Tendon Segments Research Articles

Reconstruction of neglected patellar tendon ruptures using the quadriceps graft.

Several techniques using different grafts have been described for reconstruction of the patellar tendon after a neglected rupture. Retraction of the quadriceps tendon may compromise repair integrity due to progressive stretching of the graft. The authors present a surgical technique using the central one-third of the quadriceps tendon. This is supported by the fact that the resistance to traction of this segment of the quadriceps tendon equals that of a double-looped semitendinosus graft and that the harvesting of this specific graft promotes muscle inhibition, thus protecting the reconstruction during the recovery period.

Extended Reverse Dorsal Metacarpal Artery Flap for Coverage of Finger Defects Distal to the Proximal Interphalangeal Joint

Finger reconstruction distal to the proximal interphalangeal (PIP) joint is a challenging task for hand surgeons. Although extended reverse dorsal metacarpal artery (RDMA) flaps were described for coverage of finger defects, reports on repairs beyond the PIP joint are limited. The occurrence of venous congestion of the flaps and their treatments require further clarification. Extended RDMA flaps were used to cover the finger defects extending from the PIP joints to the fingertips in a series of 16 patients. The reconstructed fingers included the index, middle, ring, and little fingers; thumb reconstruction was not included in this study. The flap size ranged from 2.5×1.8 to 5×3 cm. A composite flap with a segment of tendon was applied for a complex reconstruction in 4 cases. Either superficial branch of radial nerve or dorsal branch of ulnar nerve was included in flap elevation because of its perineural vascular network contributing to the flap perfusion. The pivot point was located at the level of the middle point of the proximal phalanx, where the communicating branches between the proper palmar digital artery and the dorsal metacarpal artery exist. A teardrop skin pedicle was used to reduce the tension of the flap pedicle. All flaps totally survived except that 1 flap had epidermal loss later salvaged by secondary skin grafting. Venous congestion occurred in the distal part of 5 flaps and was effectively relieved after multiple subcutaneous heparin injections. Neither of the 2 cases of nerve repair resulted in significant improvement in sensation. All donor sites were primarily closed. Extended RDMA flaps can be effectively applied in the reconstruction of finger defects beyond PIP joint. Its advantages include a simple dissection, single-stage reconstruction, and preservation of digital artery and nerve. The donor site can be primarily closed if the flap width is less than 3 cm. Multiple subcutaneous heparin injection is a preferred solution in cases where venous congestion occurs in the flap.

The Effect of Asymmetric Core Suture Purchase on Gap Resistance of Tendon Repair in Linear Cyclic Loading

To evaluate the biomechanical properties of an asymmetric core suture for tendon repair. Sixty porcine flexor tendons were repaired with 3 different 4-strand sutures using different core suture purchases: 2 sets of identical purchases of 10 mm, 2 sets of asymmetric purchases (8 mm proximal/distal stump and 12 mm distal/proximal stump), and 2 sets of identical purchases of 12 mm. The tendons were subjected to the cyclic loading for 20 cycles. The number of tendons with gaps at each cycle, elongation of gap area between tendon ends and tendon segment, gap formation forces, and ultimate strengths were recorded. Tendons repaired with the asymmetric core suture purchases had the smallest gaps during cyclic loading. The elongation of gaps and tendon segments were significantly smaller than those with symmetric suture purchase of 10 or 12 mm. The asymmetric core suture repair had significant higher gap resistance forces than the symmetric suture repair at the final loading cycle. A 4-strand core suture repair with asymmetric purchases on the tendon stumps generated greater gapping resistance than that with an equal length of suture purchase. The asymmetric core suture purchase may be a practical measure to improve gapping resistance and fatigue strength when the suture purchase meets essential length requirements.

MRI T2 mapping of the asymptomatic supraspinatus tendon by age and imaging plane using clinically relevant subregions

PurposeDiagnosis of partial rotator cuff tears and tendonopathy using conventional MRI has proven variable. Quantitative T2 mapping may have application for assessing rotator cuff health. In order to evaluate the usefulness of T2 mapping for the rotator cuff, methods must be refined for mapping the supraspinatus tendon, and normative T2 values must first be acquired. Materials and methodsThis study was IRB approved. Thirty asymptomatic volunteers (age: 18–62) were evaluated with sagittal and coronal T2 mapping sequences. Manual segmentation of tendon and muscle as a unit and tendon alone was performed twice by two independent raters. Segmentations were divided into medial, middle and lateral subregions and mean T2 values calculated. ResultsAnatomic comparison of mean T2 values illustrated highest values in the medial region, lowest values in the lateral region, and intermediate values for the middle region upon coronal segmentation (p<0.001). In sagittal segmentations, there were higher values in the medial region and no significant differences between the lateral and middle subregions. No significant differences were found with comparison across age groups. Inter and intra-rater segmentation repeatability was excellent, with coefficients ranging from 0.85 to 0.99. ConclusionT2 mapping illustrated anatomic variation along the supraspinatus muscle-tendon unit with low standard deviations and excellent repeatability, suggesting that changes in structure due to degeneration or changes associated with healing after repair may be detectable.

Biomechanical Evaluation of Various Suture Configurations in Side-to-Side Tenorrhaphy

Side-to-side tenorrhaphy is increasingly used, but its mechanical performance has not been studied. Two porcine flexor digitorum tendon segments of equal length (8 cm) and thickness (1 cm) were placed side by side. Eight tenorrhaphies (involving sixteen tendons) were performed with each of four suture techniques (running locked, simple eight, vertical mattress, and pulley suture). The resulting constructs underwent cyclic loading on a tensile testing machine, followed by monotonically increasing tensile load if failure during cyclic loading did not occur. Clamps secured the tendons on each side of the repair, and specimens were mounted vertically. Cyclic loading varied between 15 N and 35 N, with a distension rate of 1 mm/sec. Cyclic loading strength was determined by applying a force of 70 N. The cause of failure and tendon distension during loading were recorded. All failures occurred in the monotonic loading phase and resulted from tendon stripping. No suture or knot failure was observed. The mean loads resisted by the configurations ranged from 138 to 398 N. The mean load to failure, maximum load resisted prior to 1 cm of distension, and load resisted at 1 cm of distension were significantly lower for the vertical mattress suture group than for any of the other three groups (p < 0.031). All four groups sustained loads well above the physiologic loads expected to occur in tendons in the foot and ankle (e.g., in tendon transfer for tibialis posterior tendon insufficiency). None of the four side-to-side configurations distended appreciably during the cyclic loading phase. The vertical mattress suture configuration appeared to be weaker than the other configurations. For surgeons who advocate immediate loading or motion of a side-to-side tendon repair, a pulley, running locked, or simple eight suture technique appears to provide a larger safety margin compared with a vertical mattress suture technique.

Effects of achilles tendon immersion in saline and perfluorochemicals on T2 and T2*

To determine if immersion of Achilles tendon segments into various solutions improved qualitative delineation of tendon and affected quantitative MR values of T2 and T2*. Six Achilles tendons were dissected, sectioned (proximal, midportion, and distal tensile pieces) and imaged at 3T both at baseline in air and after immersion into saline, Fomblin, and perfluorooctyl bromide (PFOB), respectively, for 24 h. Blinded readers qualitatively assessed the delineation of tendon boundaries and quantitatively Carr-Purcell-Meiboom-Gill (CPMG) T2 and ultrashort echo time (UTE) T2* was calculated. Comparison between images obtained in air and in solution was made. On qualitative evaluation, all images obtained in air had larger air-tissue susceptibility effects. Mean T2 values of saline, Fomblin, and PFOB groups were 16.1 ± 3.7, 16.6 ± 2.9, and 18.8 ± 2.6 ms at baseline in air, and 14.8 ± 4.6, 15.9 ± 3.0, and 17.7 ± 3.0 ms after immersion in the fluid, respectively. Mean T2* values of saline, Fomblin, and PFOB groups were 2.0 ± 0.8, 1.6 ± 0.5, and 1.5 ± 0.5 ms at baseline in air, and 2.1 ± 0.5, 1.6 ± 0.5, and 1.4 ± 0.5 ms after immersion in the fluid, respectively. There was no significant effect of immersion or fluid type on measured T2 or T2* (P > 0.1). These results validate the continued use of these solutions to prevent tendon specimen dehydration and to minimize susceptibility effects.

Single Longitudinal Dorsal Incision Approach to Transfer the Flexor Digitorum Longus Tendon Between the Flexor Digitorum Brevis Hemitendons

Transposition of the flexor digitorum longus tendon has been widely reported for the correction of flexible claw and hammertoe deformities. The most common technique uses two cutaneous incisions, one plantar and another dorsal. We performed a cadaveric study to determine whether the flexor digitorum longus tendon could be transferred to the dorsum of the proximal phalanx of the toe from its lateral or medial aspect through a unique single longitudinal central dorsal incision. The rationale for this novel approach was to minimize the risk of vascular compromise to the digit associated with the two-incision approach. Transposition of the flexor digitorum longus tendon was attempted in 120 toes of cadaveric feet (60 each second and third digits) through a central longitudinal dorsal incision. The flexor digitorum longus tendon segment was long enough to be successfully transposed between the flexor digitorum brevis hemitendons of the second and third toes in 100% of the cases using the central longitudinal dorsal incision approach, with a resection arthroplasty at the proximal interphalangeal joint. Transfer of the flexor digitorum longus tendon to the dorsum of the proximal phalanx can be performed for the correction of claw and hammertoe deformities in the second and third digits. The meticulous longitudinal incision of the flexor tendon sheath to expose the flexor digitorum brevis tendon and its longitudinal incision are essential to the successful transfer of the flexor digitorum longus tendon between the flexor digitorum brevis hemitendons.

Massage-induced morphological changes of dense connective tissue in rat’s tendon

The aim of the experiment was to determine if possible changes in connective tissue induced by massage could have a positive effect justifing the use of massage in all post-traumatic connective tissue conditions, e.g. tendon injuries. The investigations were performed in a group of 18 Buffalo rats. The rats were divided into two groups (experimental and control). To standardize the massage procedure, it was performed with an algometer probe of 0.5 cm2 with constant pressure force of 1 kG (9,81 N). To analyse the number and diameter of collagen fibrils, two electron micrographs were performed for each rat of the collected segments of tendons of rat tail lateral extensor muscle. After image digitalization and calibration, the measurements were carried out using iTEM 5.0 software. The number of fibrils, their diameter and area were measured in a cross-sectional area. An increase of the number of collagen fibrils was observed in the tendons of massaged animals compared to the control group. Our study demonstrated that massage may cause a beneficial effect on metabolic activity of tendon's fibroblasts and, in consequence, may be applied for more effective use of massage for the prevention of tendon injury as well as after the injury has occurred. (Folia Histochemica et Cytobiologica 2013, Vol. 51, No. 1, 103-106).

Muscles - histology, micro/macroanatomy and US anatomy, a brand new perspective.

With a great joy did I receive the publication of anatomical-ultrasonographic interpretation of muscle structure developed by Dr. Zbigniew Czyrny(1). I encouraged him into writing such a publication many years ago when this concept appeared and was being improved as Dr. Czyrny gained more and more experience in looking at muscles from his new perspective. The most significant in Dr. Czyrny's work on muscle structure understanding for me as an anatomist are two phenomena: methodological and cognitive. Dr. Czyrny did not discover new structures because all of them have been perfectly known for many years – both the structure of endomysium and perimysium as well as the presence of intramuscular tendon segments. A truly new contribution of Dr. Czyrny is the fact that basing on the meticulous observation of many clinical cases, he combined the known, but so far not related structures in a one logical whole. In this way he gave them new functional meaning of important diagnostic and pathophysiological implications. This mechanism is possible particularly in anatomy, or perhaps wider – morphology where the sum of combined facts allows for the creation of innovative coherent concepts. This can be successfully done not only by anatomists but also the doctors capable of sufficiently holistic and unusual thinking in order to combine the known facts and their own observations and to give them a new meaning. For myself Dr. Czyrny's investigation was so significant and inspiring that I created a research team in the Department of Descriptive and Clinical Anatomy in the Center of Biostructure Research of Medical University of Warsaw carrying on an extensive study on the inner muscle structure on the macroscopic level. I am convinced that Dr. Czyrny's concepts force the revision of many myological stereotypes and in some sense create a field for writing myology from scratch. The reading of Dr. Czyrny's work should be recommended to radiologists and also anatomists, histologists, physiologists, biomechanics, neurologists, orthopedic surgeons and physiotherapists, to the ones for whom the musculoskeletal system is an important element of everyday research work and medical practice.

Effects of Tension Across the Tendon Repair Site on Tendon Gap and Ultimate Strength

Tendons repaired with varying amounts of tension result in different degrees of shortening of the tendon segment within core sutures, which may affect tensile strengths. We aimed to investigate the effects of tension across the repair site on gap formation forces and ultimate strength. Fifty-seven porcine flexor tendons were repaired with a 2-strand modified Kessler repair or a 4-strand cross-lock repair. For each type of repair, the tendons were divided into 3 groups: by 0%, 10%, or 20% shortening of tendon segment encompassed within core sutures. The repaired tendons had a single load-to-failure test in a materials testing machine. The forces required for initial and 2-mm gap formation and ultimate failure were recorded and statistically compared for each group. With either 2-strand or 4-strand repair, the tendons in the 10% tendon-segment shortening group withstood significantly higher initial and 2-mm gap formation forces than those in the group with no shortening, with average increases of 5 to 10 N after 10% shortening. Increasing the tendon-segment shortening to 20% produced a slight increase in the initial and 2-mm gap forces compared with those with 10% shortening, which was statistically significant only in the tendons with the 4-strand repair. The ultimate strengths were not significantly different among the tendons with either 2-strand or 4-strand repair of any degrees of shortening. Tensioning the core suture to shorten its encompassed tendon segment by 10% substantially increases resistance to postoperative gapping. Further tensioning to produce 20% shortening of the tendon segment increased the gapping forces by a much smaller amount. This study suggests that a slightly tensioned surgical repair, shortening the encompassed tendon segment by approximately 10%, is appropriate. Slightly tensioning core sutures across the tendon repair site, such as adding tension to cause 10% tendon-segment shortening, would greatly increase the gap resistance of the surgical repair.

Axial speed of sound is related to tendon's nonlinear elasticity

Axial speed of sound (SOS) measurements have been successfully applied to noninvasively evaluate tendon load, while preliminary studies showed that this technique also has a potential clinical interest in the follow up of tendon injuries. The ultrasound propagation theory predicts that the SOS is determined by the effective stiffness, mass density and Poisson's ratio of the propagating medium. Tendon stiffness characterizes the tissue's mechanical quality, but it is often measured in quasi-static condition and for entire tendon segments, so it might not be the same as the effective stiffness which determines the SOS. The objectives of the present study were to investigate the relationship between axial SOS and tendon's nonlinear elasticity, measured in standard laboratory conditions, and to evaluate if tendon's mass density and cross-sectional area (CSA) affect the SOS level. Axial SOS was measured during in vitro cycling of 9 equine superficial digital tendons. Each tendon's stiffness was characterized with a tangent modulus (the continuous derivative of the true stress/true strain curve) and an elastic modulus (the slope of this curve's linear region). Tendon's SOS was found to linearly vary with the square root of the tangent modulus during loading; tendon's SOS level was found correlated to the elastic modulus's square root and inversely correlated to the tendon's CSA, but it was not affected by tendon's mass density. These results confirm that tendon's tangent and elastic moduli, measured in laboratory conditions, are related to axial SOS and they represent one of its primary determinants.

Comparison of modified Kessler tendon suture at different levels in the human flexor digitorum profundus tendon and porcine flexors and porcine extensors: an experimental biomechanical study

This study compared the biomechanical behaviour of repairs in the human flexor digitorum profundus tendon in zones I, II and III with repairs of different segments of the porcine flexor tendon of the second digit and the extensor digiti quarti proprius tendon, in order to assess the validity of porcine tendons as models for human flexor tendon repairs. These porcine tendons were selected after comparing their size with the human flexor digitorum profundus tendon. The tendon repairs were done in three segments of each porcine tendon and repairs in the human tendons were done in zones I,II and III. Ten tendons in each group yielded a total of 90 specimens. A modified Kessler repair was done with 3-0 coated braided polyester suture and subjected to uniaxial tensile testing. In human flexor tendons, the ultimate force was higher in zones I and II than in zone III. The porcine flexor digitorum profundus tendon from the second digit and the proximal segment of the extensor digiti quarti proprius tendon behaved similarly to the human flexor tendon in zone III and can be considered as surrogates for the human flexor tendon.

Three-Dimensional-Construct Bioreactor Conditioning in Human Tendon Tissue Engineering

Human tendon tissue engineering attempts to address the shortage of autologous tendon material arising from mutilating injuries and diseases of the hand and forearm. It is important to maximize the tissue-engineered construct's (TEC's) biomechanical properties to ensure that the construct is in its strongest possible state before reimplantation. In this study, we sought to determine the bioreactor treatment parameters that affect these properties. Using small- and large-chamber three-dimensional-construct bioreactors (SCB and LCB, respectively), we applied cyclic axial load to TECs comprising reseeded human flexor and extensor tendons of the hand. First, small-sample pilot studies using the LCB were performed on matched-paired full-length flexor tendons to establish proof of concept. Next, large-sample studies using the SCB were performed on matched-paired extensor tendon segments to determine how reseeding, load duty cycle, load magnitude, conditioning duration, and testing delay affected ultimate tensile stress (UTS) and elastic modulus (EM). We found that compared with reseeded matched-paired controls under dynamic-loading at 1.25 N per TEC for 5 days, (1) acellular TECs had lower UTS (p=0.04) and EM (p<0.01), (2) unloaded TECs had lower UTS (p=0.01) and EM (p=0.02), (3) static-loaded TECs had lower UTS (p=0.01) and EM (p<0.01), (4) TECs conditioned for 3 days had lower UTS (p=0.03) and EM (p=0.04), and (5) TECs conditioned for 8 days had higher UTS (p=0.04) and EM (p=0.01). However, TECs conditioned at higher loads (2.5 N per TEC) and lower loads (0.625 N per TEC) possessed similar UTS (p=0.83 and p=0.89, respectively) and EM (p=0.48 and p=0.89, respectively) as controls stimulated with 1.25 N per TEC. After cycle completion, there is attrition of UTS (p=0.03) and EM (p=0.04) over a 2-day period. Our study showed that the material properties of human allograft TECs can be enhanced by reseeding and dynamic-conditioning. While conditioning duration has a significant effect on material properties, the load magnitude does not. The issue of attrition in biomechanical properties with time following cycle completion must be addressed before bioreactor preconditioning can be successfully introduced as a step in the processing of these constructs for clinical application.

The Medial Sural Artery Perforator Flap: A Versatile Donor Site for Hand Reconstruction

The challenge of modern hand reconstruction goes beyond simple coverage. Thanks to the advances of microsurgery, there are ever-improving standards of functional and esthetic outcomes in hand reconstruction. The versatile donor site of the medial sural artery perforator flap can fulfill this purpose. Between June 2006 and October 2008, we used free medial sural artery perforator flaps for hand reconstruction in 14 cases. The sites of reconstruction included digits (n=7), dorsal hand (n=3), palmar hand (n=2), and wrist (n=2). Associated tendon and nerve defects were found in five patients. The plantaris tendon (n=4), split Achilles tendon (n=1), saphenous nerve (n=1), and sural nerve (n=1) were harvested for reconstructive purpose from the same donor site in this series. The proximal perforator of the medial sural artery emerged 8 cm to 13 cm from the midpoint of the popliteal crease, correlating with the axis of the medial sural artery. Twelve flaps were raised with a single perforator. One flap failed because of perioperative vasospasm. The donor defect could be closed without skin grafts when the flap width was <6 cm. The free medial sural artery perforator flap transfer is appropriate for small- to medium-sized hand defect reconstruction. The donor site not only supplies a thin fasciocutaneous flap but also provides the option to harvest a segment of tendon or nerve graft through the same incision for composite tissue reconstruction in a single stage.

Intraoperative Ultrasonography During Percutaneous Achilles Tendon Repair

The purpose of the study was to determine whether real-time intraoperative ultrasonography improved implant positioning and stump approximation in patients with acute Achilles tendon rupture managed percutaneously. The needles were introduced percutaneously without ultrasonography and their position was checked relative to cutaneous landmarks and by palpation. Then, intraoperative ultrasonography was performed to assess needle position at the proximal tendon segment, tendon tear, and distal tendon segment. Incorrectly placed needles were removed and reinserted under real-time ultrasonographic guidance. Tendon apposition was checked ultrasonographically. We included 21 patients (19 males, two females) with unilateral acute Achilles tendon rupture, in whom 42 needles (one medial and one lateral) were inserted. Correct positioning was achieved without ultrasonographic guidance for 19 (45%) needles overall, 15 of 21 (71%) medial needles, and four of 21 (19%) lateral needles. The remaining 23 needles were correctly repositioned under ultrasonographic guidance. The correct positioning rates with and without ultrasonography differed significantly for all needles (p < 0.0001) and for lateral needles (p < 0.0001) but not for medial needles (p = 0.03). Intraoperative ultrasonography confirmed tendon stump approximation in all cases. Without imaging, 55% of needles were correctly positioned. Intraoperative ultrasonography allowed correct positioning of all needles and provided intraoperative confirmation of stump approximation.

Achillessehnen- und Tibialis-anterior-Sehnenruptur

Achilles tendon ruptures (ATR) are becoming the most frequent tendon rupture of the lower extremity, whereas less than 100 cases of tibialis anterior tendon ruptures (TATR) have been reported. Common in both tendons are the degenerative causes of ruptures in a susceptible tendon segment, whereas traumatic transections occur at each level. Triceps surae and tibialis anterior muscles are responsible for the main sagittal ankle range of motion and ruptures lead to a distinctive functional deficit. However, diagnosis is delayed in up to 25% of ATR and even more frequently in TATR. Early primary repair provides the best functional results. With progressive retraction and muscle atrophy delayed tendon reconstruction has less favourable functional results. But not all patients need full capacity, power and endurance of these muscles and non-surgical treatment should not be forgotten. Inactive patients with significant comorbidities and little disability should be informed that surgical treatment of TATR is complicated by high rates of rerupture and surgical treatment of ATR can result in wound healing problems rarely necessitating some kind of transplantation.

Emerging Ideas: Soft Tissue Applications of Radiostereometric Analysis

Currently, the movement that occurs at the site of soft tissue repair cannot be measured accurately in vivo. Radiostereometric analysis (RSA) is the gold standard for measuring movement between two skeletal segments in vivo but its application to studying soft tissue migration has been limited by the unknown stability of tantalum beads in tendons and ligaments and their ability to define rigid bodies in these structures. RSA can be used to accurately measure movement between two tendon segments or between a bony and a tendon segment in vivo. The stability of tantalum beads and the ability to use such beads to define rigid bodies in some soft tissues will be investigated in animal models of tendon repair. Several tantalum bead insertion techniques will be tested using in vivo RSA measurements of bead movement followed by morphologic studies of the repaired tendon and soft tissue reaction to the tantalum beads. RSA performed on tantalum beads encapsulated in muscles and tendons could be a powerful new tool to study the in vivo motion at the site of soft tissue repairs, for instance, the tendon gap formation. If RSA could be used to evaluate the efficiency of different tendon repair techniques in vivo, enhanced rehabilitation protocols could be developed and complications associated with prolonged protection or failure of repair could be reduced.

Neuropeptide, Mast Cell, and Myofibroblast Expression After Rabbit Deep Flexor Tendon Repair

Increased numbers of myofibroblasts, mast cells, and neuropeptide-containing nerve fibers have been found in a number of fibrotic processes in connective tissues. The purpose of the present study was to investigate the occurrence of factors implicated in a hypothesized profibrotic neuropeptide-mast cell-myofibroblast pathway in deep flexor tendon healing. In a rabbit model of flexor tendon injury, with repair of the sharply transected deep flexor tendon using a modified Kessler and a running circumferential peripheral suture, segments of flexor tendons and sheaths were analyzed. The time points chosen-3, 6, 21, and 42 days after tendon repair-represent different stages in tendon healing. The messenger RNA levels of transforming growth factor-β1 and α-smooth muscle actin were measured with conventional reverse transcription-polymerase chain reaction, and the numbers of myofibroblasts, mast cells, and neuropeptide-containing nerve fibers were determined with immunohistochemistry. The messenger RNA levels for transforming growth factor-β1 and the myofibroblast marker α-smooth muscle actin were significantly increased in deep flexor tendons after injury and repair, at all studied time points, but remained unchanged or even down-regulated in the sheaths. Myofibroblasts, mast cells, and neuropeptide-containing nerve fibers all increased significantly in the healing tendons, exhibiting similar patterns of change in percentages of total cell number over time, reaching levels resembling that of the tendon sheaths with 33% to 50% of the total cell population. After injury to the deep flexor tendon in a rabbit model, the proportion of myofibroblasts, mast cells, and neuropeptide-containing nerve fibers increases significantly. These findings support the hypothesis that the profibrotic neuropeptide-mast cell-myofibroblast pathway is activated in deep flexor tendon healing.

The Effect of Seprafilm on Adhesion Formation and Tendon Healing After Flexor Tendon Repair in Chicken

Adhesion of the tendon, which can occur during healing of tendon repair, is negatively affected by the outcome of surgery. In this experimental study, we sought to prevent adhesion of the tendon, and determined the mechanical stiffness of repair tissue by wrapping sodium hyaluronate and carboxymethylcellulose (Seprafilm; Genzyme, Cambridge, Massachusetts) around the repaired tendon segments. The study group comprised 2 groups of 20 chickens. In group I, the right gastrocnemius tendons of the chickens were cut smoothly, and after tendon and sheath repair, the skin was sutured. In group II, the right gastrocnemius tendons of the chickens were cut, the tendons were repaired, and before skin closure, Seprafilm was wrapped around the repaired tendon segments. Plastic splints were used for holding the chickens' ankles in a neutral position, and they were allowed weight bearing for 8 weeks. In group II, anatomic space between the tendon-sheath and tendon was clear and the tendon-sheath complex was sliding easily around the repaired tendon segment, and this complex was more functional both biomechanically and histologically. Also, the Seprafilm-applied tendons (group II) were observed to be biomechanically more resistant to the tensile forces in group I. Seprafilm is an easily applied interpositional material that can be used safely to prevent adhesion during the tendon healing process.

Ultrasound B‐scan image simulation, segmentation, and analysis of the equine tendon

The hypothesis is that an imaging technique based on decompression and segmentation of B-scan images with morphological operators can provide a measurement of the integrity of equine tendons. Two complementary approaches were used: (i) Simulation of B-scan images to better understand the relationship between image properties and their underlying biological structural contents and (ii) extraction and quantification from B-scan images of tendon structures identified in step (i) to diagnose the status of the superficial digital flexor tendon (SDFT) by using the proposed imaging technique. The simulation results revealed that the interfascicular spaces surrounding fiber fascicle bundles were the source of ultrasound reflection and scattering. By extracting these fascicle bundles with the proposed imaging technique, quantitative results from clinical B-scan images of eight normal and five injured SDFTs revealed significant differences in fiber bundle number and areas: mean values were 50 (+/- 11) and 1.33(+/- 0.36) mm2 for the normal SDFT data set. Different values were observed for injured SDFTs where the intact mean fiber bundle number decreased to 40 (+/- 7) (p = 0.016); inversely, mean fiber bundle areas increased to 1.83 (+/- 0.25) mm2 (p = 0.008), which indicate disruption of the thinnest interfascicular spaces and of their corresponding fiber fascicle bundles where lesions occurred. To conclude, this technique may provide a tool for the rapid assessment and characterization of tendon structures to enable clinical identification of the integrity of the SDFT.