Original Research Article MRI in Evaluation of Knee Cystic Lesions

Background: Cystic knee lesions (synovial cysts, bursae, ganglia, and meniscal cysts) are frequently discovered and can be divided into real cysts and lesions that simulate cysts (hematomas, seromas, abscesses and vascular lesions). Aim of the Work: The aim of this study was to assess the role of magnetic resonance imaging in evaluation of cysts and cyst like lesions in and around the knee. Subjects and Methods: From January 2018 to August 2019, 30 patients were referred from outpatient clinics and orthopedic surgery department to MRI unit of radiodiagnosis and medical imaging department at Tanta University Hospitals, for MRI evaluation of suspected knee cystic lesions. Results: MRI was able to detect all clinically suspected cystic lesions within the knee. It also helped to describe morphology and it’s relation to surrounding tissues. 16.7% and 3.3% of the studied cystic lesions had fine and thick septa respectively, and 67 % of the studied cystic lesions had communication with the joints. MRI could identify the associated pathology of most of the detected cystic lesions (80%). The most common pathology were meniscal degeneration (26.7%) followed by meniscal tear and osteoarthritis (23.3%) and (20%) respectively. Ligament tear / sprain formed 6.7% of the total cysts while bone contusion forms 3.3%. Conclusion: The findings of this study confirm that In spite of its high cost, limited availability and the need for highly expert radiologists, MRI remains the method of choice for both diagnosis, characterization and uncovering the associated pathology and cause of cystic lesions around the knee. The high ability of MRI to image soft tissues plays a key role.

Analysis of Risk Factors for Ramp Lesions Associated With Anterior Cruciate Ligament Injury

Background: The incidence of meniscocapsular junction tears of the medial meniscus posterior horn, known as ramp lesions, is reported to be 9.3% to 23.9%. However, these lesions are not consistently diagnosed with routine arthroscopic exploration and magnetic resonance imaging (MRI). Purpose: To determine risk factors associated with ramp lesions in anterior cruciate ligament–injured knees. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 275 patients undergoing anterior cruciate ligament reconstruction between June 2011 and March 2019 were included in this study. Exclusion criteria were revisions, fracture histories, and multiple-ligament injuries other than medial collateral ligament injury. Patients were divided into 2 groups, those with and without ramp lesions according to arthroscopic diagnosis. Binary logistic regression was used to analyze risk factors: age, sex, body mass index, time from injury to surgery (<3 or ≥3 months), mechanism of injury (contact/noncontact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial/meniscal slope, and mechanical axis angle. Receiver operating characteristic curves and area under the curve were evaluated. A prediction model was developed by multivariable regression with generalized estimating equations. Results: Overall, 95 patients (34.5%) were confirmed as having a ramp lesion. The sensitivity of MRI for ramp lesions was 85.3%, and specificity was 78.3%. Significant risk factors for ramp lesion were as follows: posterior medial tibial plateau bone contusion on MRI (odds ratio [OR], 4.201; 95% CI, 2.081-8.482; P < .001), ≥3 months from injury (OR, 4.818; 95% CI, 2.158-10.757; P < .001), varus knee >3° (OR, 2.339; 95% CI, 1.048-5.217; P = .038), steeper medial tibial slope (OR, 1.289; 95% CI, 1.002-1.66; P = .049) and meniscal slope (OR, 1.464; 95% CI, 1.137-1.884; P = .003), and gradual lateral tibial slope (OR, 0.775; 95% CI, 0.657-0.914; P = .002). The area under the curve for the prediction model developed by logistic regression was 0.779 (sensitivity, 75.8%; specificity, 71.7%; P < .001) for ramp lesions. Conclusion: Care should be taken with patients who have significant risk factors for ramp lesions, including bone contusion at the posterior medial tibial plateau, chronic injury, steeper medial tibial and meniscal slope, gradual lateral tibial slope, and varus knee >3°.

Bone Contusion on the Medial Compartment is a Predictive Factor for more Associated Injuries After ACL Rupture

Objectives: Determine the frequency of bone contusion and associated injuries, observed in patients with anterior cruciate ligament (ACL) rupture. Methods: Seventy two patients with an ACL rupture were enrolled in our prospective study. Magnetic resonance images (MRI) and arthroscopic findings of all patients were examined in order to detect bone contusions and associated injuries, such as meniscal lesions and medial collateral ligament (MCL) injury. ACL rupture and meniscal lesions were also verified with knee arthroscopy. Correlation between bone contusions and meniscal lesions or MCL injury was performed. Statistical packet STATA 8.0 was used for data analysis and significance was set at p<0.05. Results: Fifty eight (80.5%) patients presented with associated bone contusions observed on magnetic resonance imaging. Lateral aspect of the tibia plateau (71%) and lateral femoral condyle (69%) were the most common sites with contusions. Medial compartment was associated with contusions of medial aspect of the tibia plateau and medial femoral condyle in 25% and 22% of patients respectively. The frequency of lateral meniscus (p = 0.022), medial meniscus (p = 0.036) and MCL (p = 0.05) injuries, significantly increased in patients with bone contusions of medial and lateral compartments compared to those with bone contusions on lateral only compartment or without bone contusions. Conclusion: Bone contusion on the medial compartment is a predictive factor for more associated injuries, seen after ACL rupture and it suggest a higher energy trauma.