| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Clinical Observations |
1 Department of Radiology, Beth Israel Medical Center, First Ave. at 16th St.,
New York, NY 10003.
2 Department of Radiology, NYU Hospital for Joint Diseases, New York, NY
10003.
Received July 26, 2007;
accepted after revision September 26, 2007.
Address correspondence to S. Gyftopoulos
(soterios20{at}gmail.com).
Abstract
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
CONCLUSION. Axial and coronal MR images are optimal for visualizing the direct and indirect heads, the conjoined tendon, and the deep musculotendinous junction of the proximal rectus femoris. Tears of the deep musculotendinous junction are longitudinal, involving a long segment of the muscle. MRI features include a "bull's-eye" sign, longitudinal scar, retraction, pseudocyst, and hematoma.
Keywords: hip • MRI • musculotendinous junction injuries • rectus femoris • sports medicine • trauma
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The rectus femoris is a long, fusiform muscle forming the anterior superficial portion of the quadriceps muscle group [3] (Fig. 1). Its main functions include knee extension and hip flexion. The proximal rectus femoris has two tendinous origins: the direct (straight) head, arising from the anterior–inferior iliac spine, and the indirect (reflected) head, arising slightly more inferiorly and posteriorly from the superior acetabular ridge and hip joint capsule. The two heads form a conjoined tendon a few centimeters below their origins. The direct head, making up most of the superficial component of the conjoined tendon, blends more distally with the anterior fascia of the rectus femoris. The indirect head, forming most of the posterior component of the conjoined tendon, becomes intrasubstance and forms a long, deep musculotendinous junction extending approximately two thirds of the length of the muscle.
|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Institutional review board approval was obtained, and informed consent was waived for this retrospective HIPAA-compliant study.
Asymptomatic Population
A retrospective review of the normal MRI anatomy of the proximal rectus
femoris was performed in 50 MRI studies of 47 patients (23 men, 24 women; age
range, 30–71 years; mean age, 44 years). The studies were obtained from
a computer data search of MRI examinations of the hips and thighs performed at
our institution during a 2-year period. Review of the asymptomatic sides in 47
patients assessed for a variety of unilateral symptoms such as hip or groin
pain, avascular necrosis, trauma, tumor, or neurologic conditions was
performed. In three patients with sciatic neuropathy, both sides were
reviewed. The MR studies were reviewed by one musculoskeletal radiologist with
20 years' experience.
Symptomatic Population
MRI studies of the hip were obtained through a search of our institution's
computer data files. The search words included "rectus femoris
injury," "rectus femoris tear," and "rectus femoris
strain." Only cases with MRI evidence of deep muscu lotendinous junction
injury, defined as injuries of the intrasubstance tendon, were included in the
study. A total of 20 patients with deep muscu lotendinous junction injuries
were identified (16 males, four females; age range, 12–54 years; mean
age, 32 years).
Two musculoskeletal radiologists, one with 15 years and one with 20 years of musculoskeletal radiology experience, in consensus, reviewed the studies. The following parameters were recorded: grade of injury; presence of "bull's-eye" sign, retraction, or hematoma; and age of injury.
Grading of the tears was based on accepted MRI characteristics of musculotendinous strains [7]. A grade I tear is defined as high signal intensity focally or diffusely at the musculotendinous junction on fluid-sensitive images. A feathery appearance to the muscle on all pulse sequences is compatible with interstitial hemorrhage and edema. The musculotendinous junction is maintained. A grade II tear shows partial disruption of the musculotendinous junction with interstitial feathery high signal intensity or hematoma in the acute setting. Low signal representing either fibrosis or hemosiderin can be seen in chronic or old injuries. A grade III tear represents a complete musculotendinous disruption with or without retraction. The bull's-eye sign was defined as bright signal surrounding the low-signal deep tendon on axial T1 or fluid-sensitive sequences (or both) and after administration of IV gadolinium.
The age of the injury was categorized as acute when interstitial edema, fluid, and hemorrhage were present; old when there was fibrous encasement of the tendon, muscle atrophy, and fatty replacement; or chronic when there were MRI features of both acute and old injuries.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
|
|
|
|
|
Symptomatic Population
Seventeen (85%) of the 20 symptomatic patients had grade II injuries; one
(5%), a grade I tear; and one (5%), a grade III tear. One of the patient's
tears could not be accurately graded due to inadequate imaging technique. The
injuries were categorized as old (n = 9, 45%) or acute (n =
9, 45%). In two patients (10%), it was difficult to distinguish between a
subacute and old injury.
In all of our patients, the injuries extended along a long portion of the deep musculotendinous junction. The most common MRI tear pattern was a bull's-eye appearance (n = 13, 65%): a halo of bright signal around the deep tendon, noted on multiple consecutive axial T1 or fluid-sensitive images (Fig. 3A, 3B). Tendon thickening (n = 6, 30%) and partial muscle retraction (n = 6, 30%) were also seen. Other findings included hematoma (n = 8, 40%); pseudocyst (n = 4, 20%) (Fig. 4A, 4B); focal fatty muscle replacement (n = 3, 15%); and longitudinal, low-signal scars (n = 6, 30%) (Fig. 5). Scarring either encased the tendon or extended longitudinally into the adjacent muscle.
|
|
|
|
|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
We were able to confirm the anatomy described by Hasselman et al. [8] using MRI studies in an asymptomatic patient population. Our findings confirm the MRI anatomic descriptions in two previous reports [5, 6]. The direct and indirect origins of the proximal rectus femoris were best visualized on axial and coronal MR images of the hip. Each head's destination, the anterior fascia for the direct head and the intramuscular substance for the indirect head, was also clearly depicted on sequential axial images. The lengthy, deep musculotendinous junction was well depicted on axial, coronal, and sagittal images.
Deep musculotendinous junction injuries of the proximal rectus femoris are difficult to clinically diagnose partly because of the deep location of the injury and partly because of the relatively nonspecific associated physical findings. Typically, patients with acute deep musculotendinous junction injuries present with a sudden onset of thigh pain and a tearing sensation. Persistent pain, tenderness, and rectus femoris asymmetry may be present. A discrete anterior thigh mass related to muscle retraction can be mistaken for a soft-tissue neoplasm [4, 5, 8, 9].
Unlike typical strains that are depicted on MRI as focal, increased signal at the musculotendinous junction [7], strains of the deep musculotendinous junction of the rectus femoris, in our study, showed a longitudinal distribution of increased signal along the involved tendon, optimally seen on sequential axial images. This type of appearance has also been described in hamstring injuries [10].
The most common type of injury noted in our study was a grade II strain (85%). The relatively mild symptoms of a grade I strain, which rarely require MRI examination, may explain its scarcity in our study. We speculate that the length of the deep musculotendinous junction, approximately two thirds of the muscle belly, may protect it from complete tearing and, thus, may explain the rarity of grade III strains in our study. It is important to note that the current grading system of strains was developed for injuries of focal musculotendinous junctions. This grading system may be less applicable for longitudinally oriented musculotendinous injuries such as those involving the rectus femoris. A future prospective study of deep rectus femoris tendon injuries with a larger patient population may be useful to further assess and possibly to modify the present grading system.
The bull's-eye sign was seen in 65% of our patients. This sign, coined by Hughes et al. [4] as increased signal around the rectus femoris intrasubstance tendon, was seen in our study in both acute and old injuries and before and after gadolinium injection. We believe this sign represents evolving stages of injury and healing around the deep tendon. Initially, the increased signal on fluid-sensitive images likely represents edema and hemorrhage. Subsequently and after IV gadolinium injection, the increased signal may reflect increased vascularity and scarring. A bull's-eye sign with secondary atrophy and fatty infiltration of the muscle around the tendon reflects remote injury.
The treatment for patients with rectus femoris strains depends on the degree of injury and athletic involvement of the individual. In nonprofessional athletes, conservative management aimed at symptom relief is applied to grade I and II strains. Professional athletes require further intensive physical therapy to avoid reinjury [1, 11]. Surgical intervention is reserved for grade III strains, especially in young, athletic individuals but may also be necessary for evacuation of a symptomatic pseudocyst or hematoma. Scar tissue resection has also been recommended to relieve pain and improve elasticity of the rectus femoris muscle [4, 12].
There are a few limitations to our study. The retrospective nature of the study hindered our ability to get a complete clinical history and pertinent follow-up and may have introduced a sample bias. The small sample pool of patients and the lack of surgical correlation were other limitations. One needs to keep in mind, however, that only a small percentage of rectus femoris deep musculotendinous junction injuries require surgery.
In conclusion, we have outlined the normal MRI anatomy of the proximal rectus femoris musculotendinous unit and the characteristic MRI features of deep musculotendinous junction injuries. Greater familiarity with these longitudinally oriented MRI findings will expedite accurate diagnosis and appropriate treatment of proximal rectus femoris musculotendinous junction tears.
Acknowledgments
We thank Leon Rybak for providing us with two cases for this study.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  R Balius, A Maestro, C Pedret, A Estruch, J Mota, L Rodriguez, P Garcia, and E Mauri Central aponeurosis tears of the rectus femoris: practical sonographic prognosis Br. J. Sports Med., October 1, 2009; 43(11): 818 - 824. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
