Elongation Patterns of the Collateral Ligaments After Total Knee Arthroplasty Are Dominated by the Knee Flexion Angle

Abstract

The primary aim of this study was to assess the effects of total knee arthroplasty (TKA) implant design on collateral ligament elongation patterns that occur during level walking, downhill walking, and stair descent. Using a moving fluoroscope, tibiofemoral kinematics were captured in three groups of patients with different TKA implant designs, including posterior stabilized, medial stabilized, and ultra-congruent. The 3D in vivo joint kinematics were then fed into multibody models of the replaced knees and elongation patterns of virtual bundles connecting origin and insertion points of the medial and lateral collateral ligaments (MCL and LCL) were determined throughout complete cycles of all activities. Regardless of the implant design and activity type, non-isometric behavior of the collateral ligaments was observed. The LCL shortened with increasing knee flexion, while the MCL elongation demonstrated regional variability, ranging from lengthening of the anterior bundle to slackening of the posterior bundle. The implant component design did not demonstrate statistically significant effects on the collateral elongation patterns and this was consistent between the studied activities. This study revealed that post-TKA collateral ligament elongation is primarily determined by the knee flexion angle. The different anterior translation and internal rotation that were induced by three distinctive implant designs had minimal impact on the length change patterns of the collateral ligaments.

Length-Change Patterns of the Collateral Ligaments During Functional Activities After Total Knee Arthroplasty

“…This supports results of our previous in silico investigation indicating lack of significant task-dependency in the ligament elongation patterns for the knees replaced with three different implant designs. 20 However, flexion angle does not entirely explain the elongations of the collateral ligaments. We found a slightly greater aMCL elongation during level walking compared to the other activities, despite the peak flexion angle being the lowest (Fig.…”

“…43 This excessive external tibial rotation can reduce the maximum aMCL elongation at peak knee flexion during squat as confirmed by our previous sensitivity analysis. 20 However, it is critical to note that this study has investigated subjects with an ultracongruent TKA implant that is known to constrain the joint kinematics, 45 producing tibio-femoral motion that is highly flexion dependent. Other knee implant designs have been shown to present more task-dependent kinematic patterns, 44 plausibly due to the additional geometric freedom allowed by the implant.…”

Loss of Knee Flexion and Femoral Rollback of the Medial-Pivot and Posterior-Stabilized Total Knee Arthroplasty During Early-Stance of Walking in Chinese Patients

“…Inclusion criteria were late-stage primary osteoarthritis with varus or neutral deformity, passive flexion more than 90°, and good collateral stability. Priori power analysis (G ∗ Power version 3.1; Franz Faul, Universität Kiel, Germany) was performed to estimate the minimum sample size, with α = 0.05 and effect size = 1.9 which calculated according to the difference of antero-posterior translation in lateral tibial component ( Hosseini Nasab et al, 2019 ). Each group’s number of 7 is enough to evaluate the difference between the two groups with power of 0.96.…”

Techniques for In Vivo Measurement of Ligament and Tendon Strain: A Review

“…heel strike. 70 However, the lack of a consistent choice of reference length limits inter-study comparisons, and an appropriate solution should be agreed across the field. Measurement frequency and radiation exposure: Fluoroscopes can generate either continuous 57 or pulsed 107 X-ray imaging.…”