Accuracy of Ultrasound-Guided versus Unguided Pes Anserinus Bursa Injections

Original Research

Accuracy of Ultrasound-Guided versus Unguided Pes Anserinus Bursa Injections Jonathan T. Finnoff, DO, David J. Nutz, MD, Philip T. Henning, DO, John H. Hollman, PT, PhD, Jay Smith, MD Objective: To compare the accuracy of ultrasound (US)-guided versus unguided pes anserinus bursa injections in a cadaveric model. Design: Single blind, prospective study. Setting: Academic institution procedural skills laboratory. Participants: Twenty-four unembalmed, unpaired adult cadaveric lower extremity specimens. Methods: A single investigator performed 12 US-guided and 12 unguided pes anserinus bursa injections using colored liquid latex into 24 unembalmed adult cadaveric lower extremity specimens. The order of the injection techniques was randomized. The specimens were subsequently dissected by a co-investigator blinded to the injection technique used for each injection. Main Outcome Measures: The injections were graded for accuracy as follows: accurate (all injectate contained within the pes anserinus bursa), accurate with overflow (injectate within the pes anserinus bursa, but also located in adjacent structures), or inaccurate (injectate not within the pes anserinus bursa). The accuracy of the 2 approaches was compared using Pearson ␹2 test with Williams’ correction for the small sample size (P ⫽ .05). Results: The accuracy rate was 92% (11 of 12 specimens) in the US-guided condition and 17% (2 of 12 specimens) in the unguided condition. One US-guided injection was considered accurate with overflow, whereas 4 unguided injections were accurate with overflow. The US-guided injection technique was significantly more accurate than the unguided technique (Williams-corrected ␹2 ⫽ 12.528, P ⬍ .01). Conclusions: Despite its superficial location, unguided pes anserinus bursa injections rarely place the injectate within the pes anserinus bursa, whereas US-guided pes anserinus bursa injections have a high degree of accuracy. Therefore, clinicians should consider using US-guidance for diagnostic or therapeutic pes anserinus bursa injections when indicated. PM R 2010;2:732-739

INTRODUCTION The pes anserinus is a conjoint tendon formed by coalescence of the sartorius, gracilis, and semitendinosus tendons, and inserts onto the proximal anteromedial tibia approximately 5 cm distal to the medial tibial joint line [1-3]. Contraction of the 3 muscles that form the pes anserinus results in knee flexion and tibial internal rotation [4]. Deep to the pes anserinus tendon lies the pes anserinus bursa, which serves to reduce friction between the superficially located pes anserinus tendon, and the structures that lie deep to it including the medial tibia and the medial collateral ligament (MCL) [2]. Pes anserinus bursitis, a condition caused by repetitive friction over the bursa or direct trauma, was first described in 1937 [4,5]. Numerous reports regarding the prevalence, clinical presentation, diagnostic evaluation, and treatment of pes anserinus bursitis have been published since that time [1-4,6-26]. The reported prevalence of pes anserinus bursitis is between 2.5% and 70% in patients with knee pain and occurs more frequently in females, and those with any of the following: osteoarthritis, rheumatoid arthritis, diabetes mellitus, and obesity [3,4,6,7,10,13,17,18,27]. Patients usually present with proximal medial PM&R

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J.T.F. Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Mayo Clinic Sports Medicine Center, 200 First St SW, Rochester, MN 55905. Address correspondence to: J.T.F.; e-mail: finnoff.jonathan@ mayo.edu Disclosure: nothing to disclose D.J.N. Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN Disclosure: nothing to disclose P.T.H. Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Mayo Clinic Sports Medicine Center, Rochester, MN Disclosure: nothing to disclose J.H.H. Physical Therapy, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN Disclosure: nothing to disclose J.S. Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Mayo Clinic Sports Medicine Center, Rochester, MN Disclosure: nothing to disclose Disclosure Key can be found on the Table of Contents and at www.pmrjournal.org Financial support for this project was provided through the small grants program of the Mayo Clinic. Submitted for publication December 22, 2009; accepted March 8, 2010.

© 2010 by the American Academy of Physical Medicine and Rehabilitation Vol. 2, 732-739, August 2010 DOI: 10.1016/j.pmrj.2010.03.014

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tibial pain and swelling 4-5 cm distal to the medial tibial joint line [1,13]. Symptoms frequently are misinterpreted as an injury to the medial meniscus or MCL [13]. Rising from a seated position or ascending or descending stairs may aggravate their symptoms [1]. Patients with pes anserinus bursitis will be tender to palpation in the region of their pes anserinus bursa and may have local edema [1]. Typically, the diagnosis of pes anserinus bursitis is clinical, but diagnostic studies such as computed tomography, ultrasound (US), and magnetic resonance imaging can be used to evaluate this condition if the diagnosis is in question [1,2,8,9,13,15,22,23,25,28]. However, diagnostic studies are often normal despite the existence of symptoms and physical examination findings consistent with pes anserinus bursitis [1,4,8-11,14,17,18]. The treatment of pes anserinus bursitis includes avoidance of aggravating activities, local modalities such as heat, ice, US, electrical stimulation, iontophoresis, and phonophoresis; nonsteroidal anti-inflammatory drugs, and injections with either corticosteroid medications or local anesthetics [1,3,5-7,9,14,16,18,21,23-27]. Although there is no uniformly effective treatment for this condition, corticosteroid injections reportedly improve symptoms in approximately 33%-100% of patients [1,6,14,16,18,25,27]. Multiple factors may explain the discrepancy in responses between studies including differences in study design, diagnostic criteria used to define pes anserinus bursitis, follow-up duration, type of corticosteroid, injectate volume, and injection technique. Few reports exist describing how to perform a pes anserinus bursa injection [14,29]. In general, the subject is in a supine position with the affected leg extended and externally rotated. The subject’s point of maximal tenderness is identified via palpation, and a needle is inserted perpendicular to the skin and advanced until the medial tibia is contacted, at which time the needle is withdrawn approximately 2-3 mm and the injectate is delivered. Although this technique likely places the needle tip in the region of the pes anserinus bursa, to our knowledge, no study has evaluated the accuracy of this injection technique. Moreover, several research studies have demonstrated that unguided soft-tissue and intra-articular injections are frequently inaccurate [30-40]. With mounting evidence that the therapeutic efficacy of an injection may be related to its accuracy [33,37,38,41], it is possible that the highly variable therapeutic response to pes anserinus bursa injections may be due to the inaccuracy of unguided pes anserinus bursa injection techniques. Multiple studies have demonstrated the ability of US to accurately guide intra-articular and soft-tissue injections [4257]. US has many advantages over other imaging modalities used to guide procedures, including a lack of ionizing radiation exposure to the patient or physician, portability, low cost, real-time dynamic imaging capabilities, and lack of contraindications. Furthermore, US has the ability to image

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all of the structures relevant to performing a pes anserinus bursa injection including the pes anserinus tendons, medial tibia, tibial insertion of the MCL, saphenous nerve, great saphenous vein, and inferior medial geniculate and anterior tibial recurrent arteries [1,8,9,11,14,25]. However, to our knowledge, no study has determined the accuracy of USguided pes anserinus bursa injections. Therefore, the primary aim of this study was to describe an US-guided pes anserinus bursa injection technique, and to compare the accuracy of US-guided versus unguided pes anserinus bursa injections.

METHODS General A single investigator (J.S.) performed 12 unguided and 12 US-guided pes anserinus bursa injections using diluted colored liquid latex into 24 unembalmed adult cadaveric lower extremity specimens. At the time of the study, the investigator performing the injections had more than 5 years of experience performing sonographically guided injections, and more than 10 years of experience performing unguided pes anserinus bursa injections. All injections were completed in the Mayo Clinic Procedural Skills Laboratory and cadaveric specimens were obtained through the Department of Anatomy’s Mayo Foundation Bequest Program. The anatomic specimens were fully thawed at room temperature immediately before the study. Only one injection was performed on each specimen and the same color of liquid latex was used for US-guided and unguided injections. The order of the injection techniques was randomized. The specimens were subsequently dissected by co-investigators, who were blinded to the injection technique (US-guided versus unguided) used for each injection, and the injections were graded for accuracy. The project was approved by the Mayo Clinic Bio-Specimens Subcommittee of the Institutional Review Board.

Anatomic Specimens Twenty-four unembalmed adult cadaveric lower extremity specimens were used. No specimen demonstrated signs of prior surgery, trauma, or major deformity about the knee. Specimens were labeled 1 through 24, and the side (left versus right) of each specimen was recorded. Specimens were used for the investigation based upon availability and therefore were not necessarily paired (ie, left and right knee from same donor).

Equipment All procedures were performed with a Philips iU22 Ultrasound machine (Philips Ultrasound Systems, Bothell, WA), using a 17-5 MHz linear array transducer with a 38-mm

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footprint, standard US gel, and a 25-gauge, 38-mm stainless steel needle. The injectate consisted of colored latex solution diluted by 50% with tap water.

Unguided Pes Anserinus Bursa Injection Technique The unguided pes anserinus bursa injection technique used in this study was similar to the technique described in previous studies [14,29]. The cadaveric lower extremity specimen was placed in a slightly externally rotated position such that the pes anserinus region was facing upward, and the posterolateral aspect of the knee was facing the table. The knee was placed in slight flexion by placing a rolled towel beneath the knee. Because cadaveric specimens were used for this study and, therefore, the bursa could not be identified via the point of maximal tenderness, the pes anserinus bursa was localized sonographically by the principal investigator (J.S.). This minimized the possibility that an inaccurate unguided injection was related to starting the injection in the incorrect anatomic location. The following systematic sonographic scanning technique was used to identify the location of the pes anserinus bursa. The transducer was placed on the posteromedial aspect of the distal thigh in an anatomic transverse plane. In this position, the semitendinosus tendon was identified as an echogenic, oval fibrillar structure superficial and medial to the semimembranosus muscle. The transducer was glided distally along the semitendinosus tendon until the gracilis and sartorius tendons and saphenous nerve were visualized (Figure 1). As the transducer progressed distally, the saphenous nerve gradually moved superficially across the gracilis and semitendinosus tendons to assume its position posterior

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to the three tendons of the pes anserinus. Although the great saphenous vein was not readily visualized in the cadaveric specimens, its normal anatomic location is also posterior to the sartorius, gracilis, and semitendinosus tendons adjacent to the saphenous nerve [58]. The transducer was gradually translated anteromedially as the tendons were followed distally, and was gradually rotated (clockwise in the right knee and counterclockwise in the left knee) to maintain a true transverse view of the tendons. The tendons were visualized coursing superficial to the MCL at which time the tendons began to coalesce and form the pes anserinus. The inferior medial geniculate artery is located deep to the MCL in this region, and although this artery is easily identifiable in vivo, it was only occasionally visualized in the cadaveric specimens of this study [58]. At the point where the pes anserinus crossed over the anterior fibers of the MCL, the transducer was repositioned in a longitudinal orientation relative to the anterior fibers of the MCL and an oblique transverse orientation relative to the pes anserinus. In this position, the pes anserinus bursa is located between the pes anserinus and the MCL (Figure 2). With an indelible marker, a mark was placed on the skin, over the middle of the pes anserinus where it crossed the anterior margin of the MCL. This mark represented the central region of the pes anserinus bursa. After identifying the location of the pes anserinus bursa and placing a mark on the skin indicating its location, a 25-gauge 38-mm stainless steel needle was introduced through the mark, perpendicular to the skin, and advanced until os was contacted. The needle was withdrawn approximately 2-3 mm, and 2 mL of 50% diluted colored liquid latex

Figure 1. (a) Cadaveric dissection of the medial knee demonstrating the anatomic relationship of the sartorius (A), gracilis (B), and semimembranosus (C) and semitendinosus (D) tendons as they course distally to form the pes anserinus (asterisk). The black rectangle represents the transducer position used for (b). Left ⫽ distal, right ⫽ proximal, top ⫽ anterior, bottom ⫽ posterior. (b) Transverse oblique ultrasound image of the posterior medial knee demonstrating the semitendinosus (A), semimembranosus (B), and gracilis (C) tendons, and the sartorius (D) muscle. The saphenous nerve is encircled by the white oval and lies between the sartorius and gracilis tendons. Left ⫽ posterolateral; right ⫽ anteromedial; top ⫽ superficial; bottom ⫽ deep.

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rior fibers of the MCL, and an oblique transverse orientation relative to the pes anserinus. While maintaining this image, a 25-gauge 38-mm stainless steel needle was introduced through the skin distal to the transducer and advanced in a distal to proximal direction in a longitudinal axis relative to the transducer and advanced through the middle of the pes anserinus into the tissue plane between the pes anserinus and the MCL (Figure 3). When the needle tip was visualized between the middle of the pes anserinus and the MCL, 2 mL of 50% diluted colored liquid latex was injected under direct sonographic visualization. Figure 2. Ultrasound image over the anterior fibers of the medial collateral ligament (MCL with horizontal arrow) and pes anserinus (3 downward pointing arrows). The pes anserinus bursa is located in the potential space between the MCL and pes anserinus. Left ⫽ proximal; right ⫽ distal; top ⫽ superficial; bottom ⫽ deep.

was injected in this location. This was the same volume of injectate reported in previous studies [1,7,59].

US-guided Pes Anserinus Bursa Injection Technique The cadaveric lower extremity specimen was placed in the same position described for the unguided pes anserinus bursa injection technique and the same systematic sonographic scanning technique was used to identify the pes anserinus bursa. At the point where the pes anserinus crossed over the anterior fibers of the MCL, the transducer was positioned in a longitudinal orientation relative to the ante-

Postinjection Assessment At a minimum of 24 hours postinjection, an investigator other than the one performing the injection dissected the anatomic specimen to determine the location of the colored latex injectate (Figure 4). The co-investigator was blinded to the injection technique (US-guided versus unguided) used on each cadaver. The location of the colored liquid latex was graded using the following scale: accurate (all injectate contained within the pes anserinus bursa), accurate with overflow (injectate within the pes anserinus bursa, but also located in adjacent structures other than the needle track), or inaccurate (injectate not within the pes anserinus bursa).

Power Analysis A sample size of 24 specimens, 12 in the US-guided injection group and 12 in the unguided injection group, provides 70% power to detect a difference in injection accuracy equivalent

Figure 3. (a) Anatomic dissection of the medial knee demonstrating the pes anserinus (asterisk), medial collateral ligament (MCL), and sartorius (A), gracilis (B), and semitendinosus (C) tendons, with a needle placed into the pes anserinus bursa. The black rectangle over the needle demonstrates the orientation of the transducer used for (b). Left ⫽ distal; right ⫽ proximal; top ⫽ anterior; bottom ⫽ posterior. (b) Coronal oblique ultrasound image of a needle (white chevrons) in the pes anserinus bursa (asterisk) between the MCL (black arrows) and the pes anserinus (PES). Left ⫽ proximal; right ⫽ distal; top ⫽ superficial; bottom ⫽ deep.

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Table 2. Pes anserinus bursa injection accuracy using a 2-category grading scale Technique

Combined Accurate*

Inaccurate†

US-guided Unguided

12/12 (100%) 6/12 (50%)

0 6/12 (50%)

*All injectate contained within the pes anserinus bursa or some of the injectate contained within the pes anserinus bursa and some outside of the pes anserinus bursa. † Injectate not within the pes anserinus bursa.

pes anserinus bursa in both of these categories, and therefore, one could consider both of these injections are accurate enough for therapeutic injections. The combined accurate category was compared with the inaccurate category using Pearson ␹2 test with Yates’ correction for continuity because 2 cells in the contingency table had expected frequencies less than 5 (P ⫽ .05). All analyses were conducted using SPSS 15.0 for Windows (SPSS Inc, Chicago, IL).

RESULTS Figure 4. Anatomic dissection of the medial knee demonstrating solidified colored latex (dark structure) in the pes anserinus bursa. The pes anserinus (retracted by surgical loop) lies over the latex. Left ⫽ proximal; right ⫽ distal; top ⫽ anterior; bottom ⫽ posterior.

to a 90% accuracy rate in the US-guided condition and a 50% accuracy rate in the unguided condition.

Statistical Analysis Descriptive statistics were used to report the results of the US-guided and unguided pes anserinus bursa injection techniques. Because the accuracy of the injections was measured with an ordinal scale (1 ⫽ accurate, 2 ⫽ accurate with overflow, 3 ⫽ inaccurate), the accuracy of the US-guided and unguided pes anserinus bursa injection techniques were compared using Pearson ␹2 test with Williams’ correction for the small sample size (P ⫽ .05). A second analysis was performed in which the accurate and accurate with overflow categories were evaluated collectively as a “combined accurate” category because some injectate was found within the Table 1. Pes anserinus bursa injection accuracy using a three category grading scale Technique

Accurate*

Accurate with Overflow†

Inaccurate‡

US-guided Unguided

11/12 (92%) 2/12 (17%)

1/12 (8%) 4/12 (33%)

0 6/12 (50%)

*All injectate contained within the pes anserinus bursa. † Injectate within the pes anserinus bursa, but also located in adjacent structures other than the needle track. ‡ Injectate not within the pes anserinus bursa.

The accuracy data using the 3-category grading system are presented in Table 1. The accuracy rate was 92% (11 of 12 injections) for the US-guided injections. One of 12 USguided injections (8%) was considered accurate with overflow because liquid latex was found both in the pes anserinus bursa and in the MCL. No US-guided injections were inaccurate. In contrast, the accuracy rate was 17% (2 of 12 injections) for the unguided injections. Four of 12 unguided injections (33%) were considered accurate with overflow because injectate was found not only in the pes anserinus bursa, but also within (n ⫽ 1) or deep (n ⫽ 2) to the MCL, or superficial to the pes anserinus tendons (n ⫽ 1). Fifty percent (6 of 12 injections) of the unguided injections were inaccurate because no injectate was found within the pes anserinus bursa, but rather deep to the MCL (n ⫽ 4), in the semimembranosus tendon (n ⫽ 1), or in the popliteus muscle (n ⫽ 1). The US-guided injection technique was significantly more accurate than the unguided injection technique (Williamscorrected ␹2 ⫽ 12.528, P ⬍ .01). When the accurate and accurate with overflow categories were evaluated collectively in a combined accuracy category, the accuracy rate for US-guided injections was 100%, whereas the accuracy rate for unguided injections was 50% (Table 2). Despite defining injection accuracy in a less stringent manner, the difference in accuracy between the USguided injection technique and the unguided injection technique remained statistically significant (Yates’ corrected ␹2 ⫽ 5.556, P ⫽ .018).

DISCUSSION The current investigation represents the first description of an US-guided pes anserinus bursa injection technique, and

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the first study comparing the accuracy of US-guided and unguided pes anserinus bursa injection techniques. Our results demonstrate that US-guided pes anserinus bursa injections are highly accurate, with accuracy rates between 92% and 100% depending on how “accuracy” is defined. Unguided pes anserinus bursa injections have poor accuracy with accuracy rates between 17% and 50%. These findings were statistically significant despite the small sample size used in this study. However, beyond statistical significance, these findings may also have clinical significance based on previous studies that have reported better clinical outcomes following accurately placed injections relative to inaccurately placed injections [33,37,38,41]. Therefore, the results of our study may have direct clinical implications and future research should consider investigating whether accurately placed pes anserinus bursa injections provide more therapeutic benefit than inaccurately placed pes anserinus bursa injections. The high degree of accuracy demonstrated by the USguided pes anserinus bursa injections in this study is in agreement with previous research investigating the accuracy of US-guided injections [42-57]. Although it is tempting to assume that all US-guided injections will demonstrate this level of accuracy, studies are required to confirm this supposition. Therefore, the current study was important to establish scientifically that US-guided pes anserinus bursa injections are exceedingly accurate. Despite the findings of previous investigators suggesting unguided soft-tissue and intra-articular injections are frequently inaccurate [30-40], we were surprised by the degree of inaccuracy demonstrated by the unguided pes anserinus bursa injections in this study because of its superficial location. In addition, because the study was performed in a cadaveric model and pes anserinus bursa location could not be determined via palpation, the pes anserinus bursa was identified sonographically and a mark was placed on the skin directly above the center of the pes anserinus tendons before the unguided injection. Thus, despite knowing the exact location of the pes anserinus, unguided injections usually did not place the injectate into the pes anserinus bursa. It may be suggested that the reason the unguided injection did not place the injectate within the pes anserinus bursa was due to the inadequate or excessive amount the needle was withdrawn after contacting the medial tibia and before delivering the injectate. However, because the injectate of accurate with overflow and inaccurate unguided pes anserinus bursa injections was found in structures superficial and deep to the pes anserinus bursa, it does not appear that the unguided needle pes anserinus injection technique was at fault but rather the inability to determine without US visualization the appropriate needle depth required to perform an accurate pes anserinus bursa injection. Although the presence of liquid latex within or deep to the MCL, or superficial to the pes anserinus tendons following an

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accurate with overflow or inaccurate injection was expected, it was not anticipated that an unguided injection placed injectate within the popliteus muscle, whereas another placed injectate within the semimembranosus tendon. However, this finding can be explained by the anatomic relationships of the medial leg soft tissue structures. Some tendon fibers from the popliteus origin and semimembranosus insertion wrap around the medial aspect of the tibia deep to the posterior fibers of the superficial portion of the MCL. Therefore, the needle must have penetrated these fibers during 2 of the unguided pes anserinus bursa injections leading to injectate tracking posteromedially into the popliteus muscle and semimembranosus tendon, respectively. Although not seen in this study, it is theoretically possible that an unguided pes anserinus bursa injection could also result in perforation of the saphenous nerve, or penetration or injection of the local vasculature (eg, saphenous vein, inferior medial geniculate artery). Several clinical implications can be derived from this study. If a pes anserinus bursa injection is being used for diagnostic purposes, then US guidance should be used to perform the injection because of its high degree of accuracy. However, despite the presence of several studies suggesting that accuracy influences the therapeutic efficacy of an injection [33,37,38,41], to our knowledge, there is not a study comparing the therapeutic efficacy of US-guided versus unguided pes anserinus bursa injections. Therefore, we currently do not perform all of our pes anserinus bursa injections with US guidance. Rather, we use US guidance for pes anserinus bursa injections under the following circumstances: failed previous unguided injection, obese body habitus resulting in difficulty identifying anatomic landmarks, bleeding diathesis or currently taking anticoagulant medications, and when the etiology of medial pain is in doubt (ie, for diagnostic purposes). Further research to determine whether pes anserinus bursa injection accuracy influences therapeutic efficacy is required prior to recommending that all pes anserinus injections be performed with US guidance. There are several limitations to this study. First, this study was performed on cadaveric specimens and thus our results may be viewed with caution when extrapolating to patients. Second, only 12 US-guided and 12 unguided pes anserinus bursa injections were performed in this study. Although it is unlikely that injecting a larger number of cadaveric specimens would significantly alter the results of our investigation, we acknowledge that the binomial 95% confidence intervals for the accuracy rate of the US-guided pes anserinus bursa injection technique are 61.5%-99.8%, whereas those of the unguided injection technique are 2.1%-48.4%. Third, although we chose to have a single investigator perform all of the injections in this study to eliminate the confounding factor of inter-rater variability, it is unknown whether the results of this study would be reproduced if a different investigator performed the injections, particularly if the in-

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vestigator had less experience. Therefore, future investigations may wish to determine if injection experience influences the injection accuracy. However, it is unlikely that experience influenced the disparity between the accuracy of US-guided versus unguided pes anserinus bursa injections in the current investigation because the investigator who performed the injections was experienced in both injection techniques. Finally, because the same investigator who performed the unguided pes anserinus bursa injection also identified the pes anserinus bursa sonographically and placed a skin mark indicating its location, the accuracy of unguided pes anserinus bursa injections may have been overestimated in this study because of the additional knowledge the investigator performing the injections obtained while performing the diagnostic US. However, because in the clinical setting the same person who identifies the location of the pes anserinus bursa also performs the injection, the investigators thought the current study design provided the best approximation of clinical practice within the confines of a cadaveric model.

CONCLUSION Despite its superficial location, unguided pes anserinus bursa injections rarely place the injectate within the pes anserinus bursa, whereas US-guided pes anserinus bursa injections have a high degree of accuracy. Therefore, clinicians should consider using US guidance for diagnostic or therapeutic pes anserinus bursa injections when indicated.

REFERENCES 1. Yoon HS, Kim SE, Suh YR, Seo YI, Kim HA. Correlation between ultrasonographic findings and the response to corticosteroid injection in pes anserinus tendinobursitis syndrome in knee osteoarthritis patients. J Korean Med Sci 2005;20:109-112. 2. Marra MD, Crema MD, Chung M, et al. MRI features of cystic lesions around the knee. Knee 2008;15:423-438. 3. Handy JR. Anserine bursitis: A brief review. South Med J 1997;90:376377. 4. Rennie WJ, Saifuddin A. Pes anserine bursitis: Incidence in symptomatic knees and clinical presentation. Skel Radiol 2005;34:395-398. 5. Moschcowitz E. Bursitis of sartorius bursa, an undescribed malady simulating chronic arthritis. JAMA 1937;109:1362. 6. Abeles M. Anserine bursitis. Arthr Rheum 1986;29:812-813. 7. Brookler MI, Mongan ES. Anserina bursitis. A treatable cause of knee pain in patients with degenerative arthritis. Calif Med 1973;119:8-10. 8. Unlu Z, Ozmen B, Tarhan S, Boyvoda S, Goktan C. Ultrasonographic evaluation of pes anserinus tendino-bursitis in patients with type 2 diabetes mellitus. J Rheumatol 2003;30:352-354. 9. Uson J, Aguado P, Bernad M, et al. Pes anserinus tendino-bursitis: What are we talking about? Scand J Rheumatol 2000;29:184-186. 10. Cohen SE, Mahul O, Meir R, Rubinow A. Anserine bursitis and noninsulin dependent diabetes mellitus. J Rheumatol 1997;24:2162-2165. 11. de Miguel Mendieta E, Cobo Ibanez T, Uson Jaeger J, Bonilla Hernan G, Martin Mola E. Clinical and ultrasonographic findings related to knee pain in osteoarthritis. Osteoarthrit Cartilage 2006;14:540-544. 12. Fireman HH. Don’t forget anserine bursitis [comment]. CMAJ Can Med Assoc J 2001;165:1300.

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13. Forbes JR, Helms CA, Janzen DL. Acute pes anserine bursitis: MR imaging. Radiology 1995;194:525-527. 14. Gnanadesigan N, Smith RL. Knee pain: Osteoarthritis or anserine bursitis? J Am Med Directors Assoc 2003;4:164-166. 15. Hall FM, Joffe N. CT imaging of the anserine bursa. AJR Am J Roentgenol 1988;150:1107-1108. 16. Hemler DE, Ward WK, Karstetter KW, Bryant PM. Saphenous nerve entrapment caused by pes anserine bursitis mimicking stress fracture of the tibia. Arch Phys Med Rehab 1991;72:336-337. 17. Hill CL, Gale DR, Chaisson CE, et al. Periarticular lesions detected on magnetic resonance imaging: Prevalence in knees with and without symptoms. Arthr Rheum 2003;48:2836-2844. 18. Kang I, Han SW. Anserine bursitis in patients with osteoarthritis of the knee. South Med J 2000;93:207-209. 19. Koh WL, Kwek JW, Quek ST, Peh WC. Clinics in diagnostic imaging (77). Pes anserine bursitis. Singapore Med J 2002;43:485-491. 20. Maheshwari AV, Muro-Cacho CA, Pitcher JD, Jr. Pigmented villonodular bursitis/diffuse giant cell tumor of the pes anserine bursa: A report of two cases and review of literature. Knee 2007;14:402-407. 21. Marquis AM. Pes anserine bursitis. ONA J 1979;6:418-419. 22. McCarthy CL, McNally EG. The MRI appearance of cystic lesions around the knee. Skel Radiol 2004;33:187-209. 23. Muchnick J, Sundaram M. Radiologic case study. Pes anserine bursitis. Orthopedics 1997;20:1100; 092-4. 24. Nokes SR, Smith T. Acute pes anserine bursitis. J Arkansas Med Soc 2007;104:112. 25. Voorneveld C, Arenson AM, Fam AG. Anserine bursal distention: Diagnosis by ultrasonography and computed tomography. Arthrit Rheum 1989;32:1335-1338. 26. Zeiss J, Coombs RJ, Booth RL, Jr., Saddemi SR. Chronic bursitis presenting as a mass in the pes anserine bursa: MR diagnosis. J Comp Assisted Tomogr 1993;17:137-140. 27. Larsson LG, Baum J. The syndrome of anserina bursitis: An overlooked diagnosis. Arthrit Rheum 1985;28:1062-1065. 28. Clapp A, Trecek J, Joyce M, Sundaram M. Radiologic case study. Pes anserine bursitis. Orthopedics 2008;31:306. 29. Cardone DA, Tallia AF. Diagnostic and therapeutic injection of the hip and knee. Am Family Phys 2003;67:2147-2152. 30. Jackson DW, Evans NA, Thomas BM. Accuracy of needle placement into the intra-articular space of the knee [see comment]. J Bone Joint Surg Am 2002;84-A:1522-1527. 31. Hanchard N, Shanahan D, Howe T, Thompson J, Goodchild L. Accuracy and dispersal of subacromial and glenohumeral injections in cadavers [see comment]. J Rheumatol 2006;33:1143-1146. 32. Yamakado K. The targeting accuracy of subacromial injection to the shoulder: An arthrographic evaluation. Arthroscopy 2002;18:887-891. 33. Henkus HE, Cobben LP, Coerkamp EG, Nelissen RG, van Arkel ER. The accuracy of subacromial injections: A prospective randomized magnetic resonance imaging study [see comment]. Arthroscopy 2006; 22:277-282. 34. Kang MN, Rizio L, Prybicien M, Middlemas DA, Blacksin MF. The accuracy of subacromial corticosteroid injections: A comparison of multiple methods. J Shoulder Elbow Surg 2008;17(1 Suppl):61S-66S. 35. Gruson KI, Ruchelsman DE, Zuckerman JD. Subacromial corticosteroid injections. J Shoulder Elbow Surg 2008;17(1 Suppl):118S-130S. 36. Partington PF, Broome GH. Diagnostic injection around the shoulder: Hit and miss? A cadaveric study of injection accuracy. J Shoulder Elbow Surg 1998;7:147-150. 37. Eustace JA, Brophy DP, Gibney RP, Bresnihan B, FitzGerald O. Comparison of the accuracy of steroid placement with clinical outcome in patients with shoulder symptoms. Ann Rheum Dis 1997;56:59-63. 38. Naredo E, Cabero F, Beneyto P, et al. A randomized comparative study of short term response to blind injection versus sonographic-guided injection of local corticosteroids in patients with painful shoulder. J Rheumatol 2004;31:308-314.

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39. Mathews PV, Glousman RE. Accuracy of subacromial injection: anterolateral versus posterior approach. J Shoulder Elbow Surg 2005;14:145148. 40. Toda Y, Tsukimura N. A comparison of intra-articular hyaluronan injection accuracy rates between three approaches based on radiographic severity of knee osteoarthritis. Osteoarthrit Cartilage 2008;16: 980-985. 41. Sibbitt W, Peisajovich A, Michael AA, Park KS, Sibbitt RR, Band PA, Bankhurst AD. Does sonographic needle guidance affect the clinical outcome of intraarticular injections? J Rheumatol 2009;36:1892-1902. 42. Finnoff JT, Hurdle MF, Smith J. Accuracy of ultrasound-guided versus fluoroscopically guided contrast-controlled piriformis injections: A cadaveric study. J Ultrasound Med 2008;27:1157-1163. 43. Raghunathan K, Schwartz D, Connelly NR. Determining the accuracy of caudal needle placement in children: A comparison of the swoosh test and ultrasonography. Paediatr Anaesth 2008;18:606-612. 44. Marina MB, Sani A, Hamzaini AH, Hamidon BB. Ultrasound-guided botulinum toxin A injection: an alternative treatment for dribbling. J Laryngol Otol 2008;122:609-614. 45. Lohman M, Vasenius J, Nieminen O. Ultrasound guidance for puncture and injection in the radiocarpal joint [erratum appears in Acta Radiol 2008;49:336]. Acta Radiol 2007;48:744-747. 46. Eichenberger U, Greher M, Kirchmair L, Curatolo M, Moriggl B. Ultrasound-guided blocks of the ilioinguinal and iliohypogastric nerve: Accuracy of a selective new technique confirmed by anatomical dissection. Br J Anaesth 2006;97:238-243. 47. Pourbagher MA, Ozalay M, Pourbagher A. Accuracy and outcome of sonographically guided intra-articular sodium hyaluronate injections in patients with osteoarthritis of the hip. J Ultrasound Med 2005;24: 1391-1395. 48. Galiano K, Obwegeser AA, Bodner G, et al. Ultrasound guidance for facet joint injections in the lumbar spine: A computed tomographycontrolled feasibility study. Anesth Analg 2005;101:579-583.

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49. Raza K, Lee CY, Pilling D, et al. Ultrasound guidance allows accurate needle placement and aspiration from small joints in patients with early inflammatory arthritis. Rheumatology 2003;42:976-979. 50. Boon AJ, Alsharif KI, Harper CM, Smith J. Ultrasound-guided needle EMG of the diaphragm: Technique description and case report. Muscle Nerve 2008;38:1623-1626. 51. Smith J, Wisniewski SJ, Finnoff JT, Payne JM. Sonographically guided carpal tunnel injections: The ulnar approach. J Ultrasound Med 2008; 27:1485-1490. 52. Umphrey GL, Brault JS, Hurdle M-FB, Smith J. Ultrasound-guided intra-articular injection of the trapeziometacarpal joint: Description of technique. Arch Phys Med Rehab 2008;89:153-156. 53. Hurdle MF, Weingarten TN, Crisostomo RA, Psimos C, Smith J. Ultrasound-guided blockade of the lateral femoral cutaneous nerve: Technical description and review of 10 cases. Arch Phys Med Rehab 2007;88:1362-1364. 54. Hurdle M-FB, Locketz AJ, Smith J. A technique for ultrasound-guided intrathecal drug-delivery system refills. Am J Phys Med Rehabil 2007; 86:250-251. 55. Smith J, Hurdle M-F, Locketz AJ, Wisniewski SJ. Ultrasound-guided piriformis injection: Technique description and verification. Arch Phys Medi Rehab 2006;87:1664-1667. 56. Smith J, Hurdle M-FB. Office-based ultrasound-guided intra-articular hip injection: Technique for physiatric practice. Arch Phys Med Rehab 2006;87:296-298. 57. Smith J, Hurdle MF, Weingarten TN. Accuracy of sonographically guided intra-articular injections in the native adult hip. J Ultrasound Med 2009;28:329-235. 58. Hoppenfeld S, deBoer P. The Knee. In: Hoppenfeld S, deBoer P, editor. Surgical Exposures in Orthopaedics: The Anatomic Approach. 3rd ed. Philadelphia: Lippincott Williams and Wilkins; 2003, 493-568. 59. Saunders S. Knee treatments. In: Saunders S, editor. Injection Techniques in Orthopaedic and Sports Medicine. 2nd ed. Philadelphia: W.B. Saunders; 2002, 82-100.