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?
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
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 .