| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Mallinckrodt Institute of Radiology, Washington University School of Medicine,
510 S. Kingshighway Blvd., St. Louis, MO 63110.
2 Present address: Department of Radiology, Loma Linda University Medical
Center, 11234 Anderson St., Schuman Pavilion, Rm. 2605, Loma Linda, CA
92354.
3 Department of Orthopaedic Surgery, Washington University School of Medicine,
St. Louis, MO 63110.
Received March 19, 2002;
accepted after revision August 1, 2002.
Address correspondence to S. I. Ward.
Abstract
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
MATERIALS AND METHODS. The anterior bundle of the medial collateral ligament in five cadaveric elbows was imaged and injected with contrast material by experienced musculoskeletal radiologists using a 12-MHz linear array transducer. Immediate ligament dissection was performed. The bilateral ligaments in 30 healthy 21- to 34-year-old male volunteers were imaged with gravitational stress. Of these, five randomly selected subjects also received approximately 5 lb (11.3 kg) of applied stress.
RESULTS. Contrast material was injected directly into all five cadaveric ligaments. The anterior bundle of the medial collateral ligament in all 30 asymptomatic male volunteers was hyperechoic in comparison with surrounding muscle and had a fibrillar pattern and fanlike shape. Its mean dimensions were 2.6 ± 0.31 x 2.2 ± 0.47 x 4.0 ± 0.88 mm on the right and 2.6 ± 0.36 x 2.1 ± 0.42 x 4.0 ± 0.86 mm on the left, in longitudinal short, transverse short, and transverse long axes, respectively. Differences in ligament measurements in sidedness, stress application, and hand dominance did not approach statistical (Bonferroni corrected, p > 0.01) or clinical (all differences, <0.2 mm) significance.
CONCLUSION. Radiologists can accurately use sonography to identify and measure the size of the anterior bundle of the normal medial collateral ligament of the elbow. These baseline parameters for the normal ligament may prove useful when evaluating the injured ligament.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
|
Physical and radiographic examinations are generally used to evaluate the stability of the anterior bundle of the medial collateral ligament. MR imaging with or without arthrography has proven to be reliable in the evaluation of the anterior bundle of the medial collateral ligament [4, 5]. We propose that sonography—a rapid, noninvasive, and inexpensive test—can also be an accurate adjunct to a physical and standard radiographic examination of the anterior bundle of the medial collateral ligament. Reliable identification and knowledge of the normal sonographic appearance of the anterior bundle of the medial collateral ligament are essential for accurate assessment of normal and injured states. A few sonographic pictorial references revealing the anterior bundle of the medial collateral ligament [6,7,8] have been published. To our knowledge, however, precise sonographic delineation, scanning technique, and imaging parameters have not been thoroughly described, and there is no sonographic standard of reference for the normal anterior bundle of the medial collateral ligament. The purpose of this study was to determine whether sonography could reveal the anterior bundle of the medial collateral ligament in the cadaveric elbow and to characterize its appearance in a group of healthy adult male volunteers.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
All sonograms were obtained in real time with the use of an Elegra scanner (Siemens Medical Systems, Issaquah, WA) and a high-resolution linear array transducer (VFX 13-5, 12 MHz). Two radiologists experienced with musculoskeletal sonography studied all cadaveric elbows. Initially, images were obtained of the structure presumed to represent the anterior bundle of the medial collateral ligament on the basis of anatomic knowledge. To determine correct localization of the ligament, we injected 0.1 mL of methylene blue dye into the structure identified as the anterior bundle of the medial collateral ligament under sonographic guidance using a 25-gauge needle. Immediately after localization and injection, an experienced orthopedic surgeon dissected the elbow using a posteromedial approach to identify the ligament and to determine the location of the dye (Fig. 2A,2B,2C).
|
|
|
Volunteer Study
Thirty healthy adult male volunteers, between 21 and 34 years old,
responded to personal solicitation and agreed to participate in the study.
Written informed consent was obtained in all cases. Men between 21 and 34
years old were selected for the study because valgus elbow instability
typically occurs in men in this age group. A detailed questionnaire regarding
past and present sports activity, past elbow injury or abnormal findings on
elbow radiographs, occupation, and specific medical history was obtained from
each volunteer. None of the 30 volunteers were professional athletes or had a
history of a connective tissue disorder, inflammatory arthritis, or prior
elbow injury or other abnormality. One of two orthopedic surgeons with
expertise in elbow injuries and sports medicine examined both elbows of each
volunteer. The examination included range of motion, dynamic valgus stress,
resisted pronation and wrist flexion, laxity, and ulnar nerve irritability
tests. None of the 30 volunteers showed evidence of prior ligament injury or
abnormality at physical examination, and all were entered into the study.
All sonographic images were obtained by one of two radiologists experienced with musculoskeletal sonography. One of the radiologists examined 19 volunteers and the other radiologist, 11.
Both anterior bundles of the medial collateral ligament were imaged with gravitational valgus stress. Sonography was performed with the subject in the supine position and the head elevated to approximately 45°. The shoulder was abducted 60° and externally rotated, and the elbow was placed in 90° of flexion (so that the wrist was level with the shoulder) (Fig. 3A). Three measurements of the ligament were obtained. First, the transducer was positioned in a longitudinal orientation to the anterior bundle of the medial collateral ligament (parallel to the common flexor tendon at its attachment to the medial epicondyle). This orientation was used because the anterior bundle can best be evaluated at physical examination and is best visualized on MR imaging in this position [4, 5]. The short axis of the ligament in the longitudinal plane was then measured midway between its origin and insertion (Figs. 1A and 3B). Ligament echogenicity was also determined using this view. Next, the transducer was rotated 90° to visualize the ligament in a transverse plane. Because of the small size and oval shape of the ligament and the difficulty in determining that the transverse image was precisely at the level of the previously obtained short axis in the longitudinal plane, it was decided to measure both the short and long (thickness) axes of the ligament in this transverse plane (Fig. 3C). Both elbows of each volunteer were scanned. The time required to image both elbows was also recorded.
|
|
|
Five of the 30 subjects were randomized to undergo evaluation with applied stress using a 5-lb (11.3 kg) ankle weight (25 N). The weight was wrapped around the wrist with the subject in the gravitational stress position described previously, and the anterior bundle of the medial collateral ligament was imaged. Both elbows were studied, and measurements were obtained as described previously.
Descriptive statistics were calculated for the variables of the study.
Differences in size with respect to side (right vs left), stress, and hand
dominance were tested with paired t tests. Because of the multiple
comparisons, a Bonferroni adjusted 
value of 0.01 was used.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Volunteer Study
The mean age of the 30 recruited subjects was 29.6 years (age range,
21-34). Eight were involved in collegiate sports, three in intramural sports,
and 16 in high school sports; and three never participated in sports. Eight of
30 subjects engaged in manual labor. Twenty-six subjects were right-handed and
four were left-handed. None of the patients reported a history of arthritis or
ligamentous laxity. The findings of the physical examinations in 28 of 30
subjects were normal. One subject showed right ulnar nerve hypermobility and
mild left ulnar nerve irritability and subluxation at physical examination,
and another subject showed mild left ulnar nerve subluxation at physical
examination. The findings of the ligament examinations were normal in all
subjects.
On sonography, all 30 subjects had a hyperechoic, fibrillar-appearing anterior bundle of the medial collateral ligament. The dimensions of the mean longitudinal short axis, mean transverse short axis, and mean transverse long axis (thickness) of the ligament are shown in Table 1. As a result of time constraints, one subject lacked a transverse measurement in the nonstress (gravity valgus stress) condition. For each of the three measurements between the right and left anterior bundle of the medial collateral ligaments, differences were less than 0.1 mm. The mean (± SD) dimensions of the anterior bundle of the medial collateral ligament were as follows: 2.6 ± 0.31 x 2.2 ± 0.47 mm x 4.0 ± 0.88 on the right and 2.6 ± 0.36 x 2.1 ± 0.42 x 4.0 ± 0.86 mm on the left (longitudinal plane short axis, transverse plane short axis, and transverse plane long axis [thickness], respectively).
|
Five subjects were randomly selected to undergo both nonstress and stress (applied 5-lb [11.3 kg] valgus stress) sonography. One of these subjects lacked a transverse measurement in the applied stress condition associated with time constraint. Mean measurements of the anterior bundle of the medial collateral ligament for the two test conditions are shown in Table 2. All differences were less than 0.2 mm.
|
Table 3 shows the mean dimensions between the anterior bundles of the dominant and nondominant sides of the medial collateral ligament. All differences were less than 0.1 mm. None of the differences presented in Tables 1,2,3 were statistically significant with a Bonferroni correction (p > 0.01).
|
The mean time for sonographic examination of both elbows was approximately 6 min. The time to apply the weights for stress images was negligible.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
One potential of sonography is its ability to visualize the anterior bundle of the medial collateral ligament during stress testing, yielding a dynamic study. Thus, sonography can potentially yield the same information as that obtained on stress radiography and MR imaging. In addition, visualization of the ligament during stress may provide information not possible with static MR images.
To our knowledge, only a few sonographic studies have investigated the anterior bundle of the medial collateral ligament or have provided images of the normal ligament. One recent study compared MR imaging, sonography, and stress radiography of the elbows of uninjured professional handball players [8]. In this study, the authors investigated differences in sonographic thickness and radiographic laxity in the dominant and nondominant anterior bundle of the medial collateral ligament but did not compare the ability of each test to consistently and accurately identify the normal anterior bundle of the medial collateral ligament or determine the complete dimensions of the ligament. Two published pictorial essays have illustrated the normal anterior bundle of the medial collateral ligament with sonography [6, 7]. In those articles, however, there was little if any description of the normal sonographic appearance of the ligament. The purpose of our study was to determine the ability of sonography to identify and determine the echogenicity and size of the normal anterior bundle of the medial collateral ligament to establish a standard of reference that could be used when comparing a normal ligament with an injured ligament.
Our study shows that sonography can be used to accurately localize the anterior bundle of the medial collateral ligament on the basis of our cadaveric dissections after sonographically guided injection of dye into the ligament. Moreover, we could consistently identify and measure the normal ligament in all 30 uninjured male volunteers. The ligament was easiest to identify in the longitudinal plane. In fact, our measurement of the mean transverse plane long axis or thickness of approximately 4.0 ± 0.88 mm on the right and 4.0 ± 0.86 mm on the left falls within the thickness range at gross anatomic dissection of the anterior bundle of the medial collateral ligament of 4.7 ± 1.2 mm reported by Morrey and An [12]. Their measurements were also obtained at the midpoint of the ligament. Measurements in the transverse plane were more difficult to obtain because of the small size and tapered appearance of the ligament in the longitudinal plane. However, we could recognize this change in morphologic appearance from proximal to distal in both our cadavers and male volunteers.
Anatomic studies show that the ligament extends from the posteroinferior surface of the medial epicondyle of the humerus and attaches to the ulnar sublime tubercle [3, 12]. The origin and insertion of the ligament are easily apparent on sonography, although we were unable to show both on one image, given the ligament's slight oblique orientation. A study that assessed throwing athletes with tears of the reconstructed anterior bundle of the medial collateral ligament showed that most tears occur in the mid substance of the ligament rather than at the origin or insertion [9]. Because of the location of most tears and the ease of visualizing the ligament's mid aspect and its attachments, sonography should be accurate in detecting tears. Future studies will be necessary to confirm the accuracy of sonography in detecting not only full thickness but also partial thickness tears.
Our data also showed that there is little, if any, variation in the dimensions or echogenicity of the ligament when comparing sides (left vs right), stress conditions, or handedness. Although the sonographic measurements of the ligaments with stress radiographs did not differ from those values obtained with gravity only, caution is recommended in extrapolating these data to the high-performance athlete. These findings may not be consistent in the population of throwing professional athletes. Measurement differences are also likely to be found in the dominant versus the nondominant ligaments in this population. A study of uninjured elite team handball players suggests that there are bilateral differences in thickness of the anterior bundle of the medial collateral ligament on sonography, which are greater on the dominant side [8]. Further studies of professional athletes are required to better interpret dynamic sonographic studies in this specific population.
Our study has several limitations. Time constraints prevented us from determining interobserver variability between the two radiologists. Additionally, a Telos radiographic stress device (Austin and Associates, Fallston, MD) was unavailable during our study. The stress device has been used to reproducibly and consistently stress the anterior bundle of the medial collateral ligament in several studies [8, 9, 13, 14]. This equipment is not readily accessible in most centers, and free weights have proven to be an adequate stress mechanism [10].
Although sonography is an operator-dependent study, proficiency with the technique occurred within a reasonable amount of time for both radiologists and can be achieved by most radiologists familiar with musculoskeletal sonography. In fact, our mean screening time for scanning both elbows was approximately 6 min.
In summary, we believe that sonography has the potential to be used as a rapid, noninvasive, and inexpensive adjunct to physical and standard radiographic examination of the anterior bundle of the medial collateral ligament. Our study shows that radiologists can use sonography to accurately identify and measure the anterior bundle of the medial collateral ligament. We were also able to establish normal reference values of dimensions for the anterior bundle of the medial collateral ligament in young men. These values can be used when injury of the ligament is suspected. The potential of sonography as a dynamic study in subjects with suspected injury of the anterior bundle of the medial collateral ligament is also promising. Further studies are needed to assess the usefulness of sonography in the diagnosis of injury in the medial collateral ligament.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  H.-M. Kim, N. Dahiya, S. A. Teefey, J. D. Keener, and K. Yamaguchi Sonography of the Teres Minor: A Study of Cadavers Am. J. Roentgenol., March 1, 2008; 190(3): 589 - 594. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
