The lateral notch sign associated with acute anterior cruciate ligament disruption

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

BACKGROUND

The 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.

METHODS

Sixty 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.

RESULTS

A 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).

CONCLUSIONS

Patients 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 EVIDENCE

III.

Could medial femoral notching be a marker in posterolateral corner injuries?

INTRODUCTION

Posterolateral corner (PLC) injuries constitute 16 % of all knee ligament injuries and are often seen with other ligamentous injuries. PLC injuries can be overlooked. If left untreated, other ligamentous reconstructions are at risk, residual laxity may occur, and early osteoarthritis may result.

MATERIALS AND METHODS

Patients diagnosed with PLC injury and who underwent surgical treatment between November 2018 and November 2022 were retrospectively analyzed. Two groups were formed 44 PLC patients with a concomitant ligament injury and 50 patients with an isolated ACL injury (control group). Preoperative MRI findings and arthroscopic surgery findings of the patients were evaluated. Medial femoral condyle notching sign (MFNS) and lateral femoral condyle notching sign (LFNS) data were obtained from preoperative MRI sections. If the lesion depth was less than 1.5 mm, it was not considered a notching sign.

RESULTS

In group 1, there were 44 patients with PLC injuries accompanied by other ligamentous injuries. In group 2, there were 50 patients with isolated ACL injuries not accompanied by other ligamentous injuries. Medial femoral notching sign (MFNS) was higher in Group 1 (p < 0.00001). The lateral femoral notching sign (LFNS) was higher in Group 2 (p:0.023).

CONCLUSION

PLC injuries are difficult to diagnose. MFNS is a finding that may facilitate diagnosis in PLC injuries.

Impaction Fractures of the Lateral Femoral Condyle Related to Anterior Cruciate Ligament Injury: A Scoping Review Concerning Diagnosis, Prevalence, Clinical Importance, and Management

Background

During pivot-shift anterior cruciate ligament (ACL) injury, bone bruises or impaction fractures of the lateral femoral condyle (LFC-IF) may occur due to impaction between the posterior part of the lateral tibial plateau and anterocentral part of the LFC. The purpose of the study was to systematically review the literature concerning the diagnosis, prevalence, clinical importance, and management of LFC-IF occurring during ACL injuries.

Methods

Included were studies concerning impaction fractures of the anterocentral part of the LFC occurring during ACL injuries. Studies concerning only bone bruises or cartilage lesions, without subchondral bone impaction, were not included. A search was performed in Medline and Scopus databases, with final search in May 2022. A secondary search was conducted within the bibliographies of included articles and using "Cited In" option. Two authors independently extracted data in three domains: study design, LFC-IF characteristics, and LFC-IF importance and management.

Results

A total of 35 studies were included for review with several studies reporting on multiple domains. Summarily, 31 studies were on the diagnosis and prevalence, 19 studies reported on the clinical importance, and 4 studies reported on the management of LFC-IF.

Conclusions

A LFC-IF occurs due to the pivot-shift mechanism of ACL injury. Its radiological feature is defined as an impaction of terminal sulcus deeper than 1 mm and is present in up to 52% of patients with a torn ACL. An LFC-IF causes injury to the cartilage, probably leads to its progressive degeneration, and is significantly associated with an increased risk of a lateral meniscus injury. A large LFC-IF might be associated with greater rotational knee instability. Although several techniques of LFC-IF treatment were proposed, none of them has been evaluated on a large cohort of patients to date.

Pivot Shift Syndrome of the Knee

The pivot shift test, in contrast to the Lachman or anterior drawer, is a manually subjective clinical test that simulates the injury mechanism. It is the most sensitive test to determine ACL insufficiency. This paper reviews the history, development, research, and treatment associated with the pivot shift phenomenon which is associated with tearing and loss of function of the knee anterior cruciate ligament. The pivot shift test most closely recapitulates what the symptomatic anterior cruciate ligament deficient patient feels is happening which is an abnormal translation and rotation of the injured joint during flexion or extension. The test is best conducted in the relaxed patient by applying knee flexion, tibial external rotation, and valgus stress. The pivot shift biomechanics and treatment measures are reviewed.

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

INTRODUCTION

Anterior 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.

METHODS

All 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.

RESULTS

A 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).

CONCLUSION

This 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.

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

INTRODUCTION

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.

MATERIALS AND METHODS

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.

RESULTS

The notch depth of lateral femoral condyle in the experimental group (0.99 ± 0.56 mm) was significantly greater than that in the control group (0.49 ± 0.28 mm) (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 ± 0.74 mm, respectively, which were significantly higher than those in patients with only ACL injury (0.89 ± 0.49 mm) (P < 0.05). It also was revealed that when the optimal cut-off point of LFNS was 0.72 mm (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).

CONCLUSION

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 0.72 mm can be basically considered as the optimal cut-off point for LFNS in statistics.

Anterior Tibial Subluxation of Lateral Compartment Is Associated With High-Grade Rotatory Instability for Acute But Not Chronic Anterior Cruciate Ligament Injuries: An Magnetic Resonance Imaging Case-Control Study

PURPOSE

To investigate whether anterior tibial subluxation obtained from magnetic resonance imaging (MRI) could be a predictor of high-grade rotatory instability for anterior cruciate ligament (ACL) injuries, including acute and chronic cases.

METHODS

From September 2016 to August 2018, we retrospectively investigated 163 patients with ACL injuries who subsequently underwent primary ACL reconstruction. Among them, 30 patients with high-grade rotatory instability (grade II/III pivot shift) were included in the high-grade group, and their age and sex were matched 1:2 to low-grade cases (<grade II pivot shift). On preoperative MRI, we measured anterior tibial subluxation, posterior tibial slope, as well as the time from injury to surgery. Meniscal lesions were documented from arthroscopy. Multivariable logistic regression was used to determine predictors of high-grade rotatory instability. Furthermore, subgroup comparisons between 2 groups were divided into acute (≤3 months) and chronic (>3 months) phases.

RESULTS

The high-grade group had a larger anterior tibial subluxation of lateral compartment (8.1 mm vs 5.9 mm; P =.004) than the low-grade group, whereas no significant difference was found in anterior tibial subluxation of medial compartment (P > .05). Moreover, high-grade anterior tibial subluxation of lateral compartment (≥6 mm) was found to be an independent predictor (odds ratio, 12.992; P = .011) associated with concomitant meniscal tears after ACL injuries. Anterior tibial subluxation of lateral compartment demonstrated statistical significance between the two groups when comparing subgroups within 3 months but not beyond 3 months.

CONCLUSION

In ACL-injured patients, high-grade anterior tibial subluxation of lateral compartment (≥6 mm) could be a unique predictor of high-grade knee rotatory instability for acute but not chronic injuries. Prolonged time from injury to surgery and lateral meniscus tears were risk factors for high-grade rotatory laxity in chronic patients.

LEVEL OF EVIDENCE

Level III, retrospective prognostic trial.

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

Purpose

To 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.

Methods

Forty-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.

Results

Six 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.

Conclusion

The presence of the lateral femoral notch sign and the coronal LCL sign did not indicate greater dynamic tibial laxity as measured using the GNRB.

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

Objective

To summarize the relationship between lateral femoral notch sign (LFNS) and anterior cruciate ligament (ACL) rupture.

Methods

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.

Results

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.

Conclusion

The diagnostic criteria and influencing factors of LFNS in diagnosis of ACL rupture are still unclear and controversial, which needs further study.

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

PURPOSE

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).

METHODS

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.

RESULTS

115 patients (mean age: 29.5 ± 11.3 years) 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).

CONCLUSION

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 OF EVIDENCE

Level IV.

Arthroscopy-assisted surgery: The management of posterolateral tibial plateau depression fracture accompanying ligament injury: A case series and review of the literature

Tibial plateau fractures are multiple fracture patterns associated with soft-tissue injuries. Among which, the combined existence of posterolateral tibial plateau depression fracture with anterior cruciate ligament (ACL) rupture has been reported rarely. Meanwhile, surgical method for the treatment of depression fracture is fairly complex. The aim of this article is to show a case series of this unusual injury pattern and the therapy of posterolateral tibial plateau depression fracture accompanying ACL rupture. In our treatment, arthroscopy assisted reduction of depression fracture and ACL reconstruction reduces surgical trauma and leads to good functional recovery. We also review the current literature.

Fate of the lateral femoral notch following early anterior cruciate ligament reconstruction

BACKGROUND

The goal of this longitudinal study was to investigate the fate of the lateral femoral notch (LFN), which is frequently seen as an impaction fracture of the lateral femoral condyle in patients with anterior cruciate ligament (ACL) tears.

METHODS

Patients who underwent early ACL reconstruction between 2006 and 2010 were reviewed. If post-injury magnetic resonance images showed an LFN greater than 1.5 mm in depth, patients with untreated LFN were followed. Two blinded observers performed quantitative and qualitative imaging analysis.

RESULTS

Sixteen patients (five women, 11 men) were available for follow-up nine years (six to 10 years) post-injury. The median defect area of the LFN significantly decreased from 2.3 cm² (range: 0.9-3.8 cm²) to 1.6 cm² (range: 0.4-3.2 cm²) (P < .001). The defect depth did not significantly change from 2.3 mm (range: 2.0-3.6 mm) to 2.5 mm (range: 1.3-3.6 mm) (P > .05). The International Cartilage Repair Society (ICRS) score increased from 1.5 (range: 0-3) post-injury to 2.0 (range: 0-4) at follow-up (P < .01). The Lysholm score was 93 (72-100), the Tegner activity level was 6 (3-9) and the knee injury and osteoarthritis outcome score (KOOS) score was 97 (91-100).

CONCLUSIONS

The defect area of the LFN decreased overtime, whereas the depth of the impression remained. Focal cartilage lesions were found in all except two patients post-injury and progressed during follow-up. However, patient-reported outcome scores were satisfying.

Triaxial accelerometer evaluation is correlated with IKDC grade of pivot shift

PURPOSE

The purpose of this study was to evaluate the correlation between tibial acceleration parameters measured by the KiRA device and the clinical grade of pivot shift. The secondary objective was to report the risk factors for pre-operative high-grade pivot shift.

METHODS

Two-hundred and ninety-five ACL deficient patients were examined under anesthesia. The pivot shift tests were performed twice by an expert surgeon. Clinical grading was performed using the International Knee Documentation Committee (IKDC) scale and tibial acceleration data was recorded using a triaxial accelerometer system (KiRA). The difference in the tibial acceleration range between injured and contralateral limbs was used in the analysis. Correlation coefficients were calculated using linear regression. Multivariate logistic regression was used to identify risk factors for high grade pivot shift.

RESULTS

The clinical grade of pivot shift and the side-to-side difference in delta tibial acceleration determined by KiRA were significantly correlated (r = 0.57; 95% CI 0.513-0.658, p < 0.0001). The only risk factor identified to have a significant association with high grade pivot shift was an antero-posterior side to side laxity difference > 6 mm (OR = 2.070; 95% CI (1.259-3.405), p = 0.0042).

CONCLUSION

Side-to-side difference in tibial acceleration range, as measured by KiRA, is correlated with the IKDC pivot shift grade in anaesthetized patients. Side-to-side A-P laxity difference greater than 6 mm is reported as a newly defined risk factor for high grade pivot shift in the ACL injured knee.

DIAGNOSTIC STUDY

Level II.

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

PURPOSE

To 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.

METHODS

Patients (≤ 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.

RESULTS

The 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.

CONCLUSION

This 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 EVIDENCE

Diagnostic study, level II.

Lateral femoral notch depth is not associated with increased rotatory instability in ACL-injured knees: a quantitative pivot shift analysis

PURPOSE

A deep lateral femoral notch (LFN) on lateral radiographs is indicative of ACL injury. Prior studies have suggested that a deep LFN may also be a sign of persistent rotatory instability and a concomitant lateral meniscus tear. Therefore, the purpose of this study was to evaluate the relationship between LFN depth and both quantitative measures of rotatory knee instability and the incidence of lateral meniscus tears. It was hypothesized that greater LFN depth would be correlated with increased rotatory instability, quantified by lateral compartment translation and tibial acceleration during a quantitative pivot shift test, and incidence of lateral meniscus tears.

METHODS

ACL-injured patients enrolled in a prospective ACL registry from 2014 to 2016 were analyzed. To limit confounders, patients were only included if they had primary ACL tears, no concurrent ligamentous or bony injuries requiring operative treatment, and no previous knee injuries or surgeries to either knee. Eighty-four patients were included in the final analysis. A standardized quantitative pivot shift test was performed pre-operatively under anesthesia in both knees, and rotatory instability, specifically lateral compartment translation and tibial acceleration, was quantified using tablet image analysis software and accelerometer sensors. Standard lateral radiographs and sagittal magnetic resonance images (MRI) of the injured knee were evaluated for LFN depth.

RESULTS

There were no significant correlations between LFN depth on either imaging modality and ipsilateral lateral compartment translation or tibial acceleration during a quantitative pivot shift test or side-to-side differences in these measurements. Patients with lateral meniscus tears were found to have significantly greater LFN depths than those without on conventional radiograph and MRI (1.0 vs. 0.6 mm, p < 0.05; 1.2 vs. 0.8 mm, p < 0.05, respectively).

CONCLUSION

There was no correlation between lateral femoral notch depth on conventional radiographs or MRI and quantitative measures of rotatory instability. Concomitant lateral meniscus injury was associated with significantly greater LFN depth. Based on these findings, LFN depth should not be used as an indicator of excessive rotatory instability, but may be an indicator of lateral meniscus injury in ACL-injured patients.

LEVEL OF EVIDENCE

Prognostic level IV.

Risk Factors Associated With Grade 3 Pivot Shift After Acute Anterior Cruciate Ligament Injuries

BACKGROUND

Recent literature has demonstrated that involvement in pivoting sports at the time of injury, increased posterior-inferior tibial slope (PITS), anterolateral capsular ligament (ALCL) disruptions, and combined lateral meniscal lesions all contribute to a higher grade of pivot shift after acute anterior cruciate ligament (ACL) injuries.

PURPOSE

To identify risk factors associated with grade 3 pivot shift after acute ACL injuries.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A database of patients undergoing primary ACL reconstruction from 2009 to 2015 after acute ACL injuries was retrospectively reviewed. A total of 30 patients (30 knees) with grade 3 pivot shift were identified as the study group. Moreover, 30 patients (30 knees) with grade 1 and 30 patients (30 knees) with grade 2 pivot shift were randomly chosen as the 2 control groups. All pivot-shift tests were performed with the patients under anesthesia. Predictors of grade 3 pivot shift that were explored included patient age, sex, time from injury to surgery, pivoting sports involvement at the time of injury, lateral PITS, medial PITS, ALCL disruptions, preoperative KT-1000 arthrometer side-to-side difference, and combined lateral or medial meniscal lesions. Comparisons were performed between the study group and the 2 control groups. Univariable and multivariable logistic regressions were used to identify independent risk factors that were associated with grade 3 pivot shift.

RESULTS

Univariable and multivariable logistic regressions between the study group and the 2 control groups showed that pivoting sports involvement at the time of injury (odds ratio1 [OR1; grade 3 vs grade 1 pivot shift with grade 1 = reference], 11.88; 95% CI, 1.94-149.91; OR2 [grade 3 vs grade 2 pivot shift with grade 2 = reference], 3.41; 95% CI, 1.92-22.60), abnormal degree of lateral PITS (OR1, 14.41; 95% CI, 1.69-174.78; OR2, 6.41; 95% CI, 1.48-47.70), ALCL disruptions (OR1, 8.28; 95% CI, 1.71-117.14; OR2, 4.96; 95% CI, 1.07-28.75), and combined lateral meniscal lesions (OR1, 27.56; 95% CI, 5.48-240.52; OR2, 5.83; 95% CI, 1.21-38.56) were independent risk factors of grade 3 pivot shift after acute ACL injuries.

CONCLUSION

For acute ACL injuries, the best set of predictors of grade 3 pivot shift were pivoting sports involvement at the time of injury, abnormal lateral PITS, ALCL disruptions, and combined lateral meniscal lesions. These results may provide additional information for counseling patients on residual laxity and risks for graft rerupture after ACL reconstruction.

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

PURPOSE

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.

METHODS

Lateral plain radiographs and sagittal magnetic resonance images (each performed within 1 month 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.

RESULTS

A total of 26.4 % of the patients had a lateral femoral notch sign deeper than 2.0 mm with a mean depth of 2.8 ± 0.8 mm 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).

CONCLUSION

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 2.0 mm also correlates with lateral meniscus tears. Hence, the lateral femoral notch sign is a useful diagnostic tool in daily clinical practice.

LEVEL OF EVIDENCE

IV.

Two Cases of Contact Anterior Cruciate Ligament Rupture Combined with a Posterolateral Tibial Plateau Fracture

Background. The combined occurrence of ACL rupture with a posterolateral tibial plateau fracture has not yet been reported. Two cases of such injuries have been treated in our department for the past three years. Findings. The two patients both suffered injuries from traffic accidents. The radiological examinations showed a ruptured ACL with fracture of the posterolateral tibial plateau. Reconstruction of the ACL was performed via a standard anatomical single bundle ACL reconstruction technique with autologous tendon by arthroscopy. A posterolateral tibia plateau approach was used to reduce and fix the fractured area with the aid of lag screws. After a one-year follow-up, the two patients recovered well and physical examinations showed full knee range of motion with no evidence of ACL instability. Conclusions. The cause of this type injury of ACL rupture with a posterolateral tibial plateau fracture was thought to be by a violent internal tibial rotation/anterior tibial translation without any valgus or varus knee force mechanism during the accident. Satisfactory clinical results were achieved with a standard anatomical single bundle ACL reconstruction by arthroscopy and ORIF for the posterolateral plateau fracture. Both patients reported excellent knee function and fracture healing.

Deep lateral notch sign and double notch sign in complete tears of the anterior cruciate ligament: MR imaging evaluation

OBJECTIVE

To systematically compare the notches of the lateral femoral condyle (LFC) in patients with and without complete tears of the anterior cruciate ligament (ACL) in MR studies by (1) evaluating the dimensions of the lateral condylopatellar sulcus; (2) evaluating the presence and appearance of an extra or a double notch and its association with such tears.

MATERIALS AND METHODS

This retrospective study was approved by our institutional review board, and informed written patient consent was waived. In 58 cases of complete ACL tears and 37 control cases with intact ACL, the number of notches on the LFC was determined, and the depth and anteroposterior (AP) length of each notch were measured in each third of the LFC. The chi-square test, t-test, and logistic regression model were used to analyze demographic data and image findings, as appropriate.

RESULTS

Presence of more than one notch demonstrated a sensitivity of 17.2%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 43.5% for detecting a complete ACL tear. Lateral third depth measurement (p = 0.028) was a significant associated finding with a complete ACL tear.

CONCLUSION

A deep notch in the lateral third of the LFC is a significant associated finding with a complete ACL tear when compared with an ACL-intact control group, and the presence of more than one notch is a specific but insensitive sign of such a tear.

Radiographic evidence of anterior cruciate ligament insufficiency

Anterior cruciate ligament (ACL) tears are commonly seen injuries. Initially, these injuries are routinely evaluated with radiographs, followed by magnetic resonance imaging (MRI). The altered kinematics at the time of injury or for the duration of a chronic tear can create indirect findings on radiographs and MRI. These signs may help establish a diagnosis of an ACL tear or the chronicity of the injury. This article discusses these signs.

Defining the terms acute and chronic in orthopaedic sports injuries: a systematic review

BACKGROUND

Although many authors report on acute injuries and chronic injuries in the orthopaedic literature, the actual terms are seldom explicitly defined.

HYPOTHESIS

Much of the literature pertaining to sports injuries that are acute or chronic does not define these terms. It is believed that definitions will provide clarity and specificity in future literature.

STUDY DESIGN

Systematic review.

METHODS

A systematic review of 116 articles was conducted to determine whether and how the terms acute and chronic were defined as they pertain to several commonly treated conditions: Achilles tendon rupture, distal biceps tendon rupture, pectoralis major tendon rupture, anterior cruciate ligament (ACL) tear, anterior shoulder instability, and acromioclavicular (AC) joint dislocation. Articles were isolated from various databases and search engines by use of keywords to identify relevant literature.

RESULTS

This study determined that the terms acute and chronic for each injury are defined, respectively, as follows: Achilles tendon rupture: <1 week, >4 weeks; distal biceps tendon rupture: <6 weeks, >12 weeks; pectoralis major tendon rupture: <6 weeks, >6 weeks; ACL tear: <6 weeks, >6 months; anterior shoulder instability: <2 weeks, >6 months; AC joint dislocation, <3 weeks, >6 weeks.

CONCLUSION

The current literature varies greatly in defining the terms acute and chronic in common sports injuries. The vast majority of authors imply these terms, based on the method of their studies, rather than define them explicitly. Injuries involving tendons showed greater consistency among authors, thus making a definition based on consensus easier to derive. The literature on ACL and shoulder instability in particular showed great variability in defining these terms, likely representing the more complex nature of these injuries and the fact that timing of surgery in the majority of patients does not particularly affect the complexity of the surgical approach and treatment.

CLINICAL RELEVANCE

Defining injuries as acute or chronic is clinically relevant in many cases, particularly concerning tendon injuries, where these terms have implications regarding the anatomic pathologic changes and tissue quality, which may necessitate augmentation and alter the initial surgical plan. In cases where these terms are less pertinent to operative treatment considerations, they bring clarity to the discussion of the acuity of the injury (as it pertains to time from insult).

Acute traumatic knee radiographs: beware of lesions of little expression but of great significance

Knee radiographs are the first imaging modality performed in acute knee trauma, and in most of cases, the findings are obvious. Nevertheless, sometimes, only subtle clues can indicate a potentially more severe underlying abnormality, such as ligamentous, tendinous or meniscal tears. Knowledge of the origin of such signs and of the related underlying injury mechanism, might lead to additional imaging investigation, which may facilitate appropriate patient work-up and prevent consequences of delayed treatment.

Displaced osteochondral fracture of the lateral femoral condyle associated with an acute anterior cruciate ligament avulsion fracture: a corollary of "the lateral femoral notch sign"

Anterior cruciate ligament (ACL) rupture is usually accompanied by bone contusions resulting from impact of tibia on femur. The injury sometimes becomes manifest as a depression on the lateral femoral condyle giving rise to "lateral femoral notch" sign. The authors describe a rare case of impaction of the tibia and femur resulting in an osteochondral fracture rather than the usual bone contusion, which frequently occurs with ACL rupture. Open reduction and internal fixation of both the ACL avulsion fracture and the osteochondral fracture from the lateral femoral condyle were done, and the patient had a good outcome at 1-year follow-up. Level of evidence V.

Combined osteochondral fracture of the posterolateral tibial plateau and Segond fracture with anterior cruciate ligament injury in a skeletally immature patient

A case of a 14-year-old boy with a rare injury--an osteochondral fracture of the posterolateral tibial plateau associated with the anterior cruciate ligament (ACL) rapture, and Segond fracture characterized by an avulsion fracture of the lateral tibial plateau--is reported. This case was noteworthy because it involved a rare combination of ACL injuries. This injury was thought to be caused by the impaction between the posterior aspect of the lateral tibial plateau and the lateral femoral condyle during internal rotational displacement of the knee joint at the time of injury, because the osteochondral fracture of the posterolateral tibial plateau matched the site where the bone bruise was observed.

Gender differences in the knees of Chinese population

The goal of this study was to characterize the geometry of the distal femur and proximal tibia in the Chinese population. Three-dimensional models of twenty female and twenty male knees were constructed using CT images. The morphologic measurements of the distal femur included mediolateral (ML) and anteroposterior dimension of medial and lateral condyles (MAP, LAP), femoral aspect ratio (ML/LAP), medial and lateral condylar width, intercondylar notch width, notch width index (NWI), and trochlear groove orientation. The sagittal profiles of the medial and lateral femoral condyles and tibial plateaus were also characterized. The results showed that the size of the distal femur of the females was significantly smaller than that of the males. Furthermore, when normalized by LAP, the females had a significantly narrower distal femur (ML), and a shorter MAP compared to the males. In the sagittal plane, the radius of the lateral distal circle of the femur was significantly smaller than that of the medial condyle in both genders. There were no significant gender differences in the proximal tibial geometry. The data of the present study may enable suitable modification of total knee prosthesis sizing/geometry for Asia-Pacific patients.

Arthroscopic treatment of a large lateral femoral notch in acute anterior cruciate ligament tear

A 24-year-old professional soccer player suffered an acute anterior cruciate ligament tear associated with a radiologically evident impression fracture of the lateral femoral condyle, the so-called "lateral femoral notch sign". Following MRI validation of the injury with detection of an additional lateral meniscus tear, arthroscopy was carried out 3 days after the injury. Due to the extended impression of about 5 mm, arthroscopically assisted closed reduction of the depression fracture was performed. A 3.2 mm tunnel was drilled at the lateral femoral condyle in a supero-inferior direction using an ACL tibial guide and the depressed area could be restored using an elevator. The resulting subchondral bone defect in the femoral condyle was filled with freeze-dried human cancellous bone allograft. As a one-stage procedure ACL reconstruction was carried out using a hamstring tendon technique. At 1-year follow up the patient has returned to full sporting function, including playing soccer with a radiographically reduced lateral femoral notch sign.

Arthroscopically assisted reduction of a lateral femoral notch in acute tear of the anterior cruciate ligament

We report the case of a 20-year-old soccer player who suffered a tear of the anterior cruciate ligament with a depression fracture of the lateral femoral condyle. In addition to repairing the ligament we were able to arthroscopically reduce the depression fracture using a bioabsorbable screw. We tamped the surrounding cancellous bone with dilatators and chisels to create a bearing for an interference screw. This prepared for the placing of the screw and resulted in a sufficient reshaping of the condyle. We then inserted a threaded bioabsorbable interference screw into the lateral condyle under arthroscopic guidance to reline the fracture and reduce joint incongruity. Postoperative magnetic resonance imaging showed a significant reduction of the fracture.