Lateral Notch Sign Research Articles

The presence of a deep lateral femoral notch sign in ACL-injured patients is associated with a 2.7° steeper posterior tibial slope and a 19% higher frequency of lateral meniscal injuries.

The purpose of this study was to study the relationship between the presence of a deep lateral femoral notch sign (DLFNS) in anterior cruciate ligament (ACL)-injured patients and a higher posterior lateral tibial slope (LPTS), a reduced meniscal bone angle (MBA), a higher LPTS/MBA ratio and a higher incidence of concomitant injuries in primary ACL tears. A retrospective case-control study was performed in patients submitted to primary ACL reconstruction with an available preoperative magnetic resonance imaging (MRI) scan. Patients with ACL tears and a femoral impactation with a depth ≥2 mm were assorted to the DLFNS groupand patients with ACL tear and without a DLFNS to the control group. LPTS and MBA were measured in MRI. The presence of concomitant injuries (meniscal, posterior cruciate ligament, medial collateral ligament, lateral collateral ligament and bone injuries) was assessed in MRI. Quantitative data are presented in the median ± interquartile range (IQR). There were 206 patients included in the study, with 46 patients assorted to the DLFNS group and 160 patients to the control group. In the DLFNS group, the median LPTS was 6.7° (IQR: 4.0-8.2) versus 4.0° in the control group (IQR: 2.2-6.5) (p = 0.003). The LPTS/MBA ratio was significantly higher in the DLFNS group, with a median of 0.32 (IQR: 0.19-0.44), in comparison to the control group, with a median of 0.19 (IQR: 0.11-0.31) (p < 0.001). The multivariable logistic regression analysis showed that the LPTS is an independent risk factor to having a DLFNS (odds ratio [OR] = 1.161; 95% confidence interval [CI]: 1.042-1.293, p = 0.007). There was a higher incidence of concomitant lateral meniscal injuries in the DLFNS group (67% vs. 48%, p = 0.017). In patients with ACL tears, the presence of a DLFNS is associated with a steeper lateral posterior tibial slope, as well as a higher incidence of concomitant lateral meniscal injuries. Level III.

Lateral femoral chondral lesions are more frequent when an anterior cruciate ligament tear is concomitant with a lateral femoral notch sign, but do not progress over time

BackgroundThe lateral femoral notch sign (LFNS) is caused by an impact to the lateral femoral condyle during a pivot shift injury and affects 25% to 33% of patients with an anterior cruciate ligament (ACL) rupture. The primary aim of this study was to compare the incidence of chondral lesions 1year after ACL reconstruction, while taking into consideration preoperative chondral damage, in patients with and without a preoperative LFNS. The primary outcome measure was the presence of chondral lesions involving the lateral femoral condyle, confirmed on magnetic resonance imaging (MRI) using the Outerbridge classification, at 1year postoperative. The secondary outcome measures were bone bruise of the lateral femoral condyle confirmed on MRI, the International Knee Documentation Committee (IKDC), Lysholm and Tegner functional scores taken 1year after surgery. MethodsSixty patients were included—30 with preoperative LFNS and 30 without—in a retrospective, comparative study of prospectively collected data on patients operated between August 2018 and December 2020. ResultsA lateral femoral chondral lesion 1year after surgery was significantly more common in the group with a preoperative LFNS (37% [n=11] versus 13% [n=4] in the group without a preoperative LFNS, p=0.036). Adjusting the statistical analysis for preoperative body mass index (BMI) did not impact these results (adjusted odds ratio [OR]=3.83 [95%CI: 1.03–14.24]; p=0.045). Adjusting for a preoperative lateral femoral chondral lesion had an impact on these results (adjusted OR=0.78 [95%CI: 0.12–5.08]; p=0.793). This indicates that a preoperative LFNS is not significantly and independently associated with a lateral femoral chondral lesion at 1year postoperative when the analysis is adjusted for a preoperative lateral femoral chondral lesion. However, having a preoperative lateral femoral chondral lesion is significantly correlated with the presence of a lateral femoral chondral lesion 1year after the surgery (adjusted OR=63.31 [95%CI: 5.94–674.8]; p=0.001). There were no significant differences in terms of bone bruise on MRI (p=1.0), or for the IKDC (p=0.310), Lysholm (p=0.416) and Tegner (p=0.644) functional scores. The LFNS was still present in 21 out of 30 patients (70%) at 1year postoperative. The preoperative LFNS was significantly smaller in the group without a chondral lesion compared to the group with a chondral lesion 1year after the surgery (median=2.30mm [IQR: 1.40; 3.00] versus 3.10mm [IQR: 2.50; 3.40]; p value=0.045). ConclusionsPatients with a preoperative LFNS are three times more likely to have a chondral lesion in the notch region 1year after surgery. These chondral lesions are concomitant to the injury and do not progress over time. Level of evidenceIII.

The posterior cruciate ligament index as a reliable indirect sign of anterior cruciate ligament rupture is associated with the course of knee joint injury.

The objective of this study was to clarify the clinical value of the posterior cruciate ligament index (PCLI) in anterior cruciate ligament (ACL) rupture, to explore the relationship between the PCLI and course of disease, and to identify the influencing factors of the PCLI. The PCLI was defined a quotient of the X (the tibial and femoral PCL attachments) and the Y (the maximum perpendicular distance from X to the PCL). A total of 858 patients were enrolled in this case-control study, including 433 patients with ACL ruptures who were assigned to the experimental group and 425 patients with meniscal tears (MTs) who were allocated to the control group. Some patients in the experimental group have collateral ligament rupture (CLR). Information, such as the patient's age, sex, and course of disease, was recorded. All patients underwent magnetic resonance imaging (MRI) preoperatively, and the diagnosis was confirmed with the aid of arthroscopy. The PCLI and the depth of the lateral femoral notch sign (LFNS) were calculated based on the MRI findings, and the characteristics of the PCLI were explored. The PCLI in the experimental group (5.1 ± 1.6) was significantly smaller than that in the control group (5.8 ± 1.6) (P < 0.05). The PCLI gradually decreased with time and was only 4.8 ± 1.4 in patients in the chronic phase (P < 0.05). This change was not due to the decrease in X but rather the increase in Y. The results also showed that the PCLI was not related to the depth of the LFNS or injuries of other structures in the knee joint. Furthermore, when the optimal cut-off point of the PCLI was 5.2 (area under the curve = 71%), the specificity and the sensitivity were 84% and 67%, respectively, but the Youden index was just 0.3 (P < 0.05). The PCLI decreases due to the increase in Y instead of the decrease in X with time, especially in the chronic phase. The change in X in this process may be offset during imaging. In addition, there are fewer influencing factors that lead to changes in the PCLI. Therefore, it can be used as a reliable indirect sign of ACL rupture. However, it is difficult to quantify the diagnostic criteria of the PCLI in clinical practice. Thus, the PCLI as a reliable indirect sign of ACL rupture is associated with the course of knee joint injury, and it can be used to describe the instability of the knee joint. III.

The lateral femoral notch sign decreases in paediatric patients following anterior cruciate ligament reconstruction

IntroductionAnterior cruciate ligament (ACL) ruptures are common amongst paediatric patients, especially those participating in competitive sports. While magnetic resonance imaging (MRI) is typically used to confirm the diagnosis, certain radiologic findings can be indicative of an ACL tear, including a lateral femoral notch sign (LFNS) > 1.5 mm (mm). No study has focussed on understanding the resolution pattern of the LFNS in paediatric patients following ACL reconstruction (ACLR). The aim of this study is to determine whether the depth of the LFNS regresses following ACLR. The authors hypothesize that following ACLR, the LFNS will resolve. MethodsAll patients who were treated for acute ACL rupture by one of two paediatric orthopaedic surgeons between 2015 and 2020 were collected; 321 patients with the age of 5–18 were collected. Patients were excluded if they underwent previous ipsilateral knee surgeries and if they did not have pre-operative knee radiographs; 274 patients met inclusion criteria. LFNS was measured on pre-operative (PreOp) and most recent post-operative (PostOp) radiographs. A comparison cohort of patients with an LFNS <1.5 mm matched by age within 1.5 years, sex, and laterality was also collected. The median difference was calculated by taking the difference between PreOp LFNS and PostOp LFNS of each participant and finding the median of those values. ResultsA total of 274 pre-operative radiographs were analysed for an LFNS depth >1.5 mm. Seventeen radiographs met these criteria with a median age of 16.3 years and a median depth of 1.70 mm. Of the 17 radiographs, 8 (47.1%) of participants were skeletally immature. The median LFNS depth at most recent follow-up and median percent decrease were 1.50 mm and 28%, respectively. Only 11.8% of patients demonstrated no change in LFNS depth from PreOp to PostOp imaging. Wilcoxon signed-rank test indicated that the PreOp LFNS was significantly greater than the PostOp LFNS (p < 0.001). Mann–Whitney U tests with cases and the comparison cohort demonstrated no difference in the percent decrease (p = 0.106). ConclusionThis study sought to understand the resolution of the LFNS depth following initial ACL rupture. At a median of 7.67 months following ACLR, the LFNS depth decreased significantly by 0.60 mm. These findings suggest that following ACL rupture, the paediatric LFNS has the potential to resolve. Future studies should aim to further assess the resolution pattern of the LFNS with advanced imaging, such as MRI.

The lateral femoral notch sign and coronal lateral collateral ligament sign in magnetic resonance imaging failed to predict dynamic anterior tibial laxity

PurposeTo investigate the relationship between the lateral femoral notch sign as well as the coronal lateral collateral ligament (LCL) sign and anterior tibial translation using the GNRB arthrometer in patients with anterior cruciate ligament (ACL) injuries.MethodsForty-six patients with ACL injuries were retrospectively included from May 2020 to February 2022; four patients were excluded due to incomplete data. Magnetic resonance imaging (MRI) were reviewed for the lateral femoral notch sign and the coronal LCL sign. The GNRB arthrometer was used to evaluate the dynamic anterior tibial translation of the knee, and the side-to-side differences (SSDs) in tibial translation between the injured knee and healthy knee were calculated at different force levels. Two types of slopes for displacement-force curves were acquired.ResultsSix patients (14.3%) had the positive lateral femoral notch sign (notch depth > 2.0 mm), and 14 patients (33.3%) had the positive coronal LCL sign. The SSD of the anterior tibial translations under different loads as well as the slopes of displacement-force curves were the same in the positive and negative notch sign groups (p all > 0.05) and between the positive and negative coronal LCL sign groups (p all > 0.05). Meanwhile, the measured notch depth and notch length were also not significantly correlated with the anterior tibial translation SSD in the GNRB.ConclusionThe presence of the lateral femoral notch sign and the coronal LCL sign did not indicate greater dynamic tibial laxity as measured using the GNRB.

Diagnostic value of the lateral femoral notch sign and kissing contusion in patients with anterior cruciate ligament injuries: a case-control study.

The lateral femoral notch sign (LFNS) and the kissing contusion (KC) are two indirect signs of anterior cruciate ligament (ACL) injuries. They can be used to diagnose ACL injuries. A total of 1000 patients were enrolled in this study, including 500 patients with ACL injuries who assigned to experimental group and 500 patients with meniscal tear (MT) who allocated to control group. All the patients underwent magnetic resonance imaging (MRI) preoperatively, and the diagnosis was confirmed with the aid of arthroscopy. The depth of LFNS and the presence of KC were determined on MRI findings. The relationship and characteristics between these two indicators was explored. The notch depth of lateral femoral condyle in the experimental group (0.99 ± 0.56mm) was significantly greater than that in the control group (0.49 ± 0.28mm) (P < 0.05). The positive rate of KC in the experimental group (183/500) was markedly higher than that in the control group (3/500) (P < 0.05). The values of notch depth in patients who had ACL rupture concomitant lateral MT injuries and medial collateral ligament (MCL) injuries were 1.12 ± 0.64 and 1.23 ± 0.74mm, respectively, which were significantly higher than those in patients with only ACL injury (0.89 ± 0.49mm) (P < 0.05). It also was revealed that when the optimal cut-off point of LFNS was 0.72mm (area under the curve (AUC) = 81%), the values of specificity and sensitivity were 67% and 84%, respectively. For KC, the corresponding values were 36.6% and 99.4%, respectively. The diagnostic outcome of LFNS was not in agreement with that of KC, as there was a poor coincidence according to the Kappa coefficient (Kappa = 0.155 < 0.4, P = 0.035). The LFNS and KC have strong clinical significance in the diagnosis of ACL injuries. A deeper notch often indicates a more complex knee injury. Notch depth equal to 0.72mm can be basically considered as the optimal cut-off point for LFNS in statistics.

Research progress of lateral femoral notch sign in diagnosis of anterior cruciate ligament rupture

To summarize the relationship between lateral femoral notch sign (LFNS) and anterior cruciate ligament (ACL) rupture. The relevant literature of LFNS at home and abroad in recent years was retrospectively reviewed, and its mechanism, diagnostic criteria and influencing factors in diagnosis of ACL rupture were summarized and analyzed. The LFNS is associated with rotational stability of the knee. As an indirect sign of ACL rupture, the LFNS has high clinical diagnostic value, especially the diagnosis of ACL rupture with lateral meniscus injury. The diagnostic criteria and influencing factors of LFNS in diagnosis of ACL rupture are still unclear and controversial, which needs further study.

Severe bicompartmental bone bruise is associated with rotatory instability in anterior cruciate ligament injury

PurposeThe presence and severity of bone bruise is more and more investigated in the non-contact anterior cruciate ligament (ACL) injury context. Recent studies have advocated a correlation between bone bruise and preoperative knee laxity. The aim of the present study was to investigate the correlation between bone bruise and preoperative rotatory knee laxity.MethodsTwenty-nine patients (29.1 ± 9.8 years) with MRI images at a maximum of 3 months after ACL injury (1.6 ± 0.8 months) were included. The bone bruise severity was evaluated according to the International Cartilage Repair Society (ICRS) scale for lateral femoral condyle, lateral tibial plateau, medial femoral condyle, and medial tibial plateau. The intraoperative rotational knee laxity was evaluated through a surgical navigation system in terms of internal–external rotation at 30° and 90° of knee flexion (IE30, IE90) and internal–external rotation and acceleration during pivot-shift test (PS IE, PS ACC). The KOOS score was also collected. The association between ICRS grade of bone bruise and rotational laxity or KOOS was investigated.ResultsSignificant correlation (p < 0.05) was found between the bone bruise severity on the medial tibial plateau and rotational laxity (IE90, PS IE, and PS ACC) and between the severity of bone bruise on femoral lateral condyle and KOOS-Symptoms sub-score. The presence of bone bruise on the medial tibial plateau was significantly associated with a lateral femoral notch sign > 2 mm (very strong odds ratio). No kinematical differences were found between none-to-deep and extensive-generalized lateral bone bruise, while higher IE30 and IE90 were found in extensive-generalized bicompartmental bone bruise than isolated extensive-generalized lateral bone bruise.ConclusionA severe bicompartmental bone bruise was related to higher rotatory instability in the intraoperative evaluation of ACL deficient knees. The severity of edema on the medial tibial plateau was directly correlated with higher intraoperative pivot shift, and the size of edema on the lateral femoral condyle was associated with lower preoperative clinical scores.Level of evidenceLevel II.

Lateral femoral notch sign and posterolateral tibial plateau fractures and their associated injuries in the setting of an anterior cruciate ligament rupture

IntroductionACL injury is one of the most common injuries of the knee joint in sports. As accompanying osseous injuries of the ACL rupture a femoral impression the so-called lateral femoral notch sign and a posterolateral fracture of the tibial plateau are described. However, frequency, concomitant ligament injuries and when and how to treat these combined injuries are not clear. There is still a lack of understanding with which ligamentous concomitant injuries besides the anterior cruciate ligament injury these bony injuries are associated.Materials and methodsOne hundred fifteen MRI scans with proven anterior cruciate ligament rupture performed at our center were retrospectively evaluated for the presence of a meniscus, collateral ligament injury, a femoral impression, or a posterolateral impression fracture. Femoral impressions were described according to their local appearance and posterolateral tibial plateau fractures were described using the classification of Menzdorf et al.ResultsIn 29 cases a significant impression in the lateral femoral condyle was detected. There was a significantly increased number of lateral meniscal (41.4% vs. 18.6% p = 0.023) and medial ligament (41.4% vs. 22.1%; p = 0.040) injuries in the group with a lateral femoral notch sign. 104 patients showed a posterolateral bone bruise or fracture of the tibial plateau. Seven of these required an intervention according to Menzdorf et al. In the group of anterior cruciate ligament injuries with posterolateral tibial plateau fracture significantly more lateral meniscus injuries were seen (p = 0.039).ConclusionIn the preoperative planning of ACL rupture accompanied with a positive femoral notch sign, attention should be paid to possible medial collateral ligament and lateral meniscus injuries. As these are more likely to occur together. A posterolateral impression fracture of the tibial plateau is associated with an increased likelihood of the presence of a lateral meniscal injury. This must be considered in surgical therapy and planning and may be the indication for necessary early surgical treatment.

High Rate of Initially Overlooked Kaplan Fiber Complex Injuries in Patients With Isolated Anterior Cruciate Ligament Injury

Background: Injuries to the Kaplan fiber complex (KFC) are not routinely assessed for in the anterior cruciate ligament (ACL)-deficient knee during preoperative magnetic resonance imaging (MRI). As injuries to the KFC lead to anterolateral rotatory instability (ALRI) in the ACL-deficient knee, preoperative detection of these injuries on MRI scans may help surgeons to individualize treatment and improve outcomes, as well as to reduce failure rates. Purpose: To retrospectively determine the rate of initially overlooked KFC injuries on routine MRI in knees with isolated primary ACL deficiency. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent isolated ACL reconstruction between August 2013 and December 2019 were identified. No patient had had Kaplan fiber (KF) injury identified on the initial reading of the MRI scan or at the time of surgery. Preoperative knee MRI scans (minimum 1.5 T) were reviewed and injuries to the proximal and distal KFs were recorded by 3 independent reviewers. KF length and distance to nearby anatomic landmarks (the lateral joint line and the lateral femoral epicondyle) were measured. Additional radiological findings, including bleeding, lateral femoral notch sign, and bone marrow edema (BME), were identified to detect correlations with KFC injury. Results: The intact KFC could reliably be identified by all 3 reviewers (85.9% agreement; Kappa, 0.716). Also, 53% to 56% of the patients with initially diagnosed isolated ACL ruptures showed initially overlooked injuries to the KFC. Injuries to the distal KFs were more frequent (48.1%, 53.8%, and 43.3% by the first, second, and third reviewers, respectively) than injuries to the proximal KFs (35.6%, 47.1%, and 45.2% by the first, second, and third reviewers, respectively). Bleeding in the lateral supracondylar region was associated with KFC injuries (P = .023). Additionally, there was a positive correlation between distal KF injuries and lateral tibial plateau BME (P = .035), but no associations were found with the lateral femoral notch sign or other patterns of BME, including pivot-shift BME. Conclusion: KF integrity and injury can be reliably detected on routine knee MRI scans. Also, 53% to 56% of the patients presenting with initially diagnosed isolated ACL ruptures had concomitant injuries to the KFC. This is of clinical relevance, as ACL injuries diagnosed by current routine MRI examination protocols may come with a high number of occult or hidden KFC injuries. As injuries to the KFC contribute to persistent ALRI, which may influence ACL graft failure or reoperation rates, significant improvements in preoperative diagnostic imaging are required to determine the exact injury pattern and to assist in surgical decision making.

The Lateral Femoral Notch Sign Is Correlated With Increased Rotatory Laxity After Anterior Cruciate Ligament Injury: Pivot Shift Quantification With A Surgical Navigation System

Background: The lateral femoral notch sign (LNS) is a bony impression on the lateral femoral condyle correlated with anterior cruciate ligament (ACL) injury. Its presence is associated with lateral meniscal injury and higher cartilage degradation on the lateral femoral condyle. Purpose/Hypothesis: The purpose was to investigate the effect of the presence and magnitude of LNS on rotatory instability. The hypothesis was that a positive LNS is correlated with a high-grade pivot shift (PS). Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 90 consecutive patients with complete ACL tears between 2013 and 2017 underwent intraoperative kinematic evaluation with the surgical navigation system and were included in the present study. The same surgeon performed a standardized PS under anesthesia. The PS was quantified through the acceleration of the lateral compartment during tibial reduction (PS ACC) and the internal-external rotation (PS IE). Presence and depth of LNS were evaluated on sagittal magnetic resonance images (1.5-T). Results: In 47 patients, the LNS was absent; in 33, the LNS depth was between 1 mm and 2 mm; and in 10 patients, it was deeper than 2 mm. Patients with a notch deeper than 2 mm showed increased PS ACC and PS IE compared with the group without the LNS. However, no significant differences were present between the group with a notch between 1 and 2 mm and the patients without LNS. Receiver operating characteristic curve analysis showed that 2 mm was the most predictive cutoff value to identify the “high-grade rotatory instability” group, with an accuracy of 77.8% and 74.4% and a specificity of 95.5% and 93.9% referred to the PS ACC and PS IE, respectively. Conclusion: The presence of a lateral LNS deeper than 2 mm could be used for the preoperative identification of patients with a high risk of increased rotatory instability.

The deep lateral femoral notch sign: a reliable diagnostic tool in identifying a concomitant anterior cruciate and anterolateral ligament injury.

The aim of the present study was to investigate the validity and reliability of the deep lateral femoral notch sign (DLFNS) in identifying a concomitant anterior cruciate ligament (ACL)/anterolateral ligament (ALL) rupture and predicting the clinical outcomes following an anatomical single-bundle ACL reconstruction. It was hypothesized that patients with a concomitant ACL/ALL rupture would have an increased DLFNS compared to patients without a concomitant ACL/ALL rupture. The lateral preoperative radiographs and MRI images of 100 patients with an ACL rupture and 100 control subjects were evaluated for the presence of a DLFNS and ACL/ALL rupture, respectively. The patients were evaluated clinically preoperatively and at a minimum 1 year following the ACL reconstruction. A receiver operator curve (ROC) analysis was performed to define the optimal cut-off value of the DLFNS for identifying a concomitant ACL/ALL injury. The relative risk (RR) was also calculated to determine whether the presence of the DLFNS was a risk factor for residual instability or ACL graft rupture following an ACL reconstruction. The prevalence of DLFNS was 52% in the ACL-ruptured patients and 15% in the control group. At a minimum 1-year follow-up, 35% (6/17) of the patients with DLFNS > 1.8mm complained of persistent instability, and an MRI evaluation demonstrated a graft re-rupture rate of 12% (2/17). In patients with a DLFNS < 1.8mm, 8% (7/83) reported a residual instability, and the graft rupture rate was 2.4% (2/83). A DLFNS > 1.8mm demonstrated a sensitivity of 89%, a specificity of 95%, a negative predictive value of 98%, and a positive predictive value of 89% in identifying a concomitant ACL/ALL rupture. Patients with a DLFNS > 1.8mm had 4.2 times increased risk for residual instability and graft rupture compared to patients with a DLFNS ≤ 1.8mm. A DLFNS > 1.8mm could be a clinically relevant diagnostic tool for identifying a concomitant ACL/ALL rupture with high sensitivity and PPV. Patients with a DLFNS > 1.8mm should be carefully evaluated for clinical and radiological signs of a concomitant ACL/ALL rupture and treated when needed with a combined intra-articular ACL reconstruction and extra-articular tenodesis to avoid a residual rotational instability and ACL graft rupture. III.

High prevalence of a deep lateral femoral notch sign in patients with anterior cruciate ligament (ACL) and concomitant posterior root tears of the lateral meniscus.

To determine the prevalence of a deep lateral femoral notch sign (LFNS) in magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) and concomitant posterior root tears of the lateral meniscus (PLRT). A retrospective chart review was conducted to identify all patients undergoing ACL reconstruction between 2016 and 2018. Based on the arthroscopic appearance of the lateral meniscus, patients were assorted to one of three groups: isolated ACL tear (ACL-Group), ACL tear with concomitant lateral meniscus tear not involving the posterolateral root (Meniscus-Group), and ACL tear with concomitant PLRT (PLRT-Group). Incidence and depth of a LFNS on preoperative MRI was compared between the three cohorts. 115 patients (mean age: 29.5 ± 11.3years) were included in the study, with 58 patients (50.4%) assorted to the ACL-Group, 24 patients (20.9%) to the Meniscus-Group, and 33 patients (28.7%) to the PLRT-Group. The prevalence of a LFNS was significantly higher in the PLRT-Group (39.4%), when compared to the ACL- (5.2%) or Meniscus-Groups (25.0%; p < 0.001, respectively). Additionally, logistic regression analysis demonstrated that patients with PLRT were 5.3 times more likely to have a LFNS as compared to those without a lateral root tear (p < 0.001). In patients with ACL tears, the presence of a LFNS on preoperative MRI may be predictive for a PLRT. As the LFNS occurs in almost 40% of the patients with combined ACL tears and PLRT, the LFNS may be a useful secondary diagnostic finding in early MRI diagnostic. Identifying PLRT on MRI is clinically relevant, as it prevents misdiagnosis and facilitates surgical decision-making, thus avoiding subsequent delayed treatment. Level IV.

Do localization and appeareance of bone bruise influence the subjective short-term outcome after ACL reconstruction?

Aims and Objectives:Large external forces in anterior cruciate ligament (ACL) injury mechanisms cause a traumatic impact between femur and tibia. Apart from concomitant intraarticular injuries like meniscal tears and chondral lesions, MRI shows a high prevalence of femorotibial bone bruise (BB) without the arthroscopic proof of macroscopic chondral defects. In recent literature, controversial results are described concerning the association between BB and subjective outcome after ACL injury. There is very limited data for the results following ACL reconstruction.Aim of this study is the evaluation of the influence of localization and appeareance of BB in isolated ACL injuries on the subjective outcome of ACL reconstruction within the first year after surgery.Materials and Methods:This study is an analysis of preoperative MRI and prospectively collected subjective functional scores in 55 patients (sex m:f = 38:17; age 33,71±11,46 years; BMI 26,08±3,44) with isolated ACL injuries without concomitant intraarticular pathologies. These patients were treated between 09/15 and 11/17 by arthroscopic ACL reconstruction with ipsilateral hamstrings.MRI evaluation was performed blinded and independently by a radiologist and a surgeon.BB was diffentiated by 8 localizations: medial/lateral femoral condyle und tibial plateau, anteriorly and posteriorly each (MFA, MFP, LFA, LFP, MTA, MTP, LTA, LTP). Classification of appeareance was done according to Costa-Paz et al. (type I-III). Demographic data and injury mechanisms were collected.Finally, localization and appeareance of BB were analyzed statistically with regard to an impact on subjective functional outcome measures - Lysholm Score (LS) and Tegner Activitiy Scale (TAS) - before surgery (t0) and at four follow-up examinations (t1-t4 within one year after ACL reconstruction.Results:The time between injury and MRI was 35,09±94,52 days, between injury and surgery 96,09±120,75 days.In 80% (n=44) non-contact injury mechanisms could be detected, sports injuries in most cases (60%).BB was found in 94,4% (n=51), the most frequent localizations were LTP (74,5%, n=41) and LFA (56,4%, n=31). A singular femoral BB could not be found.Concerning the appeareance, distribution was shown as followed: n=18 (32,7%) type I, n=26 (47,3%) type II, n=7 (12,7%) type III. In n=6 MRI revealed a depression of the lateral femoral condyle (“lateral femoral notch sign”).For the whole cohort (independently from BB) we could demonstrate a highly significant improvement for LS and TAS over time (t0/t1-t4; ANOVA, p<0,001).Neither localization nor appeareance of BB had a significant impact on LS or TAS for t0-t4.Conclusion:In conclusion, the results of the existing literature for incidence and distribution of BB in ACL injuries are confirmed. Our own data showed no influence of BB on the subjective short-term outcome following ACL reconstruction within the first year after surgery.Further studies with longer follow-up period (>2 years) and volumetric BB measurement are in preparation.

The lateral femoral notch sign: a reliable diagnostic measurement in acute anterior cruciate ligament injury

PurposeTo describe the validity and inter- and intra-observer reliability of the lateral femoral notch sign (LFNS) as measured on conventional radiographs for diagnosing acute anterior cruciate ligament (ACL) injury.MethodsPatients (≤ 45 years) with a traumatic knee injury who underwent knee arthroscopy and had preoperative radiographs were retrospectively screened for this case–control study. Included patients were assigned to the ACL injury group (n = 65) or the control group (n = 53) based on the arthroscopic findings. All radiographs were evaluated for the presence, depth and location of the LFNS by four physicians who were blind to the conditions. To calculate intra-observer reliability, each observer re-assessed 25% of the radiographs at a 4-week interval.ResultsThe depth of the LFNS was significantly greater in ACL-injured patients than in controls [median 0.8 mm (0–3.1 mm) versus 0.0 mm (0–1.4 mm), respectively; p = 0.008]. The inter- and intra-observer reliabilities of the LFNS depth were 0.93 and 0.96, respectively. Secondary knee pathology (i.e., lateral meniscal injury) in ACL-injured patients was correlated with a deeper LFNS [median 1.1 mm (0–2.6 mm) versus 0.6 mm (0–3.1 mm), p = 0.012]. Using a cut-off value of 1 mm for the LFNS depth, a positive predictive value of 96% was found.ConclusionThis was the first study to investigate the inter- and intra-observer agreement of the depth and location of the LFNS. The depth of the LFNS had a very high predictive value for ACL-injured patients and could be used in the emergency department without any additional cost. A depth of > 1.0 mm was a good predictor for ACL injury. Measuring the depth of the LFNS is a simple and clinically relevant tool for diagnosing ACL injury in the acute setting and should be used by clinicians in patients with acute knee trauma.Level of evidenceDiagnostic study, level II.

T2 relaxation times of the anterolateral femoral cartilage in patients after ACL-reconstruction with and without a deep lateral femoral notch sign

PurposeTo quantitatively assess T2 relaxation times of the anterolateral femoral cartilage following anterior cruciate ligament (ACL)-reconstruction with and without a positive deep lateral femoral notch sign (DLNS) at post-traumatic MRI. Materials and MethodsIn 52 patients post-traumatic MRI as well as 12 months after ACL-rupture (ACLR) and surgical treatment were analysed. In 28 patients a positive DLNS was present at post-traumatic MRI.For quantitative analysis, T2 relaxation time measurements (7 TE: 10–70 ms) were performed at time of re-evaluation. Three polygonal ROIs encompassing the full cartilage layer were placed in the anterolateral femoral cartilage. Clinical assessment included Lysholm-Tegner-Activity-Score, Rasmussen's clinical score and modified Cincinnati-Rating-System-Questionnaire. Description and differences were calculated as means and confidence intervals of means, controlled for the cluster effect of person, if appropriate. ResultsIn patients with a positive DLNS after ACLR, relaxation times in the notch region were significantly prolonged compared to patients without a positive DLNS (Δ 7.4 ms, CI: 5.6–9.2; p-value <0.001) as well as to the adjacent anterior (Δ 5.7 ms, CI: 4.7–6.7; p-value <0.001) and central femoral cartilage (Δ 6.6 ms, CI: 5.7–7.6; p-value <0.001).Solely insignificant differences were noticed in the performed clinical scores comparing the two groups (p > 0.05). ConclusionSignificantly prolonged T2 relaxation times of the anterolateral femoral cartilage were found in patients with a positive DLNS following ACL-reconstruction compared to patients without a DLNS. Based on these results, it has to be assumed that a positive DLNS is associated with higher cartilage degradation.

Segmentation of the lateral femoral notch sign with MRI using a new measurement technique.

BackgroundThe goal of this present study was to precisely determine the dimension and location of the impaction fracture on the lateral femoral condyle in patients with an ACL rupture.MethodsAll patients with post-injury bi-plane radiographs and MRI images after sustaining a tear to the anterior cruciate ligament were included. Lateral radiographs of the affected knee were inspected for a lateral femoral notch sign. MRIs of patients with a lateral condylopatellar sulcus ≥1.5 mm were used to segment and measure the lateral condylopatellar sulcus. The MRI examination was interpreted by an expert in musculoskeletal radiology. The study was approved by the ethics committee of the state of Salzburg.ResultsA “lateral femoral notch sign”was seen in 50 patients. The average total surface area of the lateral femoral condyle was 3271.7 mm2 (SD 739.5 mm2). The defect had a mean surface area of 266.1 mm2 (SD 125.5 mm2), a mean volume of 456.5 mm3 (SD 278.5 mm3), a mean depth of 3.0 mm (SD 0.8 mm). On average 169 mm2 (SD 99.6 mm2) of the surface of the condyle were affected by the impaction fracture which corresponds to 5.2 % (SD 2.8 %) of the surface of the lateral femoral condyle. In 51 % the impaction fracture was located in the central-external area of the femoral condyle.ConclusionsIn cases of a clinically suspected ACL rupture lateral radiographs of the knee should be checked for a lateral femoral notch sign further MRI for confirmation should be performed. Knowing of the precise defect on the lateral femoral condyle is an additionally valuable information, as concomitant injuries to a rupture of the anterior cruciate ligament increase the risk for early-onset osteoarthritis in the future.

Outcome of a Combined Anterior Cruciate Ligament and Anterolateral Ligament Reconstruction Technique With a Minimum 2-Year Follow-up

Background: The anterolateral ligament has recently been identified as an important structure involved in rotational laxity after anterior cruciate ligament (ACL) rupture. Results of a combined ACL and anterolateral ligament (ALL) reconstruction technique have never been reported. Purpose: To report subjective and objective outcomes after combined ACL and minimally invasive ALL reconstruction with a minimum 2-year follow-up. Study Design: Case series; Level of evidence, 4. Methods: A total of 92 patients underwent a combined ACL and ALL reconstruction. Indications for a combined procedure were associated Segond fracture, chronic ACL lesion, grade 3 pivot shift, high level of sporting activity, pivoting sports, and radiographic lateral femoral notch sign. Patients were assessed pre- and postoperatively with objective and subjective International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity scale. Instrumented knee testing was performed with the Rolimeter arthrometer. The Knee injury and Osteoarthritis Outcome Score (KOOS) was obtained at the last follow-up. Complications including graft failure or contralateral ACL rupture were also recorded. Results: The mean follow-up time was 32.4 ± 3.9 months. One patient (1.1%) was lost to follow-up, 1 patient (1.1%) suffered an ACL graft rupture, and 7 patients (7.6%) had a contralateral ACL rupture, leaving 83 patients for final evaluation. At the last follow-up, all patients had full range of motion. The Lysholm, subjective IKDC, and objective IKDC scores were significantly improved (all P < .0001). The Tegner activity scale at the last follow-up (7.1 ± 1.8) was slightly lower than before surgery (7.3 ± 1.7) (P < .01). The mean differential anterior laxity was 8 ± 1.9 mm before surgery and significantly decreased to 0.7 ± 0.8 mm at the last follow-up (P < .0001). Preoperatively, 41 patients had a grade 1 pivot shift, 23 had a grade 2, and 19 had a grade 3 according to the IKDC criteria. Postoperatively, 76 patients had a negative pivot shift (grade 0), and 7 patients were grade 1 (P < .0001). Conclusion: This study demonstrates that a combined reconstruction can be an effective procedure without specific complications at a minimum follow-up of 2 years. Longer term and comparative follow-up studies are necessary to determine whether these combined reconstructions improve the results of ACL treatment.

Important Signs in Musculoskeletal MRI

The purpose of this article is to review the common MRI signs of musculoskeletal pathology. In this article, 15 classic MRI signs used in musculoskeletal radiology are presented and described. These signs incl ude the anterior drawer sign, bone bruise sign, bow tie sign, celery stalk anterior cruciate ligament (ACL), cyclops lesion, deep lateral femoral notch sign, double line sign, double Oreo cookie sign, double posterior cruciate ligament (PCL) sign, fat - bloo d interface (FBI) sign, fragment in notch sign, split fat sign, T - sign, target sign, and yo - yo on a string sign. It is important to recognize common signs in musculoskeletal MRI and understand the underlying pathologies for accurate image interpretation.

The lateral femoral notch sign following ACL injury: frequency, morphology and relation to meniscal injury and sports activity.

The purpose of this study was to determine the incidence of the "lateral femoral notch sign" in acute anterior cruciate ligament (ACL) tears and its correlation with lateral meniscal tears. Lateral plain radiographs and sagittal magnetic resonance images (each performed within 1month following injury) of 500 patients with acute and arthroscopically confirmed ACL tears were retrospectively evaluated for depth, length and position of the "lateral femoral notch sign". The accompanying bone bruise was measured, as well. The correlation of the lateral femoral notch sign with high-risk and low-risk pivoting activities as well as with a lateral meniscus tear was evaluated. A total of 26.4% of the patients had a lateral femoral notch sign deeper than 2.0mm with a mean depth of 2.8±0.8mm SD. All lateral femoral notches were situated near or slightly posterior to Blumensaat's line. ACL injuries sustained during high-risk pivoting sports were more prone to a lateral femoral notch sign than ACL injuries in low-risk pivoting sports (r=0.107 vs r=-0.107). Of all patients with a lateral femoral notch sign, 40.2% also had lateral meniscus tears. The correlation between the presence of the lateral femoral notch sign and lateral meniscus tears was statistically significant (p=0.004). In more than one-quarter of patients, plain radiographs may help to establish the diagnosis of an ACL tear. Further, a lateral femoral notch sign greater than 2.0mm also correlates with lateral meniscus tears. Hence, the lateral femoral notch sign is a useful diagnostic tool in daily clinical practice. IV.