OBJECTIVETo create a 3-dimensional finite element model of knee ligaments and to analyse the stress changes of lateral collateral ligament (LCL) with or without displaced movements at different knee flexion conditions.

METHODSA four-major-ligament contained knee specimen from an adult died of skull injury was prepared for CT scanning with the detectable ligament insertion footprints, locations and orientations precisely marked in advance. The CT scanning images were converted to a 3-dimensional model of the knee with the 3-dimensional reconstruction technique and transformed into finite element model by the software of ANSYS. The model was validated using experimental and numerical results obtained by other scientists. The natural stress changes of LCL at five different knee flexion angles (0 degree, 30 degree, 60 degree, 90 degree, 120 degree) and under various motions of anterior-posterior tibial translation, tibial varus rotation and internal-external tibial rotation were measured.

RESULTSThe maximum stress reached to 87%-113% versus natural stress in varus motion at early 30 degree of knee flexions. The stress values were smaller than the peak value of natural stress at 0 degree (knee full extension) when knee bending was over 60 degree of flexion in anterior-posterior tibial translation and internal-external rotation.

CONCLUSIONLCL is vulnerable to varus motion in almost all knee bending positions and susceptible to anterior-posterior tibial translation or internal-external rotation at early 30 degree of knee flexions.

Anterior Cruciate Ligament ; physiology ; Collateral Ligaments ; physiology ; Finite Element Analysis ; Humans ; Knee Joint ; physiology ; Stress, Mechanical

BACKGROUNDWe investigated the impact of eliminating the impingement between extensor mechanism and tibial insert on patellar tracking and patellar ligament tension in high knee flexion.

METHODSSix cadaveric specimens were tested on an Oxford-type testing rig. The Genesis II knee system was implanted into each specimen knee with the traditional tibial insert and high-flex insert successively. Compared to traditional insert, the high-flex insert was characterized with a chambered anterior post and a chambered anterior lip which eliminates patella-post and patellar ligament-anterior lip impingements. The patella was tracked with an NDI Optotrak Certus system. The patellar ligament tension was measured using a NKB S-type tension transducer.

RESULTSThere was a decrease of resultant patellar translation relative to the femur with statistically significant (P<0.05) at 90 degrees to 150 degrees of knee flexion and a decrease of patellar ligament tension with statistical significance (P<0.05) at 100 degrees, 120 degrees, 130 degrees, and 140 degrees of flexion using high-flex insert compared to traditional insert.

CONCLUSIONSEliminating the impingement between extensor mechanism and implant in high knee flexion altered patellar tracking and reduced patellar ligament tension, which would facilitate high knee flexion.

Biomechanical Phenomena ; Humans ; In Vitro Techniques ; Knee Joint ; physiology ; Ligaments, Articular ; physiology ; Patellar Ligament ; physiology ; Range of Motion, Articular ; physiology

*Bone Marrow Transplantation ; Cell Differentiation/physiology ; Cell Division/physiology ; Ligaments/*cytology ; Ligaments/surgery ; *Mesenchymal Stem Cell Transplantation ; Tendon Injuries/*surgery ; Tendons/*cytology ; *Tissue Engineering ; Wound Healing/physiology

Some 3D finite element systemic models are currently established and used to simulate the foot biomechanical state. However, during most of these 3D foot finite element static analyses, ligaments and plantar fascia are generally defined by connecting the corresponding attachment points on the bones, and the spaces between the bones are fused together by solid elements with given cartilage stiffness to simulate the connection of bones. This "connection of bones" takes the place of the real interactions between neighbored bones and enhances the structure of foot, which possibly leads to the result that the effects of ligaments and other soft tissues are completely replaced by the effect of articular cartilages. Thereby, ligaments and other soft tissues maybe not play an inherent role in the finite element analysis. The objective of this study was to estimate whether there exists the effect of ligaments and plantar fascia on the biomechanical behaviors of the foot tissue stress distribution and foot structure deformation during the balanced standing stance and static finite element analysis.
Adult ; Biomechanical Phenomena ; Computer Simulation ; Fascia ; physiology ; Foot ; diagnostic imaging ; physiology ; Humans ; Ligaments ; physiology ; Male ; Models, Biological ; Radiography ; Stress, Mechanical

BACKGROUND: Tendon and ligament injuries accounted for 30% of all musculoskeletal consultations with 4 million new incidences worldwide each year and thus imposed a significant burden to the society and the economy. Damaged tendon and ligament can severely affect the normal body movement and might lead to many complications if not treated promptly and adequately. Current conventional treatment through surgical repair and tissue graft are ineffective with a high rate of recurrence.METHODS: In this review, we first discussed the anatomy, physiology and pathophysiology of tendon and ligament injuries and its current treatment. Secondly, we explored the current role of tendon and ligament tissue engineering, describing its recent advances. After that, we also described stem cell and cell secreted product approaches in tendon and ligament injuries. Lastly, we examined the role of the bioreactor and mechanical loading in in vitro maturation of engineered tendon and ligament.RESULTS: Tissue engineering offers various alternative ways of treatment from biological tissue constructs to stem cell therapy and cell secreted products. Bioreactor with mechanical stimulation is instrumental in preparing mature engineered tendon and ligament substitutes in vitro.CONCLUSIONS: Tissue engineering showed great promise in replacing the damaged tendon and ligament. However, more study is needed to develop ideal engineered tendon and ligament.
Bioreactors ; Exosomes ; In Vitro Techniques ; Incidence ; Ligaments ; Physiology ; Recurrence ; Referral and Consultation ; Stem Cells ; Tendons ; Tissue Engineering ; Transplants

Ligaments are the main parts which stabilize the knee joint. How to analog the ligaments in biomechanical model will affect the characteristics of the human knee dynamics and in the computation of the stress in ligaments between two bones. This symposium is aimed at the survey of the simplified method of the ligaments via mechanical parameters, and providing an exact method of constructing model.
Biomechanical Phenomena ; Humans ; Knee Joint ; anatomy & histology ; physiology ; Ligaments, Articular ; anatomy & histology ; physiology ; Models, Anatomic ; Models, Biological

The motions of humeral external rotation with and without the anterior band of inferior glenohumeral ligament complex (AB-IGHL) were simulated. As a result of comparison, the contact pressure and contact force are all higher when the AB-IGHL was included in the model. Therefore, it is theoretically proved that the AB-IGHL constrains the motion of humerus during humeral external rotation. The predicted values for von Mises and the maximum tense force in the AB-IGHL were 4.433 MPa and 37.32 N respectively, occurring on the humeral side of the ligament. This approach to evaluating the function of AB-IGHL would provide greater insight into the mechanical contribution of AB-IGHL to joint function, identify the mechanism of a hurt to AB-IGHL, and provide a quantitative means for developing low-risk rehabilitation protocols.
Finite Element Analysis ; Humans ; Ligaments, Articular ; physiology ; Range of Motion, Articular ; Rotation ; Shoulder Joint ; anatomy & histology ; physiology ; Tensile Strength

Three-dimensional finite element model of elbow was established to study the effect of medial collateral ligament (MCL) in maintaining the stability of elbow joint. In the present study a three-dimensional geometric model of elbow joint was established by reverse engineering method based on the computed tomography (CT) image of healthy human elbow. In the finite element pre-processing software, the ligament and articular cartilage were constructed according to the anatomical structure, and the materials and contacts properties were given to the model. In the neutral forearm rotation position and 0° flexion angle, by comparing the simulation data of the elbow joint with the experimental data, the validity of the model is verified. The stress value and stress distribution of medial collateral ligaments were calculated at the flexion angles of elbow position in 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, respectively. The result shows that when the elbow joint loaded at different flexion angles, the anterior bundle has the largest stress, followed by the posterior bundle, transverse bundle has the least, and the stress value of transverse bundle is trending to 0. Therefore, the anterior bundle plays leading role in maintaining the stability of the elbow, the posterior bundle plays supplementary role, and the transverse bundle does little. Furthermore, the present study will provide theoretical basis for clinical recognizing and therapy of elbow instability caused by medial collateral ligament injury.
Biomechanical Phenomena ; Cadaver ; Collateral Ligaments ; physiology ; Elbow Joint ; physiology ; Finite Element Analysis ; Humans ; Range of Motion, Articular ; Tomography, X-Ray Computed

OBJECTIVETo discuss the midface aging mechanism through anatomic study of malar fat pad.

METHODS10 fresh adult cadaveric heads (20 sides) fixed by vascular perfusion of formalin were used for anatomic study with microsurgery technique under microscope. The midfacial ligament and connective tissue between skin and subcutaneous fat were observed carefully in different parts of midface. The location, shape and extent of malar fat pad was also recorded and photographed.

RESULTSThe malar fat pad has a triangle shape. The bottom is a curve along the orbicularis retaining ligament at the lower eyelid. The fat pad is extended internally to the nasolabial fold and labiomandibular fold, externally from the major zygomatic muscle end point at the malar surface to the angulus oris and submandibular edge. (2) The malar fat pad is composed of meshed fibrous tissue, with big fat particles in it. It becomes tight when being stretched in horizontal direction along nasolabial fold and loosen when being stretched in vertical direction. (3) There is tight connection between skin and fat pad, which is divided into four areas as I, II, III, IV. The areas I, II, III are strip-shaped parelled to the nasolabial fold. The area IV is a irregular quadrilateral. (4) There are six fixation ligaments between malar fat pad and deep tissue: orbicularis retaining ligament upper layer of lower eyelid, orbicularis retaining ligament substratum of lower eyelid, zygomaticus ligament, zygomatic cutaneous ligament, zygomatic cutaneous ligament substratum, platysma There are four closely connected areas cutaneous forward ligament, cheek maxilla ligament.

CONCLUSIONSbetween the facial skin and malar fat pad which makes malar fat pad and skin keep relatively consistent. The malar fat pad moving down mainly resulted from slack of ligaments support which is one of the reasons for aging face.

Adipose Tissue ; anatomy & histology ; physiology ; Cadaver ; Cheek ; Eyelids ; anatomy & histology ; physiology ; Face ; anatomy & histology ; physiology ; Facial Muscles ; anatomy & histology ; physiology ; Head ; Humans ; Ligaments ; anatomy & histology ; physiology ; Lip ; anatomy & histology ; physiology ; Skin ; anatomy & histology ; Skin Aging ; pathology ; physiology

OBJECTIVETo investigate electrophysiology of cardiocytes in ligament of Marshall.

METHODSThe single cardiocytes obtained from ligament of Marshall were direct observed under inverted microscope. The cardiocyte action potential and current density of I(Na), I(Ca), L, I(to), I(K) and I(K1) were researched by whole-cell patch-clamp techniques.

RESULTSThere were two different cardiomyocytes in ligament of Marshall, one was rod shape, the other was short-rectangle shape. The short-rectangle myocyte was short and thick; the rod myocyte was long and thin. The short-rectangle myocyte was more than rod myocyte. The length/width rate of short-rectangle myocyte was less than that of rod myocyte (2.99 +/- 0.95 vs 12.05 +/- 2.41, P < 0.01). The action potential of ligament myocytes was similar to fast responsive cells. The action potential amplitude (APA) and duration (APD) of short-rectangle cells were less than those in rod cells. APA (mV), APD(50) (ms) and APD(90) (ms) were respectively 80.02 +/- 3.68 vs 91.72 +/- 7.56, 69.62 +/- 6.33 vs 83.14 +/- 3.66 and 107.55 +/- 4.25 vs 144.00 +/- 5.15, P < 0.05. The ion current density of I(Na), I(Ca), L, I(to), I(K1) was different between the two kind cells.

CONCLUSIONSThere are two different cardiocytes in ligament of Marshall. The action potential and ion current density of I(Na), I(Ca), L, I(to), I(K1) are different between the two kind cardiocytes.

Action Potentials ; Animals ; Dogs ; Electrophysiology ; Ion Channel Gating ; Ligaments, Articular ; metabolism ; Male ; Myocytes, Cardiac ; metabolism ; physiology ; Patch-Clamp Techniques