Erratum to "Impact of a Digital Balancing Tool on Femur and Tibial First Total Knee Arthroplasty: A Prospective Nonrandomized Controlled Trial" [ARTD 17 (2022) 172-178].

[This corrects the article DOI: 10.1016/j.artd.

Ligament Tension and Balance before and after Robotic-Assisted Total Knee Arthroplasty - Dynamic Changes with Increasing Applied Force.

The optimal force applied during ligament balancing in total knee arthroplasty (TKA) is not well understood. We quantified the effect of increasing distraction force on medial and lateral gaps throughout the range of knee motion, both prior to and after femoral resections in tibial-first gap-balancing TKA. Twenty-five consecutive knees in 21 patients underwent robotic-assisted TKA.

Impact of a Digital Balancing Tool on Femur and Tibial First Total Knee Arthroplasty: A Prospective Nonrandomized Controlled Trial.

Background: Recent developments in intra-operative sensor technology provide surgeons with predictive and real-time feedback on joint balance. It remains unknown, however, whether these technologies are better suited to femur-first or tibia-first workflows. This study investigates the balance accuracy, precision and early patient outcomes between the femur-first and tibial-first workflows using a digital gap-balancing tool.

Correlation between knee anatomy and joint laxity using principal component analysis.

Knee articular geometry and surface morphology greatly affect knee joint mechanics. Intra-subject variations in bone morphology and the passive range of motion have been well documented in the literature; however, the relationship between these two characteristics is not well understood. The objective of this study was to describe the correlation between knee joint anatomical features and passive range of motion using a statistical model.

Impact of intra-operative predictive ligament balance on post-operative balance and patient outcome in TKA: a prospective multicenter study.

Introduction: New technologies exist which may assist surgeons to better predict final intra-operative joint balance. Our objectives were to compare the impact of (1) a predictive digital joint tensioning tool on intra-operative joint balance; and (2) joint balance and flexion joint laxity on patient-reported outcomes.

Materials And Methods: Two-hundred Eighty patients received posterior cruciate ligament sacrificing TKA with ultra-congruent tibial inserts using a robotic-assisted navigation platform.

Improved total knee arthroplasty pain outcome when joint gap targets are achieved throughout flexion.

Purpose: Achieving a balanced knee is accepted as an important goal in total knee arthroplasty; however, the definition of ideal balance remains controversial. This study therefore endeavoured to determine: (1) whether medio-lateral gap balance in extension, midflexion, and flexion are associated with improved outcome scores at one-year post-operatively and (2) whether these relationships can be used to identify windows of optimal gap balance throughout flexion.

Methods: 135 patients were enrolled in a multicenter, multi-surgeon, prospective investigation using a robot-assisted surgical platform and posterior cruciate ligament sacrificing gap balancing technique.

Imageless, robotic-assisted total knee arthroplasty combined with a robotic tensioning system can help predict and achieve accurate postoperative ligament balance.

Background: Achieving balanced gaps is a key surgical goal in total knee arthroplasty, yet most methods rely on subjective surgeon feel and experience to assess and achieve knee balance intraoperatively. Our objective was to evaluate the ability to quantitatively plan and achieve a balanced knee throughout the range of motion using robotic-assisted instrumentation in a tibia-first, gap-balancing technique.

Methods: A robotic-assisted, gap-balancing technique was used in 121 consecutive knees.

Characterization of Ankle Kinematics and Constraint Following Ligament Rupture in a Cadaveric Model.

Ankle sprains are a common injury that may need reconstruction and extensive physical therapy. The purpose of this study was to provide a description of the biomechanics of the ankle joint complex (AJC) after anterior talofibular (ATFL) and calcaneofibular (CFL) ligament rupture to better understand severe ankle injuries. The envelope of motion of ten cadaveric ankles was examined by manual manipulations that served as training data for a radial basis function used to interpolate ankle mobility at flexion angles under load and torque combinations.

Laxity Profiles in the Native and Replaced Knee-Application to Robotic-Assisted Gap-Balancing Total Knee Arthroplasty.

Background: The traditional goal of the gap-balancing method in total knee arthroplasty is to create equal and symmetric knee laxity throughout the arc of flexion. The purpose of this study was to (1) quantify the laxity in the native and the replaced knee throughout the range of flexion in gap-balancing total knee arthroplasty (TKA) and (2) quantify the precision in achieving a targeted gap profile throughout flexion using a robotic-assisted technique with active ligament tensioning.

Methods: Robotic-assisted, gap-balancing TKA was performed in 14 cadaver specimens.

Combined measurement and modeling of specimen-specific knee mechanics for healthy and ACL-deficient conditions.

Quantifying the mechanical environment at the knee is crucial for developing successful rehabilitation and surgical protocols. Computational models have been developed to complement in vitro studies, but are typically created to represent healthy conditions, and may not be useful in modeling pathology and repair. Thus, the objective of this study was to create finite element (FE) models of the natural knee, including specimen-specific tibiofemoral (TF) and patellofemoral (PF) soft tissue structures, and to evaluate joint mechanics in intact and ACL-deficient conditions.

Variations in medial-lateral hamstring force and force ratio influence tibiofemoral kinematics.

A change in hamstring strength and activation is typically seen after injuries or invasive surgeries such as anterior cruciate reconstruction or total knee replacement. While many studies have investigated the influence of isometric increases in hamstring load on knee joint kinematics, few have quantified the change in kinematics due to a variation in medial to lateral hamstring force ratio. This study examined the changes in knee joint kinematics on eight cadaveric knees during an open-chain deep knee bend for six different loading configurations: five loaded hamstring configurations that varied the ratio of a total load of 175 N between the semimembranosus and biceps femoris and one with no loads on the hamstring.

Validation of predicted patellofemoral mechanics in a finite element model of the healthy and cruciate-deficient knee.

Healthy patellofemoral (PF) joint mechanics are critical to optimal function of the knee joint. Patellar maltracking may lead to large joint reaction loads and high stresses on the articular cartilage, increasing the risk of cartilage wear and the onset of osteoarthritis. While the mechanical sources of PF joint dysfunction are not well understood, links have been established between PF tracking and abnormal kinematics of the tibiofemoral (TF) joint, specifically following cruciate ligament injury and repair.

In Vitro Experimental Testing of the Human Knee: A Concise Review.

In vitro testing of the human knee provides valuable insight that contributes to further understanding knee biomechanics. Cadaveric testing correlates well with clinical trials because the tissue has similar properties to that of live subjects. In addition, in vitro testing allows studies to be performed that would otherwise be unethical to evaluate in vivo.

Mapping of contributions from collateral ligaments to overall knee joint constraint: an experimental cadaveric study.

Understanding the contribution of the soft-tissues to total joint constraint (TJC) is important for predicting joint kinematics, developing surgical procedures, and increasing accuracy of computational models. Previous studies on the collateral ligaments have focused on quantifying strain and tension properties under discrete loads or kinematic paths; however, there has been little work to quantify collateral ligament contribution over a broad range of applied loads and range of motion (ROM) in passive constraint. To accomplish this, passive envelopes were collected from nine cadaveric knees instrumented with implantable pressure transducers (IPT) in the collateral ligaments.

Variation in patellofemoral kinematics due to changes in quadriceps loading configuration during in vitro testing.

This study investigated changes in patellofemoral (PF) kinematics for different loading configurations of the quadriceps muscle: single line of action (SL), physiological-based multiple lines of action (ML), weak vastus medialis (WVM), and weak vastus lateralis (WVL). Fourteen cadaveric knees were flexed from 15° to 120° knee flexion using a loading rig with the ability to load different heads of the quadriceps and hamstring muscles in their anatomical orientation. PF rotation in the sagittal plane) and medial lateral translation were significantly different (p<0.