Original articleSite of maximum neovascularisation correlates with the site of pain in recalcitrant mid-tendon Achilles tendinopathy
Introduction
Achilles tendinopathy (AT) is common in elite and recreational athletes, particularly runners, basketball players and other jumping athletes (Maffulli, 1998, Reiter et al., 2004, Jarvinen et al., 2005, Vora et al., 2005, Longo et al., 2009, Rees et al., 2009). The non-athletic population can be frequently affected (Rolf and Movin, 1997, Sharma and Maffulli, 2006). Achilles tendinopathy commonly manifests as pain in the tendon during initial loading, subsiding with continued activity. As the condition becomes chronic, pain can become persistent, resulting in activity curtailment or cessation (Kvist, 1994, el Hawary et al., 1997). Many patients respond to conservative management but some do not, with this recalcitrant group being the subject of this study.
Studies using Doppler ultrasonography have shown that tendinopathic Achilles tendons can exhibit mid-tendon and insertional enlargement, disrupted fibrillar pattern, collagen disarray and tendon neovascularity (Khan and Cook, 2000, Maffulli et al., 2000, Leung and Griffith, 2008, Rompe et al., 2008). These structural changes, including neurovascular ingrowth, are associated with nocioceptive pathophysiology in recalcitrant non-insertional Achilles tendinopathy but this relationship has yet to be assessed in a systematic fashion clinically (Alfredson et al., 2003).
The correlation between neovascularisation and tendon changes, including localised thickening and focal hypoechoic areas, has been well described in symptomatic tendons (Leung and Griffith, 2008). Treatments resulting in significant symptomatic improvements in Achilles tendinopathy, such as eccentric calf loading programmes, high volume image guided injections (HVIGI) and sclerosing injections, typically result in reduction of both neovascularity and tendon thickening (Astrom and Westlin, 1994, Ohberg and Alfredson, 2004, Lind et al., 2006, Chan et al., 2008).
Although increased microcirculatory blood flow and other intratendinous changes have been reported to be closely related to pain (Astrom and Westlin, 1994, Ohberg et al., 2001), we are not aware of any published reports investigating the spatial relationships between clinically determined pain and tendinopathic changes (Knobloch et al., 2006). This would be useful to better inform clinicians about the relationship between clinical examination and the location of tendinopathic changes in this group of patients. We therefore studied the anatomical relationship between maximum clinically palpated tenderness and maximum ultrasound-determined neovascularisation in subjects with chronic recalcitrant mid-tendon Achilles tendinopathy (CRAT), hypothesizing that a measurable association existed between ultrasound sites of maximal neovascularisation and subjective location of maximal tenderness in chronic Achilles tendinopathy.
Section snippets
Subjects
All subjects referred to a single tertiary referral centre in a six month period to May 2009 with CRAT resistant to eccentric loading were considered for inclusion in the study. The study was approved by the Queen Mary Research Ethics Committee (QMREC), and all subjects gave written informed consent.
Inclusion & exclusion criteria
Subjects were included if they were between 18 and 65 years of age, participated regularly in active sports or exercise, had a clinical diagnosis of CRAT confirmed via a diagnostic ultrasound scan
Normality & reliability
Intra-observer reliability using the measuring device was assessed in 16 tendons (8 controls). Measurements ranged from 8.4 to 17.3 cm. ICC = 0.98 (95% confidence interval 0.93–0.99, p < 0.001). Intra-observer reliability of USS measures was also assessed in 16 tendons. Measurements ranged from 10.0 to 17.8 cm. The ICC = 0.97 (95% confidence interval 0.92–0.99, p < 0.001).
The one-sample Kolmogorov–Smirnov test evaluated the normality of all 6 variables, and confirmed normal distribution of the data.
Clinically palpated tenderness vs neovascularisation
There
Discussion
We found evidence of a strong association between sites of maximum clinically palpated tenderness and ultrasound-determined neovascularisation. Although a correlation between maximum pain and tenderness was observed, they did not occur at exactly the same site. This small systematic difference is unlikely to be clinically significant and may be a result of a difference in the width of the palpating finger, with site of pain defined by the patient’s index finger and site of tenderness defined by
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