Technical dvance Sonographically Guided Flexor Hallucis Longus Tendon Sheath Injection mir Mehdizade, MD, Ronald S. dler, PhD, MD Objective. The purpose of this study was to describe a sonographically guided technique to perform flexor hallucis longus (FHL) tendon sheath injections. Methods. Scans were performed with an intermediate-frequency (7.5- to 12-MHz) linear transducer with the scan plane corresponding to the anatomic axial plane and the patients positioned prone. The transducer was placed along the posteromedial ankle with the needle entry point being lateral to the chilles tendon. 25-gauge, 1.5-in needle or a 22-gauge spinal needle was positioned directly into the tendon sheath during real-time visualization with injection of a standardized therapeutic mixture (anesthetic and long-acting corticosteroid) at the level of the posterior sulcus for the FHL. Distention of the tendon sheath during real-time visualization was considered a successful injection. Results. Twenty-four injections in 20 patients (12 female and 8 male; age range, 22 64 years) were performed with this technique. In each case, distention of the FHL tendon sheath was obtained as the desired end point. part from minor paresthesias from local anesthesia, no long-term complications from these injections have occurred to date. Conclusions. We describe a method to perform sonographically guided injections of the FHL tendon sheath. Sonography provides several distinct advantages as a method to provide guidance for delivery of therapeutic injections. The most important of these is the ability to visualize the needle and make adjustments in real time to ensure that medication is delivered to the appropriate location. Given these advantages, we propose that sonographic guidance provides an excellent alternative in the administration of corticosteroids to the FHL tendon sheath. Key words: ankle sonography; flexor hallucis longus; sonographically guided injection; tendon sheath injection. bbreviations FHL, flexor hallucis longus Received July 11, 2006, from the Department of Radiology and Imaging, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York US. Revision requested ugust 1, 2006. Revised manuscript accepted for publication October 10, 2006. ddress correspondence to Ronald S. dler, PhD, MD, Department of Radiology and Imaging, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 E 70th St, New York, NY 10021 US. E-mail: adlerr@hss.edu Stenosing tenosynovitis is the development of fibrous adhesions within a tendon sheath, often as the sequela of trauma such as a malleolar or calcaneal fracture or because of chronic repetitive trauma. Stenosing tenosynovitis of the flexor hallucis longus (FHL) tendon sheath has been well described in ballet dancers and to a lesser extent in running and jumping athletes. 1,2 Conservative approaches to therapy include rest and oral nonsteroidal anti-inflammatory medication, as well as tendon sheath injection with an anesthetic and a corticosteroid. This has typically been performed as a blind technique or under fluoroscopic guidance. 3,4 We describe an alternative technique to perform FHL tendon sheath injections, which uses sonographic guidance. Sonographically guided injection has many advantages over other modalities such as fluoroscopy and computed tomography and has been described for a variety of musculoskeletal applications. 3 11 The real-time nature of sonography makes it ideally suited to provide 2007 by the merican Institute of Ultrasound in Medicine J Ultrasound Med 2007; 26:233 237 0278-4297/07/$3.50
Flexor Hallucis Longus Tendon Sheath Injection guidance for therapeutic delivery of corticosteroids and local anesthesia. number of publications have appeared illustrating the efficacy of this method for the performance of musculoskeletal interventional procedures. 3 12 Continuous observation of the needle position ensures proper placement, providing continuous monitoring of the distribution of the therapeutic agent during administration of long-acting corticosteroids and anesthetics. The potential deleterious effects of not attaining proper needle placement are well documented. 11 16 Real-time sonography allows direct visualization of the needle tip position in relation to the neurovascular bundle, thereby enabling it to be avoided. The position of the FHL relative to the neurovascular bundle presents a challenge in attaining proper needle position. s a result, patient position and the needle entry point must be optimized to successfully inject the tendon sheath under sonographic guidance. Sonographic Technique Proper positioning of the affected ankle is critical for determining the trajectory of the injection needle. Patients were placed in a prone position. folded towel was placed under the ankle to elevate the foot from the table (Figure 1). s is evident in Figures 2 and 3, the needle entry point was placed deep to the lateral margin of the chilles tendon, while scanning along the posteromedial margin of the ankle was performed. This allowed direct visualization of the FHL within the posterior talar sulcus, as well as the neurovascular bundle (artery, paired veins, and nerve). In our experience, needle positioning has usually been proximal to the bifurcation of the Figure 2., Diagram of medial ankle tendons showing the FHL coursing under the sustentaculum tali. PTT indicates posterior tibial tendon. The FHL is the deepest of the 3 poster medial ankle muscle-tendon units. The tendon abuts the posterior capsule of the ankle joint and talus almost in the midline of the leg. It then courses under the sustentaculum tali of the calcaneus as it passes toward the great toe or hallux. The neurovascular bundle, containing the posterior tibial nerve, artery, and paired veins, courses immediately superficial to the medial aspect of the FHL tendon., ird s eye view of the posterior ankle showing the transducer and needle position during placement, with the corresponding transverse sonographic image of the posterior ankle. Figure 1. The patient is placed in the prone position on the sonography table. It is important to elevate the table so that the radiologist is in a comfortable position to perform the injection. The transducer is placed along the posteromedial aspect of the ankle. The FHL and the neurovascular bundle are viewed in the axial plane. The needle is placed with the use of a lateral approach deep to the chilles tendon. 234 J Ultrasound Med 2007; 26:233 237
Mehdizade and dler Figure 3., Transverse sonogram of the posterior ankle showing the FHL tendon (arrow) in the posterior sulcus of the talus and the neurovascular bundle (arrowhead)., Corresponding axial proton density magnetic resonance image showing the anatomic location of the FHL (arrow) within the posterior sulcus, the needle trajectory (dotted line), and the ultrasound probe (rectangle). C, With the use of a short axis approach, a needle (n) is seen along the deep margin of the tendon for test injection with 1% lidocaine. posterior tibial nerve into medial and lateral plantar branches. Skin anesthesia was obtained with injection of 1 ml of 1% lidocaine through a 25-gauge, 1.5-in needle. The same needle was then advanced within the tendon sheath under direct sonographic guidance. If the patient had preexisting tendon effusion, the needle was positioned directly into the distended tendon sheath, and the therapeutic mixture was delivered (Figure 4). lternatively, if there was no preexisting effusion, the needle was Figure 4. Transverse () and longitudinal () sonograms of the FHL after injection of the steroid/anesthetic mixture and removal of the needle. The anesthetic/steroid mixture appears as a hypoechoic fluid collection tracking along the tendon (arrows) and confined by the tendon sheath. There is improved conspicuity of the tendon margins due to a tenosonographic effect. C J Ultrasound Med 2007; 26:233 237 235
Flexor Hallucis Longus Tendon Sheath Injection positioned deep to the tendon within the sulcus, and a series of small test injections with 1% lidocaine were performed to distend the tendon sheath and ensure appropriate needle position (Figure 4). therapeutic mixture was then delivered during real-time observation. Distension of the tendon sheath was confirmed by the appearance of a characteristic contrast effect resulting from the steroid/anesthetic mixture. Fluid distension of the sheath resulted in a tenosonographic effect, also enabling improved visualization of the tendon margins. Scans were performed with an intermediatefrequency linear transducer with the scan plane corresponding to the anatomic axial plane. To date, we have used either a 7.5-MHz transducer and a Sonoline Elegra scanner (Siemens Medical Solutions, Mountain View, C) or a 12 5-MHz linear transducer with an IU22 scanner (Philips Medical Systems, othell, W). Injection Materials Once the needle is in position, the procedure is undertaken while imaging in real time. 25- gauge needle (or, as needed, a spinal needle) is used. The anesthetic/corticosteroid mixture is typically 0.5 ml of 1% lidocaine, 0.5 ml of 0.5% bupivacaine (Sensorcaine), and 1 ml (40 mg) of triamcinolone (Kenalog; pothecon, ristol- Myers Squibb Company, Princeton, NJ) or some equivalent long-acting agent. 9 11 Distension of the tendon sheath (Figure 4), seen in real time, is used as the determining factor for a successful injection. Results The Institutional Review oard approved this retrospective study and issued a waiver of informed consent for review of the sonographic reports and clinical data. etween January 1 and December 4, 2005, we performed this injection in 20 patients (12 female and 8 male; age range, 22 64 years). In each case, distension of the FHL tendon sheaths was obtained as the end point of a successful injection. There has been no complication in any injections performed in this cohort and to date. Discussion The foot and ankle can be involved in many acute and chronic pathologic processes that require accurate diagnosis and treatment. Sonography has been shown to provide an accurate means to guide diagnostic aspiration and both diagnostic and therapeutic injection for a variety of different abnormalities in the musculoskeletal system. 9 11 Injections are performed during real-time observation, thereby ensuring appropriate deposition of the therapeutic agent. Furthermore, direct visualization of neurovascular structures allows one to avoid these structures during needle placement. Stenosing tenosynovitis of the FHL sheath has been described in ballet dancers and to a lesser extent in running and jumping athletes, and it may be associated with posterior ankle impingement. allet dancing is a predisposing condition (as dancers go from the flat foot to the en pointe position), and at least 8 of our female patients were ballet dancers. There is swelling, pain, and tenderness posterior to the medial malleolus; triggering and pain along the tendon sheath may occur with toe flexion. Dorsiflexion of the great toe may be reduced when the ankle is placed in dorsiflexion. The FHL tendon lies deep within the tarsal tunnel, and it is immediately adjacent to the neurovascular bundle. This makes for challenging localization and potential complications during needle placement. We currently use the sonographically guided technique as the method of choice rather than the palpation technique for a variety of reasons: With sonographically guided injection, there is direct visualization of the soft tissue compartment of the tarsal tunnel throughout the procedure, allowing circumvention of the neurovascular bundle. Unlike fluoroscopy, there is no ionizing radiation. lternative fluoroscopically guided injections require careful patient positioning, and only minimal amounts of a contrast medium are injected initially to avoid obscuring the area of interest. Some authors describe a direct puncture nearly perpendicular to the FHL sheath, immediately under the sustentaculum tali. 16 236 J Ultrasound Med 2007; 26:233 237
Mehdizade and dler We have described a sonographically guided technique of performing FHL tendon sheath injections. In our experience, this is a relatively easy technique, requiring a short learning curve to develop proficiency. The risk is small. part from temporary paresthesia, we have encountered no serious complications to date. resulting tenosonographic effect can play an important complementary diagnostic role in noninvasive imaging. We have performed this procedure on approximately 20 ankles over the past year. Prior reports described opacification of the FHL sheath only under fluoroscopy, which involves indirect identification of the tendon that courses under the sustentaculum tali of the calcaneus. With sonographically guided injection, there is direct visualization of the soft tissue throughout the procedure, thereby avoiding the neurovascular bundle that runs in the vicinity. We did not find any contraindication to this procedure. Two of the patients who had successful injections were obese. Typically, they can be performed in approximately 15 minutes, including preparation time. In conclusion, sonography provides several distinct advantages as a method for guiding delivery of therapeutic injections. The most important of these is the ability to visualize the needle and make adjustments in real time to ensure that the medication is delivered to the appropriate location. Given these advantages, we think that sonographic guidance provides an excellent alternative in the administration of corticosteroids to the FHL tendon sheath. 5. Sofka CM, dler RS. Ultrasound guided interventions in the foot and ankle. Semin Musculoskelet Radiol 2002; 6:163 168. 6. Christensen R, Van Sonnenberg E, Casola G, Wittich GR. Interventional ultrasound in the musculoskeletal system. Radiol Clin North m 1988; 26:145 156. 7. Cunnane G, rophy DP, Gibney RG, FitzGerald O. Diagnosis and treatment of heel pain in chronic inflammatory arthritis using ultrasound. Semin rthritis Rheum 1996; 25:383 389. 8. rophy DP, Cunnane G, FitzGerald O, Gibney RG. Technical report: ultrasound guidance for injection of soft tissue lesions around the heel in chronic inflammatory arthritis. Clin Radiol 1995; 50:120 122. 9. Cardinal E, Chhem RK, eauregard CG. Ultrasound-guided interventional procedures in the musculoskeletal system. Radiol Clin North m 1998; 36:597 604. 10. Koski JM. Ultrasound guided injections in rheumatology. J Rheumatol 2000; 27:2131 2138. 11. Unverferth LJ, Olix ML. The effect of local steroid injections on tendon. J Sports Med 1973; 1:31 37. 12. Ford LT, Deender J. Tendon rupture after local steroid injection. South Med J 1979; 72:827 830. 13. Gottlieb NL, Riskin WG. Complications of local corticosteroid injections. JM 1980; 243:1547 1548. 14. ianchi S, Martinoli C, Gaignot C, De Gautard R, Meyer JM. Ultrasound of the ankle: anatomy of the tendons, bursae, and ligaments. Semin Musculoskelet Radiol 2005; 9:243 259. 15. Hamilton WG. Stenosing tenosynovitis of the flexor hallucis longus tendon and posterior impingement upon the os trigonum in ballet dancers. Foot nkle 1982; 3:74 80. 16. Na J, ergman G, Oloff LM, eaulieu CF. The flexor hallucis longus: tenographic technique and correlation of imaging findings with surgery in 39 ankles. Radiology 2005; 236:974 982. References 1. Sammarco GJ, Cooper PS. Flexor hallucis longus tendon injury in dancers and nondancers. Foot nkle Int 1998; 19:356 362. 2. Theodore GH, Kolettis GJ, Micheli LJ. Tenosynovitis of the flexor hallucis longus in a long-distance runner. Med Sci Sports Exerc 1996; 28:277 279. 3. Grassi W, Farina, Filippucci E, Cervini C. Sonographically guided procedures in rheumatology. Semin rthritis Rheum 2001; 30:347 353. 4. Sofka CM, Collins J, dler RS. Use of ultrasonographic guidance in interventional musculoskeletal procedures: a review from a single institution. J Ultrasound Med 2001; 20:21 26. J Ultrasound Med 2007; 26:233 237 237