Bucket-handle meniscal tears of the knee: sensitivity and specificity of MRI signs

MRI in the Diagnosis of Bucket Handle Tears: What Is the Current Situation?

Introduction The purpose of this study was to determine the utility of current magnetic resonance imaging (MRI) in the diagnosis of bucket-handle meniscal tears. Materials and methods Patients treated for arthroscopic meniscal tears between March 2019 and March 2022 were reviewed. The current study included all patients with bucket handle tears diagnosed arthroscopically and having MRI scans (n=51). A control group of 58 individuals with similar demographic characteristics and meniscal tears apart from bucket handle tears was also formed. The assessment of bucket handle and non-bucket handle tears was performed blindly by a musculoskeletal (MSK) radiologist with 20 years of experience and a trainee radiologist, achieving consensus on group allocation. The MRIs were examined for various findings, including the presence of a bucket handle tear, tear location, presence of anterior cruciate ligament (ACL) rupture, intercondyler notch sign, double anterior horn sign, flipped meniscus sign, double posterior cruciate ligament (PCL) sign, absent bow sign, and the disproportionate posterior horn sign. These well-known signs, detailed in the literature, were evaluated. Additionally, less studied and less commonly known signs such as the V sign and double anterior cruciate ligament sign were assessed. The V sign appears similarly to the letter V, resulting from the displacement of the bucket handle tear and the angle of the intact meniscus on axial images. The double anterior cruciate ligament sign is the appearance formed by the compression of the displaced meniscal part behind the anterior cruciate ligament in bucket handle tears. Results Following the retrospective evaluation of MRI scans, 44 out of 51 tears diagnosed as bucket handle tears by arthroscopy were accurately identified (sensitivity: 86.27%). The same conclusion was reached for MRI scans in 52 out of 58 tears where arthroscopy did not detect a bucket handle tear (specificity: 89.66%). The most prevalent MRI signs in patients with bucket handle tears identified by arthroscopy in the study were the intercondylar notch sign (84.31%), V sign (72.55%), double PCL sign (56.86%), double anterior horn sign (49.02%), absent bow sign (43.14%), flipped meniscus sign (19.61%), disproportionate posterior horn sign (9.80%), and double ACL sign (5.88%). The intercondylar notch sign, V sign, and double PCL sign exhibited the highest sensitivity, while flipped meniscus, disproportionate posterior horn, and double ACL sign demonstrated the highest specificity. Conclusion MRI demonstrates a high level of sensitivity and specificity in identifying meniscal bucket handle tears, particularly when considering the eight MRI signs investigated in this study.

Diagnostic Accuracy of 128-Slice Single-Source CT for the Detection of Dislocated Bucket Handle Meniscal Tears in the Setting of an Acute Knee Trauma—Correlation with MRI and Arthroscopy

(1) Background: Meniscal tears are amongst the most common knee injuries. Dislocated bucket handle meniscal tears in particular should receive early intervention. The purpose of this study was to evaluate the diagnostic performance of CT in detecting dislocated bucket handle meniscal tears compared with the gold-standard MRI and arthroscopy. (2) Methods: Retrospectively, 96 consecutive patients underwent clinically indicated CT of the knee for suspected acute traumatic knee injuries (standard study protocol, 120 kV, 90 mAs). Inclusion criteria were the absence of an acute fracture on CT and a timely MRI (<6 months). Corresponding arthroscopy was assessed. Two experienced musculoskeletal radiologists analyzed the images for dislocated bucket handle meniscal tears, associated signs thereof (double posterior cruciate ligament sign, double delta sign, disproportional posterior horn sign), and subjective diagnostic confidence on a 5-point-Likert scale (1 = ‘non-diagnostic image quality’, 5 = ‘very confident’). (3) Results: Dislocated bucket handle meniscal tears were detected on CT by standard three-plane bone kernel reconstructions with a sensitivity of 90.7% and a specificity of 99.3% by transferring the knowledge of established MRI signs. The additional use of soft-tissue kernel reconstructions in three planes increased the sensitivity by 4.0% to 94.7%, specificity to 100%, inter-rater agreement to 1.0, and the diagnostic confidence of both readers improved to a median 4/5 (‘confident’) in both readers. (4) Conclusions: Trauma CT scan of the knee with three-plane soft-tissue reconstructions delivers the potential for the detection of dislocated bucket handle meniscal tears with very high diagnostic accuracy.

The Pelican Sign: Case Series Demonstrating A Unique Description of an Anteriorly Flipped Bucket-Handle Meniscal Tear of the Knee

Introduction Bucket-handle tears (BHTs) of the menisci are not uncommon and can occur in isolation or in conjunction with other injuries. The torn fragment can be displaced within the intercondylar notch or flipped anteriorly. In case of anterior flipped fragment, appearances of such tears on magnetic resonance imaging (MRI) scan have been described as various signs in literature (for example double posterior cruciate ligament sign, double delta sign) but mostly in the sagittal or coronal planes.

Purpose The aim of this study was to describe a unique ancillary sign that helps to identify this injury on the axial MRI plane where the anterior flipped BHT figuratively resembles a “pelican bird.”

Materials and Methods A retrospective review of MRI sequences of 10 consecutive patients over a 3-month period referred following a traumatic knee injury with anterior flipped meniscal tears was performed. Demographic details, clinical indication, and other associated features on the MRI were correlated following the observation of characteristic MRI appearance of a BHT.

Results All 10 patients (M:F = 7:3) with a mean age of 24.7 (17–38 years) presented following a twisting injury. 6 out of 10 patients had associated soft-tissue injuries in the knee visualized on the MRI. All patients demonstrated the distinctive “pelican bird” sign on the axial sequences of anterior flipped BHT of either menisci. This was not present with BHTs with displaced fragment within the intercondylar notch.

Conclusion We conclude that the “pelican sign” on an axial sequence when present correlates well with a BHT and its anterior displaced/flipped meniscal fragment. This ancillary sign can complement other previously described signs on different MRI sequences used to confirm a displaced BHT.

Selective Unique Signs of Meniscus Tears as Visualized by Magnetic Resonance Imaging

The meniscus is an organized collection of fibrocartilaginous tissue that is located between the femoral condyles and the tibial plateau of the knee which primarily assists with load transmission. The complex composition of articulating soft-tissue structures in the knee causes the menisci to become a common source of injury, especially in the realm of athletic trauma. Magnetic resonance imaging (MRI) has become the imaging modality of choice for evaluating patients with suspected meniscal pathology because of its numerous advantages over plain radiographs. Most forms of meniscal tears have classic MRI findings and are used in correlation with physical examination findings to confirm or rule out a diagnosis. These imaging findings are referred to as signs and have been well studied, and the associated eponyms for each sign are well published throughout the literature. This article will review and describe a unique selection of meniscal pathology as visualized by MRI that is more commonly published in musculoskeletal radiology literature when compared with orthopedics and sports medicine literature.

The "sleeper's sign" is valid and suggestive of a medial sub-meniscal flap tear

PURPOSE

To describe, evaluate and validate the diagnostic performance of a new clinical sign, the sleeper's sign, for the diagnosis of a medial submeniscal flap tear (MSMFT).

METHODS

This retrospective single-center series included patients aged 18-55 years old who underwent arthroscopic treatment in 2013-2015 for a medial meniscal tear. This study was performed according to STARD (standards for reporting of diagnostic accuracy) guidelines, and the reference test was a peroperative diagnosis of a MSMFT. The preoperative consultation reports were all analyzed to search for the sleeper's sign, defined as night time medial tibiofemoral pain when the patient is in the fetal position with both knees in contact and no pain during daytime activities.

RESULTS

Three-hundred and ten patients responded to the study criteria, mean age 41.7 ± 9.7 years old. The sleeper's sign was identified in 39 (12.6%) patients and a MSMFT was confirmed during arthroscopy in 47 (15.2%) cases, with significant agreement between this sign, arthroscopy (kappa = 0.78, p = 10^-4) and MR-imaging (kappa = 0.72, p < 0.0001). The performance parameters of the sleeper's sign were: sensitivity 74.5 ± 12.5%, specificity 98.5 ± 1.6%, Youden index 0.73 and accuracy 96.9%. MR imaging was found to be more sensitive (91.5 ± 8%). Multivariate analysis identified the sleeper's sign as a risk factor of MSMFT during arthroscopy: OR 131.9 CI 95% [26.9-646.2], p < 0.0001 and a bone edema next to the flap tear on MR-imaging: OR 13, CI 95% [1.9-7.1], p = 0.008.

CONCLUSION

The "sleeper's sign" is a new, valid, highly specific clinical sign for the diagnosis of a medial submeniscal flap tear. MRI was found to be more sensitive than the sleeper's sign.

LEVEL OF EVIDENCE

II.

[Clinical observation of arthroscopic all-inside combined with outside-in "suture loop" repair for meniscus bucket-handle tear]

OBJECTIVE

To investigate the effectiveness of arthroscopic all-inside combined with outside-in "suture loop" repair for meniscus bucket-handle tear (BHT).

METHODS

Between August 2016 and May 2019, 44 case of meniscus BHT were treated with arthroscopic all-inside combined outside-in "suture loop". There were 29 males and 15 females with an average age of 26.6 years (range, 18-42 years). The causes of injury included sports injury in 31 cases, falling injury in 7 cases, and sprain in 6 cases. There were 32 cases of medial meniscus posterior horn tears and 12 cases of lateral meniscus posterior horn tears. The disease duration ranged from 6 weeks to 3 months. Thirty-three cases were complicated with anterior cruciate ligament rupture. All patients had normal lower limb alignment. The preoperative Lysholm score was 42.1±9.1. According to the evaluation criteria of MRI and Barrett et al., the healing of meniscus was evaluated, and the effectiveness was evaluated by Lysholm score.

RESULTS

All the 44 patients were followed up 8-36 months with an average of 16.8 months. At last follow-up, according to the evaluation criteria of Barrett et al., 39 cases were clinically healed, 5 cases were not healed, the clinical healing rate was 88.6%; according to MRI evaluation, 32 cases were completely healed, 7 cases were partially healed, and 5 cases were not healed, the total healing rate was 88.6%, and the complete healing rate was 72.7%. Lysholm score was 87.8±4.8, which was significantly different from that before operation ( t=31.060, P=0.000).

CONCLUSION

Arthroscopic all-inside combined with outside-in "suture loop" repair is a reliable and effective method for the meniscus BHT, which can obtain good joint function.

The influence of a meniscal bucket handle tear on the Posterior Cruciate Ligament Angle in Anterior Cruciate Ligament Rupture - A case report

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The PCL angle in ACL-deficient knee might be false-negative in the presence of bucket handle tear.

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There must be always high suspicious of ACL insufficiency in case of medial bucket handle tear.

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Profound knowledge of clinical examination patient’s history is absolutely mandatory to examine ACL insufficiency.

Introduction

Chronic anterior cruciate ligament (ACL) tear might be difficult to diagnose on MRI. Indirect signs might be a typical meniscal or cartilage lesion, or a spontaneous anterior drawer visualized by a decreased angle of the posterior cruciate ligament (PCL).

Presentation of case

A 27-year-old former ballet dancer was admitted to the emergency department for a locked left knee, without never having experienced previous symptoms of giving way or locking. The MRI performed revealed a medial meniscus bucket handle tear, without traumatic bone marrow oedema or ligament injury. The PCL angle was 130°. A former MRI of her left knee performed 1 year previously to investigate on the recurrent catching of her left knee showed a grade III medial meniscal tear of the posterior horn, and buckling of the PCL angle of 100°, as a sign of chronic ACL rupture. During arthroscopy and medial meniscal repair, the ACL showed complete loss of tension, and was therefore reconstructed simultaneously to enable proper meniscal healing.

Discussion and conclusion

Chronic ACL insuffiency is a major risk factor for subsequent medial meniscus tear, especially bucket handle tear. The locked knee might unable proper pre-operative clinical examination. The preoperative MRI therefore being the only possibility to diagnose concomitant ligamentous injury. This is the first case reported in literature showing, that a positive PCL angle sign might be falsely negative due to a locked medial meniscus bucket handle tear.

Illustrative review of knee meniscal tear patterns, repair and replacement options, and imaging evaluation

This review article aims to reinforce anatomical concepts about meniscal tears while linking associated treatment options. The main teaching points start with the basic meniscal anatomy and key differences between the medial and lateral menisci. Subsequently, various meniscal tear patterns along with their associated history and physical exam findings will be discussed with corresponding illustrations and MR images. Additional discussion will involve the different surgical repair techniques (with arthroscopic correlates), their indications with pertinent imaging findings, imaging related to previous meniscal tear repairs, and novel surgical techniques. Lastly, keys to evaluating for retear with an emphasis on MRI arthrogram findings will be reviewed. While each of these topics is not discussed in totality, the key points of the review article will enforce key concepts and help radiologists evaluate the menisci on imaging.

Double Posterior Cruciate Ligament Sign on Magnetic Resonance Imaging: Imaging Variants, Mimics, and Clinical Implications

Introduction

Double posterior cruciate ligament (PCL) sign is a sign on magnetic resonance imaging (MRI) which is suggestive of a bucket- handle tear (BHT) of the meniscus. We undertook this study to assess the presence of a double PCL sign and its correlation with arthroscopic findings. We also discussed the various mimics and variants of the double PCL sign.

Case Report

All the patients with a double PCL sign on the MRI and who underwent knee arthroscopy between January 2012 and December 2016 (total of 5 cases, 4 males and one female) were included in the study. A correlation between the imaging findings and the MRI findings was done. All these young patients were aged between 22 and 41 years. Two patients underwent arthroscopic partial meniscectomy, and three patients underwent arthroscopic meniscal repair using all inside technique.

Conclusion

It is necessary for the sports physician to understand and recognize this important and subtle sign on MRI which is suggestive of a BHT of the meniscus. It is also important to identify the mimics of this sign and its variants for better management planning and patient prognostication.

Bucket-handle meniscal tear in a 9-year-old girl: a case report and review of the literature

Bucket-handle meniscal tears used to be rare in children younger than 10 years of age. However, nowadays, we encounter more cases because of increased sport and recreational activities. In this paper, we report on a 9-year-old girl who presented with an isolated medial meniscal bucket-handle tear of the right knee and review the literature for similar cases. Bucket-handle meniscal tears are rare in young children. However, it should be ruled out in patients with knee pain and mechanical symptoms following knee injury.

KNEE ARTHROSCOPIC VISIBILITY ALTERATIONS IN OBESE AND NON-OBESE PATIENTS

Background

Obesity is a chronic disease and has become the most prevalent public health problem worldwide. The impact of obesity on knee is strong and the BMI is correlated with the different alterations.

Aim

Compare surgical visualization of arthroscopic field in partial meniscectomy in obese and non-obese.

Method

Sixty patients were selected, 30 obese and 30 non-obese who underwent arthroscopic partial meniscectomy. The arthroscopic surgical procedures were recorded and analyzed. For the analysis of visualization was used the Johnson's classification (2000).

Results

Were analyzed 48 men and 12 women, the average age was 42.9 years with BMI between 21.56 to 40.14 kg/m2. The distribution of visibility of the surgical field according to the classification was: grade 1 - 38/60 (63.3%); grade 2 - 13/60 (21.6%); grade 3 - 6/60 (10%); grade 4 - 3/60 (5%).

Conclusion

Knee arthroscopy did not show a significant difference in the visibility of arthroscopic field in obese and non-obese patients. Thus, it should not be indicated as the preferred method of diagnostic evaluation of joint changes in these patients.

MR imaging-based diagnosis and classification of meniscal tears

Magnetic resonance (MR) imaging is currently the modality of choice for detecting meniscal injuries and planning subsequent treatment. A thorough understanding of the imaging protocols, normal meniscal anatomy, surrounding anatomic structures, and anatomic variants and pitfalls is critical to ensure diagnostic accuracy and prevent unnecessary surgery. High-spatial-resolution imaging of the meniscus can be performed using fast spin-echo and three-dimensional MR imaging sequences. Normal anatomic structures that can mimic a tear include the meniscal ligament, meniscofemoral ligaments, popliteomeniscal fascicles, and meniscomeniscal ligament. Anatomic variants and pitfalls that can mimic a tear include discoid meniscus, meniscal flounce, a meniscal ossicle, and chondrocalcinosis. When a meniscal tear is identified, accurate description and classification of the tear pattern can guide the referring clinician in patient education and surgical planning. For example, longitudinal tears are often amenable to repair, whereas horizontal and radial tears may require partial meniscectomy. Tear patterns include horizontal, longitudinal, radial, root, complex, displaced, and bucket-handle tears. Occasionally, meniscal tears can be difficult to detect at imaging; however, secondary indirect signs, such as a parameniscal cyst, meniscal extrusion, or linear subchondral bone marrow edema, should increase the radiologist's suspicion for an underlying tear. Awareness of common diagnostic errors can ensure accurate diagnosis of meniscal tears. Online supplemental material is available for this article.

Displaced Medial and Lateral Bucket Handle Meniscal Tears With Intact ACL and PCL

Bucket handle lesions are vertical longitudinal tears in the meniscus that may displace centrally into the respective medial or lateral compartment, frequently causing mechanical symptoms, including pain, perceived instability, and mechanical locking. Bucket handle meniscal tears are most commonly from a traumatic etiology and are frequently found with concomitant anterior cruciate ligament (ACL) injuries. Multiple imaging signs and associations have been described for the diagnosis of bucket handle meniscus tears, including coronal truncation, absent bow tie sign, double posterior cruciate ligament (PCL), double ACL, displacement of the bucket handle fragment, and disproportionate posterior horn signs. Among meniscal pathology encountered on magnetic resonance imaging or during arthroscopy, bucket handle meniscal tears are infrequent occurrences. Furthermore, the occurrence of displaced medial and lateral bucket handle tears found on imaging and during arthroscopy is very uncommon and is only sparsely reported in the literature. When displaced medial and lateral bucket handle meniscal segments are visualized within the intercondylar notch along with the ACL and PCL, the radiologic findings are referred to as the "quadruple cruciate" sign or the "Jack and Jill lesion." Of the few case reports described in the literature, only one noted displaced medial and lateral bucket handle meniscus tears with an intact ACL and PCL. The current case report outlines a similar rare case of the quadruple cruciate sign: displaced medial and lateral bucket handle meniscal tears located within the intercondylar notch and an intact ACL and PCL.

The Trapped Medial Meniscus Tear: An Examination Maneuver Helps Predict Arthroscopic Findings

Background:

Numerous clinical examination maneuvers have been developed to identify meniscus tears of the knee. While meniscus injuries vary significantly in type and severity, no maneuvers have been developed that help to distinguish particular tear characteristics.

Purpose:

This nonconsecutive case series highlights a distinctive clinical finding that correlates with inferiorly displaced flap tears of the medial meniscus that become trapped in the medial gutter of the knee, as identified through magnetic resonance imaging (MRI) and arthroscopy.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

Eight patients with trapped medial meniscus tears were identified from a single surgeon’s academic orthopaedic sports medicine practice between January 2009 and January 2012. Each patient underwent clinical evaluation, MRI, and arthroscopic treatment for meniscus injury. Clinical notes, MRI images, radiology reports, and operative findings were reviewed and compared in a descriptive fashion.

Results:

Each patient displayed a positive clinical examination finding of medial knee pain inferior to the joint line with flexion and the application of valgus stress in the setting of a torn medial meniscus and intact medial collateral ligament (MCL). Preoperative MRI revealed a distinctive flap tear of the medial meniscus flipped inferiorly to lay trapped between the tibia and deep fibers of the MCL. On arthroscopy, flap tears were found displaced inferiorly and trapped in the medial gutter in 6 of the 8 patients. Displaced meniscal fragments in the remaining 2 patients were found within the medial compartment.

Conclusion:

Inferiorly displaced flap tears of the meniscus that have been displaced to the medial gutter can be localized through a careful examination technique.

Clinical Relevance:

Early identification of this injury pattern may help reduce the likelihood that the trapped fragment will be missed during arthroscopy.

The human meniscus: a review of anatomy, function, injury, and advances in treatment

Meniscal injuries are recognized as a cause of significant musculoskeletal morbidity. The menisci are vital for the normal function and long-term health of the knee joint. The purpose of this review is to provide current knowledge regarding the anatomy and biomechanical functions of the menisci, incidence, injury patterns and the advancements in treatment options of meniscal injury. A literature search was performed by a review of PubMed, Google Scholar, MEDLINE, and OVID for all relevant articles published between 1897 and 2014. This study highlights the anatomical and biomechanical characteristics of the menisci, which may be relevant to injury patterns and treatment options. An understanding of the normal anatomy and biomechanical functions of the knee menisci is a necessary prerequisite to understanding pathologies associated with the knee.

Normal anatomical variants of the menisci and cruciate ligaments that may mimic disease

There are many normal anatomical variants of the knee joint. Some are common and others are rare. With continuing improvements in the spatial resolution of MRI, smaller variants are more clearly demonstrated and can be mistaken for disease. They can all be differentiated from pathological conditions by understanding their anatomy and key differentiating features. This review compares normal variants of the menisci and cruciate ligaments with the pathological disorders that can mimic them.

Meniscal injury after adolescent anterior cruciate ligament injury: how long are patients at risk?

BACKGROUND

Delay of as much as 5 months between ACL injury and surgery is known to be associated with increased risk of a medial meniscal tear, but the risk of additional meniscal tear progression with a longer delay to surgery is unclear.

QUESTIONS/PURPOSES

We determined the (1) times of injury, MRI, and surgery in adolescents with ACL tears, and whether (2) timing of surgery, or (3) initial integrity of the meniscus seen on MR images predicted development of meniscal tears.

METHODS

We reviewed 112 adolescents who were 15 ± 1 years old (mean ± SD) (range, 11-16 years) with a torn ACL. These patients underwent surgical repair from 2005 to 2011 in a Canadian city. We compared dates of injury, MRI, and surgery. A pediatric and musculoskeletal fellowship-trained radiologist reread the MR images, and meniscal injuries were graded according to severity. This was compared with surgical findings described in the operative report.

RESULTS

Time after injury to MRI and surgery averaged 77 days (range, 1-377 days) and 342 days (range, 42-1637 days), respectively. Patients with new or worsened medial meniscal tears had waited longer for surgery (445 versus 290 days; p = 0.002). Bucket handle medial meniscal tears were more common in patients with surgery more than 1 year after injury than others (15 of 34 versus 14 of 75; p = 0.013). A medial meniscal tear observed on MR images was a significant covariate for a torn meniscus at surgery (relative risk, 5.7; 95% CI, 2.8-11.6). Medial meniscal survival continued to decline sharply greater than 1 year after injury.

CONCLUSIONS

Medial meniscal tears, especially bucket handle tears, increased steadily in frequency more than 1 year after ACL injury. Timely ACL reconstruction may be warranted to reduce the risk of further medial meniscal damage even in patients whose original injury occurred more than 1 year before.

LEVEL OF EVIDENCE

Level IV, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.

Magnetic resonance imaging and arthroscopic appearance of the menisci of the knee

The menisci are critical for normal function of the knee, providing shock absorption and load transmission that reduce stress on the articular cartilage. When torn, a meniscus may require surgery to restore function, reduce pain, and eliminate mechanical symptoms. Patterns of meniscal tears include longitudinal and bucket-handle, which are often reparable; and horizontal, radial, vertical flap, horizontal flap, and complex. Root tears are usually radial and occur in the posterior roots. When reviewing magnetic resonance images, one must be aware of normal variants and imaging pitfalls that may simulate pathology.

How I diagnose meniscal tears on knee MRI

OBJECTIVE

The goal of this article is to summarize the literature about the diagnosis of meniscal tears on MRI including the normal appearance of the meniscus and the appearance of the various types of meniscal tears. In addition, I discuss my experience with the causes of errors in the MR diagnosis of meniscal abnormalities and the nuances of meniscal abnormalities that can mimic a meniscal tear.

CONCLUSION

MRI is a highly accurate imaging method for diagnosing meniscal tears. To avoid errors in diagnosing meniscal tears, those interpreting MR examinations of the knee need to be aware of the attachments of the menisci and the normal variations in meniscal anatomy that may resemble a meniscal tear. In addition, by being aware of the patterns of meniscal tears, it is easier to diagnose the less common tears.

Bucket-handle meniscal tear in a 5-year-old child

Bucket-handle meniscus tears are a common athletic injury that occur frequently in the adult population but are extremely rare in young children. A 5-year-old male patient presented with left knee pain after a minor fall to the ground. Complaints of pain with full weight-bearing, locking of the joint during walking, a significant limp, 45° flexion contracture of the knee, and an inability to bring the leg into full extension were noted during examination. MRI showed a large bucket-handle medial meniscal tear. The patient made a full recovery after undergoing arthroscopic repair surgery. Level of evidence Case report, Level IV.

Hemi-bucket-handle tears of the meniscus: appearance on MRI and potential surgical implications

OBJECTIVES

To describe a type of meniscus flap tear resembling a bucket-handle tear, named a "hemi-bucket-handle" tear; to compare its imaging features with those of a typical bucket-handle tear; and to discuss the potential therapeutic implications of distinguishing these two types of tears.

MATERIALS AND METHODS

Five knee MR examinations were encountered with a type of meniscus tear consisting of a flap of tissue from the undersurface of the meniscus displaced toward the intercondylar notch. A retrospective analysis of 100 MR examinations prospectively interpreted as having bucket-handle type tears yielded 10 additional cases with this type of tear. Cases of hemi-bucket-handle tears were reviewed for tear location and orientation, appearance of the superior articular surface of the meniscus, presence and location of displaced meniscal tissue, and presence of several classic signs of bucket-handle tears.

RESULTS

A total of 15/15 tears involved the medial meniscus, had tissue displaced toward the notch, and were mainly horizontal in orientation. The superior surface was intact in 11/15 (73.3%). In 1/15 (6.7%) there was an absent-bow-tie sign; 6/15 (40%) had a double-PCL sign; 14/15 (93.3%) had a double-anterior horn sign.

CONCLUSION

We describe a type of undersurface flap tear, named a hemi-bucket-handle tear, which resembles a bucket-handle tear. Surgeons at our institution feel this tear would likely not heal if repaired given its predominantly horizontal orientation, and additionally speculate the tear could be overlooked at arthroscopy. Thus, we feel it is important to distinguish this type of tear from the typical bucket-handle tear.

Early magnetic resonance imaging in acute knee injury: a cost analysis

PURPOSE

Acute knee injury is common, and MRI is often only used when non-operative management fails because of limited availability. We investigated whether early MRI in acute knee injury is more clinically and cost-effective compared to conventional physiotherapy and reassessment.

METHODS

All patients with acute indirect soft tissue knee injury referred to fracture clinic were approached. Recruited patients were randomised to either the MRI group: early MRI within 2 weeks or the control group: conventional management with physiotherapy. Patients were assessed in clinic initially, at 2 weeks and 3 months post-injury. Management costs were calculated for all patients until surgical treatment or discharge.

RESULTS

Forty-six patients were recruited: 23 in the MRI and 23 in the control group. Male sex and mean age were similar in the two groups. The total management cost of the MRI group was £16,127 and control group was £16,170, with a similar mean cost per patient (NS). The MRI group had less mean physiotherapy (2.5 ± 1.9 vs. 5.1 ± 3.5, p < 0.01) and outpatient appointments (NS). Median time to surgery and time off work was less in the MRI group (NS). The MRI group had less pain (p < 0.05), less activity limitation (p = 0.04) and better satisfaction (p = 0.04).

CONCLUSIONS

Early MRI in acute knee injury facilitates faster diagnosis and management of internal derangement at a cost comparable to conventional treatment. Moreover, patients had significantly less time off work with improved pain, activity limitation and satisfaction scores.

LEVEL OF EVIDENCE

II.

Verification bias: an under-recognized source of error in assessing the efficacy of MRI of the meniscii

RATIONALE AND OBJECTIVES

The sensitivity and specificity of magnetic resonance imaging (MRI) for diagnosis of meniscal tears has been studied extensively, with tears usually verified by surgery. However, surgically unverified cases are often not considered in these studies, leading to verification bias, which can falsely increase the sensitivity and decrease the specificity estimates. Our study suggests that such bias may be very common in the meniscal MRI literature, and illustrates techniques to detect and correct for such bias.

MATERIALS AND METHODS

PubMed was searched for articles estimating sensitivity and specificity of MRI for meniscal tears. These were assessed for verification bias, deemed potentially present if a study included any patients whose MRI findings were not surgically verified. Retrospective global sensitivity analysis (GSA) was performed when possible.

RESULTS

Thirty-nine of the 314 studies retrieved from PubMed specifically dealt with meniscal tears. All 39 included unverified patients, and hence, potential verification bias. Only seven articles included sufficient information to perform GSA. Of these, one showed definite verification bias, two showed no bias, and four others showed bias within certain ranges of disease prevalence. Only 9 of 39 acknowledged the possibility of verification bias.

CONCLUSION

Verification bias is underrecognized and potentially common in published estimates of the sensitivity and specificity of MRI for the diagnosis of meniscal tears. When possible, it should be avoided by proper study design. If unavoidable, it should be acknowledged. Investigators should tabulate unverified as well as verified data. Finally, verification bias should be estimated; if present, corrected estimates of sensitivity and specificity should be used. Our online web-based calculator makes this process relatively easy.

Ressonância magnética na avaliação das variações anatômicas meniscais e da anatomia ligamentar perimeniscal: potenciais causas de erro de interpretação

O conhecimento adequado das variações anatômicas meniscais e das estruturas perimeniscais é essencial para uma avaliação adequada dos exames de ressonância magnética do joelho, tanto no diagnóstico das lesões meniscais quanto para se evitar uma série de possíveis erros diagnósticos. Este artigo revê variações anatômicas que alteram o tamanho, a forma e a estabilidade meniscais e que incluem os vários tipos de menisco discoide, outras variações morfológicas meniscais menos frequentes e o ossículo meniscal. Também é revisada a anatomia de estruturas perimeniscais, principalmente ligamentares, que incluem os ligamentos meniscocapsulares, intermeniscais, meniscofemorais e extensões meniscoligamentares.

The triple PCL sign: bucket handle tears of both medial and lateral menisci in a chronically ACL-deficient knee

Bucket handle tears of both menisci in the setting of acute or chronic anterior cruciate ligament (ACL) tears of the same knee have rarely been reported in the literature. This article presents a case of a bucket handle tear affecting both the medial and lateral menisci in a patient with chronic ACL rupture. Both bucket handle tears were displaced and locked in the intercondylar notch. A new magnetic resonance image (MRI) sign suggested on sagittal view is called the triple PCL sign, comprising the intact posterior cruciate ligament (PCL) and the 2 displaced fragments in the intercondylar notch from the two bucket handle tears. The precise diagnosis of this condition is of obvious importance for optimal operative planning. While finding the displaced fragment from the medial meniscus is expected to cause the double PCL sign, the torn ACL may have made it easier to visualize the bucket handle tear of the lateral meniscus in the same sagittal plane as the PCL. Only 5 other reports mention bimeniscal bucket handle tears of both the medial and lateral menisci in association with an ACL tear. None have shown the suggested triple PCL sign because of lack of overlap between the 2 bucket handle tears in the coronal plane while lying in the intercondylar notch causing them not to fall in the same sagittal plane. Our patient showed some overlap between the 2 meniscal fragments while lying in the notch to create the triple PCL sign on sagittal MRI.

Simultaneous bicompartmental bucket handle meniscal tears with a clinically competent Anterior Cruciate Ligament

Bucket handle meniscal tears (BHMT) of the knee occur infrequently (approximately 10% of meniscal injuries). Simultaneous, bicompartmental BHMT are extremely rare. Previously, these have only been reported in association with a ruptured anterior cruciate ligament (ACL). The pathomechanism of this injury was thought to be due to the lack of knee stability following the ACL injury. We present a case of a 38 year old male patient with bicompartmental BHMT with a clinically competent ACL. This highlights the need for clinical and radiological suspicion of simultaneous BHMTs even in the presence of an intact ACL.

Magnetic resonance imaging of the meniscus

Magnetic resonance imaging has evolved into a highly accurate modality in detecting meniscal injuries and provides the essential anatomic detail to help guide treatment options in this age of meniscal preservation. Accurate interpretation requires a thorough understanding of meniscal anatomy and function, anatomic variants, technical factors, typical appearance of tear patterns on magnetic resonance imaging, associated ligamentous injuries, causes of misdiagnoses, and the importance of correlation with the clinical examination.

The role of preoperative MRI in knee arthroscopy: a retrospective analysis of 2,000 patients

The aim of this study was to investigate, to what extent routine preoperative MRI scans could set the indications for knee arthroscopies and reduce the number of diagnostic arthroscopies. For this retrospective cohort study, 1,000 patients who had knee arthroscopies documented in 1994/1995 were compared with 1,000 patients that were treated in 2004/2005. The preoperative diagnoses that gave indications for knee arthroscopy were compared with the intraoperative findings. The congruence of preoperative diagnosis with the intraoperative findings was evaluated comparing both study populations. The number of patients who were referred to orthopaedic trauma surgeons with MRI increased from 24% to 56%. A high congruence of preoperative diagnosis and intraoperative findings was found in 49% in 1994/1995 and 55% in 2004/2005. However, regarding the most important outcome parameter, the number of diagnostic arthroscopies, no improvement was found (3% in both periods). The presented data suggests that MRI scans are not routinely necessary as an indication for knee arthroscopy, as clinical examination and plain radiograph are sufficient. However, MRI scans do allow a more detailed characterization of the expected findings and can therefore be helpful in therapy planning.

MR diagnosis of posterior root tears of the lateral meniscus using arthroscopy as the reference standard

OBJECTIVE

The purpose of our study was to determine whether tears of the posterior root of the lateral meniscus can be diagnosed using standard MR criteria of a meniscal tear in the presence or absence of an anterior cruciate ligament (ACL) tear.

MATERIALS AND METHODS

From a series of 559 knee MR examinations with arthroscopic correlation, we selected all 16 proven tears isolated to the posterior root of the lateral meniscus for retrospective blinded review, along with 45 cases of arthroscopically intact lateral meniscal posterior roots. The reviewers categorized whether there was a torn, possibly torn, or intact root based on three specific coronal and three specific sagittal image locations.

RESULTS

When all possibly torn roots were considered as torn, the sensitivity and specificity for diagnosis of a root tear were 93% and 89%, respectively. The observers' overall diagnosis of a tear based on all images gave a higher combined sensitivity and specificity than if the diagnosis of a tear had been based on one or any combination of the three coronal and three sagittal locations. Root tears were significantly more common in the presence of an ACL tear (p < 0.0001), but the presence or absence of an ACL tear did not change MR diagnostic accuracy.

CONCLUSION

The standard MR criteria of meniscal distortion and signal to the surface can be used to diagnose lateral meniscal root tears. The presence or absence of an ACL tear did not change diagnostic accuracy.

Rotura em "alça de balde" simultânea dos meniscos no mesmo joelho

Rotura em "alça de balde" de ambos os meniscos do mesmo joelho é um fenômeno raro. Apresentamos o caso de um paciente em que a ressonância magnética demonstrou rotura em "alça de balde" dos meniscos medial e lateral do mesmo joelho, associada a rotura do ligamento cruzado anterior, confirmado por videoartroscopia. A ressonância magnética demonstra sinais que permitem o diagnóstico preciso.

Meniscal gymnastics: common and uncommon locations of meniscal flip and flop

The majority of knee magnetic resonance imaging examinations are performed for meniscal evaluations. Displaced meniscal tears including free meniscal fragments are an important diagnosis as most of these tears are unstable and require surgical intervention. Magnetic resonance imaging can be an invaluable tool in the arthroscopic search for a free meniscal fragment. In addition to the commonly seen bucket-handle tears flipped into the intercondylar notch, it is important to be aware of less common locations where menisci may be displaced. First, we briefly summarize the basic meniscal anatomy and some of the more common tear patterns. We then investigate the broad range of meniscal migration.

MR imaging of the meniscus: review, current trends, and clinical implications

MR imaging is the preferred imaging modality for evaluating the meniscus. Overall, when strict criteria are followed, it is accurate in diagnosing meniscal tears in patients who have not had prior meniscal surgery. However, an accurate interpretation requires a through knowledge of the normal meniscal anatomy, common meniscal variants, and common diagnostic pitfalls. In this article, the author emphasizes the importance of describing meniscal tears properly and discusses treatment options. Diagnosing a recurrent tear is more complicated in patients who have had prior partial meniscal resection or repair, and the use of MR arthrography in this group of patients is discussed. Recent developments in areas such as 3 T and parallel imaging offer promise for accurate meniscal evaluation with even shorter scan times.

3-Dimensional ultrasound imaging for meniscal lesions

PURPOSE

The aim of this prospective study was to evaluate preoperative three-dimensional ultrasound scans for the detection of meniscal lesions with a special focus on interobserver reliability.

METHODS

Forty one patients with clinical signs of meniscal lesions were preoperatively examined by ultrasound using the 3-D technique (11.7 MHz linear transducer). The 3-D dataset was stored and examined by a second orthopaedic surgeon. The second ultrasound examiner was blinded to the results of the first. Any meniscal pathology was confirmed arthroscopically and documented.

RESULTS

At arthroscopy eight lateral meniscal lesions and 57 medial meniscal lesions were detected at different locations. The sensitivity and specificity of the original ultrasound examination was acceptable whereas the results of the second ultrasound session were not as sensitive.

CONCLUSION

Three-D-ultrasound with a high resolution transducer, in the hands of an experienced operator, provides acceptable results in the detection of meniscal lesions, however, analysis of the volume dataset from the 3-D ultrasound investigation indicates that it does not offer sufficient accuracy for clinical use.

Joint space narrowing after partial medial meniscectomy in the anterior cruciate ligament-intact knee

Osteoarthritis of the knee is common after total medial meniscectomy. In anterior cruciate ligament-intact knees, the reported outcomes of partial medial meniscectomy are variable. Radiographic assessment using a posteroanterior weight-bearing view is a reliable tool for detecting minor medial joint space narrowing, which may be an early sign of osteoarthritis. Studies that assessed the effect of partial medial meniscectomy found a low percentage of patients with >50% joint narrowing at 10 to 15 years after surgery. Digital radiography, using a posteroanterior weight-bearing view, is a highly sensitive method for observing minor joint space narrowing in the involved knee. A recent study showed that 88% of patients who underwent partial medial meniscectomy had joint space narrowing of <2 mm, and none had narrowing >or=2 mm, at a mean follow-up of 12 years. Subjective results after partial medial meniscectomy are favorable, with 88% to 95% of patients reporting good to excellent results.

Diagnostic IRM des lambeaux méniscaux médiaux déplacés le long du ligament tibial collatéral

PURPOSE OF THE STUDY

Displaced meniscus tears generally result from bucket handle tears with subsequent migration of the meniscal fragment into the intercondylar notch. More rarely, the fragment may move into the meniscal recesses. In this situation, the displaced fragment may be difficult to individualize arthroscopically, so preoperative imaging is crucial. Several studies have demonstrated the reliability of magnetic resonance imaging (MRI) for the diagnosis of meniscus injury with fragment displacement in the intercondylar notch. There have been few studies devoted to fragment displacement into the collateral capsuloligamentary structures. The purpose of this study was to describe MRI findings of medial meniscus tears with displaced fragment in the meniscal recesses.

MATERIAL AND METHODS

This prospective study was conducted over a 22-month period (May 2003 - February 2005). During this period, we selected 39 patients whose knee MRI displayed a meniscal fragment within the medial collateral recesses. These 39 patients accounted for 15% of knees with MRI-diagnosed meniscal tears (n=272) and 2% of the knee MRI examinations performed during the study period (n=2239). One the MRI series, we studied fragment migration and morphological anomalies of the injured meniscus. For 16 knees, MRI findings could be compared with arthroscopy findings.

RESULTS

For 25 knees (65%), the meniscal fragment had migrated downward along the medial tibial plateau and generally (64%) medially to the collateral tibial ligament. For 14 knees (35%) the meniscal fragment had migrated upward, along the medial femoral condyle in 93%, anteriorly to the medial collateral tibial ligament. For 95%, the MRI demonstrated rupture along the free border of the posterior segment and/or the mid segment of the medial meniscus or a decreased height of the posterior segment of the medial meniscus. For 14 of 16 cases, arthroscopy confirmed the meniscal tear and the localization of the displaced fragment. For two knees, arthroscopy confirmed the presence of the meniscal tear but could not identify the displaced meniscal fragment.

DISCUSSION

Meniscal tears with fragment displacement into the meniscal recesses has been associated with displacement of a horizontal fissuration which flap tears described arthroscopically by DJ Dandy. Other authors consider these tear flaps as oblique fissurations. In our study, it was sometimes difficult to determine the exact site and orientation of the initial meniscal tear so it is quite likely that meniscal tears with a displaced fragment in the meniscal recesses could correspond to complex predominantly horizontal or oblique meniscal fissurations. The common feature is the presence of an unstable meniscal flap susceptible to migrate. Our findings are in agreement with the literature. Regarding the two cases where the MRI findings could not be confirmed arthroscopically, the MRI visualized a characteristic image of a meniscal fragment displaced downwardly, lying between the medial tibial plateau and the collateral tibial ligament. Arthroscopy visualized the meniscal tear but failed to visualize the displaced fragment. This might be because mobile meniscal fragments return into the joint interspace when the meniscus is manipulated arthroscopically. Small meniscal fragments might also be inaccessible arthroscopically.

MRI for Traumatic Knee Injury: A Review

Magnetic resonance imaging (MRI) is a well-established technique for detecting internal derangements of the knee joint with high diagnostic accuracy. It is an effective tool to select patients for targeted therapeutic arthroscopy. In this article, indications for knee MRI and most commonly used MRI techniques are outlined, followed by an overview of the most frequently encountered traumatic knee derangements in daily practice and their appearance and grading system on MRI. Lesions discussed include fractures, osteochondral lesions, bone bruise, cruciate and collateral ligament lesions, and meniscal tears. Finally, common pitfalls and recent developments in knee MRI are addressed.

MR Imaging of the Meniscus: Review, Current Trends, and Clinical Implications

MR imaging is the preferred imaging modality for evaluating the meniscus. Overall, when strict criteria are followed, it is accurate in diagnosing meniscal tears in patients who have not had prior meniscal surgery. However, an accurate interpretation requires a through knowledge of the normal meniscal anatomy, common meniscal variants, and common diagnostic pitfalls. In this article, the author emphasizes the importance of describing meniscal tears properly and discusses treatment options. Diagnosing a recurrent tear is more complicated in patients who have had prior partial meniscal resection or repair, and the use of MR arthrography in this group of patients is discussed. Recent developments in areas such as 3 T and parallel imaging offer promise for accurate meniscal evaluation with even shorter scan times.

Bucket handle tears of the medial meniscus: meniscal intrusion rather than meniscal extrusion

OBJECTIVE

To determine the frequency of medial meniscal extrusion (MME) versus "medial meniscal intrusion" in the setting of bucket handle tears. Images were evaluated for previously reported risk factors for MME, including: medial meniscal root tear, radial tear, degenerative joint disease and joint effusion.

METHODS

Forty-one consecutive cases of bucket handle tear of the medial meniscus were reviewed by consensus by two musculoskeletal radiologists. Imaging was performed using a 1.5 GE Signa MR unit. Patient age, gender, medial meniscal root integrity, MME, medial meniscal intrusion, degenerative joint disease, effusion and anterior cruciate ligament (ACL) tear were recorded.

RESULTS

Thirteen females and 27 males (age 12-62 years, median=30 years) were affected; one had bucket handle tear of each knee. Effusion was small in 13, moderate in 9 and large in 18. Degenerative joint disease was mild in three, moderate in two and severe in one. 26 ACL tears included three partial and three chronic. Medial meniscal root tear was complete in one case and partial thickness in two. None of the 40 cases with an intact or partially torn medial meniscal root demonstrated MME. MME of 3.1 mm was seen in the only full-thickness medial meniscal root tear, along with chronic ACL tear, moderate degenerative joint disease and large effusion. Medial meniscal intrusion of the central bucket handle fragment into the intercondylar notch was present in all 41 cases.

CONCLUSION

Given an intact medial meniscal root in the setting of a "pure" bucket handle tear, there is no MME.

Bucket-handle meniscal lesions: magnetic resonance imaging criteria for reparability

PURPOSE

The purpose of this study was to determine the accuracy of magnetic resonance imaging (MRI) in predicting knee bucket-handle meniscal tear (BHMT) reparability.

METHODS

Twenty-eight patients who underwent knee arthroscopy by a single surgeon for BHMT with prior MRI examination were included. BHMTs were diagnosed by MRI based on the association of a displaced meniscal fragment on coronal images and one of the following three signs on sagittal slices: flipped meniscus sign, double posterior cruciate ligament, and meniscal fragment within the intercondylar notch. BHMT patients' MRIs were retrospectively reviewed independently to search for criteria of reparability by 2 observers with different degrees of experience in musculoskeletal radiology, and disagreements were arbitrated to consensus. The criteria for BHMT reparability were as follows: (1) rim width of less than 4 mm; (2) tear length of 1 cm or greater, regardless of total lesion length; and (3) generation of isosignals by the inner meniscal fragment and peripheral rim compared with the normal contralateral meniscus of the same knee. The first 2 criteria indicate an adequate meniscal lesion length in the vascularized zone (only the peripheral third), enabling meniscal healing after repair; the third criterion guarantees that the meniscus is nondegenerative.

RESULTS

Of the BHMTs, 5 (17.9%) were arthroscopically reparable and 23 (82.1%) were not. Interpretation of magnetic resonance images correctly predicted reparability in 4 of 5 reparable BHMTs and irreparability in 22 of 23 irreparable BHMTs (26/28 lesions). Interobserver agreement was good for the prediction of reparability (kappa = 0.7).

CONCLUSIONS

These results suggest that knee BHMTs that are predicted to be reparable by MRI would have a high likelihood of actually being reparable.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria on basis of consecutive patients and gold standard.

Wertigkeit von 3D-Sonographie und MRT des Meniskusschadens

BACKGROUND

The aim of this prospective study was the evaluation of preoperative three-dimensional ultrasound in detecting meniscal lesions compared to preoperative MRI.

METHODS

A total of 34 patients with clinical signs of meniscal lesions were examined preoperatively (11.7 MHz linear transducer) using the 3-D technique. Before ultrasound, MRI was performed, the results of which were unknown to the ultrasound examiner. The basis of the MRI result was the radiologist's written report. Arthroscopically the meniscal situation was noted and taken as reference.

RESULTS

At arthroscopy there were 10 lateral meniscal lesions at different locations and 47 medial meniscal lesions at different locations. The sensitivity (0.5-0.78) and specificity (0.75-0.95) of both imaging methods were overall comparable.

CONCLUSION

Ultrasound with the three-dimensional technique and high-resolution transducer in the hands of an experienced operator gives results comparable to the MRI interpretation by a general radiologist in detecting meniscal lesions.

Accuracy of 3-T MRI Using Fast Spin-Echo Technique to Detect Meniscal Tears of the Knee

OBJECTIVE

The purpose of this study was to evaluate the accuracy of the fast spin-echo technique in detecting meniscal tears of the knee using a 3-T MRI system.

CONCLUSION

We concluded from this study that 3-T MRI using fast spin-echo sequences is highly accurate in the detection of medial and lateral meniscal tears of the knee.

Simultaneous bucket handle tear of both medial and lateral menisci of a knee with chronic anterior cruciate ligament deficiency

Bucket handle meniscus tears constitute about 10% of all meniscal tears. Bucket handle tears of medial meniscus is three times more than lateral meniscus. Most of these tears are associated with anterior cruciate ligament (ACL) deficiency. Lateral meniscus lesions are more common with acute ACL deficiency, where medial meniscus lesions are more associated with chronic ACL deficiency. We identified bucket handle tears of each meniscus of a 30-year-old male patient while performing diagnostic arthroscopy during ACL reconstruction procedure. We present an ACL deficient knee with bucket handle tears of medial and lateral meniscus of the same knee and discuss the treatment.