EPICONDYLITIS IS AMONG the most common soft-tissue

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1 738 ORIGINAL ARTICLE Diagnostic Value of Ultrasonography for Clinical Medial Gi-Young Park, MD, PhD, Sung-Moon Lee, MD, Michael Y. Lee, MD, MHA ABSTRACT. Park G-Y, Lee S-M, Lee MY. Diagnostic value of ultrasonography for clinical medial epicondylitis. Arch Phys Med Rehabil 2008;89: Objectives: To assess the ultrasonographic findings and to evaluate the value of ultrasonography as a diagnostic method for detecting clinical medial epicondylitis. Design: A prospective, single-blind study. Setting: An outpatient rehabilitation clinic in a tertiary university hospital. Participants: Twenty-one elbows from 18 patients with clinical medial epicondylitis and 25 elbows without medial epicondylitis were evaluated. Interventions: Not applicable. Main Outcome Measures: The clinical diagnosis of medial epicondylitis was based on the patient s symptoms and clinical signs in a physical examination performed by a physiatrist. An experienced radiologist made the real-time ultrasonographic diagnosis based on the detection of at least one of the following abnormal findings: a focal hypoechoic or anechoic area, tendon nonvisualization, intratendinous calcifications, and cortical irregularity. Results: Ultrasonography revealed positive findings in 20 of 21 elbows with medial epicondylitis and was negative in 23 of 25 without medial epicondylitis. Ultrasonography showed sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for clinical medial epicondylitis of 95.2%, 92%, 93.5%, 90.9%, and 95.8%, respectively. Tendinosis was observed in 15 elbows, and a partial-thickness tear, including 1 intrasubstance tear, was detected in 5 elbows. The most common ultrasonographic abnormality was a focal echogenic abnormality (15 hypoechoic, 5 anechoic) of the tendons. Conclusions: Our results indicate that ultrasonography is informative and accurate for the detection of clinical medial epicondylitis. Therefore, ultrasonography should be considered as an initial imaging method for evaluating medial epicondylitis. Key Words: Elbow; Rehabilitation; Tendons; Ultrasonography by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation From the Department of Rehabilitation Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea (Park); Department of Diagnostic Radiology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea (SM Lee); and Department of Physical Medicine and Rehabilitation, School of Medicine, University of North Carolina, Chapel Hill, NC (MY Lee). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. Reprint requests to Gi-Young Park, MD, PhD, Dept of Rehabilitation Medicine, Catholic University of Daegu School of Medicine, , Daemyung 4-dong, Nam-gu, Daegu, , South Korea, parkgy@hotmail.com /08/ $34.00/0 doi: /j.apmr EPICONDYLITIS IS AMONG the most common soft-tissue disorders of the arm. Lateral epicondylitis, which is commonly known as tennis elbow, and medial epicondylitis, which is also known as golfer s elbow, are the result of the overuse of the common extensor and flexor tendons. The incidence of medial epicondylitis is much lower than that of lateral epicondylitis, the latter being 3 to 10 times more common. 1,2 With medial epicondylitis, most changes are observed at the musculotendinous origin of the flexor carpi radialis and pronator teres. However, large diffuse tears can occur in the palmaris longus, flexor digitorum superficialis, and flexor carpi ulnaris. 1,3,4 Tendon degeneration rather than tendon repair is the primary pathology secondary to intrinsic muscle-tendon overload in epicondylitis. Histologic analysis of the common flexor tendons in medial epicondylitis has identified angiofibroblastic tendinosis and the fibrillary degeneration of collagen. 4 Medial epicondylitis is characterized clinically by pain at the medial epicondyle that is aggravated by the resisted use of the flexor muscles of the wrist during job performance, activities of daily living, and sports. The condition causes pain and functional impairment of the upper extremities, and the resulting disability from persistent pain and weakness at the elbow can result in the need for surgical treatment. 5 Physical examination shows localized tenderness around the medial epicondyle with palpation and pain at the medial epicondyle that is exacerbated by isometric-resisted forearm pronation or wrist flexion. Several imaging procedures such as radiography, ultrasonography, and magnetic resonance imaging (MRI) are used in the diagnosis of clinical medial epicondylitis. Radiography is unable to detect the soft-tissue pathology but might reveal soft-tissue calcifications along the medial epicondyle. 6,7 Ultrasonography and MRI may be considered in patients with medial epicondylitis who have normative findings on radiography, when the diagnosis is unclear, in the case of refractory pain despite providing adequate conservative treatment, or for preoperative evaluation. MRI has been reported to be accurate in both detecting and characterizing clinical medial epicondylitis. 8,9 Specifically, intermediate to high T2-signal intensity within the common flexor tendon and high T2-signal intensity soft-tissue edema around that have been identified. 8 The disadvantages of MRI are higher cost and longer examination time when compared with ultrasonography. In addition, MRI cannot be performed in patients with claustrophobia and cardiac pacemakers. In view of the latest developments in ultrasonographic technology, ultrasonography is being increasingly used as an alternative to MRI in the diagnosis of tendon disease. Ultrasonography is a reliable, noninvasive, widely available, and inexpensive imaging study for assessing tendons. It combines direct multiplanar, tomographic evaluation of the tendons with dynamic investigation of their movement, thus providing both an anatomic and a functional assessment. Several reports have described the variable sensitivity and specificity of ultrasonography for the detection of lateral epicondylitis. In a small number of patients with epicondylitis, both ultrasonography and MRI revealed abnormalities

2 ULTRASONOGRAPHY OF MEDIAL EPICONDYLITIS, Park 739 that corresponded with the clinical diagnosis, and ultrasonography using static images has shown comparably high specificity but poorer sensitivity than MRI for diagnosing clinical epicondylitis. However, the ultrasonographic findings of medial epicondylitis have been described in only 3 patients who had a combination of the following: outward tendon bowing, a hypoechoic region deep in the tendon, tendon thickening, tendon thinning, and decreased echogenicity of the tendon. 14 This paucity of literature is probably because of the low prevalence of medial epicondylitis. The aim of this study was to assess the ultrasonographic findings and to evaluate the ability of ultrasonography to diagnose clinical medial epicondylitis. METHODS Participants Ultrasonography of the elbow was performed in 18 consecutive patients (3 men, 15 women; mean age, 50y; age range, 44 63y) who showed symptoms of medial epicondylitis and visited the outpatient rehabilitation clinic. Patients with entrapment neuropathies of the upper limb, fracture or bony metastases of the elbow, and a history of prior surgery or corticosteroid injections within 6 months before the ultrasonographic examination were excluded. Their mean symptom duration was 17.6 months (range, 1 60mo). The clinical diagnosis of medial epicondylitis was based on the patient s symptoms and clinical signs in a physical examination performed by a physiatrist. The physical examination included an inspection, palpation to localize the tenderness around the elbow including the ulnar nerve compression, measurement of the elbow range of motion, elbow stability, manual muscle testing, and a sensory examination of light touch and pinprick. Additional examinations were performed when ulnar neuropathy at the elbow was suspected, which included the elbow flexion test and Tinel sign. Entrapment neuropathies, such as ulnar neuropathy at the elbow, pronator syndrome, and carpal tunnel syndrome, were excluded by clinical examination. The criteria for medial epicondylitis included pain over the medial elbow that increased on palpation of the medial epicondyle and resisted flexion of the wrist with the elbow extended. Fifteen patients had unilateral medial epicondylitis, and 3 had bilateral medial epicondylitis. Ultrasonography was performed bilaterally in 18 patients and 5 volunteer subjects (1 men, 4 women; mean age, 43y; age range, 40 59y) with neither a history of elbow pain nor positive physical examination. A total of 25 elbows (15 in patients, 10 in volunteers) were included as a control group. The institutional ethics committee approved our study, and informed consent was obtained from all patients and volunteers. Measures Radiographs of all elbows were taken before the ultrasonographic examination. An experienced musculoskeletal radiologist performed ultrasonographic examination by using an ALT HDI 500 a with a 7.5- to 15-MHz linear transducer and an iu22 a with a 5- to 17-MHz linear transducer. The radiologist was blinded to the patient s identification, clinical data, and the results of the physical examination. All the patients and volunteers were referred to the radiologist with the clinical diagnosis of elbow pain. The subject was placed comfortably in a seated position with the elbow in extension, the wrist in supination, and the arm in external rotation resting on a table during the ultrasonographic examination. Grayscale and color Doppler images of the common flexor tendons were acquired in the longitudinal and Fig 1. A longitudinal ultrasonographic image of the common flexor tendon of the left elbow in a 56-year-old woman with medial epicondylitis. The tendon had a focal hypoechoic area (arrow) that was consistent with tendinosis. transverse planes from the musculotendinous junction to the insertion on the medial epicondyle. To avoid anisotropy (ie, the angle-dependent appearance of the tissue structures), an attempt was made to keep the transducer parallel to the tendons in the longitudinal plane and perpendicular in the transverse plane. The weight of the transducer was applied without additional pressure in an attempt to minimize any compression that might cause the localized pain. Bilateral examinations were performed in the same manner. The common flexor tendons were assessed for ultrasonographic abnormalities, such as abnormal echogenicity (anechoic or hypoechoic relative to normal hyperechoic tendon), thickening, nonvisualization, increased vascularity, and intratendinous calcifications. If an echogenic abnormality of the tendons was identified, the margins were characterized as either well defined or ill defined, and the extent of the abnormality was characterized as partial thickness or full thickness. The radiologist determined a diagnosis of medial epicondylitis at the time of real-time imaging based on the detection of at least 1 of the following: a focal hypoechoic or anechoic area, tendon nonvisualization, intratendinous calcifications, and cortical irregularity. 14,15 According to the diagnostic criteria described in previous studies, 10,15 the severity of the tendon pathology was described as a tendinosis (focal hypoechoic area without fiber discontinuity or intratendinous calcifications) (fig 1), a partial-thickness tear (focal anechoic area with fiber discontinuity that involves only the partial width of the tendons) (figs 2, 3A, 3B), or a full-thickness tear (distinct complete interval extending through the full width or nonvisualization of the tendon). Other abnormal findings, such as cortical irregularity, tendon thickening, increased vascularity, and intratendinous calcifications, were also evaluated. Cortical irregularity was defined as the loss of the normal, smooth hyperechoic bony surface of the medial epicondyle (see figs 3A, 3B). It was inappropriate for tendon thickening to be regarded as the diagnostic criterion of ultrasonography for medial epicondylitis because tendon thickening was evaluated subjectively because of difficulties in comparing and reproducing the tendon measurements and was assessed in only those patients with unilateral medial epicondylitis. The color Doppler velocity technique was used to show the direction and velocity of blood flow as per Kiris et al 16 who found a significant correlation between color Doppler ultrasonography grading and pain or tenderness in the enthesis. The degree of vascularity in the tendon was graded semiquantita-

3 740 ULTRASONOGRAPHY OF MEDIAL EPICONDYLITIS, Park Fig 2. A longitudinal ultrasonographic image of the common flexor tendon of the left elbow in a 49-year-old man with medial epicondylitis. The tendon was thickened and had a focal linear anechoic area (arrow) that was consistent with intrasubstance tear. Abnormal Ultrasonographic Findings Abnormal ultrasonographic findings were detected in 20 elbows with medial epicondylitis. When abnormal echogenicity of the tendons was assessed, a focal hypoechoic area was observed in 14 elbows (67%), and a focal anechoic area was present in 5 elbows (24%). Cortical irregularity of the medial epicondyle was observed in 10 elbows (48%), and tendon thickening was found in 6 elbows (29%). Intratendinous calcifications were shown in 5 (24%) elbows, and the morphology of the calcifications was classified as punctuated and fragmented in 4 and 1 elbows, respectively. Increased vascularity was observed in 4 elbows (19%) and was graded as mild and moderate in 3 and 1 elbows, respectively. A focal hypoechoic area was observed in 2 of the 25 elbows without medial epicondylitis. According to the severity of tendon abnormalities, ultrasonography revealed 15 elbows (71%) with tendinosis and 5 elbows (24%) with partial-thickness tear, including 1 intrasubstance tear. However, none of the elbows had a fullthickness tear. tively on the color Doppler image as follows: no flow signal, mild (separate dot signals or short linear signals), moderate (clearly discernible vascularity with either many small vessels or several long vessels with or without visible branching involving less than half of the tendon), and severe (vessels involving more than half of the tendon) (see fig 3B). The morphology of calcifications on ultrasonography was classified into the following 4 types (fig 4): an arc shape (echogenic arc with clear shadowing), fragmented (at least 2 separated echogenic plaques with or without shadowing) or punctuated (tiny calcific spots without shadowing), nodular (echogenic nodule without shadowing), and cystic (bold echogenic wall with an echo-free content). 17 Statistical Analysis The clinical diagnosis was used as the reference standard for the diagnosis of medial epicondylitis. 14 True positives were defined as cases in which medial epicondylitis was diagnosed on ultrasonography by the radiologist in the affected elbows of patients. True negatives were defined as cases in which abnormal ultrasonographic findings of medial epicondyle were not found in the elbows of the control group. Calculations were performed to determine the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasonography for making a diagnosis of clinical medial epicondylitis. RESULTS Diagnostic Value of Ultrasonography Twenty of the 21 elbows with medial epicondylitis and 2 of the 25 elbows without medial epicondylitis showed positive findings on ultrasonography. Negative ultrasonographic findings were detected in 23 of 25 elbows without medial epicondylitis and in 1 of 21 elbows with medial epicondylitis (table 1). Ultrasonography showed a sensitivity of 95.2% (20/21), specificity of 92% (23/25), accuracy of 93.5% (43/46), positive negative predictive value of 90.9% (20/22), and negative predictive value of 95.8% (23/24) for medial epicondylitis. Fig 3. Ultrasonographic images of the common flexor tendon of the left elbow in a 52-year-old woman with medial epicondylitis. (A) Longitudinal grayscale and (B) transverse color Doppler images. The tendon had a focal anechoic area (white arrow) that was consistent with a partial-thickness tear, with increased vascularity, cortical irregularity (black arrow), and spur formation (arrowhead).

4 ULTRASONOGRAPHY OF MEDIAL EPICONDYLITIS, Park 741 Fig 4. A transverse grayscale image of the common flexor tendon of the left elbow in a 53-year-old woman with medial epicondylitis. The tendon had hyperechoic tiny punctuated calcifications (arrows). DISCUSSION The results of our study showed that ultrasonography displayed sensitivity and specificity of 95% and 92%, respectively, in the detection of clinical medial epicondylitis. The sensitivity and specificity were comparable to the results of other studies in which ultrasonography had been used to diagnose lateral epicondylitis. Ultrasonography can provide valuable information when lateral epicondylitis is clinically suspected. However, several studies have reported variable results in the detection of lateral epicondylitis. Our results are similar to those of Maffulli et al 18 who showed a 93% sensitivity of real-time ultrasonography in tennis players with lateral epicondylitis. However, our study showed a higher diagnostic value of ultrasonography than those of previous studies using static images. In a study by Levin et al, 11 ultrasonography displayed sensitivity and specificity ranging from 72% to 88% and 36% to 62%, respectively. Miller et al 14 reviewed the static images of 11 patients with epicondylitis and showed sensitivity and specificity ranging from 73% to 82% and 67% to 100%, respectively. Struijs et al 12 reported a 75% sensitivity of ultrasonography in diagnosing lateral epicondylitis. One explanation for this discrepancy would be that ultrasonography is a dynamic diagnostic method, with operator dependency being the main disadvantage. Therefore, it is difficult for the ultrasonographer to evaluate the ultrasonographic findings using static images instead of real-time imaging, and real-time ultrasonography might have improved the results. Other explanations might be the difference in disease entities, diagnostic criteria, and the techniques and equipment used for ultrasonography. Tendons are particularly suitable for ultrasonographic examination. The dynamic imaging of ultrasonography can be used to assess the level of tendon subluxation, and determine the severity of a tendon injury, either partial or complete. Connell et al 10 described the ultrasonographic severity of tendon pathology in patients with lateral epicondylitis. They classified 60 of 72 elbows as having tendinopathy, 18 of 72 elbows as having a partial-thickness tear, and 2 of 72 elbows as having a full-thickness tear. Their results showed a similar distribution with our results, which were classified as tendinosis in 15 elbows and partial-thickness tears, including 1 intrasubstance tear, in 5 elbows. However, none of the elbows had a fullthickness tear. Focal hypoechoic areas in the common extensor tendons correspond histologically to areas of collagen degeneration and intrasubstance tendon rupture, which might fill in with reparative granulation tissue. 10 The most common ultrasonographic abnormality in our patients with medial epicondylitis was a focal echogenic abnormality (14 hypoechoic, 5 anechoic) of the tendons, followed by cortical irregularity, tendon thickening, intratendinous calcifications, and increased vascularity. Our findings are similar to those reported in the previous ultrasonographic studies 10 of lateral epicondylitis. Therefore, focal echogenic abnormalities are the most important finding of epicondylitis on ultrasonography. The diagnosis of intratendinous calcifications focused mainly on radiographs of the elbow. 6 Recently, high-resolution ultrasonography has been applied in evaluating intratendinous calcifications and has proven to be a good diagnostic method in this field. 17 The radiographs of the elbows of the medial epicondylitis patients in this study were normative. However, ultrasonography revealed intratendinous calcifications in 5 of 20 elbows (4 punctuated, 1 fragmented). The same ultrasonographic morphology of intratendinous calcifications was described in patients with lateral epicondylitis. 10 There are 4 descriptive stages of epicondylar tendonitis, and stage 4 represents fibrosis or calcification. 19 The periarticular-calcified deposits that appear defined and homogeneous are associated with subacute or chronic symptoms. 20 Therefore, tiny calcifications might be present in cases of chronic tendinosis. Five elbows with calcifications had a long symptom duration (mean, 25.6mo; range, 12 60mo), and all calcifications showed a defined homogeneous morphology. This might explain the higher incidence of intratendinous calcifications in contrast to the 4 of 72 elbows with a mean duration of 7.1 months in the previous study. 10 Color Doppler ultrasonography has been used to examine blood flow in musculoskeletal structures. Blood flow cannot be detected in normal tendons because of the low-flow rates but is detected quite readily in lateral epicondylitis and painful chronic Achilles tendinosis. 13,21 In a recent study using color Doppler ultrasonography, 13 increased vascularity was not found to be associated with inflamed tendons but was associated with neurogenic inflammation in patients with lateral epicondylitis with a long duration of pain (mean, 18mo). In our study, color Doppler ultrasonography showed increased vascularity in only 4 elbows, which had a long duration of symptoms (mean, 32mo; range, 12 60mo). In addition, 3 elbows with increased vascularity also had intratendinous calcifications. Therefore, there might be a difference in vascularity according to the stages of epicondylitis. The importance of cortical irregularity in tendon diseases has been examined in rotator cuff tears. 22,23 Cortical irregularity of the medial epicondyle was present in 10 of 21 elbows with medial epicondylitis. Cortical irregularity would be useful in both diagnosing and determining the chronic stage of medial epicondylitis. In our study, a patient with unilateral medial epicondylitis showed no abnormal ultrasonographic findings. His symptom Table 1: Comparison Between the Clinical and Ultrasonographic Diagnosis in Medial Ultrasonographic Diagnosis Medial (n 21) Clinical Diagnosis No Medial (n 25) Total (N 46) Medial epicondylitis No medial epicondylitis

5 742 ULTRASONOGRAPHY OF MEDIAL EPICONDYLITIS, Park duration before the ultrasonographic examination was 1 month. In a previous study, 8 2 patients with clinically diagnosed medial epicondylitis showed no MRI abnormalities of the common flexor tendons but showed paratendinous soft-tissue edema. It is possible that our patient had been clinically diagnosed before the tendon pathology became clear enough to cause ultrasonographic changes in the morphology and echogenicity of the tendons. Previous studies on epicondylitis reported hypoechoic areas on ultrasonography and an abnormal T1-signal intensity on MRI in the asymptomatic tendons. 9,11,12 A focal hypoechoic area was detected in 2 of the 25 elbows in our control group. This finding might be because of previous unrecognized medial epicondylitis, asymptomatic degeneration within the tendon, or anisotropy as an ultrasonographic artifact. Other disorders such as tears of the ulnar collateral ligament and ulnar neuropathy may also coexist with medial epicondylitis and are common in the throwing athletes, resulting from the tremendous valgus stress that occurs during the acceleration phase of throwing. 8,24 However, our patients had neither tears of the ulnar collateral ligaments nor ulnar neuropathy. One possible explanation for this might be the mild symptoms of the nonathletic patients. Study Limitations There were several limitations in our study. First, ultrasonographic results were not compared with the surgical and MRI findings because most patients responded well to conservative treatment and opted not to participate in MRIs because of excessive cost. Therefore, clinical diagnosis was used as the reference standard. Second, a relatively small number of patients and control subjects were examined. Third, the blinding of the clinical findings might have been incomplete because the radiologist might have been aware of the patient s pain when localized pain was evoked as a result of compression of the transducer at the medial epicondyle. Finally, the interrater and intrarater reliability of ultrasonographic findings were not evaluated. In this study, the same experienced musculoskeletal radiologist performed all real-time ultrasonographic examinations in a similar manner. Therefore, a further study will be needed to compare ultrasonography with MRI in the diagnosis of medial epicondylitis and to determine the diagnostic value of ultrasonography in a large number of cases using ultrasonographers with different levels of experience. CONCLUSIONS Although these results were based on a relatively small number of cases, ultrasonography was found to be highly sensitive and specific for the detection of clinical medial epicondylitis. In addition, it provided useful information on the severity and stage of tendon pathology for treatment planning as well as for determining the outcome and prognosis. Therefore, ultrasonography is recommended as an initial imaging method for the diagnosis of clinical medial epicondylitis. Acknowledgment: We thank Jung-Ho Bae, MD, Department of Rehabilitation Medicine, Keimyung University School of Medicine, Republic of Korea, for data collection. References 1. Leach RE, Miller JK. Lateral and medial epicondylitis of the elbow. Clin Sports Med 1987;6: Shiri R, Viikari-Juntura E, Varonen H, Heliovaara M. Prevalence and determinants of lateral and medial epicondylitis: a population study. Am J Epidemiol 2006;164: Bennett JG. Lateral and medial epicondylitis. Hand Clin 1994;10: Ollivierre CO, Nirschl RP, Pettrone FA. Resection and repair for medial tennis elbow. A prospective analysis. Am J Sports Med 1995;23: O Dwyer KJ, Howie CR. Medial epicondylitis of the elbow. 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