Value of quantitative MRI parameters in predicting and evaluating clinical outcome in conservatively treated patients with chronic midportion Achilles tendinopathy: A prospective study

Three‐dimensional morphology and volume of the free Achilles tendon at rest and under load in people with unilateral mid‐portion Achilles tendinopathy

“…The tendinopathic tendon experienced a volume reduction of 28% relative to resting volume, whereas volume was conserved under load in the contralateral and healthy control tendons. This finding is consistent with studies that reported a volume reduction in MAT after repeated isometric loading (Nuri et al., ) and a prolonged bout of exercise (Shalabi et al., ; Tsehaie et al., ). Volume loss of the tendinopathic tendon might play an important role in the regulation of tendon hydrostatic pressure, homeostasis, mechanotransduction and remodelling (Lavagnino et al., ) and could provide a basis for developing new or improved therapies for tendon repair.…”

“…These findings provide the first in vivo data that describe free tendon morphological characteristics across all tendon regions in both tendinopathic and contralateral tendons. Our finding that the free tendon with MAT has a larger CSA and AP diameter throughout the entire tendon length at rest supports earlier studies that have shown an increase in the thickness and area of the mean whole free AT (Docking & Cook, ; Nuri et al., ) and a single site of free AT mid‐portion (Docking et al., ; Grigg et al., ; Tsehaie et al., ) as a result of pathological alterations in tendon structure and composition in individuals with MAT. The widespread alteration in tendon morphology of the tendinopathic tendon (i.e.…”

“…Pathological alterations in the tendon structure and composition in MAT include disruption and disorganization of collagen bundles, an increase in the proportion of type III relative to type I collagen, hypercellularity, hypervascularity, a high content of glycosaminoglycan, and accumulation of free and bound water molecules (Åström & Rausing, ; Corps et al., ; de Mos et al., ; Pingel et al., ). Such micropathological changes in tendon structure and composition have been shown to alter tendon macromorphology (Docking & Cook, ; Docking, Rosengarten, Daffy, & Cook, ; Grigg, Wearing, & Smeathers, ; Nuri, Obst, Newsham‐West, & Barrett, ; Shalabi, Kristoffersen‐Wilberg, Svensson, Aspelin, & Movin, ; Tsehaie, Poot, Oei, Verhaar, & de Vos, ) and adversely affect Achilles tendon (AT) mechanical behaviour and material properties (Arya & Kulig, ; Chang & Kulig, ; Child et al., ; Nuri et al., ; Wang, Lin, Su, Shih, & Huang, ).…”

“…Achilles tendons with MAT have been reported to have a greater free tendon [i.e. soleus muscle–tendon junction (MTJ) to calcaneus] cross‐sectional area (CSA), anteroposterior (AP) diameter and volume relative to healthy control tendons at rest (Docking & Cook, ; Docking et al., ; Grigg et al., ; Nuri et al., ; Shalabi et al., ; Tsehaie et al., ). However, reports of tendon resting transverse morphology (i.e.…”

“…Furthermore, although the normal free AT is known to remain isovolumetric and experience a reduction in tendon CSA and mediolateral (ML) diameter, and an increase in AP diameter throughout the entire tendon length during tensile loading (Iwanuma et al., ; Nuri, Obst, Newsham‐West, & Barrett, ; Obst, Renault, Newsham‐West, & Barrett, , ), relatively little is currently known about how three‐dimensional (3‐D) tendon morphology during tensile loading is altered in MAT. Studies of the tendinopathic Achilles and patellar tendons have demonstrated an immediate decrease in AP diameter and water content after an acute bout of eccentric exercise (Grigg et al., ; Ho & Kulig, ; Wearing, Locke, Smeathers, & Hooper, ) and 1 h floor‐ball match (Fahlström & Alfredson, ), and an immediate reduction in tendon CSA and volume during repeated isometric loading (Nuri et al., ) and after long‐term eccentric exercise (Shalabi et al., ; Tsehaie et al., ). Such acute reductions in tendinopathic tendon CSA, AP diameter, water content and volume are suggested to be the result of load‐induced fluid exudation from the tendon core to the peri‐tendinous space and collagen fibre realignment (Grigg et al., ; Hannafin & Arnoczky, ; Helmer, Wellen, Grigg, & Sotak, ).…”