Dynamic augmentation restores anterior tibial translation in ACL suture repair: a biomechanical comparison of non-, static and dynamic augmentation techniques.

Purpose: There is a lack of objective evidence investigating how previous non-augmented ACL suture repair techniques and contemporary augmentation techniques in ACL suture repair restrain anterior tibial translation (ATT) across the arc of flexion, and after cyclic loading of the knee. The purpose of this work was to test the null hypotheses that there would be no statistically significant difference in ATT after non-, static- and dynamic-augmented ACL suture repair, and they will not restore ATT to normal values across the arc of flexion of the knee after cyclic loading.

Methods: Eleven human cadaveric knees were mounted in a test rig, and knee kinematics from 0° to 90° of flexion were recorded by use of an optical tracking system.

Tribological properties of PVA/PVP blend hydrogels against articular cartilage.

This research investigated in-vitro tribological performance of the articulation of cartilage-on- polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) blend hydrogels using a custom-designed multi-directional wear rig. The hydrogels were prepared by repeated freezing-thawing cycles at different concentrations and PVA to PVP fractions at a given concentration. PVA/PVP blend hydrogels showed low coefficient of friction (COF) values (between 0.

Anterolateral Tenodesis or Anterolateral Ligament Complex Reconstruction: Effect of Flexion Angle at Graft Fixation When Combined With ACL Reconstruction.

Background: Despite numerous technical descriptions of anterolateral procedures, knowledge is limited regarding the effect of knee flexion angle during graft fixation.

Purpose: To determine the effect of knee flexion angle during graft fixation on tibiofemoral joint kinematics for a modified Lemaire tenodesis or an anterolateral ligament (ALL) complex reconstruction combined with anterior cruciate ligament (ACL) reconstruction.

Study Design: Controlled laboratory study.

The Effects of Anterolateral Tenodesis on Tibiofemoral Contact Pressures and Kinematics.

Background: Anterolateral tenodeses are increasingly popular in combination with intra-articular anterior cruciate ligament reconstructions. Despite the perception of risk of overconstraint and lateral osteoarthritis, evidence is lacking regarding the effect of graft tensioning on knee kinematics and intra-articular compartmental joint pressures.

Purpose: To investigate tibiofemoral joint contact pressures and kinematics related to an anterolateral lesion and the effectiveness of a MacIntosh tenodesis in restoring these when varying (1) graft tension and (2) tibial rotation during graft fixation.

Assessment of pose repeatability and specimen repositioning of a robotic joint testing platform.

This paper describes the quantitative assessment of a robotic testing platform, consisting of an industrial robot and a universal force-moment sensor, via the design of fixtures used to hold the tibia and femur of cadaveric knees. This platform was used to study the contributions of different soft tissues and the ability of implants and reconstruction surgeries to restore normal joint functions, in previously published literature. To compare different conditions of human joints, it is essential to reposition specimens with high precision after they have been removed for a surgical procedure.

Stability of small pegs for cementless implant fixation.

Most glenoid implants rely on large centrally located fixation features to avoid perforation of the glenoid vault in its peripheral regions. Upon revision of such components there may not be enough bone left for the reinsertion of an anatomical prosthesis. Multiple press-fit small pegs would allow for less bone resection and strong anchoring in the stiffer and denser peripheral subchondral bone.

Anterolateral knee biomechanics.

This article reviews the evidence for the roles of the anterolateral soft-tissue structures in rotatory stability of the knee, including their structural properties, isometry, and contributions to resisting tibial internal rotation. These data then lead to a biomechanical demonstration that the ilio-tibial band is the most important structure for the restraint of anterolateral rotatory instability. Level of evidence V.

Lateral soft-tissue structures contribute to cruciate-retaining total knee arthroplasty stability.

Little information is available to surgeons regarding how the lateral structures prevent instability in the replaced knee. The aim of this study was to quantify the lateral soft-tissue contributions to stability following cruciate-retaining total knee arthroplasty (CR TKA). Nine cadaveric knees were tested in a robotic system at full extension, 30°, 60°, and 90° flexion angles.

Strain rate dependency of fractures of immature bone.

Radiological features alone do not allow the discrimination between accidental paediatric long bone fractures or those sustained by child abuse. Therefore, there is a clinical need to elucidate the mechanisms behind each fracture to provide a forensic biomechanical tool for the vulnerable child. Four-point bending and torsional loading tests were conducted at more than one strain rate for the first time on immature bone, using a specimen-specific alignment system, to characterise structural behaviour at para-physiological strain rates.

Can Iron Treatments Aggravate Epistaxis in Some Patients With Hereditary Hemorrhagic Telangiectasia?

Objectives/hypothesis: To examine whether there is a rationale for iron treatments precipitating nosebleeds (epistaxis) in a subgroup of patients with hereditary hemorrhagic telangiectasia (HHT).

Study Design: Survey evaluation of HHT patients, and a randomized control trial in healthy volunteers.

Methods: Nosebleed severity in response to iron treatments and standard investigations were evaluated by unbiased surveys in patients with HHT.

Parametric analysis of glenoid implant design and fixation type.

Common post-operative problems in shoulder arthroplasty such as glenoid loosening and joint instability may be reduced by improvements in glenoid design, shape, material choice, and fixation method. A framework for parametric analysis of different implant fixation configurations was developed in order to efficiently sift through potential glenoid component designs. We investigated the influence of design factors such as fixation type, component thickness, and peg position, number, diameter, and length in a multi-factorial design investigation.

Child labour in low- and middle-income countries and its consequences for mental health: a systematic literature review of epidemiologic studies.

In low- and middle-income countries, large numbers of children are involved in work. Whilst studies have shown that child labour may be harmful to children's physical health, little is known about child labour's effects on mental health. It is important to understand the relationship between work and mental health problems during childhood, and identify possible risk factors for poorer mental health.

An in vitro analysis of medial structures and a medial soft tissue reconstruction in a constrained condylar total knee arthroplasty.

Purpose: The aim of this study was to quantify the medial soft tissue contributions to stability following constrained condylar (CC) total knee arthroplasty (TKA) and determine whether a medial reconstruction could restore stability to a soft tissue-deficient, CC-TKA knee.

Methods: Eight cadaveric knees were mounted in a robotic system and tested at 0°, 30°, 60°, and 90° of flexion with ±50 N anterior-posterior force, ±8 Nm varus-valgus, and ±5 Nm internal-external torque. The deep and superficial medial collateral ligaments (dMCL, sMCL) and posteromedial capsule (PMC) were transected and their relative contributions to stabilising the applied loads were quantified.

Posteromedial Meniscocapsular Lesions Increase Tibiofemoral Joint Laxity With Anterior Cruciate Ligament Deficiency, and Their Repair Reduces Laxity.

Background: Injury to the posteromedial meniscocapsular junction has been identified after anterior cruciate ligament (ACL) rupture; however, there is a lack of objective evidence investigating how this affects knee kinematics or whether increased laxity can be restored by repair. Such injury is often overlooked at surgery, with possible compromise to results.

Hypotheses: (1) Sectioning the posteromedial meniscocapsular junction in an ACL-deficient knee will result in increased anterior tibial translation and rotation.

The superficial medial collateral ligament is the primary medial restraint to knee laxity after cruciate-retaining or posterior-stabilised total knee arthroplasty: effects of implant type and partial release.

Purpose: The aim of this study was to quantify the contributions of medial soft tissues to stability following cruciate-retaining (CR) or posterior-stabilised (PS) total knee arthroplasty (TKA).

Methods: Using a robotic system, eight cadaveric knees were subjected to ±90-N anterior-posterior force, ±5-Nm internal-external and ±8-Nm varus-valgus torques at various flexion angles. The knees were tested intact and then with CR and PS implants, and successive cuts of the deep and superficial medial collateral ligaments (dMCL, sMCL) and posteromedial capsule (PMC) quantified the percentage contributions of each structure to restraining the applied loads.

A comparison of non-invasive imaging modalities: Infrared thermography, spectrophotometric intracutaneous analysis and laser Doppler imaging for the assessment of adult burns.

Background: Currently, the only evidence-based adjunct to clinical evaluation of burn depth is laser Doppler imaging (LDI), although preliminary studies of alternative imaging modalities with instant image acquisition are promising. This is a study to investigate the accuracy of infrared thermography (IRT) and spectrophotometric intracutaneous analysis (SIA) for burn depth assessment, and compare this to the current gold standard: LDI. We include a comparison of the three modalities in terms of cost, reliability and usability.