Patella height influences patellofemoral contact and kinematics following cruciate‐retaining total knee replacement

Abstract

The role of patella height is discussed controversially in total knee arthroplasty (TKA). Therefore, this computational study aims to systematically analyze the biomechanical effect of different patella heights on patellofemoral (PF) forces and kinematics after cruciate-retaining (CR) TKA. We implemented a CR bicondylar TKA with a dome patellar button in a validated dynamic musculoskeletal multibody model of a male human knee joint. Retropatellar dynamics (contact force [N], shear force[N], patellar shift [mm], tilt [°], and rotation [°]) were evaluated during dual-limb squat motion (flexion from 0°to 90°) with simulated active muscle forces and the effects of different patella heights (Blackburne-Peel [BP] ratio of 0.39, 0.49, 0.65, 0.85, 1.01, and 1.1 were systematically examined). As active knee flexion increased, PF contact force also increased. Patella alta (BP = 1.1) resulted in higher PF contact forces compared to normal patella height (BP = 0.65) by up to 16%. Contrarily, patella baja was associated with decreased PF forces by 7%. Compared to patella baja (BP = 0.39), patella alta (BP = 1.1) considerably increased the contact force by up to 25%. Different patellar heights mainly affected PF shear forces during early knee flexion. Concerning PF kinematics, patella alta (BP = 1.1) yielded a greater lateral tilt of more than 4°and higher patellar rotation by up to 3°during deep knee flexion, compared to normal patella height (BP = 0.65). Our computational study indicates that patella alta is associated with the highest PF contact and shear force after the implantation of a CR bicondylar TKA. This should be considered in PF disorders following TKA.

Association between the most superior point of patella-entrance of femoral trochlea distance ratio (SP-ET index) and chondromalacia patella: an investigation via magnetic resonance imaging

“…This condition also leads to a decreased contact area between the patellar and trochlear articular surfaces [ 4 , 9 ]. The biomechanical effect of different patellar heights was analysed, and patella alta was found to be associated with the highest patellofemoral contact and shear force after cruciate retaining total knee arthroplasties in a computational study [ 21 ]. The patello-femoral contact force increases with increasing knee flexion.…”

Impact of Structural Compliance of a Six Degree of Freedom Joint Simulator on Virtual Ligament Force Calculation in Total Knee Endoprosthesis Testing

“…When comparing the findings of the present study to results from the literature, it must be considered that the experimental results are affected by the structural compliance of the VIVO simulator as described. In addition, the absence of a patellar implant component affects joint dynamics as well and can represent an important factor in TKR dynamics [11,32]. The consideration of ligament wrapping also influences the dynamics of the artificial knee joint, as it helps to ensure that non-physiological motions do not occur [33], but consideration of wrapping is not feasible by means of the virtual ligament model.…”

Exploration of the Advanced VIVOTM Joint Simulator: An In-Depth Analysis of Opportunities and Limitations Demonstrated by the Artificial Knee Joint

“…Bioengineering 2024, 11, 178 2 of 25 Contrarily, computational simulations are efficient to analyse the effect of various test parameters on joint dynamics and can support clinical decision making [8][9][10][11][12]. However, it remains challenging to effectively replicate realistic contact conditions [13] which therefore need to be validated experimentally [14].…”