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ABSTRACT |
Thursday, May 10, 10:00 AM–12:00 PM
Abstracts 206-217
Moderator(s): John Carrino and Mark Robbin
10:00 AM
206. Magnetic Resonance Imaging of Interstitial Tears of the Rotator Cuff: Their Relationship with Rotator Cuff Tears and their Clinical Significance
Manvar S.*; Kamireddi A.; Major N. Duke University, Durham, NC
Address correspondence to S. Manvar (smm14{at}duke.edu)
Objective: Secondary signs have been sought to help aid the MR diagnosis of rotator cuff tears, especially partial-thickness tears. We seek to determine if interstitial tears are always present with rotator cuff tears; the types of rotator cuff tears they present with; and establish the clinical significance of finding interstitial tears.
Materials and Methods: A retrospective analysis of our institution's database of 5,101 MRIs of the upper extremity joint between 01/98 and 04/06, resulted in 187 exams in 185 patients thought to have interstitial tear, intramuscular cyst, intrasubstance tear or ganglion cyst. Several keywords were searched due to the interchangeable usage of these terms in describing the presence of fluid signal parallel to the fibers of a rotator cuff muscle or tendon contained within a fascial sheath, and the term interstitial tear was used for consistency. Of the 187 exams, 134 shoulders in 132 patients (62 women, 70 men) met our criteria for an interstitial tear.
Results: Of the 134 shoulders examined with interstitial tear, 102/134 (76.1%) shoulders possessed radiological evidence of both interstitial tear and rotator cuff tears. 32/134 (23.9%) shoulders were diagnosed with only an interstitial tear and were not associated with rotator cuff tears. Importantly, 55/102 (53.9%) shoulders consisted of interstitial tear associated with full-thickness rotator cuff tears and 47/102 (46.1%) shoulders presented partial-thickness rotator cuff tears. Furthermore, 48/102 (45.1%) shoulders with both interstitial tear and rotator cuff tears were followed with the gold standard of arthroscopy to confirm the MR findings. In 46/48 (95.8%) shoulders followed by arthroscopy the arthroscopic findings confirmed the radiological findings; the other two cases were shown to have an intact rotator cuff at arthroscopy.
Conclusion: Our study echoes the sentiments of previous studies that suggest a relationship between interstitial tears and rotator cuff tears, but illustrates that the incidence of isolated interstitial tears is higher than previously expected. When interstitial tears present with rotator cuff tears, they present with full-thickness and partial-thickness rotator cuff tears in relatively equitable proportions. The presence of an interstitial tear on MR imaging, while it may represent an isolated finding, should prompt a thorough search of all the rotator cuff tendons for tears by a radiologist such that the patient may receive appropriate follow-up.
207. High-resolution MRI of Suspected Acromioclavicular Dislocation Compared to Digital Weightbearing Radiographs
Krestan C. R.1*; Fialka C.2; Weber M.1; Mayerhoefer M.1; Czerny C.1 1. Osteoradiology, Vienna, Austria; 2. Trauma Surgery, Vienna, Austria
Address correspondence to C. Krestan (christian.krestan{at}meduniwien.ac.at)
Objective: To evaluate the diagnostic performance of high resolution MRI of the AC-joint compared to Weightbearing digital radiographs with respect to the Rockwood classification in patients with suspected AC-dislocation
Materials and Methods: 47 patients (36 women, 11 men) from the department of trauma surgery were enrolled into the study, which was approved by the local ethics committee and all patients signed an informed consent. 3 patients were excluded due to metal artefacts. Inclusion criteria was a suspected acromioclavicular dislocation after prior shoulder trauma. Digital radiographs of both shoulders were performed on a Super 80 CP system (Philips Medical Systems, Hamburg, Germany) in two views according to standard clinical procedures (ap. non- and weightbearing with 5 kg, 55 kV/9 mAs; axial views). MRI exams were performed on both sides in a 1.0 T MRI scanner (T10 -NT, Philips Medical Systems, Best Netherlands) using a dedicated surface coil: coronal 3D T1-FFE WATS (water-selective) sequence images were obtained by two excitations using 24/11.95 (TR/TE) and a flip angle of 50°. The field of view (FOV) was 150 mm, and the reconstructed imaging matrix was 512. The reconstructed voxel size was 0.29/0.29/1.00 mm. Total scan duration was 3.56 min. For coronal pew-TSE sequences images were obtained by three excitations using 1500/25 (TR/TE) and a flip angle of 90° and a TSE-factor of 5. The field of view (FOV) was 90 mm, and the reconstructed imaging matrix was 512. The reconstructed voxel size was 0.18/0.18/2.00 mm. Total scan duration was 5.12 minutes. The acromioclavicular, coracoclavicular and coracoacromial ligament were evaluated by 2 musculoskeletal radiologists in consensus and blinded to the radiographs. An adapted Rockwood score was used for the classification of the MRI-exams.
Results: In 14 patients X-ray classification led to Rockwood stage I, which was downstaged in 50%, upstaged in 28% and unchanged by MRI in 21%. For Rockwood stage II the figures were 26 patients /38-19-42%; Rockwood III 6 patients /33-17-50% and unchanged for one patient with stage IV.
Conclusion: We conclude that high-resolution MRI of the AC-joint changes the Rockwood classification based on radiographs in a high proportion of patients and thus led to more accurate diagnosis and patient management. MRI can be recommended for diagnostic work-up of traumatic AC-dislocations in selected patients.
208. Magnetic Resonance Imaging Features of SLAP (Superior Labrum Anterior-Posterior) Lesions Versus Normal Meniscoid Insertions
Manvar S.*; Garrigues G.; Major N. Duke University, Durham, NC
Address correspondence to S. Manvar (smm14{at}duke.edu)
Objective: The presence of a "meniscoid-type" superior labrum may be mistaken for a tear rather than a normal anatomic form during MRI interpretation leading to an incorrect diagnosis of SLAP lesion and unnecessary surgery.
Materials and Methods: A retrospective analysis of our institution's database of 1132 MRIs of the shoulder performed from 9/2004 through 4/2006, yielded 144 patients thought to have SLAP tears of the glenoid labrum on conventional and/or MR arthrography (MRa). Results were correlated with arthroscopic records. 55 patients (39 men, 16 women) had arthroscopy and MRI (n = 38) or MRa (n = 17). Furthermore, analysis of the orthopedic database for SLAP repair surgeries performed in the same time frame yielded 4 patients without prospective MRI or MRa diagnosis of SLAP tear.
Results: Two of 17 (11.8%) patients thought to have SLAP tears by MRa were found to have no labral pathology at arthroscopy. Both cases failed to have extension of high signal intensity behind the biceps anchor on fat-saturated oblique coronal T1-weighted images. Fifteen of 17 patients were correctly diagnosed with SLAP lesions prospectively on MRa (PPV 88.2%) and all cases demonstrated extension of high signal intensity to the most posterior image. Nine of 38 (23.7%) patients thought to have SLAP tears by conventional MRI were found to have no labral pathology at arthroscopy with meniscoid insertion of superior labrum. 29 of the 38 patients were correctly diagnosed as SLAP tears on MRI and classified as a type II-IV SLAP lesion by arthroscopy and required repair (PPV 76.3%). Three of the 4 patients known to have SLAP tears by arthroscopy but no tear by initial MRa impression, were retrospectively found to have anteroposterior extension of high signal intensity in the superior labrum. One of the 4 patients did not receive contrast and signaling was difficult to appreciate.
Conclusion: Normal meniscoid insertions, regardless of intraarticular contrast, demonstrated an area of high, globular signal mimicking a SLAP lesion immediately posterior to the biceps labral complex. However, posterior to the complex the superior labrum was low in signal and normal in appearance. Therefore, the superior labrum should not be considered torn unless signal abnormality continues through the remainder of the labrum posterior to the biceps anchor. Awareness of the imaging features of SLAP tears and normal meniscoid insertions prevents patients from unnecessary surgery and use of MRa will help improve classification and diagnosis.
209. Comparison of Shoulder Injection Methods
Charles S. S.*; Davis K. W.; Tuite M. J.; Blankenbaker D. G.; Fine J. P. University of Wisconsin School of Medicine and Public Health, Madison, WI
Address correspondence to S. Charles (ssccharles{at}yahoo.com)
Objective: Shoulder joint injections are extremely common procedures in radiology, both for therapeutic purposes and for instilling contrast media for various types of arthrography. The traditional (Schneider) method to perform shoulder injections in the fluoroscopy suite uses an anterior approach to the lower glenohumeral joint. Recently, an anterior approach through the rotator cuff interval has been popularized and has been purported to be easier and faster to perform and easier to teach. The purpose of this study is to determine if either approach confers any advantage in procedure related pain, procedure time, fluoroscopy time, ease of accessing the joint, and image quality at MR arthrography.
Materials and Methods: The IRB approved this study in which 100 consecutive subjects presenting to the Radiology Department for shoulder injection would be randomized to either the Schneider approach or the rotator interval approach. Collected data include procedural pain rated on a 100 mm Visual Analog Scale (higher numbers corresponding to more pain), fluoroscopy time, procedure time, level of training of the primary operator, number of attempts to access the joint, needle length, subjective assessment rating of ease of the procedure, and complications. Statistical tools include the two sample t-test and Fisher's exact test. 35 subjects have been enrolled at abstract submission time.
Results: These 35 subjects demonstrated a statistically significant reduction in procedure time for the rotator interval (RI) approach over the Schneider technique. Mean procedure time (standard deviation) was recorded as 139 seconds (74 seconds) for RI approach and 258 seconds (130 seconds) for the Schneider technique (p = 0.002). Pain scores were 14.8mm (8.0 mm) for RI and 27.6 mm (19.3 mm) for Schneider, also statistically significant (p = 0.02). Mean fluoroscopy time (42 vs. 55 seconds), number of attempts required, and subjective procedure ease all demonstrated trends in favor of the rotator interval approach, although none was statistically significant.
Conclusion: The rotator interval approach for performing shoulder injections demonstrates statistically significant reductions in procedure time and procedural pain. The RI approach also demonstrates trends toward advantages in other performance measures. As additional data are accrued, they may lend further strength to the conclusion that the rotator interval approach is the method of choice for most fluoroscopy-guided shoulder injections.
210. Indirect MR Arthrography for Evaluating Glenoid Labral Pathology
Malone W. J.2*; Zoga A. C.3; Bergin D.3; Gopez A. G.3; Boylan D.1; Morrison W. B.3 1. Doylestown Orthopaedics Specialists, Doylestown, PA; 2. Geisinger Medical Center, Danville, PA; 3. Thomas Jefferson University Hospital, Philadelphia, PA
Address correspondence to W. Malone (wjmalone{at}geisinger.edu)
Objective: Direct MR arthrography has been established as the imaging gold standard to evaluate for native labral pathology due to its superb contrast. High-esolution noncontrast protocols have also been reported as accurate. As remote interpretation of MR images becomes more prevalent, direct intraarticular contrast infusion may not always be feasible. We present our initial experience using a high-resolution indirect arthrographic (IMRA) protocol for assessment of the glenoid labrum on native, nonoperative shoulders with clinical instability.
Materials and Methods: 31 patients (M:F = 23:8, mean age = 27.5) with clinical instability referred from a single orthopaedics practice for MR arthrography were imaged on a short bore 1.0-T MR system after IV infusion of 15–20 cc gadolinium contrast. An IMRA protocol tailored to evaluate glenohumeral pathology was used with T1 SE fat suppressed images in conjunction with our standard nonenhanced high resolution T2 FSE and PD FSE sequences. Exams were retrospectively reviewed by 2 musculoskeletal radiologists in consensus. Labral tears as well as location, extent and morphology were logged. Readers graded the arthrographic T1 sequences against the standard high resolution sequences for demonstration of labral pathology using a confidence scale. 11 patients had surgery and operative findings were compared with IMRA interpretation.
Results: At surgery, 10 labral tears were found in 9 patients (5 SLAPs, 4 anterio-inferior and 1 posterior). All 10 were called by IMRA in the correct location. One patient had an inferior tear called by IMRA and had no tear at surgery, but did have inferior glenoid chondromalacia. 4 patients were placed in a nonoperative course after IMRA showed no tear. Overall, 21 tears were called on the high resolution sequences and 25 were called on the arthrographic sequences. Reader confidence was 3.9/5 on the high resolution sequences, 4.5/5 on the arthrographic sequences and 4.7/5 using the entire IMRA study.
Conclusion: Indirect MRA shows promise in detecting labral pathology, especially when direct MRA is not feasible.
211. Accuracy of MR Versus MR Arthrography of the Shoulder in the Same Patient Population
Magee T.* NSI, Merritt Island, FL
Address correspondence to T. Magee (tmageerad{at}cfl.rr.com)
Objective: Shoulder injuries are common. MR imaging of the shoulder is commonly performed in patients with these injuries. Some authors have suggested MR arthrography should be performed on all MR shoulder patients to increase accuracy of diagnosis. We report our experience in diagnostic accuracy of conventional MRI compared with MR arthrography of the shoulder. All results were correlated with arthroscopy.
Materials and Methods: 100 consecutive conventional shoulder MR and MR arthrography exams performed on patients with shoulder pain were reviewed retrospectively by consensus reading of two musculoskeletal radiologists. All patients had both conventional MR exams and MR arthrography performed at the same sitting. Conventional MR exams included T2 fat-saturated coronal and sagittal, T1 coronal and axial proton density fat saturated images. Patients then had arthrography performed with a gadolinium/saline mixture and subsequently axial, coronal and sagittal fat-saturated T1-weighted images were performed. Scans were assessed for full or partial thickness supraspinatus tendon tears, superior labral anterior posterior (SLAP) tears and anterior or posterior labral tears.
Results: In this group of patients, three full-thickness supraspinatus tendon tears and nine high grade partial thickness (>50% of the supraspinatus tendon torn) were seen on MR arthrography but not on conventional MR examination. Seven SLAP tears, four anterior labral tears and two posterior labral tears were seen on MR arthrography but not on conventional MR examination. Two patients had ALPSA lesions clearly delineated on MR arthrography but not on conventional MR exam. All patients with additional findings on MR arthrography as compared with conventional MR exam had arthroscopic correlation that confirmed MR arthrography findings.
Conclusion: There is a high prevalence of positive findings on shoulder MR and MR arthrography in patients with shoulder pain. MR arthrography is considerably more sensitive for detection of partial thickness supraspinatus tears and labral tears than conventional MR imaging. There were additional findings on MR arthrography as opposed to conventional MRI in 27 out of 100 patients in this group.
212. Pediatric Shoulder MRI: Use and Accuracy in Sports Medicine
Davis K. W.*; Kijowski R.; Tuite M. J. University of Wisconsin School of Medicine and Public Health, Madison, WI
Address correspondence to K. Davis (kdavis{at}uwhealth.org)
Objective: There are limited published data regarding the use and accuracy of MRI of the shoulder in children and adolescents. The purpose of this study is to document the range of indications leading to MRI of the shoulder in pediatric sports medicine patients, the findings of these MR scans, and the accuracy of MR.
Materials and Methods: We searched our PACS archive for MR scans of the shoulder in athletes under the age of 18 within a 52 month period. Indications, demographics, reported MRI findings, and clinical and surgical follow-up information were recorded. The MRI findings used were the original reports.
Results: MR scans of 103 shoulders, including 62 direct MR arthrograms, were performed on 44 women (mean age 15.4 years) and 59 men (15.9). Among women, the most common activities included swimming (11), volleyball (9), basketball (8), and softball (7); among men, they were football (21), baseball (12), wresting (9), basketball (5), and trauma (5). The vast majority of specific indications were possible labral tear, instability, and multidirectional instability (71), with rotator cuff pathology (12) and ganglion cyst/nerve entrapment (12) suspected less often. 38 patients underwent subsequent arthroscopy. 7 of the surgical patients had conventional MRI; of those, four had tears of the glenoid labrum. Using surgical findings as the gold standard, MRI sensitivity and specificity for labral tears were 75% and 100%. Of the conventional MRI patients, there was one correctly called partial-thickness tear of the rotator cuff, one correctly called full-thickness tear, and one deep partial thickness tear with delamination that was incorrectly called a full-thickness tear. For the 31 MR arthrograms with surgical correlation, there were 25 with labral tears. Sensitivity was 84% and specificity 83%. Sensitivity for the 7 partial thickness cuff tears was only 29% but specificity was 96%. There were no full-thickness cuff tears in the arthrogram group. Surgical findings of instability (13 cases) and patulous/lax/torn capsules (10) were only occasionally diagnosed prospectively on MR.
Conclusion: MRI of the pediatric shoulder is requested more often for men than women. Specific indications usually are labral tears and instability. Full-thickness rotator cuff tears are rare under the age of 18. In this population MR arthrography is less accurate for labral tears than published data for the adult labrum, but still moderately accurate. Sensitivity for partial thickness rotator cuff tears is poor.
213. MRI of the Rotator Cuff Interval on Non-contrast MRI. Its Appearance in Association with Rotator Cuff and Biceps Tendon Abnormalities
Rao N.*; Bergin D.; Morrison W.; Parker L.; Zoga A. Thomas Jefferson University Hospital, Philadelphia, PA
Address correspondence to N. Rao (neeta.rao{at}mail.tju.edu)
Objective: To assess the lateral and medial coracohumeral ligaments (LCHL, MCHL) and normal fat of the rotator cuff interval (RCI) on noncontrast MRI. To establish what changes occur in the RCI with rotator cuff (RC) and biceps tendon abnormalities.
Materials and Methods: A database search was performed to identify patients who had 1.5 T MRI of the shoulder to include a full range of rotator cuff and biceps tendon abnormalities as well as normal exams. Exams were reviewed by two musculoskeletal radiologists at two different settings: to assess the RCI for fat, fluid, edema, and fibrosis and to score visualization of the LCHL and MCHL (1 = not seen, 5 = excellent) in all planes. On second image review the rotator cuff tendons and biceps tendon were evaluated. The mean scores for visualization of the LCHL and MCHL on axial, sagittal, and coronal views were calculated. Abnormalities of the RCI were correlated with the status of the rotator cuff and biceps tendon using Pearson's Correlation test.
Results: MR studies of 61 patients (34M, 27F, age 22–83, mean 55 yrs) were reviewed. The LCHL and MCHL were seen in at least one plane in 93%/92% with mean visualization scores of 2.9, 2.6 (axial), 2.8, 2.6 (coronal), and 3.8, 3.2 (sagittal). The MCHL/LCHL was normal in 17%/20%, thickened in 34%/32%, wavy in 23%/22%, and torn in 26%/26%. Abnormalities of the MCHL/LCHL showed significant correlation with subscapularis (r = 0.5/0.4), supraspinatus (r = 0.5/0.7), and biceps tendon (r = 0.33/0.35) pathology. LCHL abnormalities were identified in association with anterior leading edge supraspinatus tendon tears (85%). Fluid, edema, and fibrosis were seen in the RCI in 75%, 75%, and 77%, respectively. Correlation between replacement of RCI fat and supraspinatus tendon abnormality was r = 0.5, with subscapularis tendon abnormality r = 0.34, and with biceps tendon abnormality r = 0.2. RCI fat was completely replaced in 83%/77% with full thickness subscapularis and supraspinatus tendon tears.
Conclusion: The MCHL and LCHL of the RCI are seen on noncontrast 1.5-T MR. Morphological abnormalities of the RCI and replacement of its fat correlates with severity and progression of rotator cuff tendon and biceps tendon abnormalities.
Clinical Relevance/Application: The RCI plays an integral role in shoulder stability. Familiarity with the anatomy and appearance of the RCI on routine MR will allow radiologists to provide greater detail for surgical planning.
214. The Groove Entrance Lesion (GEL): MR Imaging Findings, Surgical Correlation, and Clinical Significance of Pathology of the Subscapularis and Long Head of the Biceps Brachii Tendons at the Entrance to the Bicipital Groove
Gaskin C. M.*; Anderson M. W. University of Virginia Health System, Charlottesville, VA
Address correspondence to C. Gaskin (cmg9s{at}virginia.edu)
Objective: Pathology of subscapularis and long head of the biceps brachii tendons at the entrance to the bicipital groove may be a source of persistent pain if not addressed at the time of surgery. This study examines the MR imaging findings in patients with abnormalities of these structures. It also examines their clinical importance and surgical management.
Materials and Methods: Institutional review board approval was obtained. A database search retrospectively identified 19 patients with surgical and MR imaging findings of partial tears of the biceps and/or the subscapularis tendons at the entrance to the bicipital groove. MR imaging findings and surgical reports were reviewed.
Results: At surgery, ten (52%) of 19 biceps tendons were partially torn at the bicipital groove, 5 (26%) were frayed, and 4 (21%) were intact. Of the 15 biceps tendons reported as abnormal at surgery, all demonstrated an abnormal MR imaging appearance at the entrance to the bicipital groove. On MR imaging, 14/19 (74%) of the biceps tendons were clearly subluxed or dislocated, 3 (16%) were considered possibly subluxed, and 2 (11%) were not subluxed. In the surgical reports, 10/19 (52%) biceps tendons were reported as subluxed or dislocated, 7 (37%) had no specific comment on subluxation, and 2 (11%) were described as "not subluxed." 17/19 (89%) subscapularis tendons were considered partially torn on MR imaging. 9/19 (47%) subscapularis tendons were reported partially torn at surgery, while the remaining 10 (53%) were not mentioned in the operative reports. 16/19 (84%) of the biceps tendons were treated at surgery (8/19 - tenodesis; 4 - tenotomy; 4 - debridement), and 3 (16%) were not addressed. Surgical repair of the subscapularis tendon was performed in 4 (21%) of 19 patients.
Conclusion: Abnormalities of the biceps and subscapularis tendons often coexist at the entrance to the bicipital groove. MR imaging findings may be subtle, but their identification is important to insure optimal treatment. Since these lesions can easily be missed at arthroscopy, awareness of their MR imaging appearance and clinical importance should improve preoperative diagnosis and ultimate surgical management.
215. MR Findings in Hourglass Biceps
Clifford P. D.1; Kalandiak S. P.2; Kirwan R.1* 1. University of Miami School of Medicine, Department of Radiology, MSK Section, Miami, FL; 2. University of Miami, Department of Orthopaedics, Miami, FL
Address correspondence to R. Kirwan (rkirwan{at}med.miami.edu)
Objective: "Hourglass biceps" is a mechanical condition affecting the intraarticular portion of the long head of the biceps tendon leading to pain, locking and limited elevation of the shoulder. The hourglass biceps has been described in the orthopedic literature but to our knowledge it has not been described in the radiology literature. Published orthopedic literature suggests that MR is not useful in the detection of the hourglass biceps. The purpose of this study is to describe the MR findings of surgically confirmed cases of hourglass biceps.
Materials and Methods: Three patients with surgically confirmed hourglass biceps deformities were reviewed. All patients underwent pre-operative MR studies of the shoulder in order to rule out rotator cuff tear or labral injury. Two patients were imaged at 1.5 T with one of the studies being a direct MR arthrogram and the other an indirect arthrogram. An MR diagnosis of biceps tendinosis and intraarticular tendon enlargement was made preoperatively in both cases. The first case making the radiologist familiar with the specific "hourglass biceps" moniker, the second case was diagnosed specifically as hourglass biceps prospectively. The radiologist was blinded to the clinical examination, any further clinical history or associated imaging studies. A third case of surgically confirmed hourglass biceps was performed at an outside imaging center utilizing a 0.2 T open magnet. A fourth case given an MR diagnosis compatible with an hourglass biceps has not undergone surgery.
Results: One patient had a full thickness tear and one patient had insertional partial articular surface supraspinatus tear and a SLAP lesion. The third patient had no rotator cuff tear at surgery. Each patient had an enlarged intraarticular long head of the biceps which did not freely move into the intertubercular groove upon elevation of the shoulder at surgery. MR studies each showed tendinosis and intraarticular enlargement of the long head biceps tendon. There was a rapid decrement in size of the tendon at the point of tendon entry into the intertubercular groove in all cases.
Conclusion: MR findings of surgically confirmed cases of hourglass biceps are presented. MR imaging is able to detect the hourglass biceps deformity. The radiologist should be aware of this entity and should suggest the diagnosis when MR findings are present. Prospective studies are required to determine the sensitivity and specificity of MR for detection of hourglass biceps.
216. Subscapularis Tendon Tears: A Common Sonographic Finding in Symptomatic Post-Arthroplasty Shoulders
Ives E.*; Nazarian L. Thomas Jefferson University, Philadelphia, PA
Address correspondence to E. Ives (epives{at}yahoo.com)
Objective: Subscapularis tear is a known complication of shoulder arthroplasty. The purpose of this investigation is to identify the prevalence of subscapularis tears found on sonography following shoulder arthroplasty in symptomatic patients.
Materials and Methods: Following IRB approval, a retrospective database search revealed 343 shoulder sonograms performed between 1996 and February 2005 by one experienced radiologist. Of those cases, 109 were performed on patients with previous shoulder surgery. Chart reviews identified previous surgical procedure and indication for sonographic evaluation. Dictated ultrasound reports for patients who had undergone previous arthroplasty were evaluated and compared to a control group consisting of symptomatic patients who had surgical rotator cuff repair (RCR) but no arthroplasty. Tears of the subscapularis, supraspinatus, and infraspinatus were recorded.
Results: Sixteen patients had undergone arthroplasty (10 total- and 6 hemiarthroplasty) while 63 patients had received previous RCR. Forty-seven of 63 (75%) RCR patients presented with pain, as did 11/16 (69%) arthroplasty patients. Full thickness subscapularis tears were significantly more common in arthroplasty patients (4/16, 25%) than RCR patients (6/63, 9.5%) (p < 0.05). Partial thickness subscapularis tears were not significantly different in prevalence (p > 0.05). Conversely, full thickness infraspinatus tears were significantly more common among RCR patients (13/63, 20.6%) than arthroplasty patients (0/16) (p < 0.05). Supraspinatus tears (partial + full thickness tears) were also more common in RCR patients (38/63, 60.3%) than arthroplasty patients (6/16, 37.5%), and this result approached significance (p = 0.06).
Conclusion: Full thickness subscapularis tears were seen in 25% of symptomatic post-arthroplasty shoulders referred for sonographic evaluation. Subscapularis tears were more common following arthroplasty than following rotator cuff repair.
217. Extended MRI Findings of Intersection Syndrome
Lee R.*; Hatem S. Cleveland Clinic, Cleveland, OH
Address correspondence to R. Lee (leerog8{at}hotmail.com)
Objective: The symptoms and physical findings of intersection syndrome have been well described in the clinical medical literature. However, the MRI findings in patients with intersection syndrome of the forearm have only recently been described in a small number of patients. We review our experience with imaging of intersection syndrome, describe previously unreported MRI findings, and emphasize modifications to MR imaging protocols for its evaluation.
Materials and Methods: Institutional review board approval was obtained for this retrospective review of patients with MRI imaging findings consistent with intersection syndrome of the forearm during the period from January 2004 to September 2006. Six patients were identified, three men and three women, with an average age of 39.3 years. The MRI examinations were reviewed to assess signal abnormalities within and adjacent to the first and second dorsal extensor compartments: tendinosis, peritendinous edema or fluid, muscle edema, subcutaneous edema, and periosteal reaction. The overall longitudinal extent of signal alterations was measured as well as the distance from Lister's tubercle to the crossover of the first and second dorsal extensor compartment tendons (DECT).
Results: Review of the MRIs showed increased intrasubstance tendon signal suggesting tendinosis in two of the six patients, peritendinous edema or fluid in all six patients, muscle edema in five of the six patients, and subcutaneous edema in three of the six patients. Peritendinous edema or fluid extended distally beyond the radiocarpal joint in three of the six patients. The average distance from Lister's tubercle to the crossover of the first and second DECT was 3.95 cm, in keeping with recently published data.
Conclusion: Intersection syndrome is an uncommon MRI diagnosis. In addition to the previously described MRI findings of edema adjacent to the first or second DECT, possibly with proximal extension and subcutaneous edema, we have identified additional abnormalities: tendinosis, muscle edema, and periosteal reaction. In addition, our review shows that first and second DECT signal abnormalities in patients with intersection syndrome are not necessarily limited to the site of crossover, but can extend distally beyond the radiocarpal joint. As standard wrist protocols may not include the area of intersection between the first and second DECT, coverage should extend to the mid-forearm.
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