MR imaging of anterior cruciate ligament tears: is there a gender gap?

Objective Clinically, females receive anterior cruciate ligament (ACL) tears more commonly than males. We explored whether gender differences exist in MR imaging patterns of ACL tears.Design and patients At 1.5T, two observers evaluated MR examinations of 84 consecutive age-matched patients (42 males, 42 females, aged 16–39) with ACL tears, for mechanism of injury, extent and type of tear, the presence of secondary signs and associated osseous, meniscal and ligamentous injuries.Results The most common mechanism of injury for both females and males was the pivot shift mechanism (67 and 60%, respectively). Females were more commonly imaged in the acute stage of tear than males (98 and 67%, respectively, p=0.001) and more commonly possessed the typical posterolateral tibial bone contusion pattern (88 and 62%, respectively, p=0.0131). Males exhibited a deeper femoral notch sign (2.7 and 2.0 mm, p=0.007) and medial meniscal, lateral collateral ligament and posterior cruciate ligament injuries more commonly than females (48 and 24%, p=0.009, 30 and 7%, p=0.035, 17 and 0%, p=0.035). There was no significant difference between genders for the presence of other secondary signs and contusion patterns, associated lateral meniscal tears, presence of O'Donoghue's triad or associated medial collateral ligament injuries.Conclusion Gender differences in MR imaging patterns of ACL tears exist: females are more commonly imaged in the acute stage and more commonly possess posterolateral tibial bone contusions; males have a more severe presentation than females, associated with more severe lateral femoral condyle and soft tissue injuries.     

The knee: surface-coil MR imaging at 1.5 T1

Seven normal knees (in five volunteers) and seven injured knees (in seven patients) were examined by high-resolution magnetic resonance (MR) imaging at 1.5 T with a surface coil. Seven medial meniscal tears, three anterior cruciate ligament tears, one posterior cruciate ligament avulsion, an old osteochondral fracture, femoral condylar chondromalacia, and one case of semimembranous tendon reinsertion were identified. MR images correlated well with recent double-contrast arthrograms or results of surgery. All tears were identified in both the sagittal and coronal planes. Because of its ability to demonstrate small meniscal lesions and ligamentous injuries readily, MR imaging with a surface coil may eventually replace the more invasive arthrography.     

Lateral tibial rim (Segond) fractures: MR imaging characteristics

The magnetic resonance (MR) imaging characteristics of lateral tibial rim (Segond) fractures and their associated injuries were reviewed in 12 patients with radiographic evidence of this fracture. Bone marrow adjacent to the fracture emitted a focally abnormal MR signal, which indicated an injury of the lateral capsular junction. The Segond fragment, however, was seen on MR images in only four of 12 patients. Associated ligamentous and meniscal injuries identified with MR imaging and arthroscopy involved the anterior (n = 11) and medial (n = 7) cruciate ligaments and the lateral (n = 4) and medial (n = 1) menisci. Focal bone marrow edema was due to injury of the lateral capsular junction. MR imaging evidence of such edema should indicate the presence of a lateral capsular injury and fracture, if one has not already been demonstrated with conventional radiography. A high association of Segond fractures with tears of the anterior cruciate ligament was confirmed, and MR imaging signs of a Segond fracture may therefore be used as indirect evidence for tears of that ligament.     

MR imaging of patellar retinacular ligament injuries

Seventeen patients with patellar retinacular ligament injuries were evaluated with magnetic resonance (MR) imaging. MR findings were correlated with clinical, surgical, and arthroscopic findings. The injuries involved the medial retinacular ligament in 16 of 17 patients and the medial and lateral retinacular ligament in one patient. Nine of 17 patients showed MR evidence of a patellar dislocation. In these patients, a triad of findings that included focal impaction injuries involving the lateral femoral condyle, osteochondral injuries of the medial patellar facet, and injuries of the medial retinacular ligament were seen. Seven of the nine patients with patellar dislocation injuries had frank osteochondral injuries. The injured retinaculum had an indistinct, irregular appearance associated with edema and hemorrhage. The patellar dislocations were clinically unsuspected in the initial evaluation of eight of these nine patients. In eight of 17 patients, the mechanism of injury was a patellar tendon tear (n = 1) or valgus hyperextension (n = 7). In the seven patients with hyperextension injuries, three had associated meniscal and cruciate ligament tears. MR imaging can help define patellar retinacular and associated osteochondral injuries, which may be clinically useful information.     

Acute knee injuries

Skeletally immature athletes do get major knee injuries. Hemarthrosis is associated with peripheral meniscal tears, anterior cruciate ligament ruptures, tibial tubercle avulsion injuries, and patellar/femoral osteochondral fractures and cannot be ignored. The primary diagnostic tool for patients with a knee injury is a clinical examination by a physician well trained in knee evaluation. MR imaging has significant limitations in this age group. The algorithm for anterior cruciate ligament injury treatment must take into account the patient's physiologic maturity, not chronological age.     

MR evaluation of the "arcuate" sign of posterolateral knee instability

OBJECTIVE: The purpose of this study was to evaluate associated knee injuries using MR imaging in patients with the "arcuate" sign, a term referring to avulsion fracture of the proximal fibula on conventional radiographs. MATERIAL AND METHODS: MR imaging of 18 cases (17 patients, both knees in one patient) with the arcuate sign on conventional radiographs was retrospectively interpreted to evaluate the associated meniscal, ligamentous, and bony injuries. In 12 cases, MR findings were correlated with surgical results. RESULTS: In all cases, avulsed bony fragments from the proximal pole of the fibula were attached to the fibular collateral ligament, the biceps femoris tendon, or both. Tear of the posterolateral capsule was seen in 12 cases (67%). Injury of the cruciate ligaments was noted in 16 cases (89%): injury to both the anterior cruciate ligament and posterior cruciate ligament was seen in nine cases (50%), injury to only the anterior cruciate ligament was seen in four, and injury to the posterior cruciate ligament only was noted in three. Bone bruises or gross fractures were seen in all cases: bone bruises on the anteromedial femoral condyle were noted in nine cases (50%) and were seen on the anteromedial tibial condyle in five cases (28%). Tear of the medial meniscus was seen in five cases (28%) and tear of the lateral meniscus in four cases (22%). Injury to the popliteus was seen in six cases (33%). Joint effusion was associated in all cases. CONCLUSION: MR imaging is useful for evaluation of associated soft-tissue injuries in patients with the arcuate sign on conventional radiographs. Avulsion injury to the proximal fibula is an important indicator of the internal derangement of the knee and for predicting the mechanism of an injury with varus stress. Cruciate ligament tear and bone bruises on the anteromedial condyle of the femur and tibia are common associated findings.     

Knee injuries: high-resolution MR imaging

Recent technologic advances have made high-resolution magnetic resonance (MR) imaging of the knee a clinical reality. Ten healthy volunteers and 30 patients with suspected knee injuries were imaged using receive-only surface coils and two-dimensional multisection or three-dimensional selective acquisition techniques. Arthroscopic and/or surgical correlation was available in 15 patients. Tears of the cruciate ligament, medial collateral ligament, and meniscus are illustrated. Nonorthogonal views of the anterior cruciate ligament are useful for demonstrating both femoral and tibial attachments in the same section. The posterior cruciate ligament is usually well seen on sagittal views. T2-weighted images are helpful for demonstrating collateral ligament tears and meniscal tears when joint effusion is present. Thin sections (1-5 mm) are necessary to define many meniscal and cruciate tears. High-resolution, thin-section MR imaging can be used to diagnose soft-tissue injuries of the knee and has the potential to become a major imaging method in the evaluation of knee injuries.     

胫骨平台骨折及膝关节附属结构损伤的MRI诊断

目的评价胫骨平台骨折合并膝关节附属结构损伤的MRI表现.资料与方法 27例胫骨平台骨折病例经X线平片检查后作MRI扫描,分析不同类型胫骨平台骨折所合并的膝关节附属结构损伤的MRI形态学表现.结果 MRI能准确显示骨折所合并的膝关节附属结构的损伤性病变,包括关节软骨断裂、半月板撕裂和移位、侧副韧带和肌腱的撕裂、关节腔脂肪血性积液等,其中双髁骨折引起的损伤最为严重,撕脱骨折引起的损伤较轻.结论 MRI能准确诊断胫骨平台骨折合并的膝关节附属结构损伤,应作为膝关节外伤的常规检查手段.     

Magnetic resonance imaging of knee injuries in children

The appearances of knee injuries on MR imaging are less well documented in children than adults. Some patterns of injury are shared by both groups of patients, e. g. meniscal damage. The frequency of specific injuries may differ, e. g. anterior cruciate ligament (ACL) tear. Congenital abnormality, coexistent pathology and previous treatment of the knee appear to be associated with meniscal problems. Discoid menisci are seen most frequently in children and have unique features on MR scans. Cruciate ligament tears are difficult to diagnose in the smallest children. The ACL may not be identified due to its small size. Normal bone marrow signal may be confused with marrow infiltration or bone microfracture. Radiographically occult fractures around the knee appear to be strongly associated with ligamentous injury as in adult patients. Osteochondral fractures, osteochondral lesions and articular cartilage damage are revealed on MR scans, but their long-term effects are uncertain. It is possible to diagnose a range of knee injuries on MR scans in children. The biggest diagnostic challenge is in pre-school children. Received 13 December 1996; Revision received 13 March 1997; Accepted 14 March 1997     

MR imaging of posterior cruciate ligament injuries

Posterior cruciate ligament(PCL) injuries are less frequent than anterior cruciate ligament(ACL) injuries, but are presumably more common than once thought. Thirty-nine patients with PCL injuries identified on MR images were studied. The criteria for PCL injury were complete tear, partial tear, and avulsion fracture. The approximate site of a partial tear was categorized as proximal, midsubstance, distal, or combination. Fourteen patients(35.9%) had complete tears of the PCL, 21 patients(53.8%) had partial tears, and four patients(10.3%) had avulsion fractures. A total of 12 patients (30.7%) had isolated PCL injuries, while the remaining 27 patients demonstrated evidence of other coexistent knee injuries, such as meniscal tears and ligamentous injuries. Of coexistent knee injuries, meniscal tears(18 patients, 46.2%) were most often seen.     

Imaging of the collateral ligament injuries of the knee

The role of routine and advanced imaging techniques after suspected injury to the collateral ligaments of the knee is to augment the findings on physical examination. Although radiographs may disclose avulsion injuries, the limited soft tissue contrast does not permit accurate assessment of the collateral ligaments and associated soft tissue structures. Because of its superior soft tissue contrast and multiplanar capabilities, magnetic resonance (MR) imaging has largely replaced conventional imaging techniques. Using high-contrast pulse sequences, MR imaging permits localization of the site of ligamentous trauma, as well as associated soft tissue injury, including meniscal tears, cruciate ligament tears, and injury to the structures of the posterolateral corner. Although secondary signs of ligamentous injury, including adjacent soft tissue edema and bony contusions, may be helpful in localizing the site of injury, the most important criteria remains direct visualization of the ligament, with focal discontinuity. Using such criteria, accurate preoperative assessment of the injured extremity may be made, thereby aiding in the clinical management of the patient.     

Incidence and location of bone bruises after acute posterior cruciate ligament injury

BACKGROUND: In patients suffering from an anterior cruciate ligament injury, the incidence and location of bone bruises are well documented. This study reports data regarding bone bruises after acute posterior cruciate ligament injury. HYPOTHESIS: Bone bruises associated with posterior cruciate ligament injury are common, and their location differs from those seen with anterior cruciate ligament injury. STUDY DESIGN: Retrospective cohort study. METHODS: Thirty-five consecutive patients were identified as having a grade II or III posterior cruciate ligament tear, with an intact anterior cruciate ligament, in which a magnetic resonance imaging scan had been obtained within 20 days of injury. Magnetic resonance imaging scans were reviewed to document bone bruises, associated medial or lateral ligamentous injury, and meniscal and chondral abnormalities. RESULTS: Of the 35 patients, 29 (83%) had a bone bruise in at least one location. Bone bruises were found throughout the joint, more widely dispersed than is commonly seen with anterior cruciate ligament injury. Also, 29 patients had magnetic resonance imaging findings of associated ligamentous injury. Lateral bone bruises were associated with medial collateral ligament injury, whereas medial bone bruises correlated with posterolateral injury. CONCLUSIONS: The incidence of bone bruises associated with posterior cruciate ligament injury is similar to that seen with anterior cruciate ligament injury. Their location is more widely dispersed. The location of a bone bruise should lead to careful magnetic resonance imaging inspection and physical examination for ligamentous injury to the opposite side of the joint. Truly isolated posterior cruciate ligament injuries are rare, as most occur with osseous and some degree of associated ligamentous injury.     

Characteristics of displaceable and nondisplaceable meniscal tears at kinematic MR imaging of the knee

PURPOSE: To prospectively determine if kinematic magnetic resonance (MR) imaging of the knee may demonstrate displacement of menisci with tears and, if so, to characterize displaceable and nondisplaceable meniscal tears. MATERIALS AND METHODS: The study was approved by the hospital's review board, and informed consent was obtained. Forty-two patients (30 men, 12 women; mean age, 36.9 years) with 43 arthroscopically documented meniscal tears visible at 1.5-T MR imaging underwent kinematic MR imaging with an open-configuration 0.5-T MR imager with their knees in supine neutral, supine with 90 degrees flexion and external or internal rotation, and upright weight-bearing positions. Analysis of meniscal movement was performed in different knee positions in the coronal MR imaging plane. Meniscal displacement--that is, meniscal movement of 3 mm or more (in the medial direction for the medial meniscus, in the lateral direction for the lateral meniscus)--was compared with the patient's pain level as assessed with a visual analog scale by using analysis of variance. RESULTS: Between the different knee positions, meniscal displacement of 3 mm or more (displaceable meniscal tears) was noted in 18 (42%) of 43 menisci with tears. Simultaneous occurrence of grade II or III ipsilateral collateral ligament lesions was present in all 18 displaceable meniscal tears, whereas a normal-appearing collateral ligament or collateral ligament lesion (grade I) was present in 22 of 25 nondisplaceable tears (P < .05). Displaced menisci most commonly had complex, radial, or longitudinal tear configurations (16 of 18, 89%). Patients with displaceable meniscal tears had significantly more pain than did patients with nondisplaceable meniscal tears (P < .001), independent of the concomitant knee abnormalities. CONCLUSION: Displaceable meniscal tears usually have longitudinal, radial, or complex configurations; such tears are associated with substantial ipsilateral collateral ligament lesions and pain.     

MR imaging evaluation of knee collateral ligaments and related injuries: Comparison of T1-weighted,T2-weighted,and fat-saturated T2-weighted sequences—correlation with clinical findings

The objectives of this study were to compare the ability of T1-weighted (T1W), proton density/T2-weighted (PD/T2W), and fat saturation (FS) PD/T2W magnetic resonance (MR) sequences for depiction of the knee collateral ligaments and related injuries, and to compare MR findings with clinical findings. Ten subjects with normal knee ligaments and 64 patients with suspected collateral ligament injuries underwent coronal T1W, PD/T2W, and FS PD/T2W imaging. Abnormalities ranged from edema surrounding the collateral ligaments (grade I) to complete disruption of ligamentous fibers (grade III). FS PD/T2W images improved definition of the medial collateral ligament (MCL) and lateral collateral ligament (LCL) compared with other sequences in 78% and 81% of patients, respectively. While the apparent grade of collateral ligament injury was similar with all pulse sequences in most patients, depiction of such injury was usually most conspicuous on FS PD/T2W images (MCL, 92% of patients; LCL, 38% of patients). In no patients were clinically diagnosed collateral ligament injuries undetected or understaged with MR imaging. MR findings indicated higher-grade MCL and LCL injuries than did clinical examination in 24 and 15 patients, respectively.     

Follow-up of posttraumatic ligamentous and meniscal knee lesions detected at MR imaging: systematic review

PURPOSE: To perform a systematic review of the literature regarding the natural course of ligamentous and meniscal knee lesions detected at magnetic resonance (MR) imaging. MATERIALS AND METHODS: The MEDLINE database was searched from January 1966 to February 2003. Studies were included if all of the following criteria were met: patients had collateral ligament, cruciate ligament, or meniscal lesions; MR imaging was performed in all patients; study included a group and/or subgroup of patients who underwent conservative treatment during follow-up; patients returned to the clinic for follow-up and clinical data or MR imaging outcomes were noted; and article was written in English, Dutch, German, French, Spanish, Italian, Swedish, Danish, or Norwegian. The quality of each study was assessed by using a standardized criteria set, and kappa statistics were used to grade the level of agreement between the two reviewers. Studies with quality scores of 8 or more were designated as high quality. Results were compared with regard to study design and quality scores. RESULTS: The literature search identified 649 articles, and 11 studies (five on posterior cruciate ligament [PCL] injuries, five on anterior cruciate ligament [ACL] injuries, and one on meniscal injuries) met the inclusion criteria. No studies on the follow-up of collateral ligament injuries were identified. Four studies were of high quality, and the kappa value for quality items was 0.80. Between 77% and 93% of the partial or complete PCL ruptures regained continuity. In cases of partial or total ACL rupture, repair of continuity was also possible. A possible association between MR imaging continuity and clinical stability was identified. CONCLUSION: The ACL and PCL can regain continuity after partial or complete rupture. On the basis of this review, no conclusions can be drawn about the natural course of meniscal or collateral ligament injury seen at MR imaging.     

Injury patterns to the posteromedial corner of the knee in high-grade multiligament knee injuries: a MRI study

Injury patterns to the posteromedial corner of the knee have not been previously studied in the context of multiligament knee injuries. We performed a retrospective magnetic resonance imaging and clinical review of a consecutive series of 27 dislocatable knees presenting to a single level-one trauma center from 2005 to 2008. Post-injury magnetic resonance imaging studies were reviewed by two fellowship-trained musculoskeletal radiologists to assess injury patterns to the posteromedial corner. In our series, injury to at least one structure within the posteromedial corner was observed in 81% (22/27) of cases while injury to the superficial medial collateral ligament alone was seen in 63% (17/27) of cases. Furthermore, injuries to the posterior horn of the medial meniscus were associated with a tear of the meniscotibial ligaments in all cases and with a tear of the posterior oblique ligament in 67% of cases. All patients with grade III laxity (>10 mm medial opening) under an examination under anesthesia had a complete tear of the posterior oblique ligament and meniscotibial ligament in addition to a medial collateral ligament injury. Injury to the semimembranosus attachment alone was not associated with clinically significant laxity under an examination under anesthesia. Our findings demonstrate that injuries to the posteromedial corner are common in the setting of traumatic knee dislocations. Interestingly, high-grade medial instability during an examination under anesthesia and injury to the posterior horn of the medial meniscus may be important indicators for further posteromedial corner injury.     

Grading medial collateral ligament injury: comparison of MR imaging and instrumented valgus-varus laxity test-device. A prospective double-blind patient study

Purpose: The role of MR imaging in grading medial collateral ligament (MCL) injury of the knee in comparison to other grading methods (clinical findings and instrumental measurement) is hardly documented in the literature. The purpose of this study is to compare the results of MR imaging in grading acute MCL injuries to the results of a clinical grading by an instrumented valgus-varus laxity tester (VVLT). Materials and methods: Twenty-one patients clinically suspected of acute MCL injury were tested by VVLT, a well documented and instrumented test-device. All patients subsequently underwent MR imaging of the knee. MCL injury was graded independently by VVLT and MR imaging using a classification method with reference to Petermann. Results: Ninteen patients had corresponding grading results by VVLT and MR imaging (kappa, 0.83; S.E., 0.10); 14 patients had a Grade I, four a Grade II and two patients had a Grade III MR imaged MCL injury. Associated lesions were also depicted on MR imaging (bone contusion (n = 3), ACL disruption (n = 2) and medial meniscal rupture (n = 1)). Conclusions: This study shows a very high degree of agreement between the results in grading acute MCL injuries with MR imaging and an instrumented valgus-varus laxity tester (VVLT). MR imaging depicted important, clinically undetected, additional lesions which can determine the treatment of MCL injury.     

MR imaging of the knee. Part I. Traumatic disorders

One hundred thirty patients with a diversity of knee joint injuries were evaluated with a high-resolution magnetic resonance (MR) imaging technique. The authors report the accuracy of this technique in the evaluation of 105 patients with suspected meniscal tears, 26 patients with suspected cruciate ligament tears, and eight patients with suspected patellar tendon injuries. Of those menisci rated as definitely or probably torn on MR imaging, 80% were found to be torn at subsequent arthroscopy. The predictive value of negative MR imaging results was 100%. MR imaging was 92% accurate in predicting the clinical outcome in patients with suspected meniscal tears who did not undergo surgery. MR permitted complete disruption of the patellar tendon to be differentiated from partial tears, ligamentous inflammation, and localized effusion of the infrapatellar bursa. Injuries to the anterior and posterior cruciate ligaments were identified on MR images, and the status of synthetic grafts of the anterior cruciate ligament was ascertained.     

Recent advances in magnetic resonance imaging of the knee

The examination of the knee has rapidly become the most important non-neurologic application of MR imaging. The widespread availability of high signal-to-noise knee coils has made routine imaging with T2-weighted sequences in both coronal and sagittal planes possible in 30 minutes. The spin-echo sequence remains the most important imaging technique, although many newer sequences have also been applied to the knee, with varying degrees of success. Important pitfalls in diagnosis, such as high signal intensity in the posterior horn of the medial meniscus and the transverse meniscal ligament, displaced buckethandle meniscal tears, and discoid menisci, can be recognized with experience. Common clinical problems that are encountered include meniscal cysts, osteonecrosis, and bone bruises. Detection of subtle injuries of the medial collateral ligament, patellar tendon, and anterior cruciate ligament requires careful observation. Intra-articular loose bodies can be reliably detected with MR imaging, and it should be recognized that localized pigmented villonodular synovitis can sometimes simulate the appearance of a loose body. MR imaging is a valuable noninvasive procedure that is complementary to arthroscopy in the evaluation of diseases of the knee.     

Is intra-articular pathology associated with MCL edema on MR imaging of the non-traumatic knee?

Objective Edema surrounding the medial collateral ligament (MCL) is seen on MR imaging in patients with MCL injuries and in patients with radiographic osteoarthritis in the non-traumatic knee. Because we noted MCL edema in patients without prior trauma or osteoarthritis, we studied the association between intra-articular pathology and MCL edema in patients without knee trauma.Design and patients We evaluated the MR examinations of 247 consecutive patients (121 male, 126 female with a mean age of 44 years) without recent trauma for the presence of edema surrounding the MCL, meniscal and ACL tears, medial meniscal extrusion, medial compartment chondromalacia, and osteoarthritis. The percentages of patients illustrating MCL edema with and without each type of pathology were compared using Fishers exact test to determine if there was a statistically significant association.Results We found MCL edema in 60% of 247 patients. MCL edema was present in 67% of patients with medial meniscal tears, 35% with lateral meniscal tears, 100% with meniscal extrusion of 3 mm or more, 78% with femoral chondromalacia, 82% with tibial chondromalacia, and 50% with osteoarthritis. The percentage of patients with edema increased with the severity of the chondromalacia. These associations were all statistically significant ( p <0.02). The mean age of those with MCL edema was 49.7 years compared with 34.9 years without MCL edema ( p <0.001). Patient gender and ACL tear did not correlate with MCL edema. Nine (4%) of the 247 patients had MCL edema without intra-articular pathology. None of these 9 patients had MCL tenderness or joint laxity on physical examination.Conclusions We confirmed that MCL edema is associated with osteoarthritis, but is also associated with meniscal tears, meniscal extrusion, and chondromalacia. In addition, MCL edema can be seen in patients without intra-articular pathology, recent trauma or MCL abnormality on physical examination.Presented at the International Skeletal Society Meeting Closed Scientific Session, October 3, 2004, Malta