Tendons Research Papers - Academia.edu (original) (raw)

To evaluate the results of our method of surgical treatment of traumatic knee dislocation with injury to the posterolateral corner by use of a standardized protocol. Twenty-five consecutive patients presented with a grossly dislocated or reduced knee. Five of these patients were not included in this series. The remaining 20 patients were treated by primary arthroscopic reconstruction. The anterior cruciate ligament (ACL) was reconstructed using gracilis tendon reinforced with artificial ligament (Ligament Augmentation and Reconstruction System [LARS] ligament); the posterior cruciate ligament (PCL) was reconstructed with semitendinosus tendon and reinforced with LARS ligament; and the posterolateral corner was treated using the gracilis and semitendinosus tendons from the uninjured knee. Twenty patients returned for subjective and objective evaluation at a minimum of 24 months after surgery. Early mobilization through continuous and active exercise was started on the fourth day postoperatively. At a mean follow-up of 44 months, the mean Lysholm score was 90 points, the mean score on the survey of daily activities was 90 points, and the sports activities score on the knee outcome survey averaged 80 points. By the rating of Meyers et al. the results were excellent in 6 patients, good in 10 patients, fair in 3 patients, and poor in one patient. The final International Knee Documentation Committee (IKDC) rating was not normal in any knee. The mean loss of extension was 2° (range, 0° to 3°) and loss of flexion was 12° (range, 10° to 15°). By using the described method of arthroscopically assisted reconstruction of the cruciate ligaments and the posterolateral corner, 80% of the patients had good subjective results and functional stability, and according to the IKDC scale, 45% of knees were nearly normal, 45% were abnormal, and 10% were severely abnormal. No patient&amp;amp;amp;amp;amp;amp;amp;#39;s rating returned to normal. Level IV, therapeutic case series.

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- Adolescent, Anterior Cruciate Ligament, Arthroscopy, Young Adult

Reconstruction after pan-plexus root avulsions often includes gracilis free functioning muscle transfer. For elbow flexion reconstruction, the free functioning muscle transfer distal tendon is inserted into the biceps tendon or more distally (i.e., flexor digitorum profundus/flexor pollicis longus tendons) for combined elbow and finger flexion; the theoretical drawback of the latter approach is weaker elbow flexion. The authors compared elbow flexion strength with a biceps tendon versus a flexor digitorum profundus/flexor pollicis longus tendon attachment to determine which insertion point resulted in better elbow flexion. Thirty-nine patients underwent free functioning muscle transfer with either a biceps tendon or a distal attachment. Groups were compared on postoperative elbow flexion strength, preoperative and postoperative Disabilities of the Arm, Shoulder, and Hand questionnaire scores, range of motion, and other surgical and demographic characteristics. A biomechanical analys...

Transforming growth factor alpha (TGFα) belongs to the epidermal growth factor (EGF) family and is known to play an important role during eyelid morphogenesis. In this study, we showed that ectopic expression of TGFα in the stroma of Kera-rtTA/tet-O-TGFα bitransgenic mice results in precocious eye opening, abnormal morphogenesis of the meibomian gland, tendon and tarsal plate malformation and epithelium hyperplasia. TGFα did not change proliferation and differentiation of meibocytes, but promoted proliferation and inhibited differentiation of the tarsal plate tenocytes. These results suggest that proper formation of the tendon and tarsal plate in the mouse eyelid is required for normal morphogenesis of the meibomian gland.

- by Winston Kao
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- Developmental Biology, Biology, Immunohistochemistry, Morphogenesis

An extremely well-preserved dinosaur ( Cf. Edmontosaurus sp.) found in the Hell Creek Formation (Upper Cretaceous, North Dakota) retains soft-tissue replacement structures and associated organic compounds. Mineral cements precipitated in the skin apparently follow original cell boundaries, partially preserving epidermis microstructure. Infrared and electron microprobe images of ossified tendon clearly show preserved mineral zonation, with silica and trapped carbon dioxide forming thin linings on Haversian canals within apatite. Furthermore, Fourier transform infrared spectroscopy (FTIR) of materials recovered from the skin and terminal ungual phalanx suggests the presence of compounds containing amide groups. Amino acid composition analyses of the mineralized skin envelope clearly differ from the surrounding matrix; however, intact proteins could not be obtained using protein mass spectrometry. The presence of endogenously derived organics from the skin was further demonstrated by p...

- by R. Wogelius
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- Chemistry, Medicine, Biological Sciences, Dinosaurs

Previous research suggests that the moment arm of the m. triceps surae tendon (i.e., Achilles tendon), is positively correlated with the energetic cost of running. This relationship is derived from a model which predicts that shorter ankle moment arms place larger loads on the Achilles tendon, which should result in a greater amount of elastic energy storage and return. However, previous research has not empirically tested this assumed relationship. We test this hypothesis using an inverse dynamics approach in human subjects (n = 24) at speeds ranging from walking to sprinting. The spring function of the Achilles tendon was evaluated using specific net work, a metric of mechanical energy production versus absorption at a limb joint. We also combined kinematic and morphological data to directly estimate tendon stress and elastic energy storage. We find that moment arm length significantly determines the spring-like behavior of the Achilles tendon, as well as estimates of mass-specific tendon stress and elastic energy storage at running and sprinting speeds. Our results provide support for the relationship between short Achilles tendon moment arms and increased elastic energy storage, providing an empirical mechanical rationale for previous studies demonstrating a relationship between calcaneal length and running economy. We also demonstrate that speed and kinematics moderate tendon performance, suggesting a complex relationship between lower limb geometry and foot strike pattern. The role of the Achilles tendon (AT) in elastic energy storage with subsequent return during stance phase is well established 1-7. Recovery of elastic energy imparted to the AT is potentially influenced by AT morphology in three ways: (1) material properties of the tendon, (2) cross-sectional area of the tendon, and (3) the moment arm of the calcaneal tuberosity loading the tendon against the muscle force of the m. triceps surae (i.e., foot geometry). Previous work suggests that foot geometry may explain variation in how much potential energy is stored in the tendon, finding that a shorter AT moment arm is correlated with lower mass-specific energy costs of locomotion (COL; L O 2 kg −1 s −1) 8, 9. This finding suggests that shorter AT moment arms are associated with greater elastic loads imparted to the tendon, which are then recovered as kinetic energy during the support phase of each gait cycle 9 , thereby reducing COL. Scholz et al. 9 also suggest that the length of the AT moment arm is a more significant factor in explaining COL than variation in material properties of the tendon itself or size-related variation in the cost of swinging the leg forward during the aerial phase of the gait cycle 9. However, assumptions about the interacting roles of AT moment arm length, tendon cross-sectional dimensions, and tendon material properties on variation in elastic energy storage have yet to tested in an integrated manner. Moreover, Scholz et al. 9 doesn't directly measure the variables in the model which predict variation in elastic energy storage, including muscle force and the external moment arm. Finally, because previous studies of how AT moment arm length influences COL have used trained runners running on a treadmill at a speed of 16 km/h, it is still unknown how variation in speed and athletic training impacts elastic loading to the tendon in relation to moment arm length. While previous work has explored elastic loading of the AT at different speeds and under different loading conditions 10-21 , this study is the first to investigate the potential correlation between foot geometry like the AT moment arm length and spring-like behavior of this tendon in humans. In this study, we model elastic loading of the AT by characterizing the spring-like behavior over the support phase of each gait cycle using two metrics. First, we calculate specific net work (SNW) at the ankle joint. SNW is OPEN

- by Adam Foster
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- Biological Anthropology, Functional Anatomy, Anatomy, Human Anatomy

Anterior approaches to the shoulder involve partial or complete detachment of the subscapularis muscle. We have developed a new technique that permits adequate access to the humeral attachment of the inferior glenohumeral ligament (IGHL) without any detachment of the subscapularis, and have used this to successfully repair humeral avulsions of glenohumeral ligament lesions. Preliminary diagnostic arthroscopy using air insufflation of the glenohumeral joint is used to identify and grade the lesion. A 1-inch axillary incision is used to access the subscapularis tendon through the deltopectoral approach. Thereafter, anatomic landmarks are identified to expose the lateral aspect of the inferior border of the subscapularis muscle. Blunt dissection is used to separate the musculocapsular plane, and the subscapularis is retracted in an anterosuperior direction. Adequate exposure for visualization and repair of the avulsed IGHL is possible in a majority of cases where this approach is attempted. The use of arthroscopic instruments and suture anchors facilitates suture passage through the mid and posterior regions of the IGHL. If exposure is inadequate, the approach can be easily converted to a conventional L-shaped tenotomy approach through the lower or upper region of the subscapularis.

- by Joe De Beer
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- Orthopedic Surgery, Treatment, Arthroscopy, Technique

Purpose: To report a new technique of arthroscopic biceps tenodesis using bioabsorbable interference screw fixation and the early results. Type of Study: Prospective, nonrandomized study. Methods: Technique: The principle of arthroscopic biceps tenodesis is simple: after biceps tenotomy, the tendon is exteriorized and doubled on a suture; the biceps tendon is then pulled into a humeral socket (7 or 8 mm ϫ 25 mm) drilled at the top of the bicipital groove, and fixed using a bioabsorbable interference screw (8 or 9 mm ϫ 25 mm) under arthroscopic control. Patients: 43 patients treated with this technique between 1997 and 1999 were followed-up for at least 1 year. The technique was indicated in 3 clinical situations: (1) with arthroscopic cuff repair (3 cases), (2) in case of isolated pathology of the biceps tendon with an intact cuff (6 cases), and (3) as an alternative to biceps tenotomy in patients with massive, degenerative and irreparable cuff tears (34 cases). The biceps pathology was tenosynovitis (4 cases), prerupture (15 cases), subluxation (11 cases), and luxation (13 cases). Results: The absolute Constant score improved from 43 points preoperatively to 79 points at review (P Ͻ .005). There was no loss of elbow movement and biceps strength was 90% of the strength of the other side. Two patients, operated on early in the series, presented with a rupture of the tenodesis. In both cases the bicipital tendon was very friable and the diameter of the screw proved to be insufficient (7 mm). No neurologic or vascular complications occurred. Conclusions: Arthroscopic biceps tenodesis using bioabsorbable screw fixation is technically possible and gives good clinical results. This technique can be used in cases of isolated pathologic biceps tendon or a cuff tear. A very thin, fragile, almost ruptured biceps tendon is the technical limit of this arthroscopic technique.

- by Pascal Boileau
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- Tendon and Ligament injuries, Treatment Outcome, Prospective studies, Shoulder

Anterior knee pain is a common presenting complaint amongst adolescent athletes. We hypothesised that patellar tendinopathy may occur at a younger age than is generally recognised. Thus, we studied the patellar tendons in 134 elite 14-to 18-year-old female (nΩ64) and male (nΩ70) basketball players and 29 control swimmers (17 female, 12 male) clinically and with ultrasonography. We found that of 268 tendons, 19 (7%) had current patellar tendinopathy on clinical grounds (11% in males, 2% in females). Twenty-six percent of the bas

- by K Khan
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- Adolescent, Swimming, Basketball, Scandinavian

To evaluate the feasibility and repeatability of in vivo measurement of stiffness gradients by means of acoustoelastography in the superficial digital flexor tendons (SDFTs) of clinically normal horses. 15 clinically normal horses. For each horse, stiffness gradient index and dispersion values for SDFTs in both forelimbs were evaluated in longitudinal orientation by use of acoustoelastography at 3 sites (5, 10, and 15 cm distal to the accessory carpal bone) by 2 observers; for each observer, data were acquired twice per site. The left forelimb was always scanned before the right forelimb. Lifting of the contralateral forelimb with the carpus flexed during image acquisition resulted in the required SDFT deformation in the evaluated limb. Interobserver repeatability, intraobserver repeatability, and right-to-left limb symmetry for stiffness gradient index and dispersion values were evaluated. Stiffness gradient index and dispersion values for SDFTs at different locations as well as ef...

- by Ray Vanderby
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- Acoustics, Biological Sciences, Horses, Analysis of Variance

The purpose of this study was to evaluate active knee flexion range of motion and hamstring strength following hamstring anterior cruciate ligament (ACL) reconstruction. Case control study, consecutive sample. Seventy-four consecutive patients who had undergone hamstring ACL reconstruction underwent isokinetic muscle strength testing at 2 years post surgery. Measurements of the maximum standing active knee flexion angle with the hip extended were also taken. During isokinetic testing, we evaluated flexion torque at 90 degrees of knee flexion, in addition to the peak flexion torque. We further compared these parameters of muscle strength around the knee for the patients in whom only semitendinosus tendon was harvested as a graft source (ST group), and those from whom the semitendinosus tendon and the gracilis tendon were harvested (ST/G group). Isokinetic testing showed that, in both the ST and ST/G groups, the knee flexor strength of the involved leg was less effectively restored at 90 degrees of knee flexion than at the angle at which the peak torque was generated. Conversely, no significant difference was seen in the side-to-side ratio in either the peak flexion torque or the 90 degrees flexion torque between the groups. The side-to-side ratio in mean maximum standing knee flexion angle was significantly lower in the ST/G group than in the ST group. This study suggests that the loss of knee flexor strength following the harvest of the hamstring tendons may be more significant than has been previously estimated. Furthermore, multiple tendon harvest may affect the range of active knee flexion.

The purpose of this prospective, randomized, computed tomographyebased study was to investigate whether the press-fit technique reduces tunnel volume enlargement (TVE) and improves the clinical outcome after anterior cruciate ligament reconstruction at a minimum follow-up of 1 year compared with conventional technique. Methods: Sixty-nine patients undergoing primary ACL reconstruction using hamstring autografts were randomly allocated to either the press-fit technique group (group A) or conventional technique group (group B). All patients were evaluated for TVE and tunnel widening using computed tomography scanning, for functional outcome using International Knee Documentation Committee and Lysholm scores, for rotational stability using the pivot-shift test, and for anterior laxity using the KT-2000 arthrometer at a minimum of 1-year follow-up. Results: There were no significant differences in TVE between the 2 groups. In group A, in which the press-fit technique was used, mean volume enlargement in the femoral tunnel was 65% compared with 71.5% in group B (P ¼ .84). In group A, 57% (20 of 35) of patients developed femoral TVE compared with 67% (23 of 34) of patients in group B (P ¼ .27). Both groups showed no significant difference for functional outcome (mean Lysholm score P ¼ .73, International Knee Documentation Committee score P ¼ .15), or knee laxity (anterior P ¼ .78, rotational P ¼ .22) at a minimum follow-up of 1 year. Conclusions: In a comparison of press-fit and conventional techniques, there were no significant differences in TVE and clinical outcome at short-term follow-up. Level of Evidence: Level II, therapeutic study, prospective randomized clinical trial.

- by michael muñoz
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- Adolescent, Femur, Arthroscopy, Young Adult
- by Alberto Gobbi
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- Motion Analysis, Adolescent, Anterior Cruciate Ligament, Prospective studies

The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress-strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r 2 0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity.

- by samuel miller
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- Skeletal muscle biology, Muscle strength, Biological Sciences, Elasticity
- by Ilyas Khan
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- Stem Cells, Cell Adhesion, Phenotypic Plasticity, Transcription Factors

Patellar tendinitis is an overuse syndrome affecting the origin of the patellar tendon and its underlying part. Ultrasonography is useful to investigate tendinous pathology. It describes the anatomical lesions and their extent. Surgical excision of irreversible lesions, demonstrated on ultrasonography, is a logical attitude which provides good results.

- by Daniel Fritschy
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- Treatment Outcome, Prospective studies, Ultrasonography, Tendinopathy

To evaluate the ability of ultrasonography to predict eventual symptoms in an at-risk population, 52 elite junior basketball players' patellar tendons were studied at baseline and again 16 months later. The group consisted of 10 study tendons (ultrasonographically hypoechoic at baseline) and 42 control tendons (ultrasonographically normal at baseline). By design, all tendons were asymptomatic at baseline. No differences were noted between subjects and controls at baseline for age, height, weight, training hours, and vertical jump. Functional (P < 0.01) and symptomatic outcome (P < 0.05) were poorer for subjects' tendons than for controls. Relative risk for developing symptoms of jumper's knee was 4.2 times greater in case tendons than in control tendons. Men were more likely to develop ultrasonographic changes than women (P < 0.025), and they also had significantly increased training hours per week (P < 0.01) in the study period. Half (50%) of abnormal tendon...

- by Zoltan Kiss
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- Ultrasound, Adolescent, Prospective studies, Basketball

Although surgical repair has been reported to provide improved outcomes compared with nonoperative treatment in the management of complete proximal hamstring origin avulsions, no intact or avulsion repair biomechanical data exist to support various repair strategies or guide postoperative rehabilitation. To compare failure load among 4 proximal hamstring tendon conditions: (1) intact, (2) repair with 2 small anchors (2S), (3) repair with 2 large anchors (2L), and (4) repair with 5 small anchors (5S). Controlled laboratory study. Twenty-four human cadaveric hemipelvises were randomly allocated to 1 of the 4 testing groups. Intact and repaired specimens were subjected to cyclic loading at 1 Hz between 25 N and a progressively increasing maximum load that was incremented by 200 N every 50 cycles, beginning at 200 N and increasing to 1600 N. Displacement, maximum load, stiffness, number of cycles to failure, and mode of failure during cyclic loading were recorded and analyzed. The intac...

The interest in reconstructing an insufficient posterior cruciate ligament (PCL) has increased over the past years. Whilst many variables will affect the outcome of surgery, an essential part during the planning of this procedure is the choice of graft material and the appropriate fixation technique. In this article we provide an overview of graft materials that may be used for PCL reconstruction and of the various fixation techniques of such graft options.

- by J. Höher
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- Bone graft, Tibia, Femur, Clinical Sciences
- by P. Onnerfjord
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- Mass Spectrometry, Proteomics, Biological Chemistry, Extracellular Matrix

Palmaris longus muscle, although of little functional use to the human upper limb, assumes great importance when used as a donor tendon for transfer or transplant. The variability in the prevalence of palmaris longus agenesis among various ethnic groups has been established, and the surgeon’s awareness of the prevalence in a population or ethnic group is desirable. The prevalence of palmaris longus agenesis has, to the best of the authors’ knowledge, not been reported in Indian patients. Five hundred Indian patients were examined for the presence or absence of palmaris longus tendon, using the conventional test for presence of palmaris longus. The prevalence and pattern of palmaris longus agenesis was analyzed statistically and any difference in prevalence or pattern of palmaris longus agenesis with regard to body side or sex was looked for. All statistical analysis was done using SPSS (version 12). ÷ 2 test was used to analyze the association of agenesis with limb laterality and sex. The prevalence of palmaris longus agenesis was found to be 17.2% (8% bilateral and 9.2% unilateral). The prevalence of agenesis was significantly more common on the left side. Male subjects had a greater likelihood of unilateral agenesis, while female subjects were more likely to have bilateral agenesis. That prevalence of palmaris longus agenesis is race dependent is reaffirmed in the present study. Although the prevalence of palmaris longus agenesis in Indian patients was found to be much higher than the reported average prevalence in an Asian population, this tendon can still be counted on by surgeons treating Indian patients for use as a donor tendon, which will be present in a vast majority of Indian patients.

- by Akshay Kapoor
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- Skeletal muscle biology, Statistical Analysis, Adolescent, India

The purpose of this study was to describe the anatomy and characterize the biomechanics of the posterolateral aspect of the canine knee. Ten adult canine knees were each used for anatomy and biomechanical testing. Distances and motion limits were measured using a 6 degree-of-freedom electromagnetic tracking system. Canine knee dissection reproducibly identified structures present in the human posterolateral knee. The course and attachment sites of the fibular collateral ligament, popliteofibular ligament, and popliteus tendon were similar to human anatomy. Sequential sectioning of the fibular collateral ligament, popliteofibular ligament, and popliteus tendon all significantly increased varus translation at full extension, 608, and 908 of knee flexion. Sectioning of the fibular collateral ligament significantly increased external rotation at flexion angles near full extension, while popliteus tendon sectioning also significantly increased external rotation at 908 of knee flexion. Based on the fact that the anatomy of the fibular collateral ligament, popliteus tendon, popliteofibular ligament, and the biomechanical properties of the canine posterolateral knee are similar to the human knee, we believe the canine knee is a suitable model to study the natural history of posterolateral knee injuries. The canine model will also prove valuable in the validation of reconstruction techniques and studying the potential development of medial compartment osteoarthritis following posterolateral knee injuries. ß

- by Robert F . LaPrade
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- Biomedical Engineering, Orthopaedic, Dogs, Clinical Sciences

Total longitudinal disruptions of the interosseous membrane can allow proximal radius migration and are seen in Essex-Lopresti lesions. We propose an original technique of ligamentoplasty using the semitendinosus tendon. The graft corresponds to the forearm rotation axis for an optimized isometry and longitudinal stabilization. Our ligamentoplasty technique was performed on ten fresh frozen right forearms. We successively assessed the innocuousness, efficiency and resistance of the ligamentoplasty. The ligamentoplasty induced neither passive limitation of pronation -supination nor neurovascular lesions. It prevented from radius proximal migration. The mean load to failure was 28 kg at both ulnar and radial sides of the graft. Our technique is original for the type and position of the graft. It seems safe, efficient and resistant enough for in vivo procedures. This technique decreases longitudinal loads on the radius. It should be indicated in patients with Essex-Lopresti syndrome, in association with radial head internal fixation or arthroplasty.

- by Clarisse Lafont
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- Medical Physiology, Cadaver, Radius, Ulna

Results of mechanical analyses of running may be helpful in the search for the etiology of running injuries. In this study a mechanical analysis was made of the landing phase of three trained heel-toe runners, running at their preferred speed and style. The body was modeled as a system of seven linked rigid segments, and the positions of markers defining these segments were monitored using 200 Hz video analysis.

- by Maurice Yeadon
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- Mechanical Engineering, Biomedical Engineering, Biomechanics, Running

The purpose of this study was to determine if changes in triceps-surae tendon stiffness (TST K) could affect running economy (RE) in highly trained distance runners. The intent was to induce increased TST K in a subgroup of runners by an added isometric training program. If TST K is a primary determinant of RE, then the energy cost of running (EC) should decrease in the trained subjects. EC was measured via open-circuit spirometry in 12 highly trained male distance runners, and TST K was measured using ultrasonography and dynamometry. Runners were randomly assigned to either a training or control group. The training group performed 4 9 20 s isometric contractions at 80% of maximum voluntary plantarflexion moment three times per week for 8 weeks. All subjects (mean _ VO 2 max = 67.4 ± 4.6 ml kg -1 min -1 ) continued their usual training for running. TST K was measured every 2 weeks. EC was measured in both training and control groups before and after the 8 weeks at three submaximal velocities, corresponding to 75, 85 and 95% of the speed at lactate threshold (sLT). Isometric training did neither result in a mean increase in TST K (0.9 ± 25.8%) nor a mean improvement in RE (0.1 ± 3.6%); however, there was a significant relationship (r 2 = 0.43, p = 0.02) between the change in TST K and change in EC, regardless of the assigned group. It was concluded that TST K and EC are somewhat labile and change together.

- by Jared Fletcher
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- Skeletal muscle biology, Ultrasound, Running, Energy Metabolism

Purpose: The purpose of this study was to biomechanically evaluate several configurations of the Krackow stitch and determine which configuration provided the best fixation with regard to load to failure and elongation. Type of Study: Biomechanical study. Methods: Thirty fresh-frozen porcine Achilles tendons were randomly assigned into 6 groups. For 3 of the groups, 1 suture was used (No. 5 Ethibond; Ethicon, Somerville, NJ) with 2, 4, or 6 Krackow locking loops. For the other 3 groups, 2 sutures (interlocking and at 90°) with 2, 4, or 6 Krackow locking loops were used. Data were evaluated using analysis of variance. Results: There were no statistical differences in peak load to failure and elongation among any of the 1-suture techniques regardless of the number of locking loops (2, 290 N; 4, 302 N; and 6, 298 N; standard deviation, 25.2, 9.0, and 28.6, respectively). Similarly, there were no statistical differences among any of the 2-suture techniques regardless of the number of locking loops (2, 534 N; 4, 492 N; and 6, 505 N; standard deviation, 42.0, 65.4, and 76.3, respectively). There was, however, a significant difference (P Ͻ .05) in peak load to failure between the 1-suture and the 2-suture groups. The mechanism of failure was suture rupture in all cases. Conclusions: Load to failure did increase with the addition of a second interlocking suture placed at 90°to the first. Clinical Relevance: Tendon fixation with gap formation or suture rupture is at risk of failure. This study identifies that increasing the number of sutures is more important than increasing the number of locking loops.

- by John Fulkerson
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- Orthopedic Surgery, Treatment, Comparative Study, Method

Seventy-two patients with subacute or chronic rupture of the anterior cruciate ligament were randomly assigned to autograft reconstruction with four-strand gracilis and semitendinosus tendon (N = 37) or with patellar tendon-bone (N = 35) from the ipsilateral side. The groups were similar in terms of age, sex, level of activity, degree of laxity, meniscal lesions found surgically, and rehabilitation program. The follow-up was performed at another hospital by independent observers after 6, 12, and 24 months. Sixty-one patients (32 with hamstring tendon grafts and 29 with patellar tendon grafts) complied with the follow-up routine for the full 24 months. No differences were found between the groups with respect to Cincinnati functional score, KT-1000 arthrometer measurements, or stairs hopple test results. The subjective result and the single-legged hop test result were better for the hamstring tendon group after 6 and 12 months, but no differences were found after 24 months. The hamst...

- by May Risberg
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- Mechanical Engineering, Biomedical Engineering, Skeletal muscle biology, Adolescent

Magnetic resonance (MR) imaging is important in diagnosing musculoskeletal injuries in horses. However, there is still much to learn regarding the significance of lesions identified in equine MR images. Of particular importance is the clinical significance of signal change as a function of pulse sequence. We hypothesized that a resolution of tendon, ligament, and bone marrow lesions on short-tau inversion recovery (STIR) images would be associated with a return to soundness, and that a persistence of tendon and ligament lesions on only T1weighted (T1w) gradient recalled echo (GRE) images would not be associated with persistent lameness. The medical records and MR images of 27 horses that had a hyperintense lesion in initial STIR MR images followed by a subsequent follow-up MR imaging examination were reviewed. Horses whose tendon or ligament lesions had resolved on STIR images at the time of the recheck examination were significantly more likely to be sound than horses whose lesions persisted on STIR images (P ¼ 0.039). This association did not exist in horses with bone marrow lesions (P ¼ 1.00). Horses whose tendon or ligament lesions persisted only on T1w GRE images were no more likely to be sound than horses whose lesion persisted on at least one other sequence type (P ¼ 0.26). However, the low number of horses included in this analysis may have precluded identification of a significant difference in lameness status. Tendon or ligament lesions visualized on STIR images may represent active lesions that may contribute to lameness in the horse. r

- by Maureen Holowinski
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- Magnetic Resonance Imaging, Bone marrow, Horses, Veterinary Sciences

The vascular and microvascular anatomy ofthe equine deep digital flexor tendon (DDFT) within the digital sheath was studied by injecting the vasculature with either colored latex or barium sulphate for radiographic, microangiographic, histologic, and computed tomographic (CT) evaluation. Consecutive 4-mm thick two-dimensional CT slice data were reconstructed to 3-dimensional volumetric images to enhance spatial evaluation of the blood supply. Gross dissection and angiographic studies identified three major vascular sources. Above the fetlock, the DDIT was supplied by either a branch of the medial palmar artery (Arteriae digitalis palmaris communis 11) or a branch of the medial palmar digital artery (A. digitalis [palmaris propria 1111 medialis). Below the fetlock, the DDFT was supplied by branches from the lateral and medial palmar branches to the proximal phalanx (Ramus palmaris phalangis proximalis). The most distal aspect of the tendon received small branches from the medial and lateral palmar digital arteries. Using histology and microangiography we observed an extensive and uniform intratendinous vascular network above and below the fetlock, with a relatively avascular region of tendon palmar to the fetlock. The most distal 2.0 to 2.5 cm of the tendon within the sheath was heavily infiltrated with fibrocartilage along its dorsal aspect. @Copyrighi I995 by The American ColIege of Veterinary Surgeons NJURIES TO the tendon of the deep digital flexor From the

- by Carl Kirker-head
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- Skeletal muscle biology, Microcirculation, Horses, Veterinary Surgery

Purpose: Thumb carpometacarpal joint arthritis has been commonly treated with some combination of resection of the trapezium and interposition of a spacer using either a biologic or artificial material plus tenodesis to reconstruct the volar oblique ligament. The purpose of this study was to evaluate the biomechanic stability of the classic ligament reconstruction with tendon interposition (LRTI) or without tendon interposition compared with a newly developed 1-piece silicone trapezium implant. Methods: Twelve cadaver arm specimens had the following procedures: resection of the trapezium, tendon interposition, ligament reconstruction, LRTI, and the silicone implant. Biomechanic testing of joint stability was performed with a physiologic loading protocol before and after each procedure. Results: The implant significantly corrected the axial displacement after trapeziectomy and resulted in less radial displacement than LRTI. It significantly reduced angulation of the thumb metacarpal base but resulted in more rotation of the thumb during simulated pinch. There was no significant difference in stability measures between trapeziectomy and LRTI or ligament reconstruction without tendon interposition. Conclusions: We found several biomechanic advantages to the implant compared with LRTI. Advantages include reduction in axial and radial displacement and maintenance of the trapezial space. We attribute these advantages to the effect of the implant as a spacer. The significant rotation with the implant, however, raises questions concerning implant design and fixation. We found no biomechanic advantage to LRTI or ligament reconstruction without tendon interposition over trapeziectomy alone. (J Hand Surg 2007;32A:697-706.

- by Shai Luria
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- Biomechanics, Treatment, Osteoarthritis, Orthopedics

Objective To describe the normal MR anatomy and variations of the distal semimembranosus tendinous arms and the posterior oblique ligament as seen in the three orthogonal planes, to review the biomechanics of this complex and to illustrate pathologic examples. Results and conclusion The distal semimembranosus tendon divides into five tendinous arms named the anterior, direct, capsular, inferior and the oblique popliteal ligament. These arms intertwine with the branches of the posterior oblique ligament in the posterior medial aspect of the knee, providing stability. This tendon-ligamentous complex also acts synergistically with the popliteus muscle and actively pulls the posterior horn of the medial meniscus during knee flexion. Pathologic conditions involving this complex include complete and partial tears, insertional tendinosis, avulsion fractures and bursitis.

- by Luis Beltran
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- Skeletal muscle biology, Magnetic Resonance Imaging, Knee, Clinical Sciences

This systematic review explores management strategies for intraoperative anterior cruciate ligament (ACL) graft contamination. Two databases (Medline and EMBASE) were screened for studies involving ACL graft contamination published between 1946 and April 2013. We included studies evaluating the management of a contaminated graft and excluded small case-series studies. We conducted a full-text review of eligible studies, and the references were searched for additional eligible studies. Inclusion and exclusion criteria were applied to the searched studies. Our search yielded 6 laboratory investigations with a total of 495 graft samples used. These samples were contaminated and cleansed by various methods. The most successful sterilization protocols used chlorhexidine or mechanical agitation with a polymyxin B-bacitracin solution to achieve sterility in 100% of their respective experimental graft tissues. A chlorhexidine soak and plain bacitracin soak were also effective, at 97.5% and ...

- by Devin Peterson and +1
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- Anterior Cruciate Ligament, Sterilization, Clinical Sciences, Anti-Bacterial Agents

Injuries to the Anterior Cruciate Ligament (ACL) are becoming more frequent. Correspondingly there has been an increase in the number of ACL reconstructions performed, with more than 150,000 procedures documented annually in the United States. 1 This increase in primary ACL reconstructions almost certainly will lead to an increase in the number of revision procedures. A successful outcome after revision ACL reconstruction depends on many factors, including a comprehensive knowledge of the etiology of failure. There is no universally accepted definition of failure after ACL reconstruction. In most cases, however, the cause of failure may be grouped into one or a combination of the following: 1. Graft failure a. Pathologic laxity b. Clinical instability c. Nonfunctional or detrimental graft 2. Loss of motion

- by Timothy Whitehead
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- Mechanical Engineering, Anterior Cruciate Ligament, Infection, Risk factors

Forces, moments and stresses at the knee are dependent upon external and internal loading factors including muscle forces, segmental position and velocity, load carried, and the moment arms (mechanical advantage) of the muscletendon units. Requisite to prediction of forces and moments is a detailed understanding of effective moment arms throughout the knee range-of-motion (ROM). Existing muscle models for the knee are based upon limited static studies of only a few preserved specimens. The objectives of this report are to develop a comprehensive description of muscle-tendon moment arms for the normal knee and the anterior cruciate ligament (ACL)-minus knee during flexion-extension motion. Recent research results describe two nonorthogonal, nonintersecting axes of motion for the knee-one describing flexion-extension (FE) and the other longitudinal rotation (LR, equivalent to internal-external rotation). The effective flexion-extension moment arms of the muscles crossing the knee were developed with respect to the FE axis in 15 fresh, hemi-pelvis cadaver specimens. The normal moment arms for each of 13 muscles plus the patellar tendon exhibited variable, yet repeatable and recognizable patterns throughout the ROM. For most muscles there was no significant difference between the normal and ACL-minus moment arms. The results provide a basis for more accurate predictions of joint reaction forces and moments as well as useful knowledge for practitioners and therapists to assist in the assessment of muscle balance at the knee following injury, repair, and throughout rehabilitation.

- by Duc Nguyen
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- Rehabilitation, Skeletal muscle biology, Anterior Cruciate Ligament, Movement

Objective: To evaluate the usefulness and accuracy of fine needle aspiration cytology in the diagnosis of parotid gland tumors. Methods: We reviewed files of all patients who underwent parotidectomy for various parotid pathologies at Aga Khan University Hospital. Study design included a comparison between results of preoperative FNAC with final histopathological diagnosis. Galen & Ganbino method was used to calculate sensitivity and specificity of FNAC. Results: Among 50 patients reviewed, there was one false positive and 3 false negative results reported on FNAC. This gives a sensitivity of FNAC for reporting malignancy to be 74% and specificity to rule out malignancy 97%. No significant complications were reported while performing the procedure. Conclusion: FNAC is a safe and effective modality in diagnosis and treatment planning of patients with parotid tumors (JPMA 54:617;2004).

- by zafar ahmad
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- Pakistan, Crystallization, Adolescent, Wildlife Diseases

Purpose: There is significant debate concerning the morbidity of hamstring harvest for use during anterior cruciate ligament (ACL) reconstruction. We hypothesized that harvest of the semitendinosus and gracilis tendons for ACL reconstruction would result in no measurable hamstring weakness, but that abnormalities of the semitendinosus and gracilis muscle would be observed on magnetic resonance imaging (MRI) scans. Type of Study: Case series. Methods: Nine patients undergoing ACL reconstruction with doubled semitendinosus and gracilis tendons had MRI cross-sectional area measurements of both limbs made from axial images and muscle contour was studied on coronal images at 3 and 12 months. The semitendinosus, semimembranosus, gracilis, sartorius, and biceps muscles were evaluated. Isokinetic testing was performed on the operative and nonoperative legs at 60°and 180°per second at 6 and 12 months postoperatively. Results: The gracilis cross-sectional area at 1 year averaged 2 cm 2 on the operative side and 3.7 cm 2 on the contralateral side. The semitendinosus averaged 2.1 cm 2 on the operative side and 6.6 cm 2 on the contralateral side at 1 year. Both of these differences were statistically significant (P Ͻ .05). In most cases, the semitendinosus muscle was retracted. Distally, the gracilis and occasionally the semitendinosus were blending with the gastrocnemius or sartorial fascia. The gracilis and semitendinosus in 1 case extended to near the original attachment site. Hamstring strength testing revealed a 26% deficit on the operative side at 60°/second at 6 months and 16% at 180°/second. At 12 months the mean 60°/second deficit was 21% and the deficit at 180°/second was 13%. Conclusions: At 1 year, the semitendinosus and gracilis muscles showed significant and persistent atrophy on the operative side and frequent retraction of the semitendinosus muscle belly. There were also hamstring strength deficits persisting at 1 year after the use of the tendons for ACL reconstruction. Level of Evidence: Level IV.

The bouncing mechanism of human running is characterized by a shorter duration of the brake after ‘landing’ compared with a longer duration of the push before ‘takeoff’. This landing–takeoff asymmetry has been thought to be a consequence of the force–velocity relation of the muscle, resulting in a greater force exerted during stretching after landing and a lower force developed during shortening before takeoff. However, the asymmetric lever system of the human foot during stance may also be the cause. Here, we measure the landing–takeoff asymmetry in bouncing steps of running, hopping and trotting animals using diverse lever systems. We find that the duration of the push exceeds that of the brake in all the animals, indicating that the different lever systems comply with the basic property of muscle to resist stretching with a force greater than that developed during shortening. In addition, results show both the landing–takeoff asymmetry and the mass-specific vertical stiffness to be greater in small animals than in large animals. We suggest that the landing–takeoff asymmetry is an index of a lack of elasticity, which increases with increasing the role of muscle relative to that of tendon within muscle–tendon units.

- by Mario Legramandi and +1
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- Skeletal muscle biology, Locomotion, Biological Sciences, Elasticity

Divergence of the interference screw placement used for femoral fixation during endoscopically assisted reconstruction of the anterior cruciate ligament has been described. This study is a biomechanical evaluation in 12 pairs of fresh intact bovine knees of femoral interference screws placed divergently and parallel relative to the bone block and its tunnel. One knee of each pair had the interference screw placed in a parallel fashion and the other knee had a 15" divergence from the bone plug. Paired specimens were used to provide an optimal comparison of biomechanical data of the two different screw placements. No statistically significant differences were seen between the two groups when looking at ultimate load, deformation, and stiffness. Mode of failure was of more concern: in 4 of 12 divergent constructs, bone plug pullout occurred compared with only 1 of 12 in the parallel construct. The pullout strength remains high even with divergence of up to 15" between the bone plug and femoral interference screws placed endoscopitally. Key Words: Interference screws-fixation-divergent and parallel screw placement.

- by Mark Lemos
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- Anterior Cruciate Ligament, Femur, Arthroscopy, Statistical Significance

In a prospective study on ACL reconstruction we treated 17 patients with a "central third-bone-patellar tendon-bone" autograft (PT group) and 32 patients with a doubled semitendinosus/doubled gracilis autograft (HS group). Patients were reviewed at 6 weeks, and at 3, 6, and 12 months postoperatively and the groups compared. Up till 6 months, the KT-1000 side-to-side difference was significantly greater in the HS group (P<0.05) and at 6 and 12 months isokinetic hamstrings strength was lower (P<0.05). No significant differences were noted at any stage with respect to quadriceps strength, functional scores, range of motion, or swelling.

- by Johan Bellemans
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- Skeletal muscle biology, Treatment Outcome, Adolescent, Probability

Objective. The purpose of this investigation was to describe two sonographically guided popliteus tendon sheath injection techniques and determine their accuracy in a cadaveric model. Methods. A single experienced operator completed 24 sonographically guided popliteus tendon sheath injections, 12 using a longitudinal approach and 12 using a transverse approach relative to the tendon. The injection order was randomized, and all injections were completed with diluted colored latex. Coinvestigators blinded to the injection technique dissected each specimen and graded the colored latex location as accurate (in the sheath), accurate with overflow (within the sheath but also in other regions), or inaccurate (no latex in the sheath). Results. All 12 sonographically guided popliteus sheath injections using the longitudinal approach placed latex into the sheath. Eight of these injections (67%) also resulted in overflow into the knee joint. Ten of 12 transverse approach injections placed latex into the sheath (83%), with 7 of these (70%) also producing overflow into the knee joint. Two of 12 transverse injections (17%) placed latex only into the knee joint and were therefore inaccurate. Conclusions. Sonographic guidance can be used to inject the popliteus tendon sheath with a high degree of accuracy. Although the longitudinal approach is potentially more accurate, both approaches may result in injectate overflow into the knee joint, likely through the popliteus hiatus.

- by Troy Henning
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- Ultrasound, Medicine, Clinical Sciences, Reproducibility of Results
- by Freeman Miller
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- Mechanical Engineering, Skeletal muscle biology, Treatment Outcome, Cerebral Palsy

The lateral ligaments of talocrural articulation, namely anterior talofibular liga- ment, posterior talofibular ligament and cal- caneofibular ligament, are important in an- atomic reconstruction. If reconstructed improperly, they are known to limit the movements of talocrural articulation and sub- talar articulation (talocalcaneal articulation) Studies on anatomy of anterior talofibular lig- ament, posterior talofibular ligament and cal- caneofibular ligament known as the lateral ligaments have some discrepancies. Knowing

- by Muzaffer Sindel
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- Mechanical Engineering, Biomedical Engineering, Medicine, Anatomy

This prospective study examined 50 patients who underwent ACL surgery using hamstring tendons with a modification including intra- and extra-articular reconstruction. All patients were athletes competing at a high level in various sports. Full return to sports was allowed at 4 months. IKDC score and KT-2000 were used for assessing clinical outcome at a mean of 6.4 years (5-7 years) Resumption of sport, Tegner activity score, and isokinetic test were also used. The IKDC score showed 92% of normal or nearly normal knees. Of the 50 patients 48 regained full extension, and only two had extension deficit between 0 degrees and 3 degrees. KT evaluation was less than 3 mm in 38 cases (76%), 3-5 mm in 9 (18%), and more than 5 mm in 3 (6%). In 90% of cases the patient resumed sport at the same level. The mean Tegner activity score was 8.1 (5-10). The isokinetic test showed no deficit for hamstring and quadriceps muscles. Removal of staples was necessary in eight cases (16%) due to femoral lat...

- by Stefano Zaffagnini and +1
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- Pain, Treatment Outcome, Adolescent, Linear models

We present a patient with a history of revision trigger release who experienced post-surgery limitation of active flexion as a result of bowstringing of the flexor tendons and required a double loop pulley reconstruction using a palmaris... more

- by Corey Pacek
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- Surgery, Treatment, Orthopedics, Recurrence

Seventeen cerebral palsy patwnts (29 hips) underwent psoas recession at the Hugh Williamson Gait Laboratory, Royal ChiMren"s Hosp~titl. Mcihour~e~ pelvic brim !&erhodo/o~: The operative technique is a direct anterior approach lateral to the femoral sheath All of the subrects underwent pre-and postoperative gait analysis. i<e.wl/.% There were no mfect~ons, nerve or arterial injuries. Following surgery, clinical cxammtion revealed that fixed hip flexion contractures decreased significantly in all patients. All of the subjeas retained the ability to flex the hip against gravity and agaiost manual resistance. Stance phase dynamic minimum hip flexion decreased significrottly. Dyoamic pelvic tilt did improve to a statistically sign&ant level for the younger children but did not for the group as a whole There w+s less improvement with increasing age Step length wns significantly increased and cadence significantlv decreased in all patients. 1)I.~~IJIO~I: We conclude that psoas recession at the pelvic brim, using the anterior approach, lateral to the femoral sheath, is a safe, reliable, and effective procedure for children with cerebral palsy who have excessive anterior pelvic tilt and excessive dynamic hip flexion or hip flexion c*ntraCt"re Session Five

- by Kenton Kaufman
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- Mechanical Engineering, Treatment Outcome, Cerebral Palsy, Adolescent

In order to determine the mechanical properties of the fibro-osseous pulleys in the hand, the diaphyseal annular pulleys, the volar plate annular pulleys and the cruciate or condensable portions were tested. A custom-made loading device provided proper fit of the soft tissues for a uniform distribution of the pulley load during testing. The A2 pulley was found to be the strongest of the pulleys; the Al and A4 were the next strongest. The A3 pulley was nearly equal in mean breaking strength to the other annular pulleys, but in absolute breaking load was considerably weaker because of its shortness. The A4 was the least compliant of the pulleys. We concluded that the fibro-osseous A2 and A4 were mechanically stronger and stiffer pulleys than the Al, A3, A5 (volar plate) pulleys. In testing one type of pulley reconstruction, we found that the "belt loop" technique of Karev nearly matched the annular pulleys in strength and energy absorption.

- by William Cooney
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- Clinical Sciences, Cadaver, Tendons, Finger Joint

While the increased incidence of serious knee injuries in female athletes is well established, the underlying neuromuscular mechanisms related to the elevated ACL injury rate has yet to be delineated. Video analysis of ACL injury during competitive sports play indicates a common body position associated with non-contact ACL injury; the tibia is externally rotated, the knee is close to full extension, the foot is planted and as the limb is decelerated it collapses into valgus. The purpose of the current prospective study was to evaluate gender differences in quadriceps muscle activation strategies when performing a physically challenging, but reproducible maneuver that mimics the high ACL injury risk position (in the absence of high velocity and high loads). Twenty physically active college-aged subjects (10 male and 10 female) performed multiple sets of the prescribed exercise. EMG recordings were employed to measure the ratio of activation between the medial and lateral quadriceps during the 4, 8, 12, 16, and 20th sets of exercise. Females demonstrated decreased RMS medial-to-lateral quadriceps ratios compared to males (F(1,18) = 5.88, p = 0.026). There was no main effect of set number on RMS quadriceps ratio (p > 0.05). The results of this study suggest that females utilize neuromuscular activation strategies which may contribute to ''dynamic valgus'' and ACL rupture when performing high-risk maneuvers.

Purpose: A new and increasingly popular suture material, Fiberwire, allows for strong flexor tendon repair that may allow early active rehabilitation. The purpose of this biomechanic study was to evaluate the mechanical characteristics of... more

- by Shai Luria
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- Clinical Sciences, Cadaver, Aged, Hand