Are undesirable contact kinematics minimized after kinematically aligned total knee arthroplasty? An intersurgeon analysis of consecutive patients In vivo deep-flexion kinematics in patients with posterior-cruciate retaining and anterior-cruciate substituting total knee arthroplasty. In vivo kneeling biomechanics after posterior stabilized total knee arthroplasty Do we need a gender-specific total knee replacement? A randomised controlled trial comparing a high-flex and a gender-specific posterior design. In vivo kinematic comparison of posterior cruciate-retaining and posterior stabilized total knee arthroplasties under passive and weight-bearing conditions. Gait analysis of fixed bearing and mobile bearing total knee prostheses during walking: do mobile bearings offer functional advantages? Kinematics of a highly congruent mobile-bearing total knee prosthesis Does ligament balancing technique affect kinematics in rotating platform, PCL retaining knee arthroplasties? Prosthesis alignment affects axial rotation motion after total knee replacement: a prospective in vivo study combining computed tomography and fluoroscopic evaluations Kinematics and early migration in single-radius mobile- and fixed-bearing total knee prostheses. Mobile vs. fixed bearing unicondylar knee arthroplasty: A randomized study on short term clinical outcomes and knee kinematics. Knee kinematics and kinetics in former soccer players with a 16-year-old ACL injury – the effects of twelve weeks of knee-specific training Effects of Pelvic Asymmetry and Low Back Pain on Trunk Kinematics During Sitting: A Comparison With Standing Kinematics of posterior cruciate ligament-retaining and -substituting total knee arthroplasty: a prospective randomised outcome study. Achieving Accurate Ligament Balancing Using Robotic-Assisted Unicompartmental Knee Arthroplasty Effects of an implantable two-channel peroneal nerve stimulator versus conventional walking device on spatiotemporal parameters and kinematics of hemiparetic gait. In vivo noninvasive evaluation of abnormal patellar tracking during squatting in patients with patellofemoral pain. Interactions between kinematics and loading during walking for the normal and ACL deficient knee. Effects of Various Treadmill Interventions on the Development of Joint Kinematics in Infants With Down Syndrome After Partial Knee Replacement, Patients Can Kneel, But They Need to Be Taught to Do So: A Single-Blind Randomized Controlled Trial Effects of ankle foot orthosis in stiff knee gait in adults with hemiplegia. Lower extremity kinematics and ground reaction forces after prophylactic lace-up ankle bracing. Does the Dual-Mobility Hip Prosthesis Produce Better Joint Kinematics During Extreme Hip Flexion Task?
Purpose Tibiofemoral contact kinematics or knee implant motions have a direct influence on patient function and implant longevity and should be evaluated for any new alignment technique such as kinematically aligned total knee arthroplasty ( TKA ) . Edge loading of the tibial liner and external rotation ( reverse of normal ) and adduction of the tibial component on the femoral component are undesirable contact kinematics that should be minimized . Accordingly , this study determined whether the overall prevalence of undesirable contact kinematics during st and ing , mid kneeling near 90 degrees and full kneeling with kinematically aligned TKA are minimal and not different between groups of consecutive patients treated by different surgeons . Methods Three surgeons were asked to perform cemented , kinematically aligned TKA with patient-specific guides in a consecutive series of patients with their preferred cruciate-retaining ( CR ) implant .  In vivo tibiofemoral contact positions were obtained using a 3- to 2-dimensional image registration technique in 69 subjects ( Vanguard CR – TKA N = 22 , and Triathlon CR – TKA N = 47 ) . Results Anterior or posterior edge loading of the tibial liner was not observed . The overall prevalence of external rotation of the tibial component on the femoral component of 6 % was low and not different between surgeons ( n.s . ) . The overall prevalence of adduction of the tibial component on the femoral component of 4 % was low and not different between surgeons ( n.s . ) . Conclusions Kinematically aligned TKA minimized the undesirable contact kinematics of edge loading of the tibial liner , and external rotation and adduction of the tibial component on the femoral component during st and ing and kneeling , which suggests an optimistic prognosis for durable long-term function . Level of evidence III BACKGROUND Posterior-cruciate ligament retaining total knee arthroplasty design s have long been used with excellent clinical success , but often have shown kinematics and flexion performance that are significantly different from the natural knee . The purpose of this study was to compare deep-flexion knee kinematics in patients with two types of posterior-cruciate ligament retaining total knee arthroplasty .  METHODS One group received a traditional curved symmetric articular configuration , and one group received a design incorporating a lateral compartment which constrains the lateral condyle to the antero-posterior center of the tibial plateau in extension , but allows translation in flexion -- roughly approximating the role of the anterior cruciate ligament . In vivo kinematics were analyzed using three-dimensional model registration and plain radiographs of kneeling and squatting activities in 20 knees in 18 patients . FINDINGS Knees with the anterior cruciate ligament substituting design exhibited greater flexion , femoral antero-posterior translation and tibial internal rotation . INTERPRETATION Geometric features intended to improve knee flexion , including greater antero-posterior stability , a more posterior tibial sulcus , and reshaped femoral condyles , do provide measurable and significant differences in deep-flexion knee kinematics Background Kneeling is one of the activities sought by patients after total knee arthroplasty ( TKA ) . This study investigated the six degrees of freedom ( DOF ) kinematics and three-dimensional ( 3D ) contact during weight-bearing kneeling . Methods A total of 16 South Korean female patients ( 22 knees ) after posteriorly stabilized ( PS ) TKA ( LPS-Flex ) were r and omly recruited and had the same surgeon . The patients were imaged using a dual fluoroscopic technique while they kneeled from initial to maximum flexion . The acquired images and 3D models were then used to recreate the in vivo pose of the components . Contact was determined by locating the surface intersections in the tibiofemoral and cam/post ( between the femoral cam and tibial post ) articular compartments . Results Patients flexed , on average , from 107.3 ° to 128.0 ° during the kneeling activity . Changes in kinematics included 1.0 mm of proximal , 0.9 mm of medial , and 7.6 mm of posterior translation and 1.7 ° of varus rotation ( P < 0.04 ) . A difference in internal tibial rotation was not detected . Articular contact moved posteriorly by 5.9 mm and 6.4 mm in the medial and lateral compartments , respectively . Contact also moved medially by 3.2 mm and 5.8 mm in the medial and lateral compartments . A decrease in articular contact was observed in both condyles , and lateral condylar lift-off increased with flexion ( P = 0.0001 ) . More than 80 % of the patients demonstrated cam/post engagement , which always occurred in the distal portion of the post . Conclusions In this patient cohort , the knee joint was constrained during the weight-bearing activity such that femoral subluxation and dislocation were not observed . Furthermore , posterior cam/post engagement occurred only in the distal portion of the tibial post , which may improve the longevity of the post . The tibiofemoral and cam/post articular contact data presented in this study further suggest that kneeling may be performed by patients after clinical ly successful PS TKA who feel comfortable with the activity and are free of pain The purpose of this study was to investigate whether a gender-specific high-flexion posterior-stabilised ( PS ) total knee replacement ( TKR ) would offer advantages over a high-flex PS TKR regarding range of movement ( ROM ) , ' feel ' of the knee , pain and satisfaction , as well as during activity . A total of 24 female patients with bilateral osteoarthritis entered this prospect i ve , blind r and omised trial in which they received a high-flex PS TKR in one knee and a gender-specific high-flexion PS TKR in the other knee . At follow-up , patients were assessed clinical ly measuring ROM , and question ed about pain , satisfaction and daily ' feel ' of each knee . Patients underwent gait analysis pre-operatively and at one year , which yielded kinematic , kinetic and temporospatial parameters indicative of knee function during gait . At final follow-up we found no statistically significant differences in ROM ( p = 0.82 ) . The median pain score was 0 ( 0 to 8) in both groups ( p = 0.95 ) . The median satisfaction score was 9 ( 4 to 10 ) in the high-flex group and 8 ( 0 to 10 ) in the gender-specific group ( p = 0.98 ) . The median ' feel ' score was 9 ( 3 to 10 ) in the high-flex group and 8 ( 0 to 10 ) in the gender-specific group ( p = 0.66 ) . Gait analysis showed no statistically significant differences between the two prosthetic design s in any kinematic , kinetic or temporospatial parameters . Both design s produced good clinical results with significant improvements in several gait parameters without evidence of any advantage in the gender-specific design An in vivo comparison of flexion kinematics for  posterior cruciate-retaining ( PCR ) and posterior stabilized ( PS ) total knee arthroplasty ( TKA ) was performed . Twenty patients who underwent bilateral paired TKAs were included in this prospect i ve study . Both PCR and PS prostheses were from the same TKA series with comparable surface geometries , and all were implanted by a single surgeon . Of these 20 patients , 3-dimensional kinematics during flexion could be analyzed using a computer model fitting technique in 18 patients . The follow-up period ranged from 18 to 53 months . In the PCR TKA , an anterior femoral translation from 30 degrees to 60 degrees of flexion was observed in the weight-bearing condition . In contrast , flexion kinematics for the PS TKA was characterized by the maintenance of a constant contact position under weight-bearing conditions and posterior femoral rollback in passive flexion BACKGROUND Limited previous findings have detailed biomechanical advantages following implantation with mobile bearing ( MB ) prostheses after total knee replacement ( TKR ) surgery during walking . The aim of this study was to compare three dimensional spatiotemporal , kinematic , and kinetic parameters during walking to examine whether MBs offer functional advantages over fixed bearing ( FB ) design s. METHODS Sixteen patients undergoing primary unilateral TKR surgery were r and omised to receive either a FB ( n=8 ) or MB ( n=8 ) total knee prosthesis .  Eight age and gender matched controls underwent the same protocol on one occasion . A 12 camera Vicon system integrated with four force plates was used . Patients were tested pre-surgery and nine months post-surgery . RESULTS No significant differences between FB and MB groups were found at any time point in the spatiotemporal parameters . The MB group was found to have a significantly reduced frontal plane knee range of motion ( ROM ) at pre-surgery than the FB group ( FB=14.92±4.02 ° ; MB=8.87±4.82 ° ) , with the difference not observed post-surgery . No further significant kinematic or kinetic differences were observed between FB and MB groups . Fixed bearing and MB groups both displayed spatiotemporal , kinematic , and kinetic differences when compared to controls . Fixed bearing and MB groups differed from controls in six and five parameters at nine months post-surgery , respectively . CONCLUSIONS No functional advantages were found in knees implanted with MB prostheses during walking , with both groups indicative of similar differences when compared to normal knee biomechanics following prosthesis implantation . LEVEL OF EVIDENCE Level II Purpose Limited or absent axial rotation of the mobile insert of total knee prostheses could lead to high contact stresses and stresses at the bone-implant interface , which in turn might lead to implant loosening . The aim of this study was to assess knee kinematics and muscle activation and their possible change over time in patients with a highly congruent , mobile-bearing total knee prosthesis . Methods A prospect i ve series of 11 rheumatoid arthritis patients was included to participate in this fluoroscopic and EMG study ; only 7 patients completed the study .  Kinematic evaluations took place 7 months , 1 and 2 years post-operatively . Repeated measurements ANOVA and linear mixed-effects model for longitudinal data were used to compare the differences between the follow-ups . Results There are no significant changes in axial rotations between follow-up moments for the femoral component as well as the mobile insert . The insert remained mobile and followed the femoral component from 0 ° until approximately 60 ° of knee flexion . Diverging and reversed axial rotations and translations were seen during the dynamic motions . Conclusions Knee kinematics and muscle activation do not appear to change in the first 2 post-operative years . Reversed and divergent axial rotations with increasing knee flexion indicate that as soon as the congruency decreases , the femoral component is no longer forced in a certain position by the insert and moves to a self-imposed position . At lower knee flexion angles , the femoral component might be obstructed by the highly congruent insert and therefore might not be able to move freely . Level of evidence Therapeutic study , Level IV The goal of this prospect i ve , r and omized , blinded trial was to determine if ligament balancing techniques for rotating platform TKA affect postoperative knee kinematics .  Sixteen patients with unilateral rotating platform TKA consented to participate in this institutional review board approved study . Eight patients were r and omly selected to receive ligament balancing with an instrumented joint spreader device and eight patients received ligament balancing using fixed thickness spacer blocks .  A single plane shape matching technique was used for kinematic analysis of static deep knee flexion and dynamic stair activities . There were no differences in knee kinematics between groups during static deep flexion activities . The spreader group demonstrated kinematics more similar to the normal knee during the ascending phase of the dynamic stair activity . Knee kinematics in static knee flexion were unaffected by ligament balancing technique , while knees balanced with the spreader demonstrated a medial pivot motion pattern during stair ascent . This medial pivot motion pattern may improve long-term results by more closely replicating normal knee kinematics Background Clinical consequences of alignment errors in  total knee replacement ( TKR ) have led to the rigorous evaluation of surgical alignment techniques . Rotational alignment in the transverse plane has proven particularly problematic , with errors due to component malalignment relative to bone anatomic l and marks and an overall mismatch between the femoral and tibial components ’ relative positions . Ranges of nominal rotational alignment are not well defined , especially for the tibial component and for relative rotational mismatch , and some studies advocate the use of mobile-bearing TKR to accommo date the result ing small rotation errors . However , the relationships between prosthesis rotational alignment and mobile-bearing polyethylene insert motion are poorly understood . This prospect i ve , in vivo study evaluates whether component malalignment and mismatch affect axial rotation motions during passive knee flexion after TKR . Methods Eighty patients were implanted with mobile-bearing TKR .  Rotational alignment of the femoral and tibial components was measured from postoperative CT scans . All TKR were categorized into nominal or outlier groups based on defined norms for surgical rotational alignment relative to bone anatomic l and marks and relative rotational mismatch between the femoral and tibial components . Axial rotation motion of the femoral , tibial and polyethylene bearing components was measured from fluoroscopic images acquired during passive knee flexion . Results Axial rotation motion was generally accomplished in two phases , dominated by polyethylene bearing rotation on the tibial component in early to mid-flexion and then femoral component rotation on the polyethylene articular surface in later flexion . Opposite rotations of the femur-bearing and bearing-baseplate articulations were evident at flexion greater than 80 ° . Knees with outlier alignment had lower magnitudes of axial rotation and distinct transitions from external to internal rotation during mid-flexion . Knees with femoral-tibial rotational mismatch had significantly lower total axial rotation compared to knees with nominal alignment . Conclusions Maintaining relative rotational mismatch within ±5 ° during TKR provided for controlled knee axial rotation during flexion . TKR with rotational alignment outside of defined surgical norms , with either positive or negative mismatch , experienced measurable kinematic differences and presented different patterns of axial rotation motions during passive knee flexion compared to TKR with nominal mismatch . These findings support previous studies linking prosthesis rotational alignment with inferior clinical and functional outcomes .Trial Registration Clinical Trials BACKGROUND The mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component . This would reduce the contact stresses and wear which in turn may have a positive effect on the fixation of the prosthesis to the bone and thereby decreases the risk for loosening . The aim of this study was to evaluate early migration of the tibial component and kinematics of a mobile-bearing and fixed-bearing total knee prosthesis of the same single-radius design . METHODS Twenty Triathlon single-radius posterior-stabilized knee prostheses were implanted ( 9 mobile-bearing and 11 fixed-bearing ) .  Fluoroscopy and roentgen stereophotogrammetric analysis ( RSA ) were performed 6 and 12 months post-operatively . FINDINGS The 1 year post-operative RSA results showed considerable early migrations in 3 out of 9 mobile-bearing patients and 1 out of 11 fixed-bearing patients . The range of knee flexion was the same for the mobile-bearing and fixed-bearing group . The mobile insert was following the femoral component during motion . INTERPRETATION Despite the mobile insert following the femoral component during motion , and therefore performing as intended , no kinematic advantages of the mobile-bearing total knee prosthesis were seen . The fixed-bearing knee performed as good as the mobile-bearing knee and maybe even slightly better based on less irregular kinematics and less early migrations The literature contains limited yet controversial information regarding whether a fixed or a mobile bearing implant should be used in unicompartmental knee arthroplasty ( UKA ) . This r and omized study was to further document the performance and comparison of the two design s. Fifty-six knees in 48 patients ( mean age of 72 years ) undergoing medial UKA were r and omized into a fixed bearing ( Miller/Galante ) or a mobile bearing ( Oxford ) UKA . The 2 year clinical outcomes ( clinical scores ) , radiographic findings , and weight bearing knee kinematics ( assessed using RSA ) were compared between the two groups . The mobile bearing knees displayed a larger and an incrementally increased tibial internal rotation ( 4.3 degrees , 7.6 degrees , 9.5 degrees vs. 3.0 degrees , 3.0 degrees , 4.2 degrees respectively at 30 degrees , 60 degrees , 90 degrees of knee flexion ) compared to the fixed ones . The medial femoral condyle in the mobile bearing knees remained 2 mm from the initial position vs. a 4.2 mm anterior translation in the fixed bearing knees during knee flexion . The contact point in the mobile bearing implant moved 2 mm posteriorly vs. a 6 mm anterior movement in the other group . The mobile bearing knees had a lower incidence of radiolucency at the bone implant interface ( 8 % vs. 37 % , p < 0.05 ) . The incidence of lateral compartment OA and progression of OA at patello-femoral joint were equal . No differences were found regarding Knee Society Scores , WOMAC , and SF-36 scores ( p > 0.05 ) . This study indicates that mobile bearing knees had a better kinematics , a lower incidence of radiolucency but not yet a better knee function at 2 years Background Training of neuromuscular control has become increasingly important and plays a major role in rehabilitation of subjects with an injury to the anterior cruciate ligament ( ACL ) . Little is known , however , of the influence of this training on knee stiffness during loading . Increased knee stiffness occurs as a loading strategy of ACL-injured subjects and is associated with increased joint contact forces . Increased or altered joint loads contribute to the development of osteoarthritis . The aim of the study was to determine if knee stiffness , defined by changes in knee kinetics and kinematics of gait , step activity and cross-over hop could be reduced through a knee-specific 12-week training programme . Methods A 3-dimensional motion analysis system ( VICON ) and a force plate ( AMTI ) were used to calculate knee kinetics and kinematics before and after 12 weeks of knee-specific training in 12 males recruited from a cohort with ACL injury 16 years earlier . Twelve uninjured males matched for age , sex , BMI and activity level served as a reference group . Self-reported patient-relevant data were obtained by the KOOS question naire . Results There were no significant changes in knee stiffness during gait and step activity after training . For the cross-over hop , increased peak knee flexion during l and ing ( from 44 to 48 degrees , p = 0.031 ) and increased internal knee extensor moment ( 1.28 to 1.55 Nm/kg , p = 0.017 ) were seen after training , indicating reduced knee stiffness . The KOOS sport and recreation score improved from 70 to 77 ( p = 0.005 ) and was significantly correlated with the changes in knee flexion during l and ing for the cross-over hop ( r = 0.6 , p = 0.039 ) . Conclusion Knee-specific training improved lower extremity kinetics and kinematics , indicating reduced knee stiffness during dem and ing hop activity . Self-reported sport and recreational function correlated positively with the biomechanical changes supporting a clinical importance of the findings . Further studies are needed to confirm these results in women and in other ACL injured population Study Design . A prospect i ve study was conducted on a group of patients with unilateral nonspecific low back pain ( LBP ) and healthy controls . Objectives . To answer 3 questions : ( 1 ) Does pelvic asymmetry measured in st and ing affect the dynamics of motion performed in sitting ? ( 2 ) Do patients with LBP perform trunk motions differently from non-LBP participants in sitting position ? and ( 3 ) Do the kinematics of lateral flexion and axial rotation differ between sitting and st and ing positions ? Summary of Background Data . The effect of pelvic asymmetry on trunk motion while sitting remains unclear . LBP has been associated with altered trunk kinematics in st and ing ; however , there is limited information available describing trunk kinematics in sitting position in comparison to st and ing . Methods . Pelvic asymmetry was measured in 54 patients with unilateral nonspecific LBP and 59 control subjects .  A motion- analysis system was used to test the  range and symmetry of lateral flexion and axial rotation  in sitting and st and ing positions . Bivariate correlations , regression , multivariate analysis of variance , and paired sample t tests were used to test for associations between variables and differences between groups . Results . We found significant : ( 1 ) correlations between pelvic asymmetry and asymmetric trunk motion performed in sitting , ( 2 ) differences between the LBP and control groups in patterns of trunk motion performed in a sitting posture , and ( 3 ) differences between kinematics of motions performed in sitting versus st and ing postures . Conclusions . This study shows a link between pelvic asymmetry and altered trunk motion in sitting position . We suggest that people with LBP may have a distinct compensatory mechanism , secondary to pelvic asymmetry , which puts the lumbar spine under higher stress . Movement asymmetry , rather than range of motion , may be a better indicator of disturbed function for people with LBP . Structural and functional asymmetries are factors that may be considered in the seating design and work environment We performed a prospect i ve , r and omised trial of 44 patients to compare the functional outcomes of a posterior-cruciate-ligament-retaining and posterior-cruciate-ligament-substituting total knee arthroplasty  , and to gain a better underst and ing of the in vivo kinematic behaviour of both devices . At follow-up at five years , no statistically significant differences were found in the clinical outcome measurements for either design . The prevalence of radiolucent lines and the survivorship were the same . In a subgroup of 15 knees , additional image-intensifier analysis in the horizontal and sagittal planes was performed during step-up and lunge activity . Our analysis revealed striking differences . Lunge activity showed a mean posterior displacement of both medial and lateral tibiofemoral contact areas ( roll-back ) which was greater and more consistent in the cruciate-substituting than in the cruciate-retaining group ( medial p < 0.0001 , lateral p = 0.011 ) . The amount of posterior displacement could predict the maximum flexion which could be achieved ( p = 0.018 ) . Forward displacement of the tibiofemoral contact area in flexion during stair activity was seen more in the cruciate-retaining than in the cruciate-substituting group . This was attributed mainly to insufficiency of the posterior cruciate ligament and partially to that of the anterior cruciate ligament . We concluded that , despite similar clinical outcomes , there are significant kinematic differences between cruciate-retaining and cruciate-substituting arthroplasties Unicompartmental knee arthroplasty ( UKA ) allows replacement of a single compartment in patients with limited disease . However , UKA is technically challenging and relies on accurate component positioning and restoration of natural knee kinematics . This study examined the accuracy of dynamic , real-time ligament balancing  using a robotic-assisted UKA system . Surgical data obtained from the computer system were prospect ively collected from 51 patients ( 52 knees ) undergoing robotic-assisted medial UKA by a single surgeon .  Dynamic ligament balancing of the knee was obtained under valgus stress prior to component implantation and then compared to final ligament balance with the components in place . Ligament balancing was accurate up to 0.53 mm compared to the preoperative plan , with 83 % of cases within 1 mm at 0 ° , 30 ° , 60 ° , 90 ° , and 110 ° of flexion . Ligamentous laxity of 1.31 ± 0.13 mm at 30 ° of flexion was corrected successfully to 0.78 ± 0.17 mm ( P < 0.05 ) . Robotic-assisted UKA allows accurate and precise reproduction of a surgical balance plan using dynamic , real-time soft-tissue balancing to help restore natural knee kinematics , potentially improving implant survival and functional outcomes OBJECTIVE The aims of this study were : ( i ) to compare the neuro-prosthetic effect of implantable peroneal nerve stimulation to the orthotic effect of a st and ard of care intervention ( no device , shoe or ankle foot orthosis ) on walking , as assessed by spatiotemporal parameters ; and ( ii ) to examine whether there is evidence of an enhanced lower-limb flexion reflex with peroneal nerve stimulation and compare the kinematic effect of an implantable peroneal nerve stimulation device vs st and ard of care intervention on initial loading response of the paretic limb , as assessed by hip , knee and ankle kinematics . DESIGN R and omized controlled trial . SUBJECTS A total of 23 chronic stroke survivors with drop foot . METHODS The intervention group received an implantable 2-channel peroneal nerve stimulator for correction of drop foot . The control group continued using a conventional walking device .  Spatiotemporal parameters and hip , knee and ankle kinematics were measured while subjects walked with the device on using a 3-dimensional video camera system during baseline and after a follow-up period of 26 weeks . RESULTS Peroneal nerve stimulation normalized stance and double support of the paretic limb and single support of the non-paretic limb , in comparison with using a conventional walking device . In addition , peroneal nerve stimulation is more effective to provide ankle dorsiflexion during swing and result ed in a normalized initial loading response . CONCLUSION Although peroneal nerve stimulation and ankle foot orthosis are both prescribed to correct a drop foot in the same patient population , spatiotemporal parameters , dorsiflexion during swing and loading response are influenced in a functionally different way BACKGROUND Patellofemoral pain syndrome is one of the most common knee problems and may be related to abnormal patellar tracking . Our purpose was to compare , in vivo and noninvasively , the patellar tracking patterns in symptomatic patients with patellofemoral pain and those in healthy subjects during squatting . We tested the hypothesis that patients with patellofemoral pain exhibit characteristic patterns of patellar tracking that are different from those of healthy subjects . METHODS Three-dimensional patellar kinematics were recorded in vivo with use of a custom-molded patellar clamp and an optoelectronic motion capture system in ten healthy subjects and nine subjects with patellofemoral pain . The position of osseous knee l and marks was digitized while subjects stood upright , and then patellofemoral kinematics were recorded during squatting . The tracking technique was vali date d with use of both in vitro and in vivo method ologies , and the average absolute error was < 1.2 degrees and < 1.1 mm . RESULTS At 90 degrees of knee flexion , the patella showed lateral spin ( the distal pole of the patella rotated laterally ) in subjects with patellofemoral pain ( mean and st and ard deviation , -10.13 degrees + /- 2.24 degrees ) and medial spin in healthy subjects ( mean , 4.71 degrees + /- 1.17 degrees ) ( p < 0.001 ) . At 90 degrees of knee flexion , the patella demonstrated significantly more lateral translation in subjects with patellofemoral pain ( mean , 5.05 + /- 3.73 mm ) than in healthy subjects ( mean , -4.93 + /- 3.93 mm ) ( p < 0.001 ) . CONCLUSIONS Kinematic differences between healthy subjects and subjects with patellofemoral pain were demonstrated through a large , dynamic range of knee flexion angles . Increased lateral patellar translation and lateral patellar spin in subjects with patellofemoral pain suggest that the patella is not adequately balanced during functional activities in this group . Prospect i ve studies are needed to identify when patellofemoral pain-related changes begin to occur and to determine the risk for the development of patellofemoral pain in individuals with abnormal kinematics The relationships between extrinsic forces acting at the knee and knee kinematics were examined with the purpose of identifying specific phases of the walking cycle that could cause abnormal kinematics in the anterior cruciate ligament ( ACL ) deficient knee .  Intersegmental forces and moments in directions that would produce anterior-posterior ( AP ) translation , internal-external ( IE ) rotation and flexion-extension ( FE ) at the knee were compared with the respective translation and rotations of the tibia relative to the femur during four selected phases ( heel strike , weight acceptance , terminal extension and swing ) of the walking cycle . The kinematic changes associated with loss of the ACL occurred primarily during the terminal portion of swing phase of the walking cycle where , for the ACL deficient knee , the tibia had reduced external rotation and anterior translation as the knee extended prior to heel strike . The kinematic changes during swing phase were associated with a rotational offset relative to the contralateral knee in the average position of the tibia towards internal rotation . The offset was maintained through the entire gait cycle . The abnormal offsets in the rotational position were correlated with the magnitude of the flexion moment ( balanced by a net quadriceps moment ) during weight acceptance . These results suggest that adaptations to the patterns of muscle firing during walking can compensate for kinematic changes associated with the loss of the ACL . The altered rotational position would cause changes in tibiofemoral contact during walking that could cause the type of degenerative changes reported in the meniscus and the articular cartilage following ACL injury Background Infants with Down syndrome ( DS ) have delayed walking and produce less-coordinated walking patterns . Objective The aim of this study was to investigate whether 2 treadmill interventions would have different influences on the development of joint kinematic patterns in infants with DS . Design Thirty infants with DS were r and omly assigned to a lower-intensity , generalized ( LG ) treadmill training group ( LG group ) or a higher-intensity , individualized ( HI ) treadmill training group ( HI group ) and trained until walking onset .  Twenty-six participants ( 13 in each group ) completed a 1-year gait follow-up assessment . Methods During the gait follow-up assessment , reflective markers were placed bilaterally on the participants to measure the kinematic patterns of the hip , knee , and ankle joints . Both the timing and the magnitude of peak extension and flexion at the hip , knee , and ankle joints , as well as peak adduction and abduction at the hip joint , in the 2 groups were compared . Results Both the LG group and the HI group showed significantly advanced development of joint kinematics at the gait follow-up . In the HI group , peak ankle plantar flexion occurred at or before toe-off , and the duration of the forward thigh swing after toe-off increased . Limitations Joint kinematics in the lower extremities were evaluated in this study . It would be interesting to investigate the effect of treadmill interventions on kinematic patterns in the trunk and arm movement . Conclusions The timing of peak ankle plantar flexion ( before toe-off ) in the HI group implies further benefits from the HI intervention ; that is , the HI group may use mechanical energy transfer better at the end of stance and may show decreased hip muscle forces and moments during walking . It was concluded that the HI intervention can accelerate the development of joint kinematic patterns in infants with DS within 1 year after walking onset Background and Purpose : Kneeling is an important functional activity frequently not performed after knee replacement , thus affecting a patient 's ability to carry out basic daily tasks . Despite no clinical reason preventing kneeling , many patients fail to resume this activity . The purpose of this study was to determine whether a single physical therapy intervention would improve patient-reported kneeling ability  following partial knee replacement ( PKR ) . Subjects : Sixty adults with medial compartment osteoarthritis , suitable for a PKR , participated . Methods : This was a single-blind , prospect i ve r and omized controlled trial . Six weeks after PKR , participants r and omly received either kneeling advice and education or routine care where no specific kneeling advice was given . Re assessment was at 1 year postoperatively . The primary outcome measure was patient-reported kneeling ability , as assessed by question 7 of the Oxford Knee Score . Other factors associated with kneeling ability were recorded . These factors were scar position , numbness , range of flexion , involvement of other joints , and pain . Statistical analysis included nonparametric tests and binary logistic regression . Results : A significant improvement in patient-reported kneeling ability was found at 1 year postoperatively in those participants who received the kneeling intervention . Group allocation was the only factor determining an improvement in patient-reported kneeling ability at 1 year postoperatively . Discussion and Conclusion : The single factor that predicted patient-reported kneeling ability at 1 year postoperatively was the physical therapy kneeling intervention given at 6 weeks after PKR . The results of this study suggest that advice and instruction in kneeling should form part of a postoperative rehabilitation program after PKR . The results can be applied only to patients following PKR Stroke survivors present a less efficient gait compared to healthy subjects due to abnormal knee flexion during the swing phase of gait , associated with spasticity of the rectus femoris muscle and overactivity of the ankle plantarflexors . It is relevant to underst and the effect of the ankle foot orthosis ( AFO ) on gait in individuals with plantarflexor spasticity . The aim of this study was to compare the knee kinematics with an AFO/footwear combination and barefoot in post-stroke subjects with plantarflexor spasticity . Ten subjects with chronic hemiplegia were measured . Two kinematic variables were assessed during the swing phase of the paretic limb : knee flexion angle at toeoff and peak knee flexion angle . We also analyzed gait speed and step length of the non-paretic limb . All variables were obtained with and without the orthosis . Kinematic data were acquired using a motion capture system ( ELITE ) . Subjects wearing an AFO showed significant improvements in gait speed ( 0.62 m/s ( 0.08 SD ) vs. 0.47 m/s ( 0.13 SD ) ( p=0.007 ) ) , step length of the non-paretic limb ( 42 cm ( 5.9 SD ) vs. 33.5 cm ( 6.6 SD ) ( p=0.005 ) ) and peak knee flexion angle during the swing phase : 30.7 ° ( 14.1 ° SD ) vs. 26.3 ° ( 11.7 ° SD ) p=0.005 . No significant differences were obtained in the knee flexion angle at toeoff between no AFO and AFO conditions . We described benefits with AFO/footwear use in the kinematics of the knee , the step length of the non-paretic limb , and the gait velocity in hemiplegic subjects after mild to moderate stroke . We conclude that the use of an AFO can improve the gait pattern and increase velocity in these subjects CONTEXT Long-term effects of ankle bracing on lower extremity kinematics and kinetics are unknown . Ankle motion restriction may negatively affect the body 's ability to attenuate ground reaction forces ( GRFs ) . OBJECTIVE To evaluate the immediate and long-term effects of ankle bracing on lower extremity kinematics and GRFs during a jump l and ing . DESIGN Experimental mixed model ( 2 [ group ] x 2 [ brace ] x 2 [ time ] ) with repeated measures . SETTING Sports medicine research laboratory . PATIENTS OR OTHER PARTICIPANTS A total of 37 healthy subjects were assigned r and omly to either the intervention ( n = 11 men , 8 women ; age = 19.63 + /- 0.72 years , height = 176.05 + /- 10.58 cm , mass = 71.50 + /- 13.15 kg ) or control group ( n = 11 men , 7 women ; age = 19.94 + /- 1.44 years , height = 179.15 + /- 8.81 cm , mass = 74.10 + /- 10.33 kg ) . INTERVENTION(S ) The intervention group wore braces on both ankles and the control group did not wear braces during all recreational activities for an 8-week period . MAIN OUTCOME MEASURE(S ) Initial ground contact angles , maximum joint angles , time to reach maximum joint angles , and joint range of motion for sagittal-plane knee and ankle motion were measured during a jump-l and ing task . Peak vertical GRF and the time to reach peak vertical GRF were assessed also . RESULTS While participants were wearing the brace , ankle plantar flexion at initial ground contact ( brace = 35 degrees + /- 13 degrees , no brace = 38 degrees + /- 15 degrees , P = .024 ) , maximum dorsiflexion ( brace = 21 degrees + /- 7 degrees , no brace = 22 degrees + /- 6 degrees , P = .04 ) , dorsiflexion range of motion ( brace = 56 degrees + /- 14 degrees , no brace = 59 degrees + /- 16 degrees , P = .001 ) , and knee flexion range of motion ( brace = 79 degrees + /- 16 degrees , no brace = 82 degrees + /- 16 degrees , P = .036 ) decreased , whereas knee flexion at initial ground contact increased ( brace = 12 degrees + /- 9 degrees , no brace = 9 degrees + /- 9 degrees , P = .0001 ) . Wearing the brace for 8 weeks did not affect any of the outcome measures , and the brace caused no changes in vertical GRFs ( P > .05 ) . CONCLUSIONS Although ankle sagittal-plane motion was restricted with the brace , knee flexion upon l and ing increased and peak vertical GRF did not change . The type of lace-up brace used in this study appeared to restrict ankle motion without increasing knee extension or vertical GRFs and without changing kinematics or kinetics over time BACKGROUND  Total hip arthroplasty ( THA )  using dual-mobility ( DM ) design permits larger hip range of motion . However , it is unclear how it benefits the patients during activities of daily living . The purpose was to compare kinematic variables of the operated limb between  THA patients using either DM or single-bearing ( SB ) implants during a squat task . METHODS Twenty-four THA patients were r and omly assigned to either a DM or SB implant and matched to 12 healthy controls ( CTRLs ) . They underwent 3-dimensional squat motion analysis  before and 9 months after surgery . Sagittal and frontal plane angles of the pelvis and the hip were analyzed using statistical parametric mapping . Paired analyses compared presurgery and postsurgery squat depth . RESULTS Peak sagittal pelvis angle of DM was closer to normal compared with that of SB . Both implant groups had similar hip angle patterns and magnitude but significantly lower than the CTRLs . SB reached a much large hip abduction compared with the other groups . Both surgical groups had significantly worst squat depth than the CTRLs . CONCLUSION Neither THA implant groups were able to return pelvis and hip kinematics to the level of CTRLs . The deficit of DM implants at the pelvis combined with the poorer functional scores should caution clinicians to use this implant design in active patients . SB design causes a larger hip abduction to reach their maximum squat depth . Post-THA rehabilitation should focus on improving joint range of motion and strength
All design s demonstrated posterior – femoral translation and external rotation in kneeling , but posterior-stabilised design s were more posterior at maximal flexion when compared to cruciate retaining .
Modern  TKR prostheses are design ed to restore healthy kinematics including high flexion .
Kneeling is a dem and ing high-flexion activity .
There have been many studies of kneeling kinematics using a plethora of implant design s but no comprehensive comparisons .
Visualisation of contact patterns allows for quantification and comparison of knee kinematics .
The aim of this systematic review was to determine whether there are any differences in the kinematics of kneeling as a function of TKR design .