Downloaded from www.ajronline.org by 162.158.89.91 on 08/23/18 from IP address 162.158.89.91. Copyright RRS. For personal use only; all rights reserved Monisha Shetty 1 David P. Fessell 1 John E. Femino 2 Jon. Jacobson 1 John Lin 1,3 David Jamadar 1 Received January 23, 2002; accepted after revision March 21, 2002. 1 Department of Radiology, University of Michigan Medical Center, Taubman Center 2808, 1500 E. Medical Center Dr., nn rbor, MI 48109-0326. ddress correspondence to D. P. Fessell. 2 Department of Orthopedic Surgery, University of Michigan Medical Center, Taubman Center, nn rbor, MI 48109-0326. 3 Present address: Valley Radiology, Ltd., 5322 W. Northern ve., Glendale, Z 85301. JR 2002;179:949 953 0361 803X/02/1794 949 merican Roentgen Ray Society Original Report Sonography of nkle Tendon Impingement with Surgical Correlation OJECTIVE. This report describes sonography of ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware. CONCLUSION. Sonography can be helpful in identifying ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware. In such cases, dynamic sonography can aid assessment. S onography is increasingly being used for the evaluation of foot and ankle abnormalities [1, 2]. Dynamic sonography, or imaging during joint motion, can aid in the evaluation of tendon tears, transient subluxation, and dislocation of tendons or nerves [1, 3, 4]. Dynamic sonography can also assess tendon impingement, which may occur only with specific movements. This report describes sonography of ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware. To our knowledge, this report is the first that discusses sonography of ankle tendon impingement. Materials and Methods Institutional review board approval was obtained for this study. Six cases of sonographically diagnosed ankle tendon impingement were obtained from our clinical experience over the past 2 years. Tendon impingement is defined as a disorder due to contact with an abnormal structure such as an osteophyte, fracture fragment, or orthopedic hardware. Clinical notes, imaging studies, and operative reports were retrospectively reviewed by a single musculoskeletal radiologist to determine the cause of the impingement (osteophyte, osseous fragments, or orthopedic hardware) and the type of tendon abnormality present (tendinosis, tendon tear, or tenosynovitis). Sonography reports were also reviewed to determine whether dynamic sonography aided in the evaluation of ankle tendon impingement. When present, MR images were also reviewed for signs of impingement and associated tendon abnormality. Sonography was performed with a linear 12- to 5-MHz or 10- to 5-MHz transducer (HDI 5000; dvanced Technology Laboratories, othell, W). MR imaging was performed with a 1.5-T scanner (Signa dvantage; General Electric Medical Systems, Milwaukee, WI) using multiplanar T1-weighted, proton density weighted, and T2-weighted sequences. Results The patient population consisted of three women and three men ranging in age from 29 to 59 years. In all cases, ankle pain was present. In five of the six patients, surgical correlation was available. The causes of impingement were osteophytes in two patients, hardware in two patients, and osseous fragments in two patients. In four of the six patients, dynamic sonography was specifically mentioned in the sonography report and aided in the evaluation of ankle tendon impingement. In three of the six patients, MR imaging was also performed. Tendon Impingement by Osseous Spurs or Osteophytes In two patients, sonography revealed tendon impingement due to osseous spurs. In one patient, the original sonography report described JR:179, October 2002 949
Downloaded from www.ajronline.org by 162.158.89.91 on 08/23/18 from IP address 162.158.89.91. Copyright RRS. For personal use only; all rights reserved Shetty et al. a medial cortical spur abutting an irregular posterior tibial tendon (Fig. 1). In retrospect, MR imaging revealed a medial malleolar spur on a single coronal T1-weighted image (Fig. 1). The spur was surgically removed and the posterior tibial tendon was repaired. In a second patient, sonography showed symptomatic extensor digitorum longus excursion over a dorsal talar ridge (Fig. 2). Sonography during plantar flexion showed abnormal movement of the extensor digitorum longus over the talar ridge when compared with the opposite asymptomatic side. t surgery, the talar spur was removed with tenolysis of the scarred extensor digitorum longus. Tendon Impingement by Fracture Fragments In two patients, sonography revealed tendon impingement due to osseous fracture fragments. In one patient, a medial malleolar fracture fragment was shown impinging on the posterior tibial tendon. Longitudinal tears were also noted in the posterior tibial tendon (Fig. 3). MR images revealed the fracture fragment with, in retro- spect, a longitudinal split in the posterior tibial tendon. The fracture fragment and tendon tear were surgically repaired. In a second patient, peroneal tendon impingement was shown associated with an irregularity of the distal fibula and multiple distal fibular fracture fragments. With dynamic imaging, the sonography report noted that the tendons were in direct contact with the irregular cortex of the distal fibula. Distal fibular irregularity was revealed on MR imaging. The osseous fragments were surgically removed and the peroneal tendons were repaired. Fig. 1. 32-year-old woman with posteromedial ankle pain., Longitudinal sonogram of posterior tibial tendon (arrowheads) shows small spur in retromalleolar groove of tibia (arrow) causing impingement of posterior tibial tendon., Coronal T1-weighted MR image shows osteophyte at posteromedial tibia (arrow). Osteophyte was not well visualized on other MR sequences or on images obtained in other planes (not shown). Fig. 2. 53-year-old man with pain during palpation of extensor tendons. Transverse sonogram shows enlarged extensor digitorum longus tendon (arrowheads) with small amount of adjacent fluid (curved arrow) caused by impingement of talar osteophyte (straight arrow). 950 JR:179, October 2002
Sonography of nkle Tendon Impingement Downloaded from www.ajronline.org by 162.158.89.91 on 08/23/18 from IP address 162.158.89.91. Copyright RRS. For personal use only; all rights reserved Tendon Impingement by Hardware In two patients, sonography detected tendon impingement due to orthopedic hardware. In one patient, the head of an orthopedic screw, placed for ankle arthrodesis, was shown deviating the peroneal tendons (Fig. 4). During provacative maneuvers, sonography showed the tendons sliding over the screw head. The screw was surgically removed and the peroneal tendons were repaired. In a second patient, tenosynovitis of the anterior tibial tendon and impingement were shown associated with a distal tibial interlocking screw head (Fig. 5). Sonographic assessment during provacative maneuvers revealed a functioning tendon with reproduction of the patient s pain when imaging this region. This patient has not yet undergone surgery to remove the impinging screw. In both patients, the reverberation artifact from the metal hardware occurred deep relative to the hardware, allowing visualization of the overlying tendon [5]. Discussion Impingement of ankle tendons can be associated with pain and decreased function. Tendon impingement can lead to tendinosis, tenosynovitis, and tendon tears. Potential sources of impingement include osteophytes, spurs, fracture fragments, and orthopedic hardware. MR imaging may depict signs of ankle tendon impingement such as tenosynovitis and abnormalities of the tendon. However, small osteophytes, spurs, or fracture fragments may C D E Fig. 3. 27-year-old man with medial malleolar fracture., Transverse sonogram shows fracture fragment (arrow) from retromalleolar groove impinging on posterior tibial tendon (arrowheads)., Transverse sonogram shows posterior tibial tendon (between cursors) with longitudinal split (arrow). C, xial T1-weighted MR image shows medial malleolar fracture fragment (small arrows) adjacent to posterior tibial tendon (large arrow). D, xial proton density weighted MR image shows cleft in posterior tibial tendon (arrow) with surrounding high-signal fluid. E, Coronal T1-weighted MR image shows fracture fragment (arrow) and adjacent posterior tibial tendon (arrowheads). JR:179, October 2002 951
Downloaded from www.ajronline.org by 162.158.89.91 on 08/23/18 from IP address 162.158.89.91. Copyright RRS. For personal use only; all rights reserved Shetty et al. not be visualized on MR imaging because of their low signal intensity, which may be indistinguishable from adjacent low-signal-intensity tendons. CT can provides excellent imaging of bone abnormalities but provides less optimal imaging of tendon abnormalities. oth modalities can be limited by artifacts from hardware, such as streak artifact with CT and ferromagnetic artifact with MR imaging. Neither modality allows imaging during joint motion. Sonography can detect impingement, depict impingement during joint motion, and provide direct correlation with the patient s symptoms. Knowledge of the specific tendons involved in impingement and their associated tendon abnormalities can aid clinical treatment and preoperative planning. Sonographic findings consistent with ankle tendon impingement include an echogenic impinging body (osteophyte, spur, osseous fragment, or orthopedic hardware) contacting a tendon. The course of a tendon may be altered by an impinging body as noted in Figure 4. When tendon impingement is present, there may be associated tendon thinning, tendon thickening, or tenosynovitis. Sonographically, tendinosis is seen as enlargement of the tendon diameter with increased hypoechoic spaces between the echogenic fibrils, whereas tenosynovitis is seen as anechoic or hypoechoic fluid in the tendon sheath with or without tendinosis [1]. Small amounts of tendon sheath fluid can be normal, and in the case of the flexor hallucis longus, tendon sheath fluid can be associated with communication with tibiotalar joint fluid [1, 2]. Tendon tears are shown as disruptions of the uniformly parallel echogenic fibrils by hypoechoic or anechoic clefts or gaps in the tendons [1, 6]. Sonography performed during joint motion may reveal impingement or tendon snapping that may occur only with specific joint movements. Usually the patient is aware of the specific movement that elicits pain or snapping and can perform this movement on command while undergoing sonography. Direct visualization of tendon impingement and reproduction of the patient s symptoms by transducer pressure are highly useful aids for evaluation and diagnosis. Common sites of osteophyte formation of the ankle include the anterior tibiotalar joint, dorsal talus, and talonavicular joint. Repetitive motion such as forced dorsiflexion in dancers can lead to dorsal talar neck osteophytes [7]. Dorsal talar neck osteophytes may also be due to contact between the tibia and the talus in dorsiflexion. These osteophytes can cause impingement on the extensor tendons (Fig. 2). Osteophytes at the anterior tibiotalar joint and tenosynovitis of the extensor hallucis longus tendon can play an important role in causing the symptoms of deep peroneal nerve entrapment, also known as anterior tarsal tunnel syndrome [8]. n enlarged peroneal tubercle can cause peroneal tendon impingement and associated stenosing tenosynovitis [9]. Osseous spurs less commonly affect the posterior tibial tendon but can occur in the medial malleolar groove (Fig. 1). Sonography may have a useful role in the evaluation of both the spur and associated tendon abnormality. Sonography can also reveal ankle tendon impingement due to fracture fragments. Medial or lateral malleolar fractures, as well as calcaneal fractures, can entrap the medial or peroneal tendons [10]. Fracture fragments from these sites can also abrade the tendons and result in tendon impingement and decreased function. Early detection can allow effective treatment and prevent further tendon damage. Orthopedic hardware in the ankle is common. Such hardware can include screws, plates, and suture anchors used in ankle arthrodesis, fracture fixation, and ligament reconstruction. Tendon impingement caused by hardware may be difficult to assess with CT or MR imaging because of artifact from the metal. On sonogra- Fig. 4. 40-year-old woman with lateral ankle pain after tibiotalar joint fusion., Lateral radiograph shows multiple screws with one screw head (arrow) posterior to fibula in expected location of peroneal tendons., Longitudinal sonogram obtained at lateral ankle shows echogenic screw head (large arrow) deviating peroneal tendons (arrowheads). Reverberation artifact is shown deep relative to screw head (small arrows). 952 JR:179, October 2002
Sonography of nkle Tendon Impingement Downloaded from www.ajronline.org by 162.158.89.91 on 08/23/18 from IP address 162.158.89.91. Copyright RRS. For personal use only; all rights reserved phy, artifact occurs deep relative to the hardware, allowing visualization of the overlying tendon. Radiographs can provide clues regarding possible tendon impingement on the basis of the expected tendon anatomy in the region of the hardware. Sonography enables direct visualization of the impingement and associated tendon abnormalities (Figs. 4 and 5). Limitations of our preliminary study include a small number of patients. In one patient, surgery has not yet been performed for correlation. This study does not determine the statistical accuracy of sonography or MR imaging for assessing ankle tendon impingement or ankle tendon abnormalities. Further study is needed to assess the usefulness of sonography in cases of suspected ankle tendon impingement. In conclusion, sonography can be helpful in identifying ankle tendon impingement due to osteophytes, fracture fragments, and orthopedic hardware. In such cases, dynamic sonography can aid in the assessment of ankle tendon impingement. References Fig. 5. 59-year-old woman with anterior ankle pain., Lateral radiograph shows interlocking screw head (arrow) anterior to cortex of distal tibia., Longitudinal sonogram obtained at anterior ankle shows echogenic screw head (large arrow) impinging on anterior tibial tendon (arrowheads). Reverberation artifact is shown deep relative to screw head. Note associated tenosynovitis of anterior tibial tendon (small arrows). 1. Fessell DP, Vanderschueren GV, Jacobson J, et al. US of the ankle: technique, anatomy, and diagnosis of pathologic conditions. RadioGraphics 1998;18:325 340 2. Rawool NM, Nazarian LN. Ultrasound of the ankle and foot. Semin Ultrasound CT MR 2000;21:275 284 3. Jacobson J, Jebson PJ, Jeffers W, Fessell DP, Hayes CW. Ulnar nerve dislocation and snapping triceps syndrome: diagnosis with dynamic sonography report of three cases. Radiology 2001;220:601 605 4. Hartgerink P, Fessell DP, Jacobson J, van Holsbeeck MT. Full- versus partial-thickness chilles tendon tears: sonographic accuracy and characterization in 26 cases with surgical correlation. Radiology 2001;220:406 412 5. Moed R, Subramanian S, van Holsbeeck M, et al. Ultrasound for the early diagnosis of tibial fracture healing after static interlocked nailing without reaming: clinical results. J Orthop Trauma 1998;12:206 213 6. Waitches GM, Rockett M, rage M, Sudakoff G. Ultrasonographic-surgical correlation of ankle tendon tears. J Ultrasound Med 1984;17:249 256 7. Ogilvie-Harris DJ, Mahomed N, Demaziere. nterior impingement of the ankle treated by arthroscopic removal of bony spurs. J one Joint Surg r 1993;3:437 440 8. Masciocchi C, Catalucci, arile. nkle impingement syndromes. Eur J Radiol 1998;27[suppl 1]:70S 73S 9. ruce WD, Christofersen MR, Phillips DL. Stenosing tenosynovitis and impingement of the peroneal tendons associated with hypertrophy of the peroneal tubercle. Foot nkle Int 1999;20:464 467 10. Carr J. Complications of calcaneus fractures entrapment of the flexor hallucis longus: report of two cases. J Orthop Trauma 1990;4:166 168 JR:179, October 2002 953