Mechanical properties during healing of Achilles tendon ruptures to predict final outcome: A pilot Roentgen stereophotogrammetric analysis in 10 patients

<p>Abstract</p> <p>Background</p> <p>There are presently few methods described for in vivo monitoring of the mechanics of healing human tendon ruptures, and no methods for prediction of clinical outcome. We tested if Roentgen stereophotogrammetric analysis (RSA) can be used to follow the restoration of mechanical properties during healing of ruptured Achilles tendons, and if early measurements can predict clinical results.</p> <p>Methods</p> <p>Achilles tendon repair was studied with RSA in 10 patients with a total rupture. Tantalum beads were implanted in conjunction with surgical repair. The patients were evaluated at 6, 12 and 18 weeks, and after 1 year. RSA was performed with two different mechanical loadings, and the strain induced by increasing load was measured. The transverse area was determined by ultrasound. CT scan at 12 weeks confirmed that the tantalum beads were located within the tendons. Functional testing was done after 1 year. A heel raise index was chosen as primary clinical outcome variable.</p> <p>Results</p> <p>The strain was median 0.90, 0.32 and 0.14 percent per 100 N tendon force at 6 weeks, 18 weeks and one year respectively. The error of measurement was 0.04 percent units at 18 weeks. There was a large variation between patients, which appears to reflect biological variation. From 6 to 18 weeks, there was a negative correlation between increase in transverse area and increase in material properties, suggesting that healing is regulated at the organ level, to maximize stiffness. Modulus of elasticity during this time correlated with a heel raise index at one year (Rho = 0.76; p = 0.02).</p> <p>Conclusion</p> <p>We conclude that the RSA method might have potential for comparing different treatments of Achilles tendon ruptures.</p

Stiffness of the healing human Achilles tendon

Achilles tendon ruptures in humans are followed by a long period of immobilisation, rehabilitation and limitations of physical activity and sometimes work also. This prolonged period probably leaves a marginal for improvement in the management of this injury. Animal studies have shown that there are several possibilities to influence and improve tendon healing. The aim of this thesis was to find a way to examine the mechanical properties of the healing human Achilles tendon and, by using that method, to gain a better understanding of the tissue properties and healing process in these tendons. It was also our aim to use our knowledge from animal studies in an attempt to improve tendon healing in humans. We developed a radiological method using radiostereophotogrammetric analysis (RSA) and computed tomography (CT), which enabled us to measure the stiffness of the healing Achilles tendon. The results of these measurements, as early as 7 weeks after injury correlated with the late clinical results in all studies. Clinical results were measured using a heel-raise test comparing the injured with the non-injured tendon. We could not find a significant difference in stiffness between patients treated surgically or non-surgically. Neither could we demonstrate that platelet-rich plasma improved the mechanical properties of the healing tendon or the clinical outcome, within the limits of the statistical power. In contrast, patients following a specific training programme with early tension loading of the tendon twice a day developed stiffer tendon tissue later in the healing process. Since RSA is unsuitable for routine clinical use, we evaluated the possibility to use radiodensity findings from CT as a proxy for healing and its correlation to mechanical and clinical results. Density and mechanical properties correlated strongly when analysing all time points together, but only weakly at each particular point in time. Density may still be useful in describing mechanical properties at a later stage of repair, but this remains to be seen. In conclusion, these studies show that early mechanical properties correlate to late clinical outcome and that the early use of daily tension loading sessions leads to an improvement in the mechanical properties of the tendon tissue

Early Controlled Tension Improves the Material Properties of Healing Human Achilles Tendons After Ruptures

Background: Weightbearing in a fixed brace after acute Achilles tendon ruptures does not necessarily lead to mechanical tension in the tendon. Early motion has a positive effect on the clinical outcome, but it is not clear if this is because of effects on tendon strength or unspecific effects. The aim of this study was to examine if tensional loading leads to an improvement in the mechanical properties of the healing Achilles tendon. Hypothesis: The elastic modulus of the tendon callus is increased by early tensional loading. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Thirty-five patients with an acute Achilles tendon rupture were recruited consecutively. They underwent surgery with a single suture and received metal markers in the distal and proximal parts of the tendon. After surgery, the patients were randomized to either cast immobilization for 7 weeks or tensional loading. The latter group wore a cast for 2 weeks and then a removable foam walker boot for 5 weeks. They were instructed to remove the boot twice daily and push a special training pedal to produce a predetermined, gradually increasing tensional load on the healing tendon. At 7, 19, and 52 weeks postoperatively, the patients were investigated with roentgen stereophotogrammetric analysis under different loading conditions and computed tomography. The collected data allowed calculation of the modulus of elasticity. At 52 weeks, the clinical outcome was also examined using the Achilles tendon Total Rupture Score (ATRS) and the heel-raise index. Results: The elastic modulus at 19 and 52 weeks was higher in the tensional loading group. There was no significant difference in the ATRS or heel-raise index at 52 weeks. As in previous studies, there was a significant correlation between the modulus at 7 weeks and the heel-raise index at 52 weeks. There were no signs of tendon elongation. Conclusion: Early tensional loading improves the mechanical properties of the healing Achilles tendon.</p

Early, controlled tension improves the material properties of healing human Achilles tendons after rupture : a randomized trial

Background: Weight-bearing in a fixed brace after acute Achilles tendon rupture does not necessarily lead to mechanical tension in the tendon. Early motion has a positive effect on the clinical outcome, but it is not clear if this is due to effects on tendon strength or to unspecific effects. The aim of this study was to examine if tensional loading leads to improvement of the mechanical properties of the healing, human Achilles tendon.Hypothesis: The elastic modulus of the tendon callus is increased by early tensional loading.Study Design: Randomized controlled trial; level of evidence: 2.Methods: Thirty-five patients with an acute Achilles tendon rupture were recruited consecutively. They were operated with a single suture, and received metal markers in the distal and proximal part of the tendon. After surgery, patients were randomized to either cast immobilization for 7 weeks or tensional loading. The latter group wore a cast for 2 weeks, and then a removable foam walker boot for 5 weeks. They were instructed to remove the boot twice daily and push a special training pedal to produce a predetermined, gradually increasing tensional load on the healing tendon. At 7, 19 and 52 weeks postoperatively, patients were investigated with Roentgen Stereophotogrammetric Analysis (RSA) under different loading conditions, and computed tomography (CT). The collected data allowed calculation of modulus of elasticity. At 52 weeks, we also examined clinical outcome, using the Achilles tendon Total Rupture Score (ATRS) and a heel-raise index.Results: The elastic modulus at 19 and 52 weeks was higher in the tensional loading group. There was no significant difference in ATRS or heel-raise index at 52 weeks. As in previous studies, there was a significant correlation between the modulus at 7 weeks and the heel-raise index at 52 weeks. There was moderate tendon elongation.Conclusion: Early tensional loading improves the mechanical properties of the healing Achilles tendon.</p

Healing of human Achilles tendon ruptures : Radiodensity reflects mechanical properties

Purpose This study tests the idea of using radiodensity from computed tomography to quantitatively evaluate the healing of ruptured Achilles tendons. Methods The radiodensity of the healing tendons in sixty-five patients who were treated for Achilles tendon rupture was measured. The hypothesis was that density would correlate with an estimate for e-modulus, derived from strain, measured by radiostereometry with different mechanical loadings. Results Radiodensity 7 weeks after injury was decreased to 67 % (SD 11) of the contralateral, uninjured tendon. There was no improvement in radiodensity from 7 to 19 weeks, whereas at 1 year, it had increased to 106 % (SD 7). Only 2 of 52 measured values at 1 year were lower than the highest value at 19 weeks, i.e. there was minimal overlap. The variation in radiodensity could explain 80 % of the variation in e-modulus, but radiodensity correlated only weakly with e-modulus at each time point separately. At 1 year, both radiodensity and e-modulus correlated with functional results, although weakly. Conclusions From 19 weeks onwards, radiodensity appears to reflect mechanical properties of the tendon and might to some extent predict the final outcome. Radiodensity at 7 weeks is difficult to interpret, probably because it reflects both callus and damaged tissues. Level of evidence Prospective, diagnostic study, Level II

Copyright: American Journal of Sports Medicine

http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-64770 Autologous platelets have no effect on the healing of human Achilles tendon ruptures: a randomized single-blind stud

Elevation of systemic matrix metalloproteinase-2 and -7 and tissue inhibitor of metalloproteinases-2 in patients with a history of Achilles tendon rupture

Objectives: To compare serum levels of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) between patients with a history of Achilles tendon rupture and blood donor controls, and to relate MMPs and TIMPs to mechanical properties of the tendons during healing. Methods: More than three years after injury, we measured serum levels of MMP-1, -2, -3, -7, -8, -9 and -13 and TIMP-1 and -2 in eight patients who had suffered Achilles tendon rupture. Twelve blood donors served as controls. During the early phase of healing, the tendon modulus of elasticity was calculated from radiostereometric data and tendon cross-sectional area. Results: Patients with a history of Achilles tendon rupture had increased levels of MMP-2 (median difference (m.d.) 10 %; p = 0.01), MMP-7 (m.d. 15 %; p = 0.02) and TIMP-2 (m.d. 36%; p = 0.02), as compared to controls. Levels of MMP-7, measured three years after injury, correlated inversely to tendon modulus of elasticity (rs = -0.83; p = 0.02), and positively to tendon elongation (rs = 0.74; p = 0.05) during the early phase of healing. There was a trend towards positive correlation between MMP-7 and cross-sectional area during the early phase of healing (rs = 0.67; p = 0.08). Conclusions: Patients with a history of Achilles tendon rupture appear to have elevated levels of MMP-2, MMP-7 and TIMP-2 in serum. These pilot data support the view that the MMP-TIMP system is involved in tendinopathy and suggest that disturbances in proteolytic control might be generalised.</p

Mechanical properties during healing of Achilles tendon ruptures to predict final outcome: A pilot Roentgen stereophotogrammetric analysis in 10 patients-0

<p><b>Copyright information:</b></p><p>Taken from "Mechanical properties during healing of Achilles tendon ruptures to predict final outcome: A pilot Roentgen stereophotogrammetric analysis in 10 patients"</p><p>http://www.biomedcentral.com/1471-2474/8/116</p><p>BMC Musculoskeletal Disorders 2007;8():116-116.</p><p>Published online 26 Nov 2007</p><p>PMCID:PMC2244624.</p><p></p

La Toma de decisiones y la construcción colectiva de conocimiento en el equipo “COMUNARR” (Construcción de Mundos Alternativos “Ronco Robles”)

Proyecto de intervención en una ONG ubicada en Tarahumara que busca generar hacia afuera, pero también hacia su equipo de trabajo, formas de organizarse y operar que favorezcan la autonomía y el buen vivir. El proyecto se basa en la implementación de toma de decisiones colectiva y la construcción colectiva de conocimiento en el equipo de COMUNARR (Construcción de Mundos Alternativos Ronco Robles). Se plantea la necesidad de diseñar la toma de decisiones donde todos y cada uno de los miembros del equipo reflexionen sobre el modo como se toman y que estas sirvan para la construcción de procesos relevantes que respondan a las necesidades y perspectivas de los colectivos. Para asegurar que los sistemas sean coherentes con lo propuesto se utiliza la teoría de la actividad de Engeström. A través del análisis y la construcción de los sistemas de actividad, se crean artefactos que permitan la toma de decisiones colectiva, se recupera y sistematiza todo el conocimiento producto del proceso de la toma de decisiones