Clinical Relevance and Function of Anterior Talofibular Ligament Superior and Inferior Fascicles: A Robotic Study.

Background: Ankle lateral ligament sprains are common injuries in sports, and some may result in persistent ankle pain and a feeling of instability without clinical evidence of instability. The anterior talofibular ligament (ATFL) has 2 distinct fascicles, and recent publications have suggested that injury isolated to the superior fascicle might be the cause of these chronic symptoms. This study aimed to identify the biomechanical properties conferred by the fascicles in stabilizing the ankle in order to understand potential clinical problems that may follow when the fascicles are injured.

A Validated, Automated, 3-Dimensional Method to Reliably Measure Tibial Torsion.

Background: Tibial torsion is a twist in the tibia measured as an angle between a proximal axis line and a distal axis line. Abnormal torsion has been associated with a variety of painful clinical syndromes of the lower limb. Measurements of normal tibial torsion reported by different authors vary by 100% (ranging from 20° to 42°), making it impossible to determine normal and pathological levels.

Comparative accuracy of lower limb bone geometry determined using MRI, CT, and direct bone 3D models.

Advancements in imaging and segmentation techniques mean that three dimensional (3D) modeling of bones is now increasingly used for preoperative planning and registration purposes. Computer tomography (CT) scans are commonly used due to their high bone-soft tissue contrast, however they expose subjects to radiation. Alternatively, magnetic resonance imaging (MRI) is radiation-free: however, geometric field distortion and poor bone contrast have been reported to degrade bone model validity compared to CT.

Total knee arthroplasty reduces knee extension torque in-vitro and patellofemoral arthroplasty does not.

Patients often have difficulty recovering knee extension strength post total knee arthroplasty (TKA), and that may reflect alteration of the mechanics including geometry and rollback kinematics, so the purpose of this work was to explore this by comparing the knee extension torque (KET) of the native knee, TKA and patellofemoral arthroplasty (PFA) in response to quadriceps tension. Eight fresh-frozen knees were mounted in a knee extension rig with quadriceps loading and tibial extension torque measurement. Each knee was subject to four conditions: native knee, PFA, cruciate-retaining (CR) and posterior-stabilized (PS) TKA.

Current concepts in the management of patellofemoral pain - The role of alignment.

Background: Patellofemoral pain is a prevalent and significant clinical problem that is often reported to persist even following evidence based intervention. It is clear therefore that there is much about this complex patient group that is not presently fully understood. This is particularly concerning given the reported links between patellofemoral pain in adolescence and the subsequent development of osteoarthritis and anxiety.

Development and validation of a robotic system for ankle joint testing.

Ankle sprains are the most common sports injury. Gaining a better understanding of ankle mechanics will help improve current treatments, enabling a better quality of life for patients following surgery. In this paper, the development of a robotic system for ankle joint testing is presented.

A cadaveric model to evaluate the effect of unloading the medial quadriceps on patellar tracking and patellofemoral joint pressure and stability.

Background: Vastus Medialis Muscles (VMM) damage has been widely identified following patellar dislocation. Rehabilitation programmes have been suggested to strengthen the VMM and reduce clinical symptoms of pain and instability. This controlled laboratory study investigated the hypothesis that reduced Vastus Medialis Obliquus (VMO) and Vastus Medialis Longus (VML) muscle tension would alter patellar tracking, stability and PFJ contact pressures.

Effect of Anterolateral Complex Sectioning and Tenodesis on Patellar Kinematics and Patellofemoral Joint Contact Pressures.

Background: Anterolateral complex injuries are becoming more recognized. While these are known to affect tibiofemoral mechanics, it is not known how they affect patellofemoral joint behavior.

Purpose: To determine the effect of (1) sectioning the anterolateral complex and (2) performing a MacIntosh tenodesis under various conditions on patellofemoral contact mechanics and kinematics.

The ESSKA-AFAS international consensus statement on peroneal tendon pathologies.

Introduction: Peroneal tendon injuries are a significant cause of lateral ankle symptoms in the active population. Accurate diagnosis and prompt treatment is important for minimizing the risk of long-term sequelae associated with chronic peroneal tendinopathy. Although several studies have been published on diagnostic strategies and treatment outcomes, there is no consensus on the optimal management of peroneal tendon pathologies.

The infrapatellar fat pad is a dynamic and mobile structure, which deforms during knee motion, and has proximal extensions which wrap around the patella.

Purpose: The infrapatellar fat pad (IFP) is a common cause of knee pain and loss of knee flexion and extension. However, its anatomy and behavior are not consistently defined.

Methods: Thirty-six unpaired fresh frozen knees (median age 34 years, range 21-68) were dissected, and IFP attachments and volume measured.

Flexor digitorum longus tendon transfer to the navicular: tendon-to-tendon repair is stronger compared with interference screw fixation.

Purpose: To assess whether early rehabilitation could be safe after flexor digitorum longus (FDL) tendon transfer, the current biomechanical study aimed to measure tendon displacement under cyclic loading and load to failure, comparing a traditional tendon-to-tendon (TT) repair with interference screw fixation (ISF).

Methods: 24 fresh-frozen cadaveric below knee specimens underwent FDL tendon transfer. In 12 specimens a TT repair was performed via a navicular bone tunnel.

Strength of Interference Screw Fixation to Cuboid vs Pulvertaft Weave to Peroneus Brevis for Tibialis Posterior Tendon Transfer for Foot Drop.

Background: Tibialis posterior (TP) tendon transfer is an effective treatment for foot drop. Currently, standard practice is to immobilize the ankle in a cast for 6 weeks nonweightbearing, risking postoperative stiffness. To assess whether early active dorsiflexion and protected weightbearing could be safe, the current study assessed tendon displacement under cyclic loading and load to failure, comparing the Pulvertaft weave (PW) to interference screw fixation (ISF) in a cadaveric foot model.

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.

Differential Motion and Compression Between the Plantaris and Achilles Tendons: A Contributing Factor to Midportion Achilles Tendinopathy?

Background: The plantaris tendon (PT) has been thought to contribute to symptoms in a proportion of patients with Achilles midportion tendinopathy, with symptoms improving after PT excision.

Hypothesis: There is compression and differential movement between the PT and Achilles tendon (AT) during ankle plantarflexion and dorsiflexion.

Study Design: Descriptive laboratory study.

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.

Plantaris Excision Reduces Pain in Midportion Achilles Tendinopathy Even in the Absence of Plantaris Tendinosis.

Background: It is becoming increasingly apparent that the plantaris can contribute to symptoms in at least a subset of patients with midportion Achilles tendinopathy. However, the nature of its involvement remains unclear.

Purpose: To determine whether excised plantaris tendons from patients with midportion Achilles tendinopathy display tendinopathic changes and whether the presence of such changes affect clinical outcomes.

Biomechanical Comparison of Anterolateral Procedures Combined With Anterior Cruciate Ligament Reconstruction.

Background: Anterolateral soft tissue structures of the knee have a role in controlling anterolateral rotational laxity, and they may be damaged at the time of anterior cruciate ligament (ACL) ruptures.

Purpose: To compare the kinematic effects of anterolateral operative procedures in combination with intra-articular ACL reconstruction for combined ACL plus anterolateral-injured knees.

Study Design: Controlled laboratory study.

Effect of Medial Patellofemoral Ligament Reconstruction Method on Patellofemoral Contact Pressures and Kinematics.

Background: There remains a lack of evidence regarding the optimal method when reconstructing the medial patellofemoral ligament (MPFL) and whether some graft constructs can be more forgiving to surgical errors, such as overtensioning or tunnel malpositioning, than others.

Hypothesis: The null hypothesis was that there would not be a significant difference between reconstruction methods (eg, graft type and fixation) in the adverse biomechanical effects (eg, patellar maltracking or elevated articular contact pressure) resulting from surgical errors such as tunnel malpositioning or graft overtensioning.

Study Design: Controlled laboratory study.

The Use of Sonographically Guided Botulinum Toxin Type A (Dysport) Injections Into the Tensor Fasciae Latae for the Treatment of Lateral Patellofemoral Overload Syndrome.

Background: Pain in the anterior and lateral parts of the knee during exercise is a common clinical problem for which current management strategies are often unsuccessful.

Purpose: To investigate the effect of an ultrasound-guided botulinum toxin (BT) injection into the tensor fasciae latae (TFL), followed by physical therapy, in patients classified with lateral patellofemoral overload syndrome (LPOS) who failed to respond to conventional treatment.

Study Design: Case series; Level of evidence, 4.

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 ability of medial patellofemoral ligament reconstruction to correct patellar kinematics and contact mechanics in the presence of a lateralized tibial tubercle.

Background: Tibial tubercle (TT) transfer and medial patellofemoral ligament (MPFL) reconstruction are used after patellar dislocations. However, there is no objective evidence to guide surgical decision making, such as the ability of MPFL reconstruction to restore normal behavior in the presence of a lateralized TT.

Hypothesis: MPFL reconstruction will only restore joint contact mechanics and patellar kinematics for TT-trochlear groove (TG) distances up to an identifiable limit.

Length change patterns in the lateral extra-articular structures of the knee and related reconstructions.

Background: Lateral extra-articular soft tissue reconstructions in the knee may be used as a combined procedure in revision anterior cruciate ligament surgery as well as in primary treatment for patients who demonstrate excessive anterolateral rotatory instability. Only a few studies examining length change patterns and isometry in lateral extra-articular reconstructions have been published.

Purpose: To determine a recommended femoral insertion area and graft path for lateral extra-articular reconstructions by measuring length change patterns through a range of knee flexion angles of several combinations of tibial and femoral insertion points on the lateral side of the knee.

The effect of tibial tuberosity medialization and lateralization on patellofemoral joint kinematics, contact mechanics, and stability.

Background: Tibial tuberosity (TT) transfer is a common procedure to treat patellofemoral instability in patients with elevated TT-trochlear groove (TG) distances. However, the effects of TT lateralization or medialization on patellar stability, kinematics, and contact mechanics remain unclear.

Hypothesis: Progressive medialization and lateralization will have increasingly adverse effects on patellofemoral joint kinematics, contact mechanics, and stability.