Correlating Achilles Tendon Enthesophyte Presence and Size On Radiograph With Incidence and Severity of Tendinopathy On MRI: A Retrospective Review Landon Winget D.O., Michael Keleher D.O., Moumita Chatterjee Ph.D., Christy Collins Ph.D. OhioHealth Doctors Hospital, Columbus, Ohio

Introduction Reference Figures Results The Achilles tendon is one of the most frequently injured tendons of the Demographic characteristics of the 300 patients included in the study are body.1 While several terms have been used to describe Achilles disease, presented in Table 1. Overall, 62.7% of the evaluated patients had an tendinopathy has been suggested by many experts as the most appropriate Achilles enthesophyte on radiograph and/or tendinopathy on MRI. Those term to describe this entity.2 The incidence of Achilles tendinopathy has that had these findings were statistically older in age than those that did risen in the past several decades as a result of greater participation in not have either of these findings (mean 46.7 years old vs. 39.5 years old, recreational and competitive sporting activities. For example, the rate of see Table 1). There was no significant difference by gender. Achilles tendon injuries in runners is about ten times higher than that in age-matched controls. Despite that, Achilles disease has also been reported 3,4 There was a statistically significant positive correlation between the in inactive individuals. Achilles tendinopathy can cause pain with presence of enthesophyte on radiograph and presence of tendinopathy on significantly impaired mobility and reduced athletic performance. MRI (see Table 2, p < 0.001). 48.0% of patients with an enthesophyte on radiographs had tendinopathy on MRI, compared to 25.3% of those that Imaging plays a valuable role in diagnosing and assessing the severity of did not have an enthesophyte. Those with enthesophyte and tendinopathy Achilles tendinopathy. Plain radiographs are commonly the initial imaging had a mean enthesophyte size of 6.3 mm and mean Achilles AP thickness of of choice for Achilles pain due to being fast, readily accessible and 8.2 mm. Those without enthesophyte had a mean Achilles AP thickness of relatively inexpensive.5 While radiographs provide valuable information of 6.0 mm. the bony structures near the Achilles tendon, they do not provide adequate assessment of the tendon itself. In contrast, enthesophytes (bony spurs Lateral radiograph and axial T2 fat saturated MRI image of Figure 2: Lateral radiograph and axial T2 MRI image of the left Among patients with Achilles enthesophyte on radiograph and within a tendon) are readily seen on radiographs. It has been established Figure 1: the right ankle of a 43 year old female demonstrating no Achilles ankle of a 43 year old female demonstrating a 15 mm Achilles tendinopathy on MRI, there was a significant positive correlation between that the most common osseous abnormality in Achilles disorders is an enthesophyte and normal low T2 signal in the Achilles tendon. Note enthesophyte at the calcaneal insertion and Achilles tendinopathy, the size of the enthesophyte and the severity of tendinopathy based on AP enthesophyte at the calcaneal insertion of the tendon (see Figure 2).1 the AP thickness of the tendon measures 6 mm, which is normal. including tendon thickening (10 mm AP thickness) and patchy thickness of the tendon (r: 0.301; p=0.010). Mean size of the enthesophyte increased intratendinous signal. on radiograph was 6.0 mm for patients with mild tendinopathy, 12.7 mm In contrast to radiographs, magnetic resonance imaging (MRI) has excellent for patients with moderate tendinopathy, and 6.7 mm for those with severe soft tissue contrast capabilities and has become the modality of choice for tendinopathy. (Note: There were only 3 patients with moderate and 9 with imaging assessment of the Achilles tendon. The normal average Reference Tables severe tendinopathy). anteroposterior (AP) thickness of the Achilles tendon on MRI is 6 millimeters (mm) and a normal Achilles tendon should be low signal (black) Table 1 – Demographic Characteristics on all magnetic resonance (MR) sequences (see Figure 1).5 MRI features of Conclusion and Discussion Achilles tendinopathy include AP tendon thickening greater than 8 mm and A statistically significant increased incidence of Achilles tendinopathy exists increased intratendinous signal on T1 and T2 sequences (see Figure 2 5 ). in patients found to have an Achilles enthesophyte on radiographs. This may aid radiologists in determining whether to recommend further The objective of this study is to explore the agreement between Achilles evaluation of the Achilles tendon with MRI after encountering an enthesophyte on radiographs to Achilles tendinopathy on MRI. In addition, enthesophyte on radiographs. Certainly clinical information and a history of this study will explore any correlation between the size of the Achilles pain would be crucial in making this determination as well. enthesophyte and the severity of the tendinopathy, based on the MRI Evaluating the size of the enthesophyte may prove useful in predicting findings. There is a need for radiologists to be judicious about severity of the tendinopathy, however more research will need to explore recommending expensive MRI exams after interpreting radiographs of a this correlation as this study encountered only 12 patients with moderate diseased joint. The results of this study may aid in that judgment while or severe tendinopathy, which is a significant limitation in evaluating this interpreting ankle or foot radiographs. correlation. Further research exploring a correlation between Achilles enthesophyte and risk of Achilles tear would also prove useful in determining the significance of the enthesophytes. Methods Table 2 – Agreement Between Achilles Tendinopathy on MRI and Achilles Enthesophyte on Radiograph

A retrospective review was conducted utilizing the OhioHealth Doctors Hospital picture archiving and communication system (PACS) and randomly References selecting 300 patients age 18 and above from the dates of 1/1/2008 to 1. Schweitzer ME & Karasick D. MR imaging of disorders of the Achilles 8/1/2016 who had undergone ankle MRI and ankle/foot radiographs of the tendon. American Journal of Roentgenology. 2000;175:613-625. same ankle within two years of each other. 150 patients with an Achilles enthesophyte and 150 without enthesophyte were evaluated, the latter 2. Paavola M, Kannus P, Jarvinen TAH, Khan K, Jozsa L, Jarvinen M. Achilles serving as a control group. Exclusion criteria included age less than 18 years tendinopathy. The Journal of Bone & Joint Surgery. 2002;84-A(11):2062- old, prior diagnosed Achilles xanthoma, and history of prior Achilles 2076. surgery. 3. Maffulli N, Sharma P, Luscombe KL. Achilles tendinopathy: aetiology and management. Journal of the Royal Society of Medicine. 2004;97:472-476. Table 3 – Size of Achilles Enthesophyte on Radiograph by Severity of Tendinopathy on MRI, as Measured by The radiographs were evaluated recording presence of Achilles 4. Alfredson H& Cook J. A treatment algorithm for managing Achilles enthesophyte for each patient, as well as the largest measurement of the AP Thickness of the Tendon tendinopathy: new treatment options. British Journal of Sports Medicine. enthesophyte. Corresponding MRI images of the same ankle within 2 years 2007;41:211-216. of the radiographs were then evaluated and the presence of increased 5. Bleakney RR, White LM, Maffulli N. Imaging of the Achilles tendon. Foot Achilles intratendinous signal was recorded, utilizing the T2 images. The AP and Ankle Clinics of North America. 2005;10(2):239-254. thickness of the Achilles tendon was also recorded for each patient. Statistical analysis was then performed including utilizing McNemar’s test for paired data to determine association between enthesophyte on radiograph and tendinopathy on MRI. Among those patients that had an enthesophyte on radiographs and tendinopathy on MRI, correlation with the size of the enthesophyte and severity of tendinopathy on MRI, as measured by AP thickness of the tendon, was evaluated utilizing Pearson correlation. Statistical significance was set at p < 0.05 for all tests. a Mild tendinopathy: ≤9 mm; Moderate tendinopathy: 10-11 mm; Severe tendinopathy: ≥12 mm