Pulley Research Articles

Two stage reconstruction of flexor tendon injuries in zone II after missed injury or failed repair

Background: Reconstruction of flexor tendon injury of the hand after failed tendon repair or missed injury is a technically challenging problem. Repair of the tendon within the thin tight pulley system usually invites the formation of adhesion and failure of repair. A combination of a technique described by Paneva-Holevich and Hunter has been used for this problem with variable results. Methods: Twenty-five flexor tendons in 20 patients were reconstructed using a two-stage reconstruction of the flexor tendon injury. The preoperative condition of the finger was evaluated using Boyes and Stark grading modified by Wehbe et al. and all had a poor prognosis. The primary tendon injury was missed in nine patients. Primary tendon repair failed in seven patients and free tendon graft failed in three. One patient had two operative interventions: one failed primary tendon repair and one failed free tendon graft. The dominant hand was affected in (70%) of patients. Results: The average time between the original injury and the first stage operation was 10.6 mo. The mean follow-up after the second stage was 72 mo. The mean strength of pinch grip and power grip were 92.4% and 94.8%, respectively. The mean pulp to distal flexion crease distance was 12.32 mm. According to Buck-Gramcko scoring, excellent results were achieved in 18 fingers (72%), good in five fingers (20%), fair in one (4%), and poor in one (4%). No additional surgery was required after the second stage. Conclusions: The two-stage pedicled flexor digitorum superficialis technique provided a reliable and effective method for reconstruction of failed repair or missed injury of the flexor tendon in the hand in zone II. The modification of the technique presented in this study achieved a high rate of excellent and good results without increasing the rate of complications. Patient compliance is critical for the success of this procedure.

Electrical Monitoring of Mechanical Defects in Induction Motor-Driven V-Belt–Pulley Speed Reduction Couplings

V-belt–pulley couplings are commonly used for speed reduction in induction-motor-driven industrial applications since they provide flexible transmission of power at low cost. However, they are susceptible to mechanical defects such as belt wear or crack that can cause slippage or damage of the belt and lead to decrease in efficiency and lifetime of the system. There are many limitations to applying existing tests such as visual inspection, thermal or mechanical monitoring as they require visual, or physical access to the system and/or costly sensors. Considering the large quantity of belt–pulley systems employed in industry, the impact of the economic loss incurred by low-efficiency operation, and unplanned process outages is significant. In this paper, electrical monitoring of belt–pulley coupling defects based on the analysis and trending of the stator current frequency spectrum under steady-state and starting conditions is presented. The proposed method is verified on the following: 1) 6.6-kV motor-driven pulpers; and 2) a custom-built motor-driven air compressor with speed reduction belt–pulleys under controlled fault conditions. It is shown that the proposed method can provide automated, remote, and safe detection of belt–pulley defects based on existing current measurements for improving system reliability and efficiency. It is also shown that the proposed method can be applied to vibration measurements for motors where vibration sensors are installed.

Topographic anatomical landmarks for pulley system of the thumb.

Knowledge of anatomical landmark to pulley system of the thumb is essential in successful treatment of trigger thumb release either by percutaneous or by minimally invasive technique. Though surgical release of trigger thumb is done commonly, there is paucity of data in the literature regarding its surface landmarks. The purpose of this study is to identify palmar surface anatomical landmarks to the pulley system of the thumb. Dissection was performed on 55 fresh frozen adult cadaveric thumbs. The palmar thumb creases were given names as the proximal-proximal crease (PPC) present at the metacarpophalangeal joint, the distal-proximal crease (DPC) over the middle of the proximal phalanx and the distal crease (DC) at interphalangeal joint. The distance between the proximal edges of each pulley to the three thumb creases and longitudinal length of A1, A2, oblique and Av pulley was measured using digital vernier caliper and was expressed in mean and standard deviation. The proximal edge of A1 pulley was 1.98 ± 1.61mm proximal to the PPC. The mean longitudinal length of the A1 pulley was measured to be 5.06 ± 0.87mm, so the distal edge of the A1 pulley was calculated to lie 3.08mm distal to PPC. The proximal edge of Av and oblique pulley was situated 7.78 ± 2.5 and 15.72 ± 3.22mm distal to PPC, respectively. The proximal edge of A2 pulley was very nearer and 2.88 ± 1.79mm proximal to DC. The knowledge of anatomical skin surface landmarks is helpful in the percutaneous release or minimally invasive procedure. The PPC serves as a definite landmark for A1, Av and oblique pulley whereas it is the DC for A2 pulley.

An Active Rehabilitation System for Adhesive Capsulitis

Adhesive capsulitis is a stick of shoulder capsule that causes stick due to acute or chronic inflammation. It will cause serious impacts on patient’s daily life. Rehabilitation agencies used a shoulder abduction ladder, Pulley System for Upper Limb rehabilitation. Without electronics, networking is its drawback. The system digitizes an upper extremity rehabilitation equipment, and records the patient's rehabilitation information, such as the ability to lift the upper limbs, rehabilitation time and frequency, and so on. In addition, the system uses the Gray relational analysis to evaluate the rehabilitation efficacy. Physicians can know the patient's condition to improve his rehabilitation strategy. Patients can also know their rehabilitation effects so to encourage their rehabilitation psychology, so the arms can be recovered early.

Validation of a dynamic joint contracture measuring device in a live rabbit model of arthrofibrosis.

The current method of measuring arthrofibrosis in live rabbits is critically limited. Specifically, this method involves radioactive fluoroscopy, error-prone goniometric measurements, and static joint angle outcomes that fail to approximate the compliance of tissues surrounding the joint. This study aims to validate a novel method of capturing the compliance of contracted tissues surrounding the joint without the use of fluoroscopy or animal sacrifice. Surgically induced contractures of one-hundred and eight rabbits were measured using the current standard of contracture measurement (a pulley system) as well as a newly designed dynamic load cell (DLC) device. The DLC device was highly reliable when compared to the pulley system (r = 0.907, p < 0.001). Finally, the DLC device produced joint stiffness hysteresis curves capable of approximating the compliance of stiff joint tissues, ultimately calculating a mean joint stiffness of 1.57 ± 1.31 N · m · rad-1 (range, 0.33-6.37 N · m · rad-1 ). In conclusion, the DLC device represents a valid method for measuring joint contractures. Further, the DLC device notably improves current techniques by introducing the capacity to approximate the compliance of contracted tissues in living rabbits. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Towards Subject-Specific Strength Training Design through Predictive Use of Musculoskeletal Models.

Lower extremity dysfunction is often associated with hip muscle strength deficiencies. Detailed knowledge of the muscle forces generated in the hip under specific external loading conditions enables specific structures to be trained. The aim of this study was to find the most effective movement type and loading direction to enable the training of specific parts of the hip muscles using a standing posture and a pulley system. In a novel approach to release the predictive power of musculoskeletal modelling techniques based on inverse dynamics, flexion/extension and ab-/adduction movements were virtually created. To demonstrate the effectiveness of this approach, three hip orientations and an external loading force that was systematically rotated around the body were simulated using a state-of-the art OpenSim model in order to establish ideal designs for training of the anterior and posterior parts of the M. gluteus medius (GM). The external force direction as well as the hip orientation greatly influenced the muscle forces in the different parts of the GM. No setting was found for simultaneous training of the anterior and posterior parts with a muscle force higher than 50% of the maximum. Importantly, this study has demonstrated the use of musculoskeletal models as an approach to predict muscle force variations for different strength and rehabilitation exercise variations.

Flexor Tendon Injuries

Flexor tendon injuries are common hand injuries that can significantly affect hand function. Treatment of these injuries requires a thorough understanding of the intricate anatomy and biomechanics of flexor tendons. The goals of reconstruction include restoration of tendon continuity, preservation and reconstruction of the pulley system, maximizing tendon gliding, and minimizing adhesion formation. Surgical treatment, in conjunction with postoperative hand therapy, provides enhanced function. This review provides the surgeon with the relevant anatomy, pearls of clinical evaluation, necessary investigative studies, management algorithms, surgical techniques, rehabilitation protocols, and approaches to common complications. It ends with a discussion of basic and translational research currently being undertaken to address the challenges posed by flexor tendon injuries and how this research can potentially advance patient care. This review contains 16 figures, 5 tables and 55 references Key words: flexor tendon, flexor tendon injuries, flexor tendon reconstruction, flexor tendon repair, hand, hand surgery, injury, surgical technique, tendons

Static Characteristics of a New Three-Dimensional Linear Homeomorphic Saccade Model

A linear homeomorphic saccade model that produces 3D saccadic eye movements consistent with physiological and anatomical evidence is introduced. Central to the model is the implementation of a time-optimal controller with six linear muscles and pulleys that represent the saccade oculomotor plant. Each muscle is modeled as a parallel combination of viscosity [Formula: see text] and series elasticity [Formula: see text] connected to the parallel combination of active-state tension generator [Formula: see text], viscosity element [Formula: see text], and length tension elastic element [Formula: see text]. Additionally, passive tissues involving the eyeball include a viscosity element [Formula: see text], elastic element [Formula: see text], and moment of inertia [Formula: see text]. The neural input for each muscle is separately maintained, whereas the effective pulling direction is modulated by its respective mid-orbital constraint from the pulleys. Initial parameter values for the oculomotor plant are based on anatomical and physiological evidence. The oculomotor plant uses a time-optimal, 2D commutative neural controller, together with the pulley system that actively functions to implement Listing's law during both static and dynamic conditions. In a companion paper, the dynamic characteristics of the saccade model is analyzed using a time domain system identification technique to estimate the final parameter values and neural inputs from saccade data. An excellent match between the model estimates and the data is observed, whereby a total of 20 horizontal, 5 vertical, and 64 oblique saccades are analyzed.

Dynamic Characteristics of a New Three-Dimensional Linear Homeomorphic Saccade Model.

A linear homeomorphic eye movement model that produces 3D saccadic eye movements consistent with anatomical and physiological evidence is introduced in this second part of a two-paper sequence. Central to the model is the implementation of a time-optimal neural control strategy involving six linear muscle models that faithfully represent the dynamic characteristics of 3D saccades. The muscle is modeled as a parallel combination of viscosity [Formula: see text] and series elasticity [Formula: see text], connected to the parallel combination of active-state tension generator [Formula: see text], viscosity element [Formula: see text], and length tension elastic element [Formula: see text]. The neural input for each muscle is separately maintained while the effective pulling direction is modulated by its respective pulley. The results demonstrate that a time-optimal, 2D commutative neural controller, together with the pulley system, actively functions to implement Listing's law during both static and dynamic simulations and provide an excellent match with the experimental data. The parameters and neural input to the muscles are estimated using a time domain system identification technique from saccade data, with an excellent match between the model estimates and the data. A total of 20 horizontal, 5 vertical and 62 oblique saccades are analyzed.

Arthroscopic suprapectoral tenodesis of the long head of the biceps tendon

The aim of atenotomy of the long biceps tendon is to remedy apainful pathology in the proximal region of the tendon. Tenodesis of the tendon can restore the motor and cosmetic function of the biceps brachii muscle. Partial rupture or tendopathy of the long biceps tendon, injuries of the anchor of the long biceps tendon (SLAP lesions; SLAP: superior labrum anterior posterior), lesions of the pulley system. Infections or tumors, loss of the long head biceps tendon from the intertubercular groove. Shoulder arthroscopy via aposterior standard portal in beach chair position. Anteroinferior portal. Standard diagnostic arthroscopy. Checking the stability of the biceps anchor and the pulley system with aprobe. Testing the extra-articular portion of the long biceps tendon with the hook. By pulling the tendon into the joint, the course of the tendon can be assessed. Anterolateral portal superior of the intertubercular groove. Pulling the tendon out of the anterolateral portal. Arming of the tendon with Krackow stitches. Fixation of the tendon in the intertubercle groove with aknotless suture anchor. Three weeks immobilization with an arm sling, 6weeks no forced elbow flexion and forearm supination, 2weeks active-assisted mobilization of the shoulder up to horizontal, 30° external rotation, internal rotation free. The results published in the literature show that epiossal anchor tenodisis improves the clinical scores (preoperative vs. postoperative) and leads to abetter cosmetic result and alower rerupture rate than soft tissue tenodesis.

Concomitant glenohumeral injuries in Neer type II distal clavicle fractures

BackgroundTo identify the prevalence of concomitant glenohumeral injuries in surgically treated Neer type II distal clavicle fractures and relate its clinical importance.MethodsBetween 11/2011 and 11/2015 41 patients, suffering from a displaced and unstable distal clavicle fracture were included. 20 patients (group 1) received surgical treatment by means of plate osteosynthesis in combination with an arthroscopically assisted coraco-clavicular ligament augmentation. In group 2 (n = 21 patients) the fracture was treated by hooked plating solely, and diagnostic arthroscopy was conducted during hardware retrieval after the fracture had healed. All arthroscopies were performed in a standardized fashion, images were blinded retrospectively, and evaluated by two independent investigators.ResultsIn total, concomitant glenohumeral pathologies were found in 26.8% of cases (41 patients, mean age 43.6 ± 16.6 years). In Group 1 (n = 20, arthroscopically assisted fracture treatment) the prevalence was 25%, in Group 2 (n = 21, diagnostic arthroscopy during implant removal) 28.5% (p = 0.75). Concomitant glenohumeral injuries included Labrum- and SLAP-tears, partial and full thickness rotator cuff tears as well as lesions to the biceps pulley system. Concomitant injuries were addressed in 2 patients of group 1 (10%, 2× labrum repair) and in 3 patients of group 2 (14.3%, of Group 2 (2× arthroscopic cuff repair of full thickness tear, 1× subpectoral biceps tenodesis in an type IV SLAP lesion, p = 0.68).ConclusionThe present study could clarify the acute and for the first time mid-term implication and clinical relevance of concomitant glenohumeral injuries. They have been observed in averaged 27% of Neer type II distal clavicle fractures at these two times. However, the findings of this study show that not all concomitant lesions remain symptomatic. While lesions are still present after fracture healing, it’s treatment may be depicted upon symptoms at the time of implant removal. In turn, early diagnosis and treatment of concomitant injuries seems reasonable, as untreated injuries can remain symptomatic for more than 6 months after the fracture and recovery may be delayed.

Morphometric study of pulleys of the thumb.

Pulleys are thickened regions in flexor tendons sheaths of the digits. They are essential and act as fulcrum for the flexion and extension of the digits. The arrangement and number of pulley system differs greatly between the thumb and other digits. There is paucity of literature regarding the pulley system of thumb. We aimed to study the morphometry of the pulley system of the thumb in Indian cadavers. Dissection was carried out in 55 adult human cadaveric thumbs. The most common morphologic pattern of pulley observed in the thumb is type III (30 thumbs). The least observed is type I (4 thumbs). The mean width and standard deviation of A1, Av, oblique, and A2 pulleys are 5.06±0.87, 5.38±1.22, 4.68±1.13, and 6.04±1.41 mm, respectively. The gap distances between the pulleys were also measured. The results obtained from the present study may be helpful in surgical treatment of trigger thumb with less complication and also in reconstruction of the closed rupture of the pulley of the thumb.

Index Finger of a Human-Like Robotic Hand Using Thin Soft Muscles

This letter presents an index finger of human-like robotics hand which intends to closely replicate the human finger in terms of bones, ligaments, muscles, extensor mechanism, tendon, and its pulley system. We fabricated the muscles of the index finger using thin multifilament McKibben muscles that consist of three intrinsic and three extrinsic muscles with diameters of 1.3 mm and 4.0 mm, respectively. We present the fabrication method of the index finger and model it based on the Landsmeer Model I, II, and III. We validated the properties of our developed finger with the Landsmeer model for extension and flexion motion. Finally, we demonstrated the capabilities of the finger using motion capture, Tracker , to compare sweeps of the HR-hand finger with a cadaver finger motion for normal and finger deformity condition. Having McKibben muscles as the actuator that mimics the human muscle, one can better understand the human finger function and may use it for training and for modeling the human finger disorders.

Performance ‘S’ Type Savonius Wind Turbine with Variation of Fin Addition on Blade

Wind power has been receiving attention as the new energy resource in addressing the ecological problems of burning fossil fuels. Savonius wind rotor is a vertical axis wind turbines (VAWT) which has relatively simple structure and low operating speed. These characteristics make it suitable for areas with low average wind speed as in Indonesia. To identify the performance of Savonius rotor in generating electrical energy, this research experimentally studied the effect of fin addition for the ‘S’ shape of Savonius VAWT. The fin is added to fill the space in the blade in directing the wind flow. This rotor has two turbine blades, a rotor diameter of 1.1 m and rotor height of 1.4 m, used pulley transmission system with 1:4.2 multiplication ratio, and used a generator type PMG 200 W. The research was conducted during dry season by measuring the wind speed in the afternoon. The average wind speed in the area is 2.3 m/s with the maximum of 4.5 m/s. It was found that additional fin significantly increase the ability of Savonius rotor VAWT to generate electrical energy shown by increasing of electrical power. The highest power generated is 13.40 Watt at a wind speed of 4.5 m/s by adding 1 (one) fin in the blade. It increased by 22.71% from the rotor blade with no additional fin. However, increasing number of fins in the blade was not linearly increase the electrical power generated. The wind rotor blade with 4 additional fins is indicated has the lowest performance, generating only 10.80 Watt electrical power, accounted lower than the one generated by no fin-rotor blade. By knowing the effect of the rotor shape, the rotor dimension, the addition of fin, transmission, and generator used, it is possible to determine alternative geometry design in increasing the electrical power generated by Savonius wind turbine.

Traction reinforcement in prehensile feet of harvestmen (Arachnida, Opiliones).

Prehensile and gripping organs are recurring structures in different organisms that enhance friction by the reinforcement and redirection of normal forces. The relationship between organ structure and biomechanical performance is poorly understood, despite a broad relevance for microhabitat choice, movement ecology and biomimetics. Here, we present the first study of the biomechanics of prehensile feet in long-legged harvestmen. These arachnids exhibit the strongest sub-division of legs among arthropods, permitting extreme hyperflexion (i.e. curling up the foot tip). We found that despite the lack of adhesive foot pads, these moderately sized arthropods are able to scale vertical smooth surfaces, if the surface is curved. Comparison of three species of harvestmen differing in leg morphology shows that traction reinforcement by foot wrapping depends on the degree of leg sub-division, not leg length. Differences are explained by adaptation to different microhabitats on trees. The exponential increase of foot section length from distal to proximal introduces a gradient of flexibility that permits adaptation to a wide range of surface curvature while maintaining integrity at strong flexion. A pulley system of the claw depressor tendon ensures the controlled flexion of the high number of adesmatic joints in the harvestman foot. These results contribute to the general understanding of foot function in arthropods and showcase an interesting model for the biomimetic engineering of novel transportation systems and surgical probes.

The Hook and Release Technique During Enucleation Surgery.

To describe the results and potential benefit of direct muscle release from the globe during enucleation surgery without identifying sutures in the rectus muscle insertion sites, a technique referred to as the hook and release technique. Single center, retrospective chart review of patients who underwent enucleation with direct removal of the rectus muscles without identifying sutures in their insertion sites between January 2011 and September 2015 was carried out. The inclusion criteria were primary enucleation without previous strabismus surgery, retinal detachment surgery, or orbital surgery that entered the fibrous connective tissue framework. Forty charts of enucleated patients that had direct release of their extraocular muscles without identifying sutures before releasing them from the globe were identified and reviewed. The primary outcome measure was intraoperative or immediate postoperative complications. This retrospective chart review was performed with research ethics board approval and in compliance with the Declaration of Helsinki. Data show that following the hook and release technique, the rectus muscles were easily located and reconnected to the orbital implant wrap. The oblique muscles were not reattached. In each of the 40 patients, the 4 rectus muscles were easily located by gently applying traction anteriorly at the conjunctiva/Tenons' edge using double-pronged skin hooks. There was no instance of a lost or slipped muscle following the hook and release technique. The hook and release technique is a simple and efficient method to remove the 4 rectus muscles from the globe and still easily locate them. They are not "lost" and do not "slip out of position" but held in place by the orbital connective tissue framework and the extraocular muscle pulley system. This technique has been very helpful teaching resident staff how to do enucleation surgery as it avoids the more time consuming placement of double-armed locking sutures through the rectus muscle insertions and the potential risk of globe penetration while the muscles remain attached to the eye. If the surgeon desires to attach the muscles to the orbital implant, then sutures are passed after the eye is removed, thus eliminating the worry of globe penetration and avoiding accidentally cutting preplaced extraocular muscle sutures during the remaining enucleation procedure.

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. Methods: Eighteen fresh-frozen cadaveric ankles (mean ± SD age: 35 ± 7 years, range = 27-48 years; men, n = 9) were mounted in a customized testing rig, where the tibia was fixed but the forefoot could be moved freely. A Steinmann pin was drilled through the calcaneus, enabling a valgus torque to be applied. The soleus, gastrocnemius, and plantaris muscles were loaded with 63 N with a weighted pulley system. The test area was 40 to 80 mm above the os calcis, corresponding to where the injury is observed clinically. Medially, the AT and PT were exposed, and a calibrated flexible pressure sensor was inserted between the tendons. Pressure readings were recorded with the ankle in full dorsiflexion, full plantarflexion, and plantargrade and repeated in these positions with a 5 N·m torque, simulating increased hindfoot valgus. The pressure sensor was removed and the PT and AT marked with ink at the same level, with the foot held in neutral rotation and plantargrade. Videos and photographs were taken to assess differential motion between the tendons. After testing, specimens were dissected to identify the PT insertion. One-way analysis of variance and paired t tests were performed to make comparisons. Results: The PT tendons with an insertion separate from the AT demonstrated greater differential motion through range (14 ± 4 mm) when compared with those directly adherent to the AT (2 ± 2 mm) (P < .001). Mean pressure between the PT and AT rose in terminal plantarflexion for all specimens (P < .001) and was more pronounced with hindfoot valgus (P < .001). Conclusion: The PT inserting directly into the calcaneus resulted in significantly greater differential motion as compared with the AT. Tendon compression was elevated in terminal plantarflexion, suggesting that adapting rehabilitation tendon-loading programs to avoid this position may be beneficial. Clinical Relevance: The insertion pattern of the PT may be a factor in plantaris-related midportion Achilles tendinopathy. Terminal range plantarflexion and hindfoot valgus both increased AT and PT compression, suggesting that these should be avoided in this patient population.

Investigation Into the Functional Anatomy of the Flexor Tendon Pulley System of the Hand

Investigation Into the Functional Anatomy of the Flexor Tendon Pulley System of the Hand

Feasibility of a New Pulley Repair: ACadaver Study.

In this study, the feasibility of a new pulley reconstruction in which the tendon graft is pulled through a tunnel in the proximal phalanx, was evaluated using a cadaver model, withparticular attention paid to the weakening of the bone structure by the drill hole. Nine fingers from 6 cadaver hands with intact pulley systems were compared with 9fingers from 6 cadaver hands with missing A2 to A4 pulleys but that included a repair using the new surgical technique. Each finger was fixed to an isokinetic loading device. The forces in the flexor tendons were recorded in each finger using a force transducer. The forces recorded in the flexor tendons of the control group were significantly higher than in the reconstructed fingers. The most common event in the reconstructed fingers was graft failure. A fracture of the bone due to the drill hole was not observed. The new pulley reconstruction could represent an alternative to existing reconstructive techniques. The cause for the higher forces recorded in the control group could be attributed to sutures used in the operated fingers. The new pulley reconstruction method may enable reduced extensor tendonirritation because it avoids contact with the extensor hood and could possibly prohibitcortical bone loss, a serious side effect in the "one and one-half loop" technique.

Should the Iliotibial Band Defect be Closed After Lateral Tenodesis?

Recent evidence has suggested a key role of the superficial and deep layers of the ilio-tibial band in the control of knee rotation. In the context of an extra-articular tenodesis, we present a robotic study evaluating the presence of over-constraint following closure of the ITB defect and report no significant difference; this supports surgical preference as to whether or not to close the defect. There has been a renewed interest in lateral extra-articular tenodesis (LEAT) procedures in combination with anterior cruciate ligament reconstruction as a way of potentially reducing the rate of re-injury. A variety of these procedures have been described and mostly rely upon passing a strip of the iliotibial tract (ITT) under the lateral collateral ligament and performing a tenodesis with either proximal of distal fixation. One of the concerns with this procedure is that it may overconstrain the lateral compartment by limiting internal rotation of the tibia, potentially increasing the rate of development of osteoarthrosis. The aim of this study was to evaluate the kinematics of the knee comparing a proximally-based (Lemaire) and distally-based (Ellison) LEAT technique. A secondary aim was to evaluate the effect closure of the ITT had on lateral compartment rotation. A Lemaire LEAT results in greater restraint to internal rotation of the lateral compartment of the knee compared to an Ellison LEAT. Closure of the ITT will over constrain the knee significantly. Twelve fresh frozen cadaveric knees were tested to evaluate the kinematics of an intact anterolateral capsule, a sectioned capsule, an Ellison LEAT and a Lemaire LEAT with and without ITT closure. A 6 degrees of freedom robot with the addition of a novel pulley system to load the ITT (30-N) was used to assess knee stability using a universal force-moment sensor. At different flexion angles, anterior-posterior, internal-external, and internal rotational laxity in response to a simulated pivot-shift were tested. Data were analysed using repeated-measures analyses of variance and paired t-test. Transection of the oblique anterolateral fibers significantly increased anterior draw and rotation during isolated displacement and a simulated pivot-shift (P<0.05). No significant differences were seen between ‘defect open’ and ‘defect closed’ states after either tenodesis (P>0.05). The Ellison procedure closely restored the native kinematics of the intact knee following an anterolateral injury (P>0.05). Closure of the ITT defect following an Ellison or Lemaire lateral tendodesis does not significantly over constrain the kinematics of the knee.