Tendon Tension Research Articles

Repositioning and stabilization of the radial styloid process in comminuted fractures of the distal radius using a single approach: the radio-volar double plating technique

BackgroundA possible difficulty in intra-articular fracture of the distal radius is the displacement tendency of the radial styloid process due to the tension of the brachioradialis tendon.MethodsTen patients treated within one year for complex distal radius fractures by double-plating technique with a radial buttress plate and volar locking plate, through a single volar approach, were followed prospectively during 24 months. Outcome measures included radiographic follow-up, range of motion, grip strength and score follow-up (VAS, Gartland-Werley score and patient-rated wrist evaluation).ResultsTen patients with intraarticular distal radius fractures with dislocation of the radial styloid process were treated with this technique. This resulted after 24 months in good clinical outcome (mean visual analog scale 0.9; almost symmetric range of motion; mean Gartland-Werley score 2 ± 3; mean patient-rated wrist evaluation 3.2 ± 2.4). Radiologic evaluation according to the Dresdner Score revealed anatomic reduction without secondary dislocation during the follow-up and uneventful consolidation.ConclusionsThe described technique strongly facilitates anatomic reduction and stable fixation of intra-articular distal radius fractures with dislocation of the radial styloid process and leads to satisfactory clinical and radiographic outcome.

2P1-C19 筋骨格ヒューマノイドの張力制御を利用した姿勢教示による物体拘束の獲得

Musculo-Skeletal Humanoid has a humanlike articular structure body and redundant actuators. Musculo-Skeletal Humanoid has advantage in touching objects by controlling its tendon tension flexibly. However, its own complex body structure makes it difficult to adjust humanoid's inner coordinate to real world coordinate. To solve the issue, we focused attention on the motion when human touch or trace objects. We apply a restrain condition estimation method using the musculo-skeletal humanoid's tension control to realize operating target objects. The aim of this paper is to show that Musculo-Skeletal Humanoid can generate motions associated with touching unknown objects by being taught poses.

脳神経外科用空間確保マニピュレータの開発 : マニピュレータのメカニズムと評価実験(機械力学,計測,自動制御)

This paper presents the Workspace-creation manipulator, a multi-DOF brain spatula type manipulator for minimally invasive neurosurgery. We show the mechanical design of the manipulator and evaluation of its function. The manipulator design specification is decided in consideration of newly operative procedure by using micromanipulator system through a 20mm diameter cranial hole and operating room constraints. The tip of the manipulator is 2mm thickness, 7mm width, 110mm length and has 10-DOF serial link manipulator which is able to be inserted from small cranial hole and follow the brain shape. The Positioning manipulator has an active prismatic joint and 5 passive joints with tendon length compensation method. Tendon length compensation method is based on three techniques, using rolling contact, parallel linkage, and moving pulleys, and we confirm the effectiveness of the tendon length compensation method through tendon tension force measurement experiment. To evaluate the mechanical design effectiveness, we execute an in vivo experiment using pig brain. We are easily able to set the system because of its lightness and compactness, and we insers it between the dura mater and cerebrum smoothly, and workspace in the brain is secured. We think this result shows the availableness of the mechanical design of the manipulator.

Densitometric and biochemical values of broiler tibias at different ages

The objective of this experiment was to determine the normal values of bone radiographic density (BRD) by using the optical densitometry in radiographic images and the biochemical values represented by serum calcium, ash percentage, and minerals (calcium, phosphorus, and magnesium) from tibia ash of Cobb broilers at 8, 22, and 43 d of age. A total of 14 broilers were used for densitometric analysis, and 15 were used for biochemical dosages. The BRD values increased (P < 0.05) with age and in all tibia regions (proximal epiphysis, diaphysis, and distal epiphysis), concluding that growth was a determinative factor for bone performance, demanding a higher BRD during broiler development. Tibia proximal epiphysis presented higher BRD values in relation to the other bone regions (P < 0.05), as a result of a possible biomechanical adaptation to ligaments and tension of the muscle tendons at this region, allowing the support of the muscle mass increase. The serum calcium values were kept constant, as a result of the appropriate nutritional levels of the diet that supported the animal homeostasis. The bone ash and mineral percentage increased (P < 0.05) at 22 d of age, due to the higher mineral requirement in this age. The correlation between bone densitometry and the invasive techniques showed that the bone densitometry can substitute the determination of mineral percentage in the ash. This experiment presented normal values of the noninvasive and invasive methods more used in aviculture, allowing us to compare, subsequently, pathological and physiological values or results of broilers fed with different diets.

Transient effects of tendon disconnection on the survivability of a TLP in moderate-strength hurricane conditions

The primary objective of this paper is to investigate the dynamic stability and survivability of a four-column classic TLP (tension-leg platform) under less-than-extreme storm conditions where one or more tendons have been lost due to damage or disconnect. The transient responses of the platform and tendon tensions at the moment of disconnection are particularly underscored. The numerical simulation is based on the BE-FE hybrid hull-tendon-riser coupled dynamic analysis in time domain. Compared to the common industry practice of checking the system without a failed tendon in the beginning, the maximum tension on the neighboring tendon can be significantly increased at the moment of disconnection due to the snap-like transient effects, which can lead to unexpected failure of the total system. It is also found that the transient effects can be reduced with the presence of TTRs (top-tensioned risers) with pneumatic tensioners. It is also seen that the TLP cannot survive in the 100-yr hurricane condition after losing one tendon.

Effect of tendon tensioning: An in vitro study in porcine extensor tendons

Graft tensioning is a controversial issue in anterior cruciate ligament reconstruction (ACLR) that has not achieved consensus between peers. The purpose of this study is to determine if after tensioning tendon length and resistance to maximal load changes. We performed an in vitro study with 50 porcine extensors tendons. The first group (P = 25) was tensioned with 80 N (19.97 lb) for 10 min, using an ACL graft preparation board. The second group (C = 25) was used as control and was not tensioned. The average initial (groups P and C) and post tensioning tendon length (group C) were measured; the average initial and post tensioning tendon diameter were measured as well. All samples were fixated in a tube–clamp system connected to a tension sensor. The samples were stressed with continuous and progressive tension until ultimate failure at maximum load (UFML) occurs. The initial mean length was: P before tensioning = 13.4 mm ± 1.4 mm (range 10.5–16.5); P after tensioning = 13.8 mm ± 1.4 mm (range 11.5–16.5); C = 13 mm ± 1.35 mm ( p = 0.005). The mean diameter was: P = 5.6 mm (4.5–6); C = 5.5 mm (range 4.5–6) ( p > 0.05). The UFML was: P = 189.7 N (114–336); C = 229.9 N (143–365) ( p = 0.029). Tendon tensioning with 80 N for 10 min produced 3% average elongation. These could be beneficial in ACLR since tendon tensioning decreases elongation of the graft after fixation. Regardless, tendon tensioning is not innocuous since it diminishes their resistance when continuously stressed until complete failure occurs.

Transient effects of tendon disconnection on the survivability of a TLP in moderate-strength hurricane conditions

The primary objective of this paper is to investigate the dynamic stability and survivability of a four-column classic TLP (tension-leg platform) under less-than-extreme storm conditions where one or more tendons have been lost due to damage or disconnect. The transient responses of the platform and tendon tensions at the moment of disconnection are particularly underscored. The numerical simulation is based on the BE-FE hybrid hull-tendon-riser coupled dynamic analysis in time domain. Compared to the common industry practice of checking the system without a failed tendon in the beginning, the maximum tension on the neighboring tendon can be significantly increased at the moment of disconnection due to the snap-like transient effects, which can lead to unexpected failure of the total system. It is also found that the transient effects can be reduced with the presence of TTRs (top-tensioned risers) with pneumatic tensioners. It is also seen that the TLP cannot survive in the 100-yr hurricane condition after losing one tendon.

Comparison of tendon tensions estimated from two biomechanical models of the thumb

Despite the paramount function of the thumb in daily life, thumb biomechanical models have been little developed and studied. Moreover, only two studies provided quantitative anthropometric data of tendon moment arms. To investigate thumb tendon tensions, biomechanicians and clinicians have to know the performances and the limits of these two data sets. The aim of this study was thus to compare the results of these two models and evaluate their performances in regard to prior electromyographic measurements (EMG). Thumb posture was recorded during the classical key pinch and pulp pinch grips. Various fingertip forces applied at the distal segment were simulated in a range including extension, adduction, flexion, abduction. Input data of thumb postures and fingertip forces were used to compute tendon tensions with both models. Tendon tensions obtained using these two models were then compared and correlated to EMG measurements provided in the literature. The results showed that both models predicted relevant muscle coordination for five of the nine muscles modelled. Opponent and abductor longus muscle coordinations were badly estimated by both models. Each model was sensible to kinematic errors but not in the same proportion. This study pointed out the advantages/limits of the two models to use them more appropriately for clinical and/or research purposes.

The Consequences of Short-Range Stiffness and Fluctuating Muscle Activity for Proprioception of Postural Joint Rotations: The Relevance to Human Standing

Proprioception comes from muscles and tendons. Tendon compliance, muscle stiffness, and fluctuating activity complicate transduction of joint rotation to a proprioceptive signal. These problems are acute in postural regulation because of tiny joint rotations and substantial short-range muscle stiffness. When studying locomotion or perturbed balance these problems are less applicable. We recently measured short-range stiffness in standing and considered the implications for load stability. Here, using an appropriately simplified model we analyze the conversion of joint rotation to spindle input and tendon tension while considering the effect of short-range stiffness, tendon compliance, fluctuating muscle activity, and fusimotor activity. Basic principles determine that when muscle stiffness and tendon compliance are high, fluctuating muscle activity is the greatest factor confounding registration of postural movements, such as ankle rotations during standing. Passive and isoactive muscle, uncomplicated by active length fluctuations, enable much better registration of joint rotation and require fewer spindles. Short-range muscle stiffness is a degrading factor for spindle input and enhancing factor for Golgi input. Constant fusimotor activity does not enhance spindle registration of postural joint rotations in actively modulated muscle: spindle input remains more strongly associated with muscle activity than joint rotation. A hypothesized rigid alpha-gamma linkage could remove this association with activity but would require large numbers of spindles in active postural muscles. Using microneurography, the existence of a rigid alpha-gamma linkage could be identified from the correlation between spindle output and muscle activity. Basic principles predict a proprioceptive "dead zone" in the active agonist muscle that is related to the short-range muscle stiffness.

Stress on the rotator cuff sutures in relation to joint position

In a vitro study we evaluated the influence of surgical technique on the postoperative tension of the supraspinatus tendon in rotator cuff ruptures. In ten shoulder specimens Hall-Effect Strain Gauge (HEST) were implanted in the supraspinatus tendon close to the insertion at the humerus. We documented the tension in specimens with intact rotator cuff as well as after reconstruction of small and large tears in different joint positions. In the specimens with an intact rotator cuff there was almost no tension registered. Only in adduction with external rotation and flexion we found slightly increased values. After reconstruction we found the highest tension in adduction, flexion, and external rotation of the humerus. Release of the coracohumeral ligament resulted in a decrease of tension in flexion and external rotation. Whereas in extension coracohumeral ligament release had no influence on the tension of the tendon. However, after complete capsule release the tension in extension also decreased. If mobilisation in cases of rotator cuff reconstruction is necessary we recommend first release of the coracohumeral ligament in small and moderate tears. In major tears a complete capsule release is necessary. During physical therapy in the early postoperative course, flexion in the adducted and externally rotated arm should be avoided.

Acute tibial tubercle avulsion fractures in the sporting adolescent

The authors report 7 cases of acute tibial tubercle avulsion fractures. The fracture occurred in 6 out of the 7, after an abrupt tension of the patellar tendon in male sporting adolescents (age 13-17 years). Two patients presented symptoms of homolateral Osgood-Schlatter's disease before the lesion. According to Ogden's classification, the tibial tubercle avulsion fracture was not displaced in 3 cases (stage IA) and was treated conservatively by immobilization for 6 weeks. In 4 cases, the fracture was displaced and necessitated an internal fixation with plaster for about 6 weeks. A torn patellar tendon was noted in one adolescent having a stage IIIB avulsion fracture. The mean follow-up was of 4.5 years (1.5-7.5 years). The results were satisfactory: complete functional recovery, resumption of sport at the previous level and absence of recurvatum.

Middle and ring fingers are more exposed to pulley rupture than index and little during sport-climbing: A biomechanical explanation

Background Finger pulley injury is a common incident observed during sport-climbing. The total rupture of one or several pulleys is highly debilitating and requires surgical reconstruction and/or rehabilitation programs. Literature reports show that fingers are not equally exposed to this injury. The ring and middle fingers are usually injured while the index and little fingers are less exposed. The objective of this study was to determine the biomechanical factors leading to the enhanced exposure of ring and middle finger pulleys. Method Eight subjects were required to exert maximal four-finger force in a specific sport-climbing finger posture. External fingertip forces and finger joint postures were used as input data of a specifically developed biomechanical model of the four fingers ( i.e., index, middle, ring and little). This model was based on classical Newton static laws and used an optimization process to quantify the flexor tendon tensions and the pulley forces in each finger. Passive participation of ligaments was also considered into mechanical equations. Findings Results showed that two main factors could explain the enhanced exposure of ring and middle fingers. Firstly, the fingertip force intensities applied by these two fingers were higher than those observed for the index and little fingers. Secondly, results show that the pulley forces of the ring and middle fingers were close to their rupture thresholds, while it was not the case for the two other fingers. This could be explained by a specific localisation of the finger pulleys of the ring and middle fingers leading to enhanced pulley forces. Interpretation These results are relevant and could help clinicians to understand finger pulley pathologies and adapt the surgical interventions to reconstruct the fingers pulleys.

A new method for estimating hand internal loads from external force measurements

This study examines using force vectors measured using a directional strain gauge grip dynamometer for estimating finger flexor tendon tension. Fifty-three right-handed participants (25 males and 28 females) grasped varying-sized instrumented cylinders (2.54, 3.81, 5.08, 6.35 and 7.62 cm diameter) using a maximal voluntary power grip. The grip force vector magnitude and direction, referenced to the third metacarpal, was resolved by taking two orthogonal grip force measurements. A simple biomechanical model incorporating the flexor tendons was used to estimate long finger tendon tension during power grip. The flexor digitorum superficialis and the flexor digitorum profundus were assumed to create a moment about the metacarpal phalange (MCP) joint that equals and counteracts a moment around the MCP joint measured externally by the dynamometer. The model revealed that tendon tension increased by 130% from the smallest size handle to the largest, even though grip force magnitude decreased 36% for the same handles. The study demonstrates that grip force vectors may be useful for estimating internal hand forces.

750 異なる負荷軽減手法を施したラット膝蓋腱で計測される生体内張力の比較(S01-2 細胞と組織のバイオメカニクス(2)-ミクロからマクロまで-,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

750 異なる負荷軽減手法を施したラット膝蓋腱で計測される生体内張力の比較(S01-2 細胞と組織のバイオメカニクス(2)-ミクロからマクロまで-,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

A Novel Dynamometer for Describing Forces and Vectors in the Long Fingers during Grip

A new dynamometer has been designed that enables the capture of multiple grip force vectors in a single squeeze. The thumb is completely isolated in the measurement ensuring these vectors are a result of only forces produced only by the long fingers. The measured force vectors can be resolved to find the overall grip force magnitude and direction if a simple measure of grip force is desired. Alternatively, due to the ability of the dynamometer to easily measure multiple vector magnitudes and angles, the instrument lends itself well to the collection of grip data to be used as input into a hand biomechanical model. An experiment was conducted to measure the maximum grip exertions of sixteen subjects on a series of cylindrical handles and this data was used for the model. The results demonstrated that the model can be implemented and that tendon tension, when normalized by grip force, continues to increase as handle size increases even though grip force magnitudes decrease.

The Effect of Ankle Position on the Static Tension in the Achilles Tendon Before and After Operative Repair: A Biomechanical Cadaver Study

We hypothesized that there no need to position the foot in plantarflexion after operative repair of an Achilles tendon rupture. In five fresh cadaver lower extremity specimens, the static tension in the Achilles tendon was measured as the ankle was sequentially dorsiflexed from 30, to 20, to 10, to 0 degrees of plantarflexion. The tendon was then transected and repaired using a modified Krakow locking loop suture technique. The tension in the tendon was again measured as the foot was sequentially dorsiflexed through the same range of motion: 30, to 20, to 10, to 0 degrees. The repair was then tensile tested to failure. The intact Achilles tendons generated on average 10 N, 10 N, 15.8 N and 31.9.0 N of tension at 30, 20, 10, and 0 degrees of plantarflexion, respectively. After a modified Krakow locking loop repair, the tension across the repair site was 10 N, 11.46 N, 18.4 N, and 30.3 N at 30, 20, 10, and 0 degrees of plantarflexion. Thus, moving the ankle from 30 degrees to neutral placed an additional force of 21.9 N on the intact tendon and 20.3 N on the repaired tendon. The mean tensile strength of the modified Krakow repair was 598.6 N (range 167 1129 N). The tension in the repaired tendon at neutral position is only a small percentage (6.4%) of the strength of the tendon when operatively repaired by a modified Krakow locking loop suture technique. Our results suggest that the ankle joint does not have to be positioned in plantarflexion after operative repair using the described technique.

Using EMG data to constrain optimization procedure improves finger tendon tension estimations during static fingertip force production

Determining tendon tensions of the finger muscles is crucial for the understanding and the rehabilitation of hand pathologies. Since no direct measurement is possible for a large number of finger muscle tendons, biomechanical modelling presents an alternative solution to indirectly evaluate these forces. However, the main problem is that the number of muscles spanning a joint exceeds the number of degrees of freedom of the joint resulting in mathematical under-determinate problems. In the current study, a method using both numerical optimization and the intra-muscular electromyography (EMG) data was developed to estimate the middle finger tendon tensions during static fingertip force production. The method used a numerical optimization procedure with the muscle stress squared criterion to determine a solution while the EMG data of three extrinsic hand muscles serve to enforce additional inequality constraints. The results were compared with those obtained with a classical numerical optimization and a method based on EMG only. The proposed method provides satisfactory results since the tendon tension estimations respected the mechanical equilibrium of the musculoskeletal system and were concordant with the EMG distribution pattern of the subjects. These results were not observed neither with the classical numerical optimization nor with the EMG-based method. This study demonstrates that including the EMG data of the three extrinsic muscles of the middle finger as inequality constraints in an optimization process can yield relevant tendon tensions with regard to individual muscle activation patterns, particularly concerning the antagonist muscles.

TENDON FORCE PREDICTION IN STATIC PINCH TASK USING MULTIOBJECTIVE OPTIMIZATION BASED ON GENETIC ALGORITHM

INTRODUCTION Muscles forces are of a great interest in biomechanics, rehabilitation and physiology. Many researches used optimization techniques [1] to predict tendon tensions. This work is focused on the determination of thumb and index tendon forces in case of tip pinch task. A biomechanical model for the musculoskeletal system of the human hand, taken into account all the kinematics and the musculature, was developed. The total number of muscles is 15 and the number of degrees of freedom is 9. We proposed the use of single and multiobjective optimization process based on genetic algorithms [2,3] to solve that redundant problem, to obtain the nondominated solutions and to build the Pareto front graph.

Vibrational Tension Measurement of External Tendons in Segmental Posttensioned Bridges

A rapid and economical vibrational tension measurement method is presented to detect distress in external tendons used in segmental posttensioned bridges. This method provides a complementary technique to traditional inspection methods currently employed in the field. The natural frequency and overtones produced by an impact excitation are measured and used to determine the tendon segment’s tension and flexural stiffness using a differential equation describing a stiff string with clamped-clamped boundary conditions. The flexural stiffness is not negligible in tendons of this type causing the vibration modes to be inharmonically related. This method provides consistent (typically within 1%) and reasonably accurate (typically within 10%) estimates of tendon tension. Accuracy can be improved by lessening uncertainty in input constants such as the tendon mass and tendon length. Application examples from several in-service bridges have shown that detection of corrosion damage, improper tensioning, and force d...

ROLE OF PERIPATELLAR RETINACULUM IN TRANSMISSION OF FORCES WITHIN THE EXTENSOR MECHANISM

Background: The role of the peripatellar retinaculum as a frontal plane stabilizer of the patellofemoral joint has been well established. However, as a result of its unique orientation, the retinaculum also may influence the distribution of forces within the extensor mechanism. The objective of this study was to determine the extent to which the peripatellar retinaculum affects the magnitude of forces experienced by the patellar tendon. Methods: Ten cadaver knees were used in this investigation. Each was mounted on a custom test apparatus that was fixed to an Instron frame. The extensor mechanism was loaded by applying forces through the individual heads of the quadriceps femoris. Patellar tendon tension was measured at 0°, 20°, 40°, and 60° of knee flexion with use of a buckle transducer under two conditions: (1) with the peripatellar retinaculum intact, and (2) with the peripatellar retinaculum removed. Patellar tendon tension was compared between the two conditions across the knee flexion angles. Results: At each knee flexion angle, the patellar tendon tension was greater with the retinaculum removed than it was with the retinaculum intact. However, the difference was significant only at 0° and 60°, at which positions the force transmitted to the patellar tendon was increased by 16.6% and 9.6%, respectively. Conclusions: The observed increases in patellar tendon tension after removal of the peripatellar retinaculum is an indication of the load-sharing function of that structure as a part of the extensor mechanism. Clinical Relevance: Our results suggest that compromise of the peripatellar retinaculum may alter patellar tendon and/or patellofemoral joint forces.