Site of maximum neovascularisation correlates with the site of pain in recalcitrant mid-tendon Achilles tendinopathy

BackgroundNeovascularisation is associated with pain in Achilles tendinopathy (AT). The anatomical relationship between ultrasound (US)-defined indicators of tendinopathy and clinically determined pain sites has not been investigated.PurposeTo measure the spatial correlation between the sites of maximum palpated tenderness, site of patient-indicated pain, maximum US-determined neovascularisation and maximum antero-posterior tendon thickness in patients with chronic recalcitrant AT (CRAT).MethodsA custom-designed measuring apparatus and clinical examination were used to measure the sites of maximum tenderness and subjectively defined pain on 29 tendons from patients diagnosed with mid-tendon CRAT. All tendons had been previously non-responsive to eccentric loading. Maximal neovascularisation and tendon thickness were measured by US scanning in conjunction with the measuring device.ResultsA significant association exists between clinically determined pain and neovascularisation (r = 0.85, p < 0.001), patient reported pain (r = 0.91, p < 0.001), maximal tendon thickness (r = 0.91, p < 0.001), maximal thickness and maximal neovascularisation (r = 0.86, p < 0.001).ConclusionSites of subjectively defined pain, clinically palpated tenderness, tendon thickness and neovascularisation are anatomically associated. Palpation can be reliably used as a clinical guide when planning interventions in patients with CRAT.