This study quantified mechanical and structural responses to loading conditions at subtendon hierarchical levels. Tensile tests were performed at three strain rates on three groups of rabbit patellar tendon specimens. For each rate, tangent modulus (E) was computed from the stress-strain curves and the following structural responses were evaluated: (i) Area percent of collagen fibrils (FAR) and (ii) Skewness angle formed between proteoglycans and collagen fibrils. For 0.1%/s, 10%/s, and 70%/s, E was 48.8±20.3MPa, 64.7±29.3MPa, and 78.6±31.7MPa, respectively. For control, 0.1%/s, 10%/s, and 70%/s, the mean FAR was 0.7552±0.1476, 0.6628±0.1190, 0.6335±0.1013, and 0.6047±0.0384, respectively; and proteoglycan skewness angles were 14.70º±11.01º, 12.76º±10.13º, 15.08.0º±11.66º, and 16.68º±12.07º, respectively. For increased E, interfibrillar components had less time for effective fluid flow, energy dissipation, and structural rearrangement. The inverse relationship of FAR to strain rate may be due to broken fibrils and the Poisson effect. Proteoglycan skewness angle increase is likely due to stretched fibrils.

No description available.

archives@tulane.edu / The patellar tendon transmits loads from the quadriceps to the tibia promoting locomotion. The main etiological factor behind patellar tendinopathies is thought to be excessive loading and unloading during athletic activity (Pearson & Hussain, 2014). The extracellular matrix (ECM) composition and fibroblast-like tenocytes dictate tendon’s uniaxial mechanical properties (Kannus, 2000). Following injury, a flood of inflammatory cells and spike in certain gene expressions work together to remove damaged tissue, trigger fibroblast proliferation, and deposit a provisional collagen matrix (Thomopoulos et al., 2015). Despite these processes, healed tendons demonstrate significant functional deficits (Mienaltowski et al., 2016). Moreover decrease in cell migration and fiber alignment with age further hampers healing outcomes(Dunkman et al., 2013). Efforts to restore tendon function are impeded by a lack of understanding of the early healing process, which may be age- and sex-dependent (Fryhofer et al., 2016; Mienaltowski et al., 2016). The tendon healing process can be further understood using an agent-based model (ABM). ABMs simulate individual agents and the interactions between them and their environment. This approach has the advantage of building complexity from the ground up, mimicking the underlying tendon physiology (Conte & Paolucci, 2014). Therefore, the objectives of this study were to 1) formulate a literature based ABM of murine patellar tendon healing with varying initial conditions to recapitulate changes observed with aging, and 2) Conduct simulations to determine whether ABM recapitulated salient features of healing, and to make predictions about healing outcomes. / 1 / Jordan Robinson

Patellar Tendinopathy (PT), commonly called "Jumper's Knee", is a condition resulting from repetitive loading of the patellar tendon that presents as anterior knee pain, which is commonly seen in basketball players due to the maneuvers in the sport. Diagnosis of PT often involves a clinical exam followed by ultrasound images for confirmation of the diagnosis to look for key factors of PT. Clinical assessment of ultrasound images of tendons is subjective and requires a high level of experience for reliable interpretation. Thus, there is a need for objective, quantitative methods to assess tendon abnormalities associated with pathology. Ultrasound image texture analysis has emerged as a reliable technique to augment the utility of conventional US imaging, and has recently been shown to distinguish healthy from abnormal tendon and myofascial tissues. The objective of the present study was to conduct image texture analysis to evaluate patellar tendons of collegiate basketball athletes over two seasons. Under an IRB-approved protocol with informed consent, a total of 33 Division 1 collegiate basketball athletes (16 male, 17 female, age 19.9 +/- 1.4 years) underwent clinical evaluation and ultrasound imaging. Four imaging sessions were collected over the course of two years (pre- and post-season). Participants were imaged using a GE LOGIQ S8 (General Electric, USA) ultrasound machine equipped with ML6-15 linear probe. At each imaging session, power Doppler images were collected in the longitudinal and transverse axis, at the proximal, central, and distal regions of the patellar tendon of both knees. Image texture analysis was performed using a custom MATLAB (Mathworks, USA) program to obtain first order (mean, median, variance, skewness, kurtosis, entropy), second order (contrast, energy, and homogeneity), and blob analysis (blob count, BC, and blob area, BA, for 5%, 25%, 50%, 75%, and 95% thresholding values) texture parameters in each image, based upon borders manually drawn by a single researcher. Statistical analysis was conducted to compare imaging sessions (JMP Pro 16, SAS). P-values <0.05 were considered statistically significant. Quantitative texture parameters are able to distinguish characteristics in patellar tendon ultrasound images to distinguish between anatomic region, gender, dominance and pre- to post- season. The 25% and 75% thresholding percentiles effectively showed characteristics of collagen fibers in the patellar tendon. The abnormal diagnosis does not greatly effect texture parameters, which needs to be investigated with more incorporation of grading criteria distinctions and a larger sample size. / Master of Science / Patellar Tendinopathy (PT) is a knee injury that commonly occurs in basketball players. The recovery for PT is often long and the player can still have knee pain when returning to the sport. Diagnosis of PT requires a high level of expertise to consider the patients history, conduct a physical exam and take ultrasound images to look for factors that indicate patellar tendon is damaged. The difficulty of diagnosing PT calls for an objective method to allow for accuracy in assessing patellar tendons. In order to create a more objective measure of ultrasound images, quantitative texture parameters are explored to understand what the brightness values of each pixel and the proximity of pixels together can convey about the image. The objective of this study is to understand what characteristics of the subject (anatomic region, knee dominance, gender, and time point) texture parameters are able to distinguish in patellar tendon ultrasound images.

Introducción: Determinar la asociación entre el ángulo de inclinación del tendón patelar (AITP) y la presencia de dolor anterior de rodilla (DAR), así como conocer la prevalencia de DAR en deportistas universitarios. Material y métodos: Estudio de corte transversal en 143 deportistas universitarios. La presencia de DAR se detectó usando la Anterior Knee Pain Scale de Kujala y se calculó el AITP analizando una fotografía de ambas piernas con el programa Kinovea ®. Cada rodilla se consideró como una muestra. La razón de prevalencia entre el DAR y el AITP se calculó usando regresión de Poisson robusta. Resultados: Se evaluaron 143 sujetos, por tanto, 286 rodillas, donde 176 (61.5%) presentaban DAR. El AITP se clasificó en cuartiles. Para el análisis se unió el segundo y tercer cuartil, por lo que se obtuvo un cuartil medio (9°y 14°).Se encontró que un AITP menor a 9° tiene 1,34 (IC95%; 1,09-1,65) más probabilidad de tener DAR, y un AITP mayor a 14° tiene 1,35 (IC95%; 1,09-1,69) más probabilidades. Conclusiones: Los deportistas con un AIPT menor a 9° o mayor a 14° tienen mayor probabilidad de presentar DAR. Se recomienda que el profesional considere el ángulo de inclinación del tendón patelar en su evaluación. / Introduction: To determine the association between patellar tendon angle (AITP) and the presence of anterior knee pain (DAR) and the prevalence of DAR in college athletes. Materials and methods: Cross-sectional study of college athletes. The presence of DAR was detected using the Anterior Knee Pain Scale by Kujala and AITP was calculated by analyzing a photograph of both legs with Kinovea program ®. Each knee was considered as a sample. The prevalence ratio between the DAR and the AITP was calculated using Poisson regression robust Results: 143 subjects were evaluated, therefore, 286 knees, where 176 (61.5%) had anterior knee pain (DAR). The AITP was ranked in quartiles. To analyze was joined second and third quartile so was obtained a midquartile (9° and 14°). It was found that AITP fewer than 9° is 1.34 (95% CI, 1.09 - 1.65) more likely to have DAR, and AITP greater than 14° is 1.35 (95% CI; 1,09- 1.69) more likely. Conclusions: Athletes with AITP fewer than 9 ° or greater than 14 ° are more likely to have DAR. It is recommended that the professional considers the inclination patellar tendon angle in the evaluation / Tesis

No description available.

In conclusion, the present study firstly addressed the relationship between graft incorporation and peri-graft bone quality and quantity after ACL reconstruction in a rabbit model. The findings suggested that the non-invasive measurement of peri-graft bone would be useful to predict graft incorporation. Peri-graft bone loss was region-specific after surgery, which might be associated with stress shielding in the specific region after tunnel creation. The use of Brushite CPC might be a promising way to augment peri-graft bone and enhance graft incorporation. (Abstract shortened by UMI.) / In the fourth part, brushite CPC was successfully applied to augment the peri-tendon bone volume and connectivity. It was revealed under mechanical testing that the ultimate strength and stiffness of graft fixation in bone tunnel on experimental side was higher than that of the control by 117% and 102% respectively at 6 weeks, postoperatively (p&lt;0.05 for both). The use of brushite CPC caused a paradigm shift in failure mode from intra-tunnel to intra-articular portion at 12 weeks postoperatively (p=0.013). / Keywords. anterior cruciate ligament reconstruction, bone mass, microarchitecture, tendon-to-bone healing, graft incorporation, brushite calcium phosphate cement / The first part of this thesis compared the histological characteristics of T-B healing interface tissue in femoral and tibial tunnels following ACL reconstruction in rabbits. Results revealed that less cartilaginous interface tissue was formed in tibial tunnel than in femoral tunnel. Such cartilaginous tissue was gradually mineralized during reestablishment of a direct T-B integration. T-B healing in tibial tunnel was inferior to that in femoral tunnel. The disparity of T-B healing in various osseous milieus suggested the potential association in between. / The second part of this original work further explored the numeric relationship between the strength of T-B attachment and peri-graft bone mass and connectivity. Results of Micro-computed tomography (micro-CT) showed that peri-graft bone mass and connectivity was significantly lower on tibial side than those on femoral side. It was found under biomechanical evaluation that grafted tendon was prone to be pulled out from tibial tunnel with the bone attachment; the weakest point of the complexes shifted from the healing interface at time zero to peri-graft bone at week 6 after operation. With reverse of peri-graft bone at week 12 postoperatively, the weakest point shifted to intra-osseous tendinous portion. The stiffness of graft fixation correlated with peri-graft BV/TV (r2=0.68, p=0.001) and connectivity (r2=0.47, p=0.013) at week 6 after operation. / The third part addressed the changes of peri-graft bone in spatial and temporal manners using high resoluation multiple-slice peripheral quantitative computed tomography (pQCT) and micro-CT. Under pQCT evaluation, a decrease in BMD was present in specific regions, medial region of femoral tunnel by 26% and posterior and lateral regions of tibial tunnel by 22% and 42%, respectively at week 12 postoperatively than the baseline (p&lt;0.05 for all). It was accompanied by a decrease in trabecular number and increase in trabecular spacing, the shift of plate-like to rod-like trabeculae and loss of anisotropy under micro-CT evaluation. It was echoed by histological findings showing increased osteoclastic activities and poor T-B healing in these specific regions. The postoperative bone loss and associated poor T-B healing was region-specific. / by Wen, Chunyi. / Adviser: Kai-ming Chan. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0217. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 148-168). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

Tendinosis is a condition of chronic pain that afflicts several human tendons, not least the patellar tendon, in which case it is often clinically referred to as ‘jumper’s knee’. The exact mechanisms behind tendinosis are yet not fully understood. One draw-back in the case of patellar tendinosis has been the lack of knowledge of the innervation patterns of the human patellar tendon. It cannot be excluded that the processes of tendinosis are influenced by nerve mediators, released from nerve endings or from stimulated cells inside the tendon. Thus, the studies of the present thesis aimed to 1) map the general, sensory, cholinergic and sympathetic innervation patterns of the human patellar tendon, in both the tendon tissue proper and the loose paratendinous connective tissue surrounding the tendon, and 2) investigate the possible existence of a production of signal substances, traditionally associated with neurons, in non-neuronal tendon cells, and to see if there are signs of local cholinergic and catecholaminergic signaling pathways. Biopsies of both normal pain-free patellar tendons and patellar tendons from patients with chronic painful tendinosis were collected and investigated. The main method utilized was immunohistochemistry, using antibodies directed against synthesizing enzymes for acetylcholine and catecholamines, against muscarinic and adrenergic receptors, and against markers of general and sensory innervation. In situ hybridization (ISH) to detect mRNA for the cholinergic/catecholaminergic synthesizing enzymes was also used. It was found that the loose paratendinous connective tissue of the patellar tendon was rather richly innervated by nerve structures. These consisted of large nerve fascicles, as well as perivascular innervation in the walls of some of the larger arteries and smaller blood vessels. It was found that part of the nerve structures corresponded to sensory afferents, and that some conformed to cholinergic and, especially, sympathetic nerve fibers. The tendon tissue proper was strikingly less innervated than the paratendinous tissue. The sparse innervation that was found in the tendon tissue proper was seen in narrow zones of loose connective tissue and blood vessels, interspersed between the collagen bundles. The overall impression was that the patterns of distribution of the general, sensory, and autonomic innervations of tendinosis tendon tissue were similar to those of normal tendon tissue proper. The most pioneering findings were the immunohistochemical observations of an expression of enzymes related to production of both acetylcholine and catecholamines within the tendon cells (tenocytes) themselves, as well as of a presence of the receptors for these substances on the same cells; features that were predominantly seen in tendinosis tendons. The observations of the synthesizing enzymes for acetylcholine and catecholamines in tenocytes were confirmed by ISH findings of mRNA for these enzymes in the tenocytes. Immunoreactions for muscarinic and adrenergic receptors were also found in blood vessel walls and in some of the nerve fascicles. In summary, this thesis presents novel information on the innervation patterns of the human patellar tendon, in healthy individuals with pain-free tendons as well as in patients with chronic painful tendinosis. Furthermore, it gives the first evidence of the presence of a local, non-neuronal production in the tendon tissue of signal substances normally seen in neurons, and a basis for these substances to affect the tenocytes as these cells also display muscarinic and adrenergic receptors. Thus, the results indicate an existence of autocrine and/or paracrine cholinergic/catecholaminergic systems in the tendon tissue; systems that seem to be up-regulated in tendinosis. This is of great interest as it is known that stimulation of receptors for both catecholamines and acetylcholine can lead to cell proliferation, interfere with pain sensation, influence collagen production, and take part in vasoregulation, as well as, in the case of adrenergic receptors, promote cell degeneration and apotosis. All these processes represent biological functions/events that are reported to be affected in tendinosis. In conclusion, despite the fact that there is very limited innervation within the patellar tendon tissue proper, it is here shown that effects of signal substances traditionally associated with neurons seem to occur in the tissue, via a local production of these substances in tenocytes.

Chronic painful tendinopathies are common, not only in sports and recreationally active people, but also among people with a sedentary lifestyle. Both the lower and upper limbs are affected. There is lack of knowledge about the etiology and pathogenesis to tendinopathy, and many different treatments options have been presented. Unfortunately, most treatments have not been tested in scientific studies. Conservative (non-surgical) treatment has since long shown unsatisfactory results and surgical treatment is known to give unpredictable results. The aim of this thesis was to evaluate new models of painful eccentric training for the conservative treatment of different chronic tendinopathies. After promising results in a pilot study, using painful eccentric calf muscle training in patients with chronic mid-portion Achilles tendinopathy, we investigated if these results could be reproduced in a larger group of patients with both mid-portion and insertional Achilles tendinopathy (study I). After 12 weeks, 89% of the patients with pain from the mid-portion were satisfied and back in previous activities. In the group with insertional Achilles tendinopathy the results were poor. A new model for eccentric training was designed for patients with insertional Achilles tendinopathy. The eccentric calf muscle training was done from tip-toe to floor level (study II). With this new regimen 67% of the patients were satisfied and back in previous activities. The next step was to investigate the effects of painful eccentric quadriceps training on patients with jumper´s knee/patellar tendinopathy (study III). Two different training protocols were used. Eccentric training performed on a 250 decline board showed promising results with reduced pain and a return to previous activities, while eccentric training without the decline board had poor results. In a following prospective study, patients with jumper´s knee/patellar tendinopathy were randomised to either concentric or eccentric painful quadriceps training on a 250 decline board (study IV). After 12 weeks of training, there were significantly better results in the group that did eccentric training. In a pilot study (study V), we investigated painful eccentric deltoideus and supraspinatus muscle training on a small group of patients on the waiting list for surgical treatment of subacromial impingement syndrome. After 12 weeks of training, 5 out of 9 patients were satisfied with the results of treatment and withdrew from the waiting list for surgery. In conclusion, the present studies showed good clinical results with low risks of side effects and low costs. Thus, we suggest that painful eccentric training should be tried in patients with Achilles and patellar tendinopathy before intratendinous injections and surgery are considered. For patients with chronic painful impingement syndrome, the results of our small pilot study are interesting, and stimulates to randomised studies on larger materials.

Syfte: Sammanställa och granska studier gällande postoperativ behandling vid ruptur av ligament patella. Detta för att beskriva effekt och kvalitet på studier om postoperativ behandling. Metod: En beskrivande litteraturstudie valdes som design, med sökorden: patellar ligament, patellar tendon, rupture, knee injuries, surgery. Av totalt 1240 träffar valdes 13 relevanta artiklar publicerade mellan 1999-2013 efter sökningar i databaserna PubMed, PEDro, COCHRANE, SCOPUS, CINAHL, SPORTDiscus och AMED. Artiklarna kvalitetsgranskades enligt PEDro scale. Resultat: Två postoperativa behandlingar beskrevs, tidig och sen mobilisering. Antingen placeras knäleden i ett stabiliserande knäskydd som till en början låser knäleden i full extension eller så påbörjas tidig mobilisering av den opererade knäleden. Ingen signifikant skillnad påvisades mellan tidig och sen mobilisering vad gäller effekten på muskelstyrka, rörelseomfång och återgång till tidigare aktivitetsnivå. Vidare var kvaliteten på de granskade artiklarna genomgående låg (PEDro scale ≤ 5). Konklusion: Ytterligare forskning krävs för att fastställa vilken postoperativ behandling som ger bäst effekt. / Objective: Summarize and examine studies regarding postoperative treatment following rupture of the patellar ligament. Further the aim was to evaluate the effect of the postoperative treatment and the quality of the studies. Method: As design, a descriptive review was chosen, keywords: patellar ligament, patellar tendon, rupture, knee injuries, surgery. From a total of 1240 items, 13 relevant articles published 1999-2013 were selected after search in the databases PubMed, PEDro, COCHRANE, SCOPUS, CINAHL, SPORTDiscus and AMED. The articles were quality-graded according to PEDro scale. Results: Two postoperative treatments were described, early and delayed mobilization. There was no significant difference between them regarding the effect on muscle strength, range of motion and return to preinjury level of activity. The quality-graded articles had overall low quality (PEDro scale ≤ 5). Conclusion: Further researches are required to determine which postoperative treatment has the best effect.