Steep posterior lateral tibial slope, bone contusion on lateral compartments and combined medial collateral ligament injury are associated with the increased risk of lateral meniscal tear.

PURPOSE: To determine the risk factors for lateral meniscus and root tears in patients with acute anterior cruciate ligament (ACL) injuries. METHODS: A total of 226 patients undergoing acute ACL reconstruction were included in the study sample. Exclusion criteria were revisions, fractures, chronic cases, and multiple ligament injuries, with the exception of medial collateral ligament (MCL) injuries. The patients were divided into groups based on the presence of lateral meniscus and root tears by arthroscopy. Binary logistic regression was used to analyze risk factors including age, sex, body mass index (BMI), injury mechanism (contact/non-contact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial and meniscal slope, mechanical axis angle, and grade of pivot shift. RESULTS: Overall lateral meniscus (LM) tears were identified in 97 patients (42.9%), and LM root tears were found in 22 patients (9.7%). The risk of an LM tear in ACL-injured knees increased with bone contusion on LTP (odds ratio [OR], 3.5; 95% confidence interval [CI] 1.419-8.634; P = 0.007), steeper lateral tibial slope (OR, 1.133; 95% CI 1.003-1.28; P = 0.045), MCL injury (OR, 2.618; 95% CI 1.444-4.746; P = 0.002), and non-contact injury mechanism (OR, 3.132; 95% CI 1.446-6.785; P = 0.004) in logistic regression analysis. The risk of LM root tear in ACL-injured knees increased with high-grade pivot shift (OR, 9.127; 95% CI 2.821-29.525; P = 0.000) and steeper lateral tibial slope (OR, 1.293; 95% CI 1.061-1.576; P = 0.011). CONCLUSION: The increased risk of LM lesions in acute ACL-injured knees should be considered if significant risk factors including bone contusion on lateral compartments, MCL injury, and a steeper lateral tibial slope are present. Moreover, high-grade rotational injury with steeper lateral tibial slope are also significant risk factors for LM root tears, and therefore care should be taken by clinicians not to miss such lesions. LEVEL OF EVIDENCE: III.

Bone bruise in anterior cruciate ligament rupture entails a more severe joint damage affecting joint degenerative progression.

PURPOSE: During anterior cruciate ligament (ACL) injury, the large external forces responsible for ligament rupture cause a violent impact between tibial and femoral articular cartilage, which is transferred to bone resulting in bone bruise detectable at MRI. Several aspects remain controversial and await evidence on how this MRI finding should be managed while addressing the ligament lesion. Thus, the aim of the present review was to document the evidence of all available literature on the role of bone bruise associated with ACL lesions. METHODS: A systematic review of the literature was performed on bone bruise associated with ACL injury. The search was conducted in September 2017 on three medical electronic databases: PubMed, Web of Science, and the Cochrane Collaboration. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were used. Relevant articles were studied to investigate three main aspects: prevalence and progression of bone bruise associated with ACL lesions, its impact on the knee in terms of lesion severity and joint degeneration progression over time and, finally, the influence of bone bruise on patient prognosis in terms of clinical outcome. RESULTS: The search identified 415 records and, after an initial screening according to the inclusion/exclusion criteria, 83 papers were used for analysis, involving a total of 10,047 patients. Bone bruise has a high prevalence (78% in the most recent papers), with distinct patterns related to the mechanism of injury. This MRI finding is detectable only in a minority of cases the first few months after trauma, but its presence and persistence have been correlated to a more severe joint damage that may affect the degenerative progression of the entire joint, with recent evidence suggesting possible effects on long-term clinical outcome. CONCLUSION: This systematic review of the literature documented a growing interest on bone bruise associated with ACL injury, highlighting aspects which could provide to orthopaedic surgeons evidence-based suggestions in terms of clinical relevance when dealing with patients affected by bone bruise following ACL injury. However, prospective long-term studies are needed to better understand the natural history of bone bruise, identifying prognostic factors and targets of specific treatments that should be developed in light of the overall joint derangements accompanying ACL lesions. LEVELS OF EVIDENCE: IV, Systematic review of level I-IV studies.

Tibiofemoral bone bruise volume is not associated with meniscal injury and knee laxity in patients with anterior cruciate ligament rupture.

PURPOSE: This study aimed at evaluating the association between the volume of the bone bruises and the magnitude of knee sagittal laxity and presence of meniscal injury in patients with anterior cruciate ligament (ACL) rupture. It was hypothesized that higher volumes of bone bruises will be associated with increased knee laxity and the presence of meniscal injury. METHODS: Patients with clinical diagnosis of ACL injury were referred for magnetic resonance imaging (MRI) and knee sagittal laxity measurement with a mechanical instrumented device (Porto-Knee Testing Device). The femoral and tibial bone bruises were assessed by MRI and the volume measured by manually contouring the bone bruise using a computerized software and computed by a mathematical algorithm combining all measured areas. The ACL rupture type (partial or total), meniscal tear (medial or lateral), and the localization of bone bruise were also analyzed. RESULTS: Seventy-six ACL-ruptured participants were included and 34 patients displayed bone bruises. Tibiofemoral sagittal laxity was higher in participants with complete ACL rupture (p < 0.05), but not influenced by the volume of bone bruises and meniscal status (n.s.). The volume of bone bruises was not significantly associated with the meniscal lesion or with the tibiofemoral sagittal laxity, independently of the meniscal injury status (n.s.). CONCLUSIONS: The volume of femoral and/or tibial bone bruises was not associated with the type of ACL injury, tibiofemoral sagittal laxity or the status of meniscal injury. Bone bruises must be considered as a radiographic sign of injury and should not be suggestive of injury severity and not overvalued. LEVEL OF EVIDENCE: Retrospective cohort study, Level III. IRB NUMBER: 0011/0014.

Clinical applications of a computed tomography color "marrow mapping" algorithm to increase conspicuity of nondisplaced trabecular fractures.

PURPOSE: To explore clinical applications of a novel conventional computed tomography (CT) color post-processing algorithm to increase conspicuity of nondisplaced trabecular fractures. MATERIALS AND METHODS: The algorithm was created in Adobe Photoshop and Adobe Extendscript, utilizing DICOM images from conventional CT as source images. A total of six representative cases were selected and processed. No statistical analyses were performed. RESULTS: A total of six cases are demonstrated, five with MRI correlation demonstrating corresponding fractures and bone marrow edema, including a case of sacral insufficiency fracture, two cases of vertebral body fracture, two cases of nondisplaced hip fracture, and a knee bone marrow edema lesion (without MRI correlate). All cases were processed successfully without error. CONCLUSIONS: A conventional CT color post-processing algorithm may be clinically useful in increasing conspicuity of nondisplaced fractures and bone marrow edema. A potential pitfall is the presence of subchondral or marrow sclerosis, which may mimic edema. Future prospective studies will be necessary to evaluate diagnostic performance.

Diagnostic Value of Early Magnetic Resonance Imaging After Acute Lateral Ankle Injury.

We report a retrospective study of 171 consecutive patients with a lateral ankle sprain. All the patients with direct or blunt force trauma were excluded. Within 21 days of injury, 115 (67.25%) patients had undergone magnetic resonance imaging to evaluate for more serious or significant injuries. The average patient age was 44.09 years. Of the 115 patients, 75 (65.23%) had findings noted to be "significant." MRI can serve as a valuable and underused tool in the evaluation of acute lateral ankle injuries. The underuse of MRI might explain the high degree of variability in patients recovering from a lateral ankle sprain.

Automated quantitative assessment of bone contusions and overlying articular cartilage following anterior cruciate ligament injury.

Quantitative methods to characterize bone contusions and associated cartilage injury remain limited. We combined standardized voxelwise normalization and 3D mapping to automate bone contusion segmentation post-anterior cruciate ligament (ACL) injury and evaluate anomalies in articular cartilage overlying bone contusions. Forty-five patients (54% female, 26.4 ± 11.8 days post-injury) with an ACL tear underwent 3T magnetic resonance imaging of their involved and uninvolved knees. A novel method for voxelwise normalization and 3D anatomical mapping was used to automate segmentation, labeling, and localization of bone contusions in the involved knee. The same mapping system was used to identify the associated articular cartilage overlying bone lesions. Mean regional T1ρ was extracted from articular cartilage regions in both the involved and uninvolved knees for quantitative paired analysis against ipsilateral cartilage within the same compartment outside of the localized bone contusion. At least one bone contusion lesion was detected in the involved knee within the femur and/or tibia following ACL injury in 42 participants. Elevated T1ρ (p = 0.033) signal were documented within the articular cartilage overlying the bone contusions resulting from ACL injury. In contrast, the same cartilaginous regions deprojected onto the uninvolved knees showed no ipsilateral differences (p = 0.795). Automated bone contusion segmentation using standardized voxelwise normalization and 3D mapping deprojection identified altered cartilage overlying bone contusions in the setting of knee ACL injury.

Bone bruise distribution predicts anterior cruciate ligament tear location in non-contact injuries.

Purpose: It is unclear whether different injury mechanisms lead to divergent anterior cruciate ligament (ACL) tear locations. This study aims to analyse the relationship between bone bruise (BB) distribution or depth and ACL tear location. Methods: A retrospective analysis of 446 consecutive patients with acute non-contact ACL injury was performed. Only patients with complete ACL tears verified during subsequent arthroscopy were included. Magnetic resonance imaging (MRI) was used to classify BB location, BB depth, ACL tear location and concomitant injuries (medial/lateral meniscus and medial/lateral collateral ligament). Demographic characteristics included age, gender, body mass index (BMI), type of sport and time between injury and MRI. Multiple linear regression analysis was used to identify independent predictors of ACL tear location. Results: One hundred and fifty-eight skeletally mature patients met the inclusion criteria. The presence of BB in the lateral tibial plateau was associated with a more distal ACL tear location (ß = -0.27, p < 0.001). Less BB depth in the lateral femoral condyle showed a tendency towards more proximal ACL tears (ß = -0.14; p = 0.054). Older age predicted a more proximal ACL tear location (ß = 0.31, p < 0.001). No significant relationship was found between ACL tear location and gender, BMI, type of sport, concomitant injuries and time between injury and MRI. Conclusion: ACL tear location after an acute non-contact injury is associated with distinct patterns of BB distribution, particularly involving the lateral compartment, indicating that different injury mechanisms may lead to different ACL tear locations. Level of Evidence: Level III.

The Predicted Position of the Knee Near the Time of ACL Rupture Is Similar Between 2 Commonly Observed Patterns of Bone Bruising on MRI.

BACKGROUND: Bone bruises observed on magnetic resonance imaging (MRI) can provide insight into the mechanisms of noncontact anterior cruciate ligament (ACL) injury. However, it remains unclear whether the position of the knee near the time of injury differs between patients evaluated with different patterns of bone bruising, particularly with regard to valgus angles. HYPOTHESIS: The position of the knee near the time of injury is similar between patients evaluated with 2 commonly occurring patterns of bone bruising. STUDY DESIGN: Descriptive laboratory study. METHODS: Clinical T2- and T1-weighted MRI scans obtained within 6 weeks of noncontact ACL rupture were reviewed. Patients had either 3 (n = 20) or 4 (n = 30) bone bruises. Patients in the 4-bone bruise group had bruising of the medial and lateral compartments of the femur and tibia, whereas patients in the 3-bone bruise group did not have a bruise on the medial femoral condyle. The outer contours of the bones and associated bruises were segmented from the MRI scans and used to create 3-dimensional surface models. For each patient, the position of the knee near the time of injury was predicted by moving the tibial model relative to the femoral model to maximize the overlap of the tibiofemoral bone bruises. Logistic regressions (adjusted for sex, age, and presence of medial collateral ligament injury) were used to assess relationships between predicted injury position (quantified in terms of knee flexion angle, valgus angle, internal rotation angle, and anterior tibial translation) and bone bruise group. RESULTS: The predicted injury position for patients in both groups involved a flexion angle <20°, anterior translation >20 mm, valgus angle <10°, and internal rotation angle <10°. The injury position for the 3-bone bruise group involved less flexion (odds ratio [OR], 0.914; 95% CI, 0.846-0.987; P = .02) and internal rotation (OR, 0.832; 95% CI, 0.739-0.937; P = .002) as compared with patients with 4 bone bruises. CONCLUSION: The predicted position of injury for patients displaying both 3 and 4 bone bruises involved substantial anterior tibial translation (>20 mm), with the knee in a straight position in both the sagittal (<20°) and the coronal (<10°) planes. CLINICAL RELEVANCE: Landing on a straight knee with subsequent anterior tibial translation is a potential mechanism of noncontact ACL injury.

Multienergy Computed Tomography Applications: Trauma.

Computed tomography (CT) plays an important role in trauma because imaging findings directly impact management. Advances in CT technology, specifically multienergy CT, have allowed for simultaneous acquisition of images at low and high kilovolt peaks. This technique allows for differentiation of materials given that materials have different absorption behaviors. Various multienergy CT postprocessing applications are helpful in the setting of trauma, including bone subtraction, virtual monoenergetic imaging, iodine-selective imaging, and virtual noncontrast imaging. These techniques have been applied from head to toe and have been used to improve image quality and increase conspicuity of injuries, which increases diagnostic confidence.

Post-mortem feasibility of dual-energy computed tomography in the detection of bone edema-like lesions in the equine foot: a proof of concept.

Introduction: In this proof-of-concept study, the post-mortem feasibility of dual-energy computed tomography (DECT) in the detection of bone edema-like lesions in the equine foot is described in agreement with the gold standard imaging technique, which is magnetic resonance imaging (MRI). Methods: A total of five equine cadaver feet were studied, of which two were pathological and three were within normal limits and served as references. A low-field MRI of each foot was performed, followed by a DECT acquisition. Multiplanar reformations of DECT virtual non-calcium images were compared with MRI for the detection of bone edema-like lesions. A gross post-mortem was performed, and histopathologic samples were obtained of the navicular and/or distal phalanx of the two feet selected based on pathology and one reference foot. Results: On DECT virtual non-calcium imaging, the two pathological feet showed diffuse increased attenuation corresponding with bone edema-like lesions, whereas the three reference feet were considered normal. These findings were in agreement with the findings on the MRI. Histopathology of the two pathologic feet showed abnormalities in line with bone edema-like lesions. Histopathology of the reference foot was normal. Conclusion: DECT virtual non-calcium imaging can be a valuable diagnostic tool in the diagnosis of bone edema-like lesions in the equine foot. Further examination of DECT in equine diagnostic imaging is warranted in a larger cohort, different locations, and alive animals.

Magnetic resonance imaging (MRI) and Computed topography (CT) analysis of Schatzker type IV tibial plateau fracture revealed possible mechanisms of injury beyond varus deforming force.

BACKGROUND: Schatzker type IV tibial plateau fractures (type IV TPFs) are known for complex fracture morphology and high frequency of knee subluxation. Varus deforming force has been believed to be the cause but which fails to explain the lateral tibial plateau comminution and the lateral femoral condyle bone edema observed on injury MRI. The purpose of this study is to further explore the mechanisms of injury of type IV TPFs by synthetically analysing the information obtained from MRI and CT of a cohort of patients. METHODS: Between 2010 and 2019, 49 type IV TPFs were surgically treated in our hospital. The patients with complete preoperative CT and MRI were enrolled. They were classified according to OTA/AO and Luo's updated three-column classification (uTCC) after fracture morphology analysing and measuring. Then the injuries of cruciate/collateral ligaments and bone contusion were studied on MRI. The discrepancy between obvious fracture and occult bone contusion/soft tissue disruption among the groups of uTCC were compared and analysed. RESULTS: Thirty patients were eligible for this study. Under uTCC system, all the cases were caused by varus force according to the tibial plateau angle and were classified into three groups of uTCC referring the posterior tibial slope angle: 4 were into hyperextension-varus, 21 into the extension-varus and 5 into the flexion-varus group. Fracture morphology analysis found in the extension-varus group, there were two distinct subgroups: OTA/AO 41B1.2 (medial+posteromedial columns disruption) and 41B3.3f (41B1.2 +posterolateral column disruption). Injury MRI revealed 28 of the 30 cases had more than 2 ligamentous injuries. The incidences of anterior and posterior cruciate injury were 96.7% and 43.3% respectively while 70% for medial collateral ligament (MCL). Eighteen out of 30 demonstrated apparent lateral femoral condyle bone contusion sign. Chi-square analysis found in the extension-varus group, the posterolateral column comminution was closely associated with lateral femoral condylar contusion (p<0.05) and MCL injuries (p<0.05). This finding and the absence of medial femoral condylar contusion was unlikely caused by uTCC proposed varus deforming force. CONCLUSION: In contrast to varus impaction, some type IV TPFs was probably caused by valgus or rotation force.

Bone bruising severity after anterior cruciate ligament rupture predicts elevation of chemokine MCP-1 associated with osteoarthritis.

PURPOSE: Anterior cruciate ligament rupture is associated with characteristic bone contusions in approximately 80% of patients, and these have been correlated with higher pain scores. Bone bruising may indicate joint damage that increases inflammation and the likelihood of posttraumatic osteoarthritis. We sought to characterize the severity of bone bruising following acute anterior cruciate ligament injury and determine if it correlates with synovial fluid and serum levels of the proinflammatory chemokine monocyte chemoattractant protein-1 associated with posttraumatic osteoarthritis. METHODS: This was a retrospective analysis of data collected prospectively from January 2014 through December 2016. All patients who sustained an acute ligament rupture were evaluated within 15 days of injury, obtained a magnetic resonance imaging study, and underwent bone-patellar-tendon-bone autograft reconstruction were offered enrollment. The overall severity of bone bruising on magnetic resonance imaging was graded (sum of 0-3 grades in 13 sectors of the articular surfaces). Serum and synovial fluid levels of monocyte chemoattractant protein-1 were measured within 14 days of injury, and serum levels were again measured 6 and 12 months following surgery. Separate univariate linear regression models were constructed to determine the association between monocyte chemoattractant protein-1 and bone bruising severity at each time point. RESULTS: Forty-eight subjects were included in this study. They had a mean age of 21.4 years and were 48% female. Median overall bone bruising severity was 5 (range 0-14). Severity of bone bruising correlated with higher synovial fluid concentrations of monocyte chemoattractant protein-1 preoperatively (R2 = 0.18, p = 0.009) and with serum concentrations at 12 months post-reconstruction (R2 = 0.12, p = 0.04). CONCLUSIONS: The severity of bone bruising following anterior cruciate ligament rupture is associated with higher levels of the proinflammatory cytokine monocyte chemoattractant protein-1 in synovial fluid acutely post-injury and in serum 12-months following anterior cruciate ligament reconstruction. This suggests that severe bone bruising on magnetic resonance imaging after ligament rupture may indicate increased risk for persistent joint inflammation and posttraumatic osteoarthritis. LEVEL OF EVIDENCE: III - retrospective cohort study.

Identifying Clinical and MRI Characteristics Associated with Quality of Life in Patients with Anterior Cruciate Ligament Injury: Prognostic Factors for Long-Term.

BACKGROUND: Associated lesions in the diagnostic MRI may be related to worse long-term subjective outcomes. There is a lack of conclusive information about the long-term outcomes of associated injuries in anterior cruciate ligament (ACL) tears. The purpose of this study is to assess the long-term effects of associated injuries in ACL tears measured by means of a quality of life (QOL) assessment. METHODS: A retrospective cohort study of 225 consecutive patients admitted for physical therapy with ACL injury (42 ± 12 years, 28.2% female) were conducted. All demographic and clinical variables were used to measure a QOL. Univariate and multivariable analyses were completed. RESULTS: The mean follow-up period was 8.4 ± 2.6 years. In univariate analysis, male gender, and sports as the cause of the ACL lesion were factors significantly associated with improved International Knee Documentation Committee (IKDC) scores at the end of follow-up (all p < 0.002). In multivariable analysis, the occurrence of bone contusion was positively associated with injury (OR = 2.12) and negatively associated with sports injury (OR = 0.44) and medial collateral ligament (MCL) injury (OR = 0.48). CONCLUSIONS: After ACL injury, male gender and sports injury were associated with better clinical outcomes.

Distribution of Bone Contusion Patterns in Acute Noncontact Anterior Cruciate Ligament-Torn Knees.

BACKGROUND: Bone contusions are commonly observed on magnetic resonance imaging (MRI) in individuals who have sustained a noncontact anterior cruciate ligament (ACL) injury. Time from injury to image acquisition affects the ability to visualize these bone contusions, as contusions resolve with time. PURPOSE: To quantify the number of bone contusions and their locations (lateral tibial plateau [LTP], lateral femoral condyle [LFC], medial tibial plateau [MTP], and medial femoral condyle [MFC]) observed on MRI scans of noncontact ACL-injured knees acquired within 6 weeks of injury. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: We retrospectively reviewed clinic notes, operative notes, and imaging of 136 patients undergoing ACL reconstruction. The following exclusion criteria were applied: MRI scans acquired beyond 6 weeks after injury, contact ACL injury, and previous knee trauma. Fat-suppressed fast spin-echo T2-weighted MRI scans were reviewed by a blinded musculoskeletal radiologist. The number of contusions and their locations (LTP, LFC, MTP, and MFC) were recorded. RESULTS: Contusions were observed in 135 of 136 patients. Eight patients (6%) had 1 contusion, 39 (29%) had 2, 41 (30%) had 3, and 47 (35%) had 4. The most common contusion patterns within each of these groups were 6 (75%) with LTP for 1 contusion, 29 (74%) with LTP/LFC for 2 contusions, 33 (80%) with LTP/LFC/MTP for 3 contusions, and 47 (100%) with LTP/LFC/MTP/MFC for 4 contusions. No sex differences were detected in contusion frequency in the 4 locations (P > .05). Among the participants, 50 (37%) had medial meniscal tears and 52 (38%) had lateral meniscal tears. CONCLUSION: The most common contusion patterns observed were 4 locations (LTP/LFC/MTP/MFC) and 3 locations (LTP/LFC/MTP).

Mechanisms of non-contact anterior cruciate ligament injury as determined by bone contusion location and severity.

BACKGROUND: The location and severity of tibiofemoral bone contusions in magnetic resonance imaging scans in patients with acute non-contact anterior cruciate ligament injuries can reflect the primary mechanisms of anterior cruciate ligament injuries. There has been limited investigation to subdividing the bone contusion model in the medial and lateral directions of the tibial plateau and the femoral condyle. METHODS: A retrospective review of 93 consecutive magnetic resonance imaging examinations of patients with acute non-contact anterior cruciate ligament injuries was conducted to identify bone contusions of the knee. The locations and the severity of the bone contusions were determined using magnetic resonance imaging scans for each anatomic site, including the lateral femoral condyle, the lateral tibial plateau, the medial femoral condyle, and the medial tibial plateau. The bone contusions in the lateral-medial and anterior-posterior directions of four anatomical sites were subdivided into six compartments. The severity of the bone contusions was graded on a scale of 1-4. The location and the severity of bone contusions were accessed in the sagittal and coronal planes on the femoral and tibial sides of the knee using the radiology information system. RESULTS: The prevalence of bone contusions on the magnetic resonance imaging scans was as follows: 78.49% on the lateral femoral condyle, 88.17% on the lateral tibial plateau, 49.46% on the medial femoral condyle, and 69.89% on the medial tibial plateau. The most common and severe compartments of the lateral femoral condyle, the lateral tibial plateau, the medial femoral condyle, and the medial tibial plateau were the central-lateral (CL), the posterior-medial (PM), the CL, and the posterior-lateral (PL) compartments, respectively. CONCLUSIONS: The location patterns and severity of bone contusions in patients indicated that internal tibial rotation, valgus, and the anterior and lateral translation of the tibia were the primary mechanisms of non-contact anterior cruciate ligament injury.

Sex Difference in Contusion of the Medial Femoral Condyle Rim-Association with MRI Occult Meniscal Tears in the ACL Deficient Knee.

Background: Meniscal tears, specifically lateral meniscal tears, have a larger than expected un-derdiagnosis rate in the presence of an ACL tear. The purpose of our study was to search for an MRI bone contusion pattern associated with MRI occult meniscal tears in patients with an ACL tear, specifically a contusion of the rim of the medial femoral condyle (RMFC). Our hypothesis was that there would be a significant association between RMFC contusions and MRI occult meniscal tears in patients with an ACL tear. We also searched for a difference between sexes with respect to the presence of the RMFC contusion in the setting of an occult meniscal tear. We also categorized the type, size, and location of these occult meniscal tears in the setting of an ACL tear. Methods: This was a retrospective study that examined characteristics of occult meniscal tears and their association with a RMFC bone contusion. IRB approval was obtained. The date range of the study was June 2009 through December 2015. 6392 consecutive knee MRI reports in patients with an ACL deficient knee were reviewed. The study group included 22 patients with MRI occult meniscal tears, the control group included 110 patients. Relevant statistical values were calculated. Results: The most common type of occult meniscal tears were small radial and small longitudinal tears of the lateral meniscus. Occult meniscal tears were associated with an RMFC contusion in the study group (p=0.0457), particularly in males (p = 0.0003). In males with a torn ACL, the sensitivity of an RMFC contusion for an occult meniscal tear was 80%. Conclusion: In males with an ACL tear, there was a significant association between a contusion of the RMFC and an occult meniscal tear (commonly small radial or small peripheral partial-thickness longitudinal tears). RMFC contusions were reliably identified by radiologists in this study.Level of Evidence: II.

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°.

Evaluation of Anterolateral Ligament Healing After Anatomic Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Few studies have reported the healing process of anterolateral ligament (ALL) injuries. PURPOSE/HYPOTHESIS: This study investigated the healing status of ALL injuries after primary anterior cruciate ligament (ACL) reconstruction (ACLR). Additionally, we investigated the association between the healing status of ALL injuries and associated lesions such as osseous lesions and meniscal tears occurring at the time of an ACL rupture. We hypothesized that acute ALL injuries show a high rate (more than two-thirds) of healing at the 1-year follow-up after ACLR and that concomitant lesions observed at the time of an ACL rupture affect the healing status of the ALL. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: We retrospectively investigated patients with ALL injuries who underwent primary ACLR between March 2015 and February 2017. Using magnetic resonance imaging (MRI), we evaluated the features of ALL injuries and concomitant lesions, and MRI was performed at the 1-year follow-up to assess the healing status of the ALL. We investigated the association between the healing status of the ALL and concomitant lesions observed at the time of an ACL rupture. A subjective assessment was performed using the Lysholm score, International Knee Documentation Committee subjective score, and Tegner activity scale. Objective tests included an isokinetic strength assessment and functional performance testing. RESULTS: With respect to the severity of ALL injuries, of 54 patients, a complete rupture occurred in 16 (29.6%) of the 54 patients and a partial rupture in 38 (70%). A significant association was observed between the severity of ALL injuries and bone contusions (lateral tibial plateau and medial tibial plateau [MTP]) and meniscus ramp lesions (Fisher exact test: P = .023, .012, and .023, respectively). Good and partial healing of the ALL occurred in 16 (29.6%) and 23 (42.6%) of 54 patients, respectively. Scar formation occurred in 12 (22.2%), and nonvisualization of the ALL was observed in 3 (5.6%) of 54 patients. Poor healing of the ALL was associated with preoperative MTP bone contusions and a high-grade pivot shift. Multivariate analysis showed that an MTP bone contusion was an independent risk factor associated with poor healing of the ALL. Among the functional tests performed, significant differences were observed between the good and poor healing groups with respect to the carioca test (P = .039). The good healing group (n = 16) showed a negative pivot shift at the last follow-up, whereas 5 (13.2%) of the patients from the poor healing group (n = 38) showed a positive pivot shift, including 2 (5.3%) with a high-grade pivot shift. CONCLUSION: Approximately 70% of acute ALL injuries showed poor healing at the 1-year follow-up. Poor healing of ALL injuries was significantly associated with preoperative MTP bone contusions and a high-grade pivot shift. Therefore, a careful assessment of posteromedial bone contusions at the time of an ACL rupture is warranted, particularly in patients with a high-grade pivot shift.

Determination of the Position of the Knee at the Time of an Anterior Cruciate Ligament Rupture for Male Versus Female Patients by an Analysis of Bone Bruises.

BACKGROUND: The incidence of anterior cruciate ligament (ACL) ruptures is 2 to 4 times higher in female athletes as compared with their male counterparts. As a result, a number of recent studies have addressed the hypothesis that female and male patients sustain ACL injuries via different mechanisms. The efficacy of prevention programs may be improved by a better understanding of whether there are differences in the injury mechanism between sexes. Hypothesis/Purpose: To compare knee positions at the time of a noncontact ACL injury between sexes. It was hypothesized that there would be no differences in the position of injury. STUDY DESIGN: Controlled laboratory study. METHODS: Clinical T2-weighted magnetic resonance imaging (MRI) scans from 30 participants (15 male and 15 female) with a noncontact ACL rupture were reviewed retrospectively. MRI scans were obtained within 1 month of injury. Participants had contusions associated with an ACL injury on both the medial and lateral articular surfaces of the femur and tibia. Three-dimensional models of the femur, tibia, and associated bone bruises were created via segmentation on MRI. The femur was positioned relative to the tibia to maximize bone bruise overlap, thereby predicting the bone positions near the time of the injury. Flexion, valgus, internal tibial rotation, and anterior tibial translation were measured in the predicted position of injury. RESULTS: No statistically significant differences between male and female patients were detected in the position of injury with regard to knee flexion ( P = .66), valgus ( P = .87), internal tibial rotation ( P = .26), or anterior tibial translation ( P = .18). CONCLUSION: These findings suggest that a similar mechanism results in an ACL rupture in both male and female athletes with this pattern of bone bruising. CLINICAL RELEVANCE: This study provides a novel comparison of male and female knee positions at the time of an ACL injury that may offer information to improve injury prevention strategies.

Bone contusion progression from traumatic knee injury: association of rate of contusion resolution with injury severity.

BACKGROUND: Bone contusions are frequently encountered in magnetic resonance imaging (MRI) evaluation of knee anterior cruciate ligament (ACL) injuries. Their role as indicators of injury severity remains unclear, primarily due to indeterminate levels of joint injury forces and to a lack of preinjury imaging. PURPOSE: The purpose of this study was to 1) quantify bone contusion pathogenesis following traumatic joint injuries using fixed imaging follow-ups, and 2) assess the feasibility of using longitudinal bone contusion volumes as an indicator of knee injury severity. STUDY DESIGN: Prospective sequential MRI follow-ups of a goat cohort exposed to controlled stifle trauma in vivo were compared to parallel clinical MRI follow-ups of a human ACL tear patient series. METHODS: Reproducible cartilage impact damage of various energy magnitudes was applied in a survival goat model, coupled with partial resection of anterior portions of medial menisci. Both emulate injury patterns to the knee osteochondral structures commonly encountered in human ACL injury imaging as well as instability from resultant ligament laxity. Longitudinal clinical MRI sequences portrayed stifle bone contusion evolution through 6 months after the inciting event. RESULTS: In the first 2 weeks, biological response variability dominated the whole-joint response with no apparent correlation to trauma severity. Control goats subjected to partial meniscectomy alone exhibited minimal bone response. Thereafter, 0.6 J impact bone contusions portrayed a faster rate of resolution than those induced by 1.2 J cartilage impacts. CONCLUSION: Bone contusion sizes combined with time of persistence are likely better measures of joint injury severity than isolated bone contusion volume.