Using Sonography for the Early Detection of Elbow Injuries Among Young Baseball Players

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1 Harada et al. Sonography of Elbow Injuries Musculoskeletal Imaging Original Research A C M E D E N T U R I C A L I M A G I N G AJR 2006; 187: X/06/ American Roentgen Ray Society Y O Mikio Harada 1 Masatoshi Takahara 1 Junya Sasaki 1 Nariyuki Mura 1 Tomokazu Ito 2 Toshihiko Ogino 1 F Harada M, Takahara M, Sasaki J, Mura N, Ito T, Ogino T Keywords: elbow, injury, musculoskeletal imaging, pediatric imaging, screening, sonography, sports injuries DOI: /AJR Received June 24, 2005; accepted after revision November 11, Department of Orthopaedic Surgery, Yamagata University School of Medicine, Iida Nishi 2-2-2, Yamagata , Japan. Address correspondence to M. Takahara (mtakahar@med.id.yamagata-u.ac.jp). 2 Department of Orthopaedic Surgery, Saiseikai Yamagata Hospital, Yamagata, Japan. Using Sonography for the Early Detection of Elbow Injuries Among Young Baseball Players OBJECTIVE. The aim of this study was to determine the usefulness of sonography for detecting elbow injuries among young baseball players. SUBJECTS AND METHODS. One hundred fifty-three volunteers ranging in age from 9 to 12 years and belonging to youth baseball teams participated. Sonography of the elbow was performed in the field when baseball exercises were being conducted. We analyzed the relationship between elbow pain and sonographic abnormalities and the relationship between pitchers and sonographic abnormalities. RESULTS. Sonography showed that 33 subjects had medial epicondylar fragmentation and two had early-stage osteochondritis dissecans of the capitellum. In 25 subjects who agreed to further examination and treatment, radiography confirmed the sonographic findings. All of the 23 subjects with medial epicondylar fragmentation, who stopped throwing, obtained union of the bone and returned to baseball. The two subjects with osteochondritis dissecans of the capitellum underwent surgery before the osteochondral fragment became loosened. Sonographic abnormalities correlated with episodes of elbow pain. Pitchers statistically significantly had sonographic abnormalities. CONCLUSION. Sonography in the field can provide an opportunity to detect and treat elbow injuries before they become more advanced. lbow injuries, including medial E epicondylar fragmentation, osteochondritis dissecans of the capitellum, and ulnar collateral ligament injury, are common throwing injuries in athletes [1]. Radiography and MRI have proven effective for detecting early elbow abnormalities among young baseball players [2 13]. Recently, sonography, which is a safe, inexpensive, and portable type of diagnostic imaging, has been used to assess elbow injuries [3, 14 19]. Patients with symptoms of elbow injuries usually take some time to present to a hospital, and consequently clinical examination tends to detect a great number of advanced injuries, making treatment more difficult [20]. We speculate that players continue to play baseball because their elbow pain is not severe enough to warrant medical attention [3]. If examination of the elbow could be performed in the field where athletes are training, it might be possible to detect and treat elbow injuries before they become advanced. Therefore, we attempted to detect elbow injuries among young baseball players during training, using sonography. Players in whom abnormalities were found were recommended to undergo further examination and treatment. The aim of this study was to address the efficacy of sonography for detecting elbow injuries among young baseball players. Subjects and Methods Institutional review board approval was obtained before the start of this study, and informed consent was obtained from parents and coaches. One hundred fifty-three volunteers participated in this study from 2001 to They belonged to youth baseball teams in a league and ranged in age from 9 to 12 years (mean, 11.0 years). The duration of their active participation in baseball was years (mean, 2.1 years). The number of the subjects who had played as a pitcher in the games was 34 (pitchers). The remaining 119 players (nonpitchers) had not played as a pitcher. All subjects were asked whether they had ever had any episodes of elbow pain. The throwing and nonthrowing elbows of each subject were examined in a room next to the field where the subjects played baseball. Sonography of the medial and lateral aspects of both elbows 1436 AJR:187, December 2006

2 Sonography of Elbow Injuries Fig. 1 Photograph depicts technique for scanning medial aspect of elbow. was performed by two of the authors, who are orthopedic surgeons, using a 10-MHz annular array transducer (Aloka), as described in previous articles [3, 14, 19]. A photograph depicting the scanning technique of the medial aspect of the elbow is shown in Figure 1. Briefly, sonography of the medial aspect of the elbow showed the humeral medial epicondyle, humeral trochlea, and ulnar collateral ligament (Figs. 2A and 3A). The growth plate of the humeral medial epicondyle was visible on the coronal view (Figs. 2B 2D). On the lateral aspect of the elbow, the sonograms showed the humeral capitellum, and the radial head was visible on the sagittal view. The subchondral bone of the capitellum was identified as a hyperechoic area, whereas its articular cartilage was identified as a hypoechoic area (Figs. 3B 3D). We recommended radiographic examination only to subjects who showed abnormal sonographic findings. Twenty-five subjects agreed to undergo radiography within several days after their examination in the field. We investigated sonographic abnormalities, such as medial epicondylar fragmentation and osteochondritis dissecans of the capitellum, and then statistically analyzed the relationship between elbow pain and these sonographic abnormalities, and the relationship between pitchers and the sonographic abnormalities using chi-square tests. For the subjects who underwent radiography, two of the authors compared the radiographic findings with the sonographic findings. In subjects with medial epicondylar fragmentation, the periods from the examination to bone union and complete return to baseball were investigated. Also, the size of the fragment in cases of medial epicondylar fragmentation, shown on sonography and anteroposterior radiography with the elbow A B Fig. 2 Sonography and radiography of medial aspect of elbow in 12-year-old male baseball player. No player was symptomatic at time of sonographic examination. A, Imaging technique: transducer is placed on medial aspect of elbow in 90 of flexion. B, Diagram shows imaging plane of medial aspect of elbow. Asterisk indicates medial epicondyle. (Fig. 2 continues on next page) AJR:187, December

3 Harada et al. C E G Fig. 2 (continued) Sonography and radiography of medial aspect of elbow in 12-year-old male baseball player. No player was symptomatic at time of sonographic examination. C and D, Sonogram (C) and corresponding diagram (D) show medial aspect of elbow on nonthrowing side. Asterisk indicates medial epicondyle; large arrow, growth plate between humeral medial epicondyle and trochlea; small arrows, humeral trochlea; and arrowheads, ulnar collateral ligament. E and F, Sonogram (E) and corresponding diagram (F) show medial aspect of elbow on throwing side. Medial epicondylar fragmentation (arrow) is evident as discontinuity of medial epicondyle (asterisk). G, Anteroposterior radiograph of elbow on throwing side flexed at 45. Asterisk indicates medial epicondyle. H, Magnification of radiograph shows medial aspect of elbow on throwing side. Asterisk indicates medial epicondyle. Extent of medial epicondylar fragmentation (arrows) shown on radiography appears smaller than that shown on sonography. D F H flexed at 45, was measured using a vernier caliper. This measurement was performed by one of the authors. Statistical analyses of the data were performed using a paired Student s t test. Values were the mean ± SD, and differences at p < 0.05 were considered to be significant. Among 105 subjects examined in 2002, physical examination of the elbow, including an examination for tenderness and a stress test, was also performed 1438 AJR:187, December 2006

4 Sonography of Elbow Injuries A E B C D Fig. 3 Sonography and radiography of lateral aspect of elbow in 12-yearold male baseball player. No player was symptomatic at time of sonographic examination. A, Imaging technique: Transducer is placed on lateral aspect of elbow in 0 of extension. B, Diagram shows imaging plane of lateral aspect of elbow. C and D, Sonogram (C) and corresponding diagram (D) of lateral aspect of elbow on nonthrowing side show humeral capitellum (C) and radial head (R) from sagittal view. Subchondral bone of capitellum is identified as hyperechoic area (arrows), whereas its articular cartilage is identified as hypoechoic area (arrowheads). E and F, Sonogram (E) and corresponding diagram (F) of lateral aspect of elbow on throwing side. Gap between fragment (asterisk) and its base (arrows) in capitellum indicates osteochondritis dissecans. R = radial head, C = capitellum. G, Anteroposterior radiograph of elbow on throwing side flexed at 45. Early stage of osteochondritis dissecans of humeral capitellum is shown as radiolucent region (arrows). F G AJR:187, December

5 Harada et al. TABLE 1: Relationship Between Elbow Pain and Sonographic Abnormality Sonographic Abnormality Elbow Pain Yes No Yes (n = 62) No (n =91) 9 82 Note Significant relationship was seen between elbow pain and sonographic abnormality (p < ). TABLE 2: Relationship Between Tenderness and Medial Epicondylar Fragmentation on Sonography Medial Epicondylar Fragmentation on Sonography Tenderness Yes No Yes (n =24) 9 15 No (n = 81) Note Significant relationship was seen between tenderness and medial epicondylar fragmentation on sonography (p <0.01). TABLE 3: Relationship Between Elbow Pain at Valgus Stress Test and Medial Epicondylar Fragmentation on Sonography Pain at Valgus Stress Test Medial Epicondylar Fragmentation on Sonography Yes No Yes (n =9) 5 4 No (n = 96) Note Significant relationship was seen between elbow pain at valgus stress test and fragmentation on sonography (p <0.01). by one of the authors. We analyzed the relationship between these physical findings and the sonographic findings. The physicians performing the sonography and those performing the physical examination were unaware of the results of the other tests. Comparison between sonographic and physical examinations was performed using chi-square tests, and differences at p < 0.05 were considered to be significant. Results Among the 153 subjects, 62 experienced episodes of elbow pain while throwing. The remaining 91 never experienced elbow pain. Sonography showed that, in the throwing elbow, 35 subjects had sonographic abnormalities, including medial epicondylar fragmentation in 33 (Figs. 2E and 2F) and osteochondritis dissecans of the capitellum in two (Figs. 3E and 3F). Statistical analysis showed that most subjects with sonographic abnormalities had experienced episodes of elbow pain (Table 1). Sonography also showed that, in the nonthrowing elbow, no subjects had sonographic abnormalities. Fourteen of 34 pitchers and 21 of 119 nonpitchers had sonographic abnormalities in the throwing elbow. Pitchers statistically significantly had sonographic abnormalities. Twenty-five subjects agreed to undergo radiography, which showed medial epicondylar fragmentation in 23 (Figs. 2G and 2H) and osteochondritis dissecans of the capitellum in two (Fig. 3G). Radiography confirmed the sonographic findings in all cases. All 23 subjects with medial epicondylar fragmentation stopped throwing. They all obtained radiographic union of the bone within 2 9 months (mean, 4.5 months) and made a complete return to baseball within 2 9 months (mean, 4.9 months) after the examination. One of the two subjects with osteochondritis dissecans of the capitellum underwent fragment fixation. The other underwent arthroscopic removal of a small osteochondral fragment after most of the lesion had healed with conservative treatment. The remaining 10 subjects with sonographic abnormalities did not undergo radiography or treatment because their symptoms were not severe enough to warrant medical consultation. The mean size of the fragment in cases of medial epicondylar fragmentation was 4.0 ± 0.8 mm (range, mm) on the sonograms and 3.4 ± 1.3 mm (range, mm) on the radiographs. Although our statistical analysis showed no significant difference in the fragment size between these examinations (p = 0.26), sonography tended to show a greater degree of medial epicondylar fragmentation than radiography. Among the 105 subjects examined in 2002, 24 had tenderness of the medial epicondyle, nine had elbow pain due to valgus stress, and 20 had medial epicondylar fragmentation, as shown on sonography. The results of physical examination correlated with the sonographic findings of medial epicondylar fragmentation (Tables 2 and 3). However, tenderness of the medial epicondyle was absent in 11 subjects with medial epicondylar fragmentation as shown on sonography, and elbow pain due to valgus stress was absent in 15 subjects with medial epicondylar fragmentation. Discussion In our study, most subjects with sonographic abnormalities, including medial epicondylar fragmentation and osteochondritis dissecans of the capitellum, experienced episodes of elbow pain. However, according to the results of our questionnaire, they never considered taking a break from throwing or consulting a clinic. These results suggest that such elbow injuries may be at an early stage and have a risk of becoming advanced if individuals continue throwing. In our study, 35 of the 153 subjects examined had sonographic abnormalities, including medial epicondylar fragmentation and osteochondritis dissecans of the capitellum. Findings obtained by radiography conformed exactly to those obtained by sonography. These results suggest that sonography can detect medial epicondylar fragmentation and osteochondritis dissecans of the capitellum. In our study, the findings of physical examination correlated significantly with the findings of sonography. However, aspects of the physical examination, including tenderness and stress test results, were not definitive for the detection of medial epicondylar fragmentation, and false-negative findings were obtained in some subjects. If sonography of the medial elbow had not been performed, half of the present cases of medial epicondylar fragmentation would not have been detected. These results indicate that sonography has a greater ability to detect medial epicondylar fragmentation than physical examination has. For the early detection of osteochondritis dissecans of the capitellum, Takahara et al. [3] performed MRI and sonography and detected capitellar abnormalities in three of 44 young baseball players. Those authors showed the early findings of osteochondritis dissecans of the capitellum. Watanabe et al. [16] performed sonography of the elbows in 316 young baseball players and detected medial epicondyle irregularity in 86 and capitellar abnormalities in three. Those authors also suggested the possible effectiveness of sonography for detecting the early changes of elbow injuries. In our study, we visited the field where baseball exercises were being performed, performed sonography, and detected elbow injuries among young players. All 23 subjects with medial epicondylar fragmentation who stopped throwing obtained bone union and returned to baseball without elbow pain. The two cases of osteochondritis dissecans 1440 AJR:187, December 2006

6 Sonography of Elbow Injuries of the capitellum were also found before the osteochondral fragment of the capitellum had become loosened. These results suggest that our attempt to detect elbow injuries in the field was successful and provided an opportunity to treat the injuries before they became more advanced. Sasaki et al. [19] evaluated medial elbow laxity in college baseball players using sonography. In our study, we could not assess the medial joint space. In the young subjects whose humeral trochlea and coronoid process of the ulna are not sufficiently ossified, it is impossible to identify the joint space using sonography. We did not recommend radiography to subjects who did not have any sonographic abnormalities. Therefore, the sensitivity of sonography could not be determined in this study; however, we speculate that the sensitivity would be fairly high because sonography had a higher sensitivity than physical examination and tended to show a greater degree of the fragment than radiography. In summary, sonography in the field makes it possible to detect medial epicondylar fragmentation and osteochondritis dissecans of the capitellum. These elbow injuries can be detected even in their asymptomatic stage. Our attempt to detect these injuries in the field was successful and provided an opportunity to treat the injuries before they became more advanced. We conclude that sonography of the elbow in the field is useful for early detection of elbow injuries among young baseball players. Acknowledgments We thank the coaches and parents of the youth baseball teams for their assistance and support in this study. References 1. Cain EL Jr, Dugas JR, Wolf RS, Andrews JR. Elbow injuries in throwing athletes: a current concepts review. Am J Sports Med 2003; 31: Fritz RC, Steinbach LS. Magnetic resonance imaging of the musculoskeletal system: Part 3. The elbow. Clin Orthop Relat Res 1996; 324: Takahara M, Shundo M, Kondo M, Suzuki K, Nambu T, Ogino T. Early detection of osteochondritis dissecans of the capitellum in young baseball players: report of three cases. J Bone Joint Surg Am 1998; 80: Takahara M, Ogino T, Fukushima S, Tsuchida H, Kaneda K. Nonoperative treatment of osteochondritis dissecans of the humeral capitellum. Am J Sports Med 1999; 27: Takahara M, Ogino T, Takagi M, Tsuchida H, Orui H, Nambu T. Natural progression of osteochondritis dissecans of the humeral capitellum: initial observations. Radiology 2000; 216: Gugenheim JJ Jr, Stanley RF, Woods GW, Tullos HS. Little League survey: the Houston study. Am J Sports Med 1976; 4: Larson RL, Singer KM, Bergstrom R, Thomas S. Little League survey: the Eugene study. Am J Sports Med 1976; 4: Cotten A, Jacobson J, Brossmann J, et al. Collateral ligaments of the elbow: conventional MR imaging and MR arthrography with coronal oblique plane and elbow flexion. Radiology 1997; 204: Ellenbecker TS, Mattalino AJ, Elam EA, Caplinger RA. Medial elbow joint laxity in professional baseball pitchers: a bilateral comparison using stress radiography. Am J Sports Med 1998; 26: Lee GA, Katz SD, Lazarus MD. Elbow valgus stress radiography in an uninjured population. Am J Sports Med 1998; 26: Schwartz ML, al-zahrani S, Morwessel RM, Andrews JR. Ulnar collateral ligament injury in the throwing athlete: evaluation with saline-enhanced MR arthrography. Radiology 1995; 197: Timmerman LA, Schwartz ML, Andrews JR. Preoperative evaluation of the ulnar collateral ligament by magnetic resonance imaging and computed tomography arthrography: evaluation in 25 baseball players with surgical confirmation. Am J Sports Med 1994; 22: Woods GW, Tullos HS. Elbow instability and medial epicondyle fractures. Am J Sports Med 1977; 5: Takahara M, Ogino T, Tsuchida H, Takagi M, Kashiwa H, Nambu T. Sonographic assessment of osteochondritis dissecans of the humeral capitellum. AJR 2000; 174: May DA, Disler DG, Jones EA, Pearce DA. Using sonography to diagnose an unossified medial epicondyle avulsion in a child. AJR 2000; 174: Watanabe C, Hukunishi K, Otsuka H, Okamoto M, Abe M. Ultrasonographic evaluation of the elbow among young baseball players [in Japanese]. Nippon Seikeigeka Gakkai Zasshi 2001; 75: Nazarian LN, McShane JM, Ciccotti MG, O Kane PL, Harwood MI. Dynamic US of the anterior band of the ulnar collateral ligament of the elbow in asymptomatic major league baseball pitchers. Radiology 2003; 227: Popovic N, Ferrara MA, Daenen B, Georis P, Lemaire R. Imaging overuse injury of the elbow in professional team handball players: a bilateral comparison using plain films, stress radiography, ultrasound, and magnetic resonance imaging. Int J Sports Med 2001; 22: Sasaki J, Takahara M, Ogino T, Kashiwa H, Ishigaki D, Kanauchi Y. Ultrasonographic assessment of the ulnar collateral ligament and medial elbow laxity in college baseball players. J Bone Joint Surg Am 2002; 84: Kevin EK, Mininder SK. Little League elbow: valgus overload injury in the paediatric athlete. Sports Med 2002; 32: AJR:187, December