomfort or pain.

Performance of stair negotiation in patients with cerebral palsy and stiff knee gait

BackgroundDue to the limited knee range of motion, achieving adequate foot clearance while walking on level ground constitutes a major problem for patients with cerebral palsy and stiff knee gait. Stair negotiation as an activity of daily life requires a considerably higher knee range of motion than level ground walking, but little is known yet as to whether such patients are able to walk stairs.Research question: The aim of this study was to investigate how patients with a limited knee range of motion negotiate stairs. Do they increase their peak knee flexion and use the same pattern as in walking on level ground? How do the muscles act during stair negotiation? MethodsIn this explorative study, 17 adults with bilateral, spastic cerebral palsy and stiff knee gait and 25 healthy subjects were examined. 3D motion analysis, including electromyography, was performed while walking on level ground, upstairs, and downstairs. A linear mixed model was used for between- and within-group comparisons. ResultsWalking upstairs and downstairs, patients increased their peak knee flexion by around 30° compared to level walking. Thus, increased knee flexion may be seen as the main mechanism for maintaining foot clearance on stairs. An increased pelvic obliquity (elevation) and hip flexion were also found and involved subjects showed a slight increase in rectus femoris activity when walking on stairs compared to level walking within the phases of high knee flexion. SignificanceThis study showed that patients with cerebral palsy and stiff knee gait are able to flex their knees more than would be required for level walking. Hence, the patients are able to adapt their rectus activity to stair walking to some extent. Therefore, further investigations might help to open up new therapeutic options to facilitate level walking and stair negotiation in patients with stiff knee gait.

Quantifying high knee flexion exposures in occupational childcare to assess the potential for increased risk of knee osteoarthritis

Quantifying high knee flexion exposures in occupational childcare to assess the potential for increased risk of knee osteoarthritis

Is Achieving High Flexion Necessary for Satisfaction after Total Knee Arthroplasty in Indian Patients?

Background:Total knee arthroplasty (TKA) is a very successful operation for the treatment of end-stage arthritis of the knee joint. In spite of improvement in surgical technique, implant design, postoperative pain management, and rehabilitation, some patients are not satisfied with the outcome of the surgery. It is believed that high-flexion (H-F) activities such as cross-legged sitting and squatting are necessary for satisfaction after TKA in Indian patients due to cultural and social reasons. This has led to the development and marketing of implant designs allowing H-F after TKA without strong evidence in the literature.Materials and Methods:We carried out a retrospective study to determine the level of satisfaction in 74 patients operated for 120 TKA over a 5 year period. This was determined on the basis of a satisfaction questionnaire which included questions to assess satisfaction regarding pain relief and ability to perform routine daily activities and high knee flexion activities such as squatting and cross-legged sitting.Results:Out of a total of 74 patients, 69 patients were overall satisfied with their TKA. Out of these, only 5 patients could squat or sit in a cross-legged position. Majority of the patients were satisfied with the pain relief and improvement in their capacity to work provided by TKA.Conclusions:Ability to perform H-F activities after TKA is not a necessary prerequisite for satisfaction in Indian patients. Implant designs allowing H-F should be used in a selected group of patients with good preoperative knee flexion and specific requirements.

Prediction of thigh-calf contact parameters from anthropometric regression.

High knee flexion postures are common in industry and cultural practices, but the mechanical effect of intersegmental force, particularly thigh-calf contact force, on knee joint compressive force is poorly understood. Although some studies have measured thigh-calf contact parameters occurring in a number of high flexion postures, joint contact modeling would benefit from efforts to predict thigh-calf contact force for use in computational models. Therefore, this study assessed the strength of correlations and linear multiple regression models on the following five high flexion thigh-calf contact parameters in a young, healthy population: the onset angle of thigh-calf contact, maximum flexion angle, total thigh-calf contact force, center of force, and contact area at maximum flexion. Regressions used anthropometric values (and in some cases, maximum flexion angle). Overall, maximum flexion angle and center of force location had the most significant correlates and strong linear fits with regressive models. Thigh-calf contact onset, total force magnitude, and contact area had only moderate to weak relationships. An exploratory attempt at regression using grouped movements into gross patterns (e.g. two types of squatting were grouped into a general squatting category) using maximum flexion angle and center of force location as dependent variables resulted in similar model fitting. These findings suggest that a causal relationship between select anthropometrics and lower limb range of motion may exist, but further exploration is necessary to determine clinically reliable predictive models.

Stair Climbing and High Knee Flexion Activities in Bi-Cruciate Retaining Total Knee Arthroplasty: In Vivo Kinematics and Articular Contact Analysis

BackgroundBi-cruciate retaining (BCR) total knee arthroplasty (TKA) preserves both anterior and posterior cruciate ligaments with the potential to restore normal posterior femoral rollback and joint kinematics. However, there is limited information regarding articular contact behavior in the contemporary BCR TKA design during high knee flexion activities. This study aimed to investigate the articular knee contact performance in unilateral BCR TKA patients during strenuous flexion activities. MethodsTwenty-nine unilateral BCR TKA patients were evaluated for both knees during single deep lunges, step-ups, and sit-to-stand (STS) using a validated combined computer tomography and dual fluoroscopic imaging system. Medial and lateral condylar contact positions were quantified during weight-bearing flexion. ResultsContact excursions of the lateral condyle in BCR TKAs were significantly more anteriorly located than the contralateral non-operated knees during STS (−4.9 ± 3.1 vs −9.7 ± 4.6 mm, P < .05), single deep lunge (−5.7 ± 3.2 vs −10.0 ± 4.5 mm, P < .05), and step-ups (−4.8 ± 3.6 vs −9.1 ± 3.9 mm, P < .05). Contact points of BCR TKAs indicated reduced femoral external rotation during STS (2.1 ± 4.8° vs 7.7 ± 5.4°, P < .05), single deep lunges (1.8 ± 4.8° vs 7.0 ± 7.1°, P < .05), and step-ups (0.1 ± 4.1° vs 6.2 ± 4.9°, P < .05). Medial pivoting patterns were observed in only 59%, 56%, and 48% of the BCR TKA knees for step-ups, STS, and single deep lunge, respectively. ConclusionThe contemporary BCR TKA design demonstrated asymmetric femoral rollback, medial translation, as well as lateral pivoting in about half of the patient cohort, suggesting that in vivo tibiofemoral kinematic parameters were not fully restored in BCR patients during strenuous flexion activities.

Representing fine-wire EMG with surface EMG in three thigh muscles during high knee flexion movements

Activation waveforms of vastus intermedius, adductor magnus, and semimembranosus have not been reported for high knee flexion activities such as kneeling or squatting, likely due to the invasive procedures required for their measurement. Their relatively large physiological cross sectional areas would suggest their contributions to knee joint loading could be considerable. Therefore, the purpose of this study was to quantify the activities of these muscles using fine-wire EMG and to assess easy to measure surface sites (vastus lateralis, rectus femoris, vastus medialis, semitendinosus, and biceps femoris) for their potential as proxy measures using <10 %MVC RMS and >0.85 R2 as criteria for successful representation of deep muscle activity by that measured at a surface site. Overall, no surface and fine-wire site pair met both criteria for these movements. When fine-wire measurement of muscle activity is infeasible or impractical, the waveforms presented in supplementary material could be used as a guide for the activity of these deep muscles. Although select muscles for some participants satisfied our criteria, inter-participant variability was considerable. Therefore, future muscle models may benefit from fine-wire measurement of these muscles, but researchers should be cautious of electrode site specificity.