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 .
In vivo kneeling biomechanics after posterior stabilized total knee arthroplasty
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
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 .