Repair within the first 48 h in the treatment of acute Achilles tendon ruptures achieves the best biomechanical and histological outcomes

Abstract

Purpose To compare the biomechanical and histological properties of Achilles tendons repaired at different time points during the acute injury period. Methods Thirty‐six skeletally mature Sprague–Dawley rats underwent bilateral mid‐substance Achilles tenotomy. The Achilles tendons were repaired either in the first 24 h (group 1), 24–48 h (group 2), 48–72 h (group 3), or > 72 h (mean: 120 ± 5.2 h) (group 4) after tenotomy. Six weeks after repair, nine tendons per group were assessed biomechanically and histologically. The Stoll histological scoring system was used for histological examination. The groups were compared with each other and native tendons (control group). The correlations between biomechanical and histological results were analysed. Results There were no significant differences between groups 1, 2 and 3 regarding the mean load to failure; it was significantly lower in group 4. Healed tendons in groups 1, 2 and 3 had significantly greater stiffness than native tendons and group 4 tendons. All healed tendons had a larger cross‐sectional area than native tendons. There was no significant difference in tendon length between the groups. There was no significant difference in Young's modulus between the groups; Young's modulus was lower in all the groups than in the control group. Group 1 had significantly higher extracellular matrix organization, cell alignment, cell distribution and nucleus morphology scores and total scores than group 4. Group 1 had significantly higher extracellular matrix organization, cell distribution, vascularization and inflammation scores and total scores than group 3. A significant positive correlation was detected between the maximum load to failure and total histological score. Conclusion Repair of acute Achilles tendon rupture within 48 h, and especially in the first 24 h, provides better biomechanical and histological outcomes. In the clinical practice, the data could be used to decrease re‐rupture rates, to achieve more anatomical tendon healing and to implement more effective post‐operative rehabilitation programme.

Age and Tightness of Repair Are Predictors of Heel-Rise Height After Achilles Tendon Rupture

“…This study did not show a significant relationship between time from injury to repair and heel-rise height at 12 months postsurgery. Recently, an animal study 32 reported improved 6-week tendon mechanics in mice treated within 48 hours after injury. In humans, clinical studies 42,50 have shown conflicting outcomes for those undergoing repair within 48 hours of injury.…”

Effect of low intensity photobiomodulation associated with norbixin-based poly (hydroxybutyrate) membrane on post-tenotomy tendon repair. In vivo study

“…One cannot say that the implanted biomaterial constituted a barrier for the penetration of light emitted by LED, because the membrane was located on the deepest surface of the tendon, that is, the light did not need to pass through it before reaching the tendon. According to Park et al 35 and Misir et al 36 , reducing the inflammatory process in the early stages of repair in tendinous lesions may result in a better quality repair. On the other hand, the greater amount of fibroblasts can optimize the repair process by synthesizing collagen in the extracellular matrix of the tendinous tissue 37 .…”

“… 35 and Misir et al . 36 , reducing the inflammatory process in the early stages of repair in tendinous lesions may result in a better quality repair. On the other hand, the greater amount of fibroblasts can optimize the repair process by synthesizing collagen in the extracellular matrix of the tendinous tissue 37 .…”

Tendon mechanobiology in small-animal experiments during post-transection healing

“…Data are based on references for loaded Andersson et al, 2009;Black et al, 2012;Eliasson et al, 2009;Kaux et al, 2012;Khayyeri et al, 2020;Majewski et al, 2018;Müller et al, 2016;Murrell et al, 1997;Murrell et al, 2008;Schizas et al, 2010), mixed loading (Andersson et al, 2009;Eliasson et al, 2011;Eliasson et al, 2012;Freedman et al, 2017a;Hillin et al, 2019;Huegel et al, 2019), and unloaded (Eliasson et al, 2009Eliasson et al, 2011Eliasson et al, 2012;Freedman et al, 2017a;Hammerman et al, 2014;Huegel et al, 2019;Khayyeri et al, 2020;Schizas et al, 2010) rat Achilles tendons. Andersson et al, 2009;Best et al, 1993;Black et al, 2012;Bolt et al, 2007;Devana et al, 2018;Eliasson et al, 2009;Genc et al, 2018;Kaux et al, 2012;Khayyeri et al, 2020;Komatsu et al, 2016;Korntner et al, 2017;Kurt et al, 1999;Majewski et al, 2008;Majewski et al, 2012;Majewski et al, 2018;Misir et al, 2019;Müller et al, 2016;Müller et al, 2018;<...>…”

“…Andersson et al, 2009;Best et al, 1993;Black et al, 2012;Bolt et al, 2007;Devana et al, 2018;Eliasson et al, 2009;Genc et al, 2018;Kaux et al, 2012;Khayyeri et al, 2020;Komatsu et al, 2016;Korntner et al, 2017;Kurt et al, 1999;Majewski et al, 2008;Majewski et al, 2012;Majewski et al, 2018;Misir et al, 2019;Müller et al, 2016;Müller et al, 2018;Murrell et al, 1997;Murrell et al, 2008;Schizas et al, 2010;Staresinic et al, 2003;Usman et al, 2015;Weng et al, 2020;Wieloch et al, 2004) mixed loading (Andersson et al, 2009;Eliasson et al, 2011;Eliasson et al, 2012;Freedman et al, 2017a;Fryhofer et al, 2016;Hillin et al, 2019;, and unloaded (Andersson et al, 2012;Eliasson et al, 2009;Eliasson et al, 2011;Eliasson et al, 2012;Freedman et al, 2017a;Hammerman et al, 2014;Huegel et al, 2019;Khayyeri et al, 2020;Schizas et al, 2010;) rat Achilles tendons. Best et al, 1993;Devana et al, 2018;…”