Vol.:(0123456789) 1 3 Knee Surgery, Sports Traumatology, Arthroscopy https://doi.org/10.1007/s00167-020-05949-y KNEE Influence of component design on in vivo tibiofemoral contact patterns during kneeling after total knee arthroplasty: a systematic review and meta‑analysis Joseph T. Lynch 1  · Jennie M. Scarvell 2  · Catherine R. Galvin 3  · Paul N. Smith 1  · Diana M. Perriman 1 Received: 3 December 2019 / Accepted: 20 March 2020 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2020 Abstract Purpose Modern TKR prostheses are designed to restore healthy kinematics including high flexion. Kneeling is a demand- ing high-flexion activity. There have been many studies of kneeling kinematics using a plethora of implant designs 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. Methods A search of the published literature identified 26 articles which were assessed for methodologic quality using the MINORS instrument. Contact patterns for different implant designs were compared at 90° and maximal flexion using quality-effects meta-analysis models. Results Twenty-five different implants using six designs were reported. Most of the included studies had small-sample sizes, were non-consecutive, and did not have a direct comparison group. Only posterior-stabilised fixed-bearing and cruciate- retaining fixed-bearing designs had data for more than 200 participants. Meta-analyses revealed that bicruciate-stabilised fixed-bearing designs appeared to achieve more flexion and the cruciate-retaining rotating-platform design achieved the least, but both included single studies only. All designs demonstrated posterior–femoral translation and external rotation in kneeling, but posterior-stabilised designs were more posterior at maximal flexion when compared to cruciate retaining. However, the heterogeneity of the mean estimates was substantial, and therefore, firm conclusions about relative behaviour cannot be drawn. Conclusion The high heterogeneity may be due to a combination of variability in the kneeling activity and variations in implant geometry within each design category. There remains a need for a high-quality prospective comparative studies to directly compare designs using a common method. Level of evidence Systematic review and meta-analysis Level IV Keywords Total knee replacement · Contact patterns · Systematic review · Kneeling Introduction Being able to kneel is reported to be one of the most impor- tant activities that fails to meet the expectations of patients after total knee replacement (TKR) [38]. In TKR, high flexion is an important indicator of success, and consider- able effort has been applied to achieving normal kinematic behaviour in TKR designs. Although there are several kneel- ing variations, they all require up to 165° of flexion which is greater than other high-flexion activities [15, 31]. To achieve deep flexion, the native femur externally rotates and translates posteriorly on the tibia [9, 10]. Contact patterns enable easy visualisation and quantification of tibiofemoral * Joseph T. Lynch Joseph.lynch@anu.edu.au 1 The Trauma and Orthopaedic Research Unit, Australian National University, The Canberra Hospital, Building 6, Level 1, Garran, ACT, Australia 2 Faculty of Health, University of Canberra, Canberra, ACT, Australia 3 College of Engineering and Computer Science, Australian National University, Acton, ACT, Australia