Association of femoral intercondylar notch morphology, width index and the risk of anterior cruciate ligament injury

Decreased sagittal slope of the medial tibial spine and deep concavity of the lateral tibial spine are risk factors for noncontact anterior cruciate ligament injury

PURPOSE

This study aimed to assess the relationship between the geometric features of tibial eminence and susceptibility to noncontact anterior cruciate ligament (ACL) injuries.

METHODS

Patients with unilateral noncontact knee injuries between 2015 and 2021 were consecutively enroled in this study. Based on knee magnetic resonance imaging (MRI) and arthroscopic visualisation, patients were categorised into the case group (ACL rupture) and control group (ACL intact). Using MRI, the geometric features of tibial eminence were characterised by measuring the sagittal slopes, depth of concavity and coronal slopes of the inclined surfaces of the tibial spines. Univariate and multivariate logistic regressions were conducted to explore independent associations between quantified geometric indices of tibial eminence and the risk of noncontact ACL injuries.

RESULTS

This study included 187 cases and 199 controls. A decreased sagittal slope of the medial tibial spine (MTSSS) (combined group: odds ratio [OR]: 0.87 [0.82, 0.92], p < 0.001; females: OR: 0.88 [0.80, 0.98], p = 0.020; males: OR: 0.87 [0.81, 0.93], p < 0.001) and an increased depth of concavity in the lateral tibial spine (LTSD) (combined group: OR: 1.51 [1.24, 1.85], p < 0.001; females: OR: 1.65 [1.12, 2.43], p = 0.012; males: OR: 1.44 [1.11, 1.89], p = 0.007) were independent risk factors for noncontact ACL injuries. Moreover, a steeper coronal slope of the inclined surface of the medial tibial spine was a significant predictor of noncontact ACL injuries for males (MTSCS: OR: 1.04 [1.01, 1.08], p = 0.015) but not for females.

CONCLUSION

Geometric features of tibial eminence, particularly a decreased MTSSS and an increased LTSD, were identified as independent risk factors for noncontact ACL injuries. These findings will help clinicians identify individuals at high risk of ACL injury and facilitate the development of targeted prevention strategies.

LEVEL OF EVIDENCE

Level III.

Evaluation of Bony Femoral Morphological Parameters in Anterior Cruciate Ligament Injury Using Magnetic Resonance Imaging: A Retrospective Unmatched Case-Control Study

Background Over time, there has been a noticeable increase in anterior cruciate ligament (ACL) injuries. The current imperative is to anticipate predisposing factors and proactively prevent ACL injuries. The occurrence of ACL injuries has been linked to diverse factors associated with the morphology of the distal femur. Objectives Through this study, we aim to compare the anatomic variables of distal femur morphology such as notch width (NW), bicondylar width (BW), notch entrance width (NEW), and notch width index (NWI) between patients with ACL injuries and non-injured patients using MRI. We also aim to make a comparison of these factors between male and female genders to assess the gender variability. Material and methods A retrospective case-control study was conducted amongst patients who underwent MRI Knee scan for clinical suspicion of internal derangement during the study period. We selected the first 125 individuals who were found to have ACL injury in the MRI scans and selected another 125 individuals who had an intact ACL in the scans, to serve as controls in the study. Demographic information was retrieved from the hospital's electronic records, and the assessment of NW, NWI, BW, and NEW was conducted through a review of MRI sequences. They were then compared between the cases and control groups, as well as between male and female genders. Results The ACL-injured group exhibited statistically significant reductions in NW and NWI. While 17.39 mm was the mean NW among cases, 17.86 was the mean value among controls. Similarly, the mean NWI was 0.25 among patients with ACL injuries and 0.27 among controls. Gender-based comparisons also revealed statistically significant differences in NW and NWI measurements, where females were reported to have comparatively lower measurements. The mean NW for males and females in the injured group were 18.26 mm and 15.40 mm, respectively, while it was 18.71 mm and 16.90 mm, respectively, in the control group. In the case of NEW, males in the injured group had a slightly higher value (21.33 mm) than the controls (20.65). Females on the other hand exhibited a lower mean value of NEW in ACL-injured group (18.51 mm) in comparison to the non-injured (18.79 mm). BW did not seem to show a significant difference between the two groups. Conclusions In the studied population, ACL injuries demonstrated a higher occurrence in individuals with a narrow femoral intercondylar NWI. If any of these characteristics are identified in an MRI, it may be helpful to identify individuals who are at a higher risk of developing ACL injuries and may thereby help in planning preventative strategies.

Femoral Tunnel Malposition, Increased Lateral Tibial Slope, and Decreased Notch Width Index Are Risk Factors for Non-Traumatic Anterior Cruciate Ligament Reconstruction Failure

PURPOSE

To identify risk factors for patients who sustain nontraumatic anterior cruciate ligament reconstruction (ACLR) failure.

METHODS

A retrospective analysis was performed on patients undergoing primary or revision ACLR in our institution between 2010 and 2018. Patients sustaining insidious-onset knee instability without history of trauma were identified as nontraumatic ACLR failure and assigned to the study group. The control group of subjects who showed no evidence of ACLR failure with minimum 48-month follow-up were matched in a 1:1 ratio based on age, sex, and body mass index. Anatomic parameters including tibial slope (lateral [LTS], medial [MTS]); tibial plateau subluxation (lateral [LTPsublx], medial [MTPsublx]); notch width index (NWI); and lateral femoral condyle ratio were measured with magnetic resonance imaging or radiography. Graft tunnel position was assessed using 3-dimensional computed tomography and reported in 4 dimensions: deep-shallow ratio (DS ratio) and high-low ratio for femoral tunnel, anterior-posterior ratio and medial-lateral ratio for tibial tunnel. Interobserver and intraobserver reliability were evaluated by the intraclass correlation coefficient (ICC). Patients' demographic data, surgical factors, anatomic parameters, and tunnel placements were compared between the groups. Multivariate logistic regression and receiver operating characteristic curve analysis was used to discriminate and assess the identified risk factors.

RESULTS

A total of 52 patients who sustained nontraumatic ACLR failure were included and matched with 52 control subjects. Compared to patients with intact ACLR, those who sustained nontraumatic ACLR failure showed significantly increased LTS, LTPsublx, MTS, and deceased NWI (all P < .001). Moreover, the average tunnel position in the study group was significantly more anterior (P < .001) and superior (P = .014) at the femoral side and more lateral (P = .002) at the tibial side. Multivariate regression analysis identified LTS (odds ratio [OR] = 1.313; P = .028), DS ratio (OR = 1.091; P = .002), and NWI (OR = 0.813; P = .040) as independent predictors of nontraumatic ACLR failure. LTS appeared to be the best independent predictive factor (area under the curve [AUC] = 0.804; 95% confidence interval [CI], 0.721-0.887), followed by DS ratio (AUC = 0.803; 95% CI, 0.717-0.890), and NWI (AUC = 0.756; 95% CI, 0.664-0.847). The optimal cutoff values were 6.7° for increased LTS (sensitivity = 0.615, specificity = 0.923); 37.4% for increased DS ratio (sensitivity = 0.673, specificity = 0.885); and 26.4% for decreased NWI (sensitivity = 0.827, specificity = 0.596). Intraobserver and interobserver reliability was good to excellent, with ICCs ranging from 0.754 to 0.938 for all radiographical measurements.

CONCLUSIONS

Increased LTS, decreased NWI, and femoral tunnel malposition are predictive risk factors for nontraumatic ACLR failure.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Increasing Breast Support is Associated With a Distal-to-Proximal Redistribution of Joint Negative Work During a Double-Limb Landing Task

Female athletes exhibit greater rates of anterior cruciate ligament injury compared with male athletes. Biomechanical factors are suggested to contribute to sex differences in injury rates. No previous investigation has evaluated the role of breast support on landing biomechanics. This study investigates the effect of breast support on joint negative work and joint contributions to total negative work during landing. Thirty-five female athletes performed 5 landing trials in 3 breast support conditions. Lower-extremity joint negative work and relative joint contributions to total negative work were calculated. Univariate analyses of variance were used to determine the effect of breast support on negative joint work values. Increasing levels of breast support were associated with lower ankle negative work (P < .001) and ankle relative contributions (P < .001) and increases in hip negative work (P = .008) and hip relative contributions (P < .001). No changes were observed in total negative work (P = .759), knee negative work (P = .059), or knee contributions to negative work (P = .094). These data demonstrate that the level of breast support affects lower-extremity biomechanics. The distal-to-proximal shift in negative joint work and relative joint contributions may be indicative of a more protective landing strategy for anterior cruciate ligament injuries.

Investigation of Morphometric Factors Associated With Adolescent ACL Rupture

Background

There are no definitive anatomic morphometric risk factors for adolescent anterior cruciate ligament (ACL) injury.

Purpose

To compare the parameters used to define the tibial and femoral morphometric structure of the knee between adolescent patients with and without ACL rupture.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Included were magnetic resonance imaging (MRI) scans and radiographs of 115 patients aged 10 to 17 years who were evaluated for ACL rupture at a single institution between February 1, 2019, and January 31, 2022. Images from 115 patients with intact MRI scans were included as controls. We investigated the following imaging parameters: tibial slope (on lateral radiograph), lateral condylar height, tibial sulcus height, medial condylar height, condylar width, intercondylar notch with, intercondylar notch angle, notch index, eminence width, tibial plateau width, eminence width/tibial plateau width, medial/lateral/overall eminence height, medial plateau depth, and 2 different eminence angles. Parameters were compared between groups using the chi-square, Fisher exact, Student t, or Mann-Whitney U test, as appropriate. Receiver operating characteristic analysis was conducted for cutoff values of significant parameters.

Results

There were no significant differences in age, sex, or side affected between groups. Only the medial plateau depth was found to be statistically significant between the ACL rupture and ACL intact groups (2.6 vs 2.2 mm; P = .015). A statistically significant cutoff value could not be obtained for the medial plateau depth.

Conclusion

Medial plateau depth was found to be significantly greater in adolescent patients with ACL rupture compared with ACL-intact controls.

Assessment Of Femoral Notch Morphology In Male Patients With Anterior Cruciate Ligament Injury: An MRI Study

Aim: The objective of the present study was to evaluate the femoral notch type, notch width index (NWI), notch angle (NA) and α angle in patients with ACL injury and compare with nonathletic male population using magnetic resonance imaging (MRI). Methods: 79 patients with complete ACL tear and 80 patients as control group (aged 19-43 years) who had knee MRI were evaluated. NWI, NA measurements and notch shape were evaluated on axial fat-saturated proton-weighted sequences. Femoral notch shape was classified as A, U and W types. Results: A statistically significant association was found between notch type, NWI, NA and ACL injury (p

Narrow Notch Width and Low Anterior Cruciate Ligament Volume Are Risk Factors for Anterior Cruciate Ligament Injury: A Magnetic Resonance Imaging-Based Study

BACKGROUND

The relationship between anterior cruciate ligament (ACL) injury and anatomical structures is still a topic of debate.

PURPOSE

The aim of this study was to compare knee geometry in demographically matched ACL-injured and ACL-intact athletes.

METHODS

We conducted a case-control study comparing 2 groups, each consisting of 55 professional athletes (44 men and 11 women): 1 group with complete ACL tears (cases) and 1 group with intact ACLs (controls). The groups were compared using magnetic resonance imaging (MRI) in terms of intercondylar notch geometry, tibial plateau characteristics, and ACL volume.

RESULTS

Among cases and controls, we found the cases had lower notch width (20.24 ± 2.68 mm vs. 22.04 ± 2.56 mm, respectively) and notch width index (0.29 ± 0.03 vs. 0.31 ± 0.03, respectively). The mean ACL volume in the cases (1181.63 mm³ ± 326 mm³) was also lower than in controls (1352.61 mm³ ± 279.84 mm³). The parameters of tibial slope geometry were comparable between groups. In addition, women had lower ACL volume than men (1254 ± 310 mm³ vs. 890 ± 267 mm³, respectively) and higher medial posterior tibial slope (4.76 ± 2.6 vs. 6.63 ± 1.83, respectively). Among cases, women had narrower notch width than men (16.9 ± 2.42 mm vs. 21.08 ± 2.03 mm). However, notch width index was comparable between male (0.3 ± 0.02) and female (0.28 ± 0.03) cases.

CONCLUSION

Our findings suggest that narrow notch width and low ACL volume may enhance the risk of ACL injury among athletes. There was no association found between posterior tibial slope and ACL injury between athletes with injured ACLs and controls. Further study is indicated.

Femoral intercondylar notch: Accuracy of a novel MRI measurement protocol

OBJECTIVE

The most common mechanical complication following an anterior cruciate ligament (ACL) reconstruction is joint stiffness, due in part to cyclops syndrome. A narrow intercondylar notch is an anatomical risk factor. A reliable preoperative notch measurement would help anticipate proper graft size, or plan a notchplasty during the ligament reconstruction, if necessary. No study has yet assessed the accuracy of the methods used to measure notch size.

HYPOTHESIS

The novel measurement protocol proposed in this study would be more reproducible than the reference technique.

METHODS

A total of 20 preoperative knee MRIs performed during the assessment of an ACL rupture were randomly selected. The notch size was measured using 2 methods: traditional (ratio of the notch and metaphyseal widths measured on a line drawn through the popliteal groove) and novel. The latter was measured using the same ratio but took into account the notch width in its proximal third, according to a coronal slice that passes through the ACL tibial attachment. Three orthopedic surgeons with different levels of experience (senior surgeon, junior surgeon and surgical resident) performed these measurement protocols twice on anonymized MRI scans, 10days apart. Spearman's rank correlation coefficient was used to assess the intraobserver correlations and a concordance index was used to assess the interobserver correlations. The influence of the second MRI reading was analyzed with a bootstrap test.

RESULTS

The mean intraobserver reliability was 0.73 for the reference method and 0.83 for the proposed method. The values of the bootstrap tests were higher for the proposed method (0.45 vs. 0.45 and 0.70; p<05 for interobserver; 0.49 vs. 0.69 and 0.62; p<05 for intraobserver).

CONCLUSION

The proposed measurement protocol showed a higher reproducibility in assessing notch size than the traditional method. This technique therefore provides a reliable assessment of the intercondylar notch width.

LEVEL OF EVIDENCE

IV; retrospective study.

Analysis of intercondylar notch size and shape in patients with cyclops syndrome after anterior cruciate ligament reconstruction

Background

Cyclops lesion is the second most common cause of extension loss after anterior cruciate ligament reconstruction. This study focused on the correlation between the anatomy of the intercondylar notch and the incidence of cyclops lesion. To determine whether the size and shape of the intercondylar notch are related to cyclops lesion formation following anterior cruciate ligament reconstruction according to magnetic resonance imaging (MRI) findings.

Methods

One hundred twenty-five (125) patients were retrospectively evaluated. The notch width index (NWI) and notch shape index (NSI) were measured based on coronal and axial MRI sections in patients diagnosed with cyclops syndrome (n = 25), diagnosed with complete anterior cruciate ligament (ACL) tears (n = 50), and without cyclops lesions or ACL ruptures (n = 50).

Results

Imaging analysis results showed that the cyclops and ACL groups had lower mean NWI and NSI values than the control group. Significant between-group differences were found in NSI (p = 0.0140) based on coronal cross-sections and in NWI (p = 0.0026) and NSI (p < 0.0001) based on axial sections.

Conclusions

The geometry of the intercondylar notch was found to be associated with the risk of cyclops lesion formation and ACL rupture.

The intercondylar fossa-A narrative review

The intercondylar fossa (“intercondylar notch,” IN) is a groove at the distal end of the femur, housing important stabilizing structures: cruciate ligaments and meniscofemoral ligaments. As the risk for injury to these structures correlates with changes to the IN, exact knowledge of its morphology, possible physiological and pathological changes and different approaches for evaluating it are important. The divergent ways of assessing the IN and the corresponding measurement methods have led to various descriptions of its possible shapes. Ridges at the medial and lateral wall are considered clinically important because they can help with orientation during arthroscopy, whereas ridges at the osteochondral border could affect the risk of ligament injury. Changes related to aging and sex differences have been documented, further emphasizing the importance of individual assessment of the knee joint. Overall, it is of the utmost importance to remember the interactions between the osseous housing and the structures within.

Association of Geometric Characteristics of Knee Anatomy (Alpha Angle and Intercondylar Notch Type) With Noncontact ACL Injury

BACKGROUND

The femoral intercondylar notch type and the alpha angle (the angle between the femoral notch roof and the long axis of the femur) are easily measured in clinical settings; however, their associations with anterior cruciate ligament (ACL) injury remain unclear.

HYPOTHESIS/PURPOSE

The purpose was to determine if the alpha angle and the femoral notch type are associated with noncontact ACL injury univariately and in combination with previously identified knee geometric risk factors. We hypothesized that the alpha angle and the femoral notch type are associated with noncontact ACL injury and that the association differs between men and women.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

The alpha angle and the femoral notch type were measured via 3T magnetic resonance imaging (MRI) acquired from 61 women and 25 men with a first-time noncontact ACL injury. Each injured patient was matched with a control participant based on age, sex, and participation on the same sports team. A conditional logistic regression was used to assess univariate associations with ACL injury as well as multivariate associations using MRI-based risk factors of knee geometry identified in previous analyses: femoral intercondylar notch width at the anterior outlet, femoral intercondylar notch anteromedial ridge thickness, volume of the ACL, tibial plateau lateral compartment subchondral bone slope, lateral compartment middle articular cartilage slope, lateral compartment meniscus-cartilage height, lateral compartment meniscus-bone angle, and medial tibial spine volume.

RESULTS

For female athletes, the alpha angle (odds ratio, [OR], 1.82 per 1-degree increase; P = .001), the tibial lateral compartment articular cartilage slope (OR, 1.25 per 1-degree increase in the posterior-inferior directed slope; P = .022), and the femoral notch anteromedial ridge thickness (OR, 3.36 per 1-mm increase; P = .027) were independently associated with ACL disruption. For men, no other variables entered the models after the alpha angle was inputted as the first step (OR, 2.19 per 1-degree increase; P = .010).

CONCLUSION

For women, ACL injury was most strongly associated with increased alpha angle, increased tibial plateau slope, and increased femoral notch ridge thickness. For men, increased alpha angle was the most significant factor associated with ACL injury. The mechanism of injury might be associated with a combination of impingement of the ACL against the bone and increased ligament loading.

Stenotic Intercondylar Notch as a Risk Factor for Physeal-Sparing ACL Reconstruction Failure: A Case-Control Study

Identifying risk factors is crucial for developing strategies that minimize reinjury after anterior cruciate ligament reconstruction (ACLR). This study aims to determine whether certain features of intercondylar notch geometry are associated with failure of physeal-sparing ACLRs in skeletally immature athletes.

Notch Volume Measured on Magnetic Resonance Imaging Is Better Than 2-Dimensional Notch Parameters for Predicting Noncontact Anterior Cruciate Ligament Injury in Males

PURPOSE

To evaluate and compare intercondylar notch volume with other 2-dimensional notch parameters (measured on magnetic resonance imaging [MRI]) for prediction of noncontact anterior cruciate ligament (ACL) injury in males.

METHODS

Retrospective case-control study in males based on MRI images. The case group consisted of 80 noncontact ACL-injured males and a control group of 80 age- and height-matched ACL-intact males. Inclusion criteria were 18 to 50 years old, full-thickness tear, MRI obtained within 1 year of injury, and ACL tear visually documented during arthroscopy. Multiligamentous, bilateral, or concomitant bony injuries were excluded. Notch volume and 2D parameters in both planes, including notch depth, notch width, intercondylar notch angle, notch-width index, and notch-shape index, were measured on MRI and compared. Slice interval was included in the formula for notch-volume assessment. Bivariate Pearson correlation between notch volume and 2D parameters was estimated. Multivariate conditional logistic regression analysis was used for predictor model. Receiver operating characteristic (ROC) curves were plotted.

RESULTS

All MRIs had a standard slice thickness of 3 mm and slice interval of 0.3 mm. Notch volume (P < .001), notch angle in the axial plane (P = .001), and notch width in the coronal plane (P = .009) were significantly smaller in the ACL-injured group. Notch volume had inconsistent and negligible to low correlation with 2D parameters. Notch volume was the only significant contributor in the predictor model (P < .001). ROC curve showed that notch volume had highest area under the curve of 84.1% and optimal cutoff at 7.1550 cm³ (specificity, 88.7%; sensitivity, 65%).

CONCLUSION

Significantly smaller intercondylar notch volume is associated with noncontact ACL injury in men and is the most important predictor for such an injury (optimal cutoff of 7.1550 cm³). Two-dimensional notch parameters are inconsistently associated with noncontact ACL injury in men, and none of the 2D parameters can be used as a surrogate for notch volume. Two-dimensional notch parameters fare poorly in predicting noncontact ACL injury in males. Notch volume measurement should include slice interval as a factor.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Is There a Role of Meniscal Morphology in the Risk of Noncontact Anterior Cruciate Ligament Rupture? A Case-Control Study

The purpose of this study was to identify the anatomical risk factors and determine the role of meniscal morphology in noncontact anterior cruciate ligament (ACL) rupture. A total of 126 patients (63 with noncontact ACL rupture and 63 age- and sex-matched controls) with intact menisci were included in this retrospective case-control study. On knee magnetic resonance imaging (MRI), meniscal morphometry (anterior, corpus, and posterior heights and widths of each meniscus), tibial slope (medial and lateral separately), notch width index, roof inclination angle, anteromedial bony ridge, tibial eminence area, and Q-angle measurements were assessed. The data were analyzed using multiple regression analyses to identify independent risk factors associated with ACL rupture. Using a univariate analysis, medial and lateral menisci anterior horn heights (p < 0.001; p < 0.003), medial and lateral menisci posterior horn heights (p < 0.001; p < 0.001), lateral meniscus corpus width (p < 0.004), and notch width index (p < 0.001) were significantly higher in the control group. Lateral tibial slope (p < 0.001) and anteromedial bony ridge thickness (p < 0.001) were significantly higher in the ACL rupture group. Multivariate analysis revealed that decreased medial meniscus posterior horn height (odds ratio [OR]: 0.242; p < 0.001), increased lateral meniscus corpus width (OR: 2.118; p < 0.002), increased lateral tibial slope (OR: 1.95; p < 0.001), and decreased notch width index (OR: 0.071; p = 0.046) were independent risk factors for ACL rupture. Notch stenosis, increased lateral tibial slope, decreased medial meniscus posterior horn height, and increased lateral meniscus corpus width are independent anatomical risk factors for ACL rupture. Meniscal morphological variations also play a role in ACL injury. This is a Level III, retrospective case-control study.

The relationship of anterior cruciate ligament injuries with MRI based calculation of femoral notch width, notch width index, notch shape - A randomized control study

BACKGROUND

ACL injuries are infamously known for disability in young adults and require surgical reconstruction. The need of time is to predict predisposing factors and prevent ACL injuries.The incidence of ACL injuries has been associated with various factors related to the morphology of distal femur and proximal tibia.Hence, purpose of this study was to assess the relationship of morphology of distal femur by assessing Notch Width(NW), Notch Width Index (NWI), and Notch shape calculated preoperatively on MRI in association with an ACL tear.

METHODS

The following randomized control study had 60 patients enrolled with non contact injury to knee who were equally divided into 2 groups i.e. ACL injury group and control group. ACL group had patients who had MRI proven ACL tear along with clinical findings suggestive of ACL tear whereas control contained patients with intact ACL. Demographic data was collected and NW, NWI and Notch shape were determined on coronal sections of MRI sequences.

RESULTS

Positive correlation of ACL tear was seen with NW, BCW, NWI, NWP, and NWJ. Smaller Notch Width showed higher incidence of ACL tear (p = 0.019). The mean NWI in the injured and control knee is 0.31 ± 0.01 and 0.27 ± 0.01 respectively and was statistically significant(p < 0.001). A shaped Notch (60%) was commonly seen in ACL tear group and U shaped notch (73.3%) was commonly seen in control group.We found the cut off value for the prediction of ACL tear of NWI was 0.29 with a sensitivity of 90% and specificity of 86.7%.

CONCLUSION

ACL injuries in the given population have shown higher incidence with narrow femoral intercondylar notch, smaller notch width index, 'A' shaped femoral notch. If any of the above findings are present in the MRI, its important to counsel the subjects about the increased risk of ACL injuries in them and take preventive measures.

Predictors for Anterior Cruciate Ligament (ACL) Re-injury after Successful Primary ACL Reconstruction (ACLR)

Introduction:

Few authors have addressed risk factors related to an ipsilateral graft rupture and contralateral anterior cruciate ligament (ACL) injury after return to sports (RTS) following primary ACL reconstruction.

Material and Methods:

Patients with ACL re-injury to either knee after successful primary ACLR were included in Group I and those with no further re-injury were included in Group II. Variables including age, gender, side, body mass index (BMI), thigh atrophy, anterior knee laxity difference between both knees measured by KT-1000 arthrometer, mean time of return to sports (RTS), graft type, type of game, mode of injury, Tegner Activity Score, hormone levels, femoral tunnel length (FTL), posterior tibial slope (PTS) and notch width index (NWI) were studied. Binary logistic regression was used to measure the relative association.

Results:

A total of 128 athletes were included with 64 in each group. Mean age in Group I and II were 24.90 and 26.47 years respectively. Mean follow-up of Group I and Group II were 24.5 and 20.11 months respectively. Significant correlation was present between ACL re-injury and following risk factors; PTS of >10º, KT difference of >3.0mm, thigh atrophy of >2.50cm and time to RTS <9.50 months P value <0.05). No correlation was found with age, sex, BMI, type of game, Tegner Activity Score, mode of injury, NWI, size of graft, FTL and hormone levels.

Conclusion:

Possible risk factors include PTS of ≥ 10º, KT difference of ≥ 3.0mm at 1 year follow-up, thigh atrophy of ≥ 2.50cm at 1 year follow-up and RTS <9.5 months after primary ACLR.

Inclination of Blumensaat's line influences on the accuracy of the quadrant method in evaluation for anterior cruciate ligament reconstruction

PURPOSE

The quadrant method is used to evaluate the bone tunnel position with the grid based on the Blumensaat's line in anterior cruciate ligament (ACL) reconstruction. This study aimed to clarify the influence of variation in the Blumensaat's line on the accuracy of the quadrant method measurements.

METHODS

A retrospective review of the radiological records of patients aged 18-30 years who underwent computed tomography (CT) scanning of the knee joint was conducted. The Blumensaat's line inclination angle (BIA), along with the most posterior point of the posterior condyle (point P) position using the quadrant method and morphology of the Blumensaat's line were measured on true lateral transparent three-dimensional CT images of the distal femoral condyle in 147 patients. Statistical analysis was conducted to determine associations among these measurements.

RESULTS

BIA was 37.5° (standard deviation 4.2°; range 27°-48°). The point P position was significantly correlated with BIA in the high/low (R² = 0.590, P < 0.0001) and deep/shallow (R² = 0.461, P < 0.0001) directions. The morphology of the Blumensaat's line was straight in 35 knees (23.8%); whereas, the remaining 112 knees (76.2%) were not straight but had some hill on the Blumensaat's line. No significant difference among the morphological variation of the Blumensaat's line was observed in BIA and the point P position.

CONCLUSION

There was a strong correlation between BIA and the point P measured using the quadrant method, suggesting the influence of the Blumensaat's line on the accuracy of the quadrant method measurements in ACL reconstruction. As for the clinical relevance, surgeons should be careful in application of the quadrant method for ACL reconstruction, because the variation of the Blumensaat's line inclination influences the accuracy of this method.

Knee Morphological Risk Factors for Anterior Cruciate Ligament Injury: A Systematic Review

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction incidence has increased substantially in the past 25 years. Recently, there has been a focus on knee morphology as a contributor to ACL injury risk. The purpose of this study was to systematically review the literature to assess the influence of knee morphology on ACL injury.

METHODS

In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, PubMed, Embase, and MEDLINE were searched in September 2017 for studies reporting on knee morphology and ACL injury. The search was updated in June 2018. The following inclusion criteria were used: English language; full text available; Level-I, II, or III evidence; human studies; and skeletally mature patients.

RESULTS

After systematically screening 6,208 studies, 65 studies met the inclusion/exclusion criteria. Three additional studies were identified in the search update, for a total of 68 studies comprising 5,834 ACL-injured knees. Intercondylar notch stenosis, most commonly defined by an "A-shaped" notch, decreased notch width, or decreased notch width index, was the most commonly reported femoral morphological risk factor for ACL injury. Increased femoral condylar offset ratio (>63%) and decreased condylar radius of curvature also were associated with an increased risk of ACL injury. Increased medial and lateral tibial slopes were the most commonly reported tibial risk factors. A smaller tibial eminence, reduced ACL size, and poor tibiofemoral congruity were also associated with increased injury risk.

CONCLUSIONS

Intercondylar notch stenosis, variations in sagittal condylar shape, increased tibial slope, reduced tibial eminence size, poor tibiofemoral congruity, and reduced ACL size are substantial risk factors for ACL injury. In future research, it would be valuable to identify a slope beyond which slope correction should be performed concomitantly with ACL reconstruction, and to determine whether an optimal relationship of notch size to graft size exists. To achieve optimal outcomes, the osseous morphological risk factors should be considered in individualized anatomic ACL reconstructions.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Predictive effects of the intercondylar notch morphology on anterior cruciate ligament injury in males: A magnetic resonance imaging analysis

The effects of the intercondylar notch morphology on predicting anterior crucaite ligament (ACL) injury in males were unknown. We aimed to determine the risk factors of the intercondylar notch on ACL injury, and evaluate the predictive effects of the morphological parameters on ACL injury in males. Sixty-one patients with ACL injury and seventy-eight patients with intact ACLs were assigned to the case group and control group respectively. The notch width (NW), bicondylar width, notch width index (NWI), notch height (NH), notch cross-sectional area (CSA), notch angle (NA) and notch shape were obtained from the magnetic resonance images of male patients. Comparisons were performed between the case and control groups. Logistic regression model and the receiver operating characteristic curve were used to assess the predictive effects of these parameters on ACL injury. The NW, NWI, NH, CSA and NA in the case group were significantly smaller than those in the control group on the coronal magnetic resonance images. The NW and NWI were significantly smaller, while no significant differences of the NH and CSA were found between the 2 groups on the axial images. There was no significant difference in the notch shape between the 2 groups. The maximum value of area under the curve calculated by combining all relevant morphological parameters was 0.966. The ACL injury in males was associated with NW, NH, NWI, CSA, and NA. These were good indicators for predicting ACL injury in males.

A novel morphological classification for the femoral notch based on MRI: a simple and effective assessment method for the femoral notch

OBJECTIVE

To propose a novel morphological classification method for notches, which may provide new evidence for notchplasty based on the three-dimensional (3D) features of notches and the risk of anterior cruciate ligament (ACL) injury.

MATERIALS AND METHODS

Three hundred individuals in total were included in our study, including 150 patients with ACL ruptures (75 males and 75 females) and 150 age- and gender-matched individuals without ACL ruptures. The notches were divided into four types according to the notch widths at the notch inlet, outlet, and ACL attachment based on the preoperative MRI, the notch volume was calculated, and the risk of ACL injury was compared. The surgical records were reviewed and whether these cases performed notchplasty were collected.

RESULTS

The inlet-and-outlet stenosis notch type was associated with smaller notch volume (P = 0.007) and a higher risk of ACL injury (P < 0.001). There were no significant differences in morphological distribution between males and females. The rate of notchplasty in inlet-and-outlet stenosis type was higher than the others.

CONCLUSIONS

The new morphological classification method efficiently reflected the association of the notch shape with the 3D notch volume and the risk of ACL injury. The knees with the inlet-and-outlet stenosis notch type and smaller notch volume tended to have a higher risk of ACL injury. Level of evidence Level III, case-control study.

Intercondylar Notch Size Can Be Predicted on Preoperative Magnetic Resonance Imaging

Purpose

To develop a standardized method of intercondylar notch measurement on preoperative radiographs and magnetic resonance imaging (MRI) and validate that it could predict intraoperative notch measurements.

Methods

The charts and imaging of 50 patients undergoing anterior cruciate ligament reconstruction were reviewed. A standardized method of intercondylar notch measurement on radiographs and MRI was used by 3 blinded reviewers. Arthroscopic measurements were made by the surgeon who was blinded to the imaging measurements. Interrater reliability was determined between reviewers and between imaging and arthroscopic measurements using interclass correlation coefficients (r).

Results

The average notch base width was 16.5 (± 2.7) mm on MRI, 19.0 (± 3.4) mm on radiographs, and 15.8 (± 3.0) mm on arthroscopic measurement. The radiographic notch base width measurements were on average 1.2 times greater than the arthroscopic measurements. There was no significant difference between males and females in notch base width (16.7 mm vs 15.3 mm, P = .19) or area (312.5 mm² vs 284.3 mm², P = .17). Interrater reliability was excellent between the reviewers for notch base width measurement on both MRI (r = 0.91) and radiographs (r = 0.95). Good-to-excellent interrater reliability between notch base width measurements on MRI and arthroscopy (r = 0.78, 0.73, 0.7) and fair-to-good interrater reliability between notch base width measurements on radiographs and arthroscopy were found (r = 0.61, 0.58, 0.55).

Conclusions

This study introduces a reliable method of using preoperative MRI to predict intercondylar notch width during arthroscopy. This data can be used to identify patients with narrow notches preoperatively.

Level of Evidence

Level III, diagnostic study.

Intercondylar Notch Measurement During Arthroscopy and on Preoperative Magnetic Resonance Imaging

Small intercondylar notch size is associated with increased risk of anterior cruciate ligament (ACL) injuries and increased difficulty of ACL reconstruction. When encountering a small notch during surgery, some surgeons may resort to a notchplasty, which has been shown to have associated morbidity. The ability to predict notch size on preoperative imaging could allow the orthopaedic surgeon to anticipate surgical difficulty such as an oversized graft and graft impingement and possibly avoid a notchplasty. Many methods have been proposed for measuring intercondylar notch size, but they do not correlate with intraoperative measurements or they utilize computed tomography scanning, which is not readily obtained before ACL reconstruction. The purpose of this study was to develop a method of notch measurement on preoperative radiography and magnetic resonance imaging that match intraoperative arthroscopic measurements. The method presented here can be used to identify narrow intercondylar notches, prepare for potential intraoperative challenges, and formulate surgical plans such as for graft choice in individualized ACL reconstruction.

Posterior cruciate ligament injury is influenced by intercondylar shape and size of tibial eminence

AIMS

Little is known about the risk factors that predispose to a rupture of the posterior cruciate ligament (PCL). Identifying risk factors is the first step in trying to prevent a rupture of the PCL from occurring. The morphology of the knee in patients who rupture their PCL may differ from that of control patients. The purpose of this study was to identify any variations in bone morphology that are related to a PCL.

PATIENTS AND METHODS

We compared the anteroposterior (AP), lateral, and Rosenberg view radiographs of 94 patients with a ruptured PCL to a control group of 168 patients matched by age, sex, and body mass index (BMI), but with an intact PCL after a knee injury. Statistical shape modelling software was used to assess the shape of the knee and determine any difference in anatomical landmarks.

RESULTS

We found shape variants on the AP and Rosenberg view radiographs to be significantly different between patients who tore their PCL and those with an intact PCL after a knee injury. Overall, patients who ruptured their PCL have smaller intercondylar notches and smaller tibial eminences than control patients.

CONCLUSION

This study shows that differences in the shape of the knee are associated with the presence of a PCL rupture after injury. A smaller and more sharply angled intercondylar notch and a more flattened tibial eminence are related to PCL rupture. This suggests that the morphology of the knee is a risk factor for sustaining a PCL rupture. Cite this article: Bone Joint J 2019;101-B:1058-1062.

Anatomical Variability of Intercondylar Fossa Geometry in Patients Diagnosed with Primary Anterior Cruciate Ligament Rupture

The aims of this study were to (1) describe the three-dimensional characteristics and sources of anatomical variability in the geometry of the intercondylar fossa ("notch") in an anterior cruciate ligament (ACL)-injured sample and (2) assess the relationship between patient factors and anatomical variability of the fossa in the context of impingement risk. A retrospective analysis of preoperative magnetic resonance imaging (MRI) for 49 patients with ACL rupture was performed. Scans were examined in the axial plane using an online picture archiving and communication system (PACS) viewer and fossa width and angle assessed at multiple slices, as well as anteroposterior depth, fossa height, and calculated total volume. Principal component analysis was performed to prioritize the sources of variability. A multivariate linear regression was performed to assess relationships between different patient factors, controlling for imaging parameters and principal component loadings. Geometric properties were normally distributed for all but fossa volume, height, and distal angle. Three principal components (PCs) were identified explaining 80% of total variance, shape (PC1), size in the coronal plane (PC2), and size in the sagittal plane (PC3). Patient factors were significantly (P < 0.05) related to PC loadings; however, a substantial amount of variance in each model remained unexplained. Intercondylar fossa characteristics vary considerably within ACL-injury patients with shape and size in coronal and axial planes, explaining most of the variance. Although patient factors are associated with anatomical characteristics, further work is required to identify the correct combination of factors accurately predicting geometry of the fossa for planning ACL reconstruction. Clin. Anat. 33:610-618, 2020. © 2019 Wiley Periodicals, Inc.

Multivariable analysis of anatomic risk factors for anterior cruciate ligament injury in active individuals

OBJECTIVE

The aim of the present study was to compare the morphometric differences between patients with or without anterior cruciate ligament (ACL) injury, and identify the anatomic risk factors associated with ACL injury in active individuals.

METHODS

The knee joint magnetic resonance images (MRI) of 100 subjects were included in this study. Data from the ACL-injured group (50 patients) and matched controls (50 subjects) were obtained from the same hospital. These data were analyzed by univariable analysis or multivariable conditional logistic regression analysis to examine the effects of the following variables on the risk of suffering ACL injury for the first time: TT-TG distance, medial and lateral tibial slope, intercondylar notch width and depth, femur condylar width, lateral femoral condylar depth, notch width index (NWI), notch shape index (NSI), notch depth index (NDI), and cross-sectional area (CSA).

RESULTS

In the univariable analysis, the ACL-injured group had a larger TT-TG distance, increased medial and lateral tibial slope, narrower intercondylar notch width, deeper lateral femoral condylar depth, lesser NWI and NSI, and CSA when compared with the control group (P < 0.05). However, there were no significant between-group differences in intercondylar notch depth (P = 0.174), femur condylar width (P = 0.797), and NDI (P = 0.436). The multivariable analysis revealed that TT-TG distance [odds ratio (OR) = 1.37, 95% CI = 1.04-1.81, P = 0.028], medial tibial slope (OR = 1.30, 95% CI = 1.02-1.66, P = 0.036) and NWI (OR = 0.46, 95% CI = 0.24-0.91, P = 0.025) had significant multivariable associations with the sole independent risk of ACL injury.

CONCLUSION

Larger TT-TG distance, increased MTS, and lesser NWI are independent anatomic risk factors for active individuals with ACL injury.

LEVEL OF EVIDENCE

Case-control study; Level of Evidence, III.

The correlation between common 2D femoral notch parameters and 3D notch volume: a retrospective MRI study

Background

Although the stenotic femoral intercondylar notch was associated with anterior cruciate ligament (ACL) injuries, the parameters for notch assessment were numerous. The present study aimed to compare the 2-dimensional (2D) femoral notch parameters, including the notch width (NW) and notch width index (NWI), with the 3-dimensional (3D) notch volume based on magnetic resonance imaging (MRI), to determine appropriate femoral parameters for ACL injuries.

Methods

Two hundred forty individuals were included in this study, including 120 patients with ACL ruptures and 120 age- and gender-matched individuals without ACL ruptures. The NWs and NWIs were measured at four sites (the popliteal groove, the notch inlet and outlet, and the ACL attachment), and the notch volumes were calculated. The Pearson correlation coefficients between the 2D and 3D parameters were calculated. A multivariate analysis of the ACL injuries was conducted with these parameters and the demographic data.

Results

The associations of the NW and NWI with the notch volume at each of the four locations of the femoral notch were poor in the subgroup analysis, with the exception of the NW in the male ACL-intact group (R = 0.307, 0.256, 0.404 and 0.387 at the popliteal groove, notch inlet and outlet, and ACL attachment, respectively). The multivariate analysis revealed that the notch volume (OR = 0.679, P < 0.001) and the NW at the popliteal groove (OR = 0.844, P = 0.004), notch inlet (OR = 0.720, P < 0.001) and ACL attachment (OR = 0.871, P = 0.028) were predictable parameters to the risk of ACL injuries.

Conclusions

The correlations between the 2D parameters and the 3D volumes were weak. The notch volume and the NW at the popliteal groove, notch inlet and ACL attachment were useful parameters for predicting the risk of ACL injuries.

Level of evidence

Level III, case-control study.

Anatomical Risk Factors of Anterior Cruciate Ligament Injury

Background:

Nowadays, the anterior cruciate ligament (ACL) injury has been one of the most common diseases of the knee joint. The relationships between the ACL injury and the anatomical structures are still controversial. This study aimed to identify the anatomical risk factors of ACL injury by magnetic resonance imaging (MRI) of the knee.

Methods:

This was a retrospective study of 125 patients undergoing primary ACL reconstruction between July 2013 and May 2017. Another 125 patients without any organic knee joint injury were served as controls. The shape of intercondylar notch, the intercondylar notch width index, the intercondylar notch height index, the α angle, the β angle, and the medial and lateral tibial plateau slope were measured with MRI and compared. The data were compared by binary logistic regression to find the risk factors.

Results:

The two groups differed in the proportion of male patients (70.4% vs. 52.0%, χ² = 8.911, P = 0.003), but gender was excluded as a risk factor for ACL injury with regression analysis (odds ratio = 1.476, 95% confidence interval [CI]: 0.689–3.160, P = 0.317). The injured group was found to have a smaller notch width index (95% CI = 7.960E-23–2.154E-9, P < 0.001), a larger β angle (95% CI = 1.311–1.785, P < 0.001), and a larger lateral tibial plateau slope (95% CI = 1.201–1.683, P < 0.001). The cutoff values of notch width index, β angle, and the lateral tibial plateau slope were 0.252, 38.5°, and 7.5°, respectively.

Conclusions:

In this study, a narrow intercondylar notch (intercondylar notch width index <0.252), a larger lateral tibial slope (>7.5°), and larger β angle (>38.5°) might be the factors associated with ACL injury.

Trial Registration:

ChiCTR-RRC-17014116; http://www.chictr.org.cn/showproj.aspx?proj=24119 .

Evaluation of anatomic risk factors using magnetic resonance imaging in non-contact anterior cruciate ligament injury

BACKGROUND

The purpose of our study was to compare the significance of the tibio-femoral morphological variables (notch width index, notch shape index, intercondylar notch angle, medial and lateral tibial slopes) in predicting non-contact ACL (anterior cruciate ligament) injuries and to compare these factors between genders in South Asian population. The author hopes to provide a comprehensive analysis on the risk factors which would help in betterment of the patients at danger for anterior cruciate ligament injury.

MATERIALS AND METHODS

A total of 110 MRI knees of patients with 55 subjects of noncontact ACL injury and 55 age and sex matched controls were included in a retrospective study. Notch width index, notch shape index, intercondylar notch angle were assessed in axial and coronal MR imaging along with medial and lateral posterior tibial slopes. Morphology of the notch was also assessed.

RESULTS

ACL injured group were found to have a statistically significant narrow notch width index and decreased intercondylar notch angle with increased lateral posterior tibial slope. Type-A notches were found to have increased risk of having ACL injuries. Gender comparative results showed no statistically significant differences.

CONCLUSION

ACL tears are associated with decreased notch width index, intercondylar notch angle and increased lateral posterior tibial slope. Type-A notches are seen to have increased risk for ACL injuries.

Stenotic intercondylar notch type is correlated with anterior cruciate ligament injury in female patients using magnetic resonance imaging

PURPOSE AND HYPOTHESIS

The principal purpose of this paper was to identify whether femoral notch morphology was different in females without anterior cruciate ligament (ACL) injury from those with ACL injury. Magnetic resonance imaging (MRI) was used to assess the femoral notch type, notch width index and 'α angle' in female patients and measure these differences.

METHODS

This is a retrospective case control study of 119 female patients, 58 with ACL injury and 61 patients without ACL injury who underwent knee MRI between March 2014 and April 2016. The morphometric measurements were taken by two independent observers. The femoral notch width index was calculated as the ratio between the central notch width and transcondylar or intercondylar width; values >0.27 were considered normal. The femoral notch shape was classified as Type A, Type U or Type W, with Type A describing a stenotic notch, Type U a notch with a wider contour and Type W a wider Type U with two apices apparent. The angle between the longitudinal femoral axis and the Blumensaat line was identified as the 'α angle'. The statistical analysis was performed with t tests, simple and multivariable logistic regression analysis to evaluate the strength of these specific femoral notch morphometric values as predictive factors to ACL rupture.

RESULTS

Stenotic femoral notch Type A was identified as a high risk factor to ACL injury (odds ratio [OR] = 2.8; p = 0.03). There was no significant difference between the two groups for the notch width index (OR = 0.7; p = n.s.) and the 'α angle' (OR 1.02; p = n.s.). Significant association between NWI and stenotic notch was found (p < 0.01).

CONCLUSIONS

This study showed that Type A stenotic femoral notch can be considered as a valuable predictive factor for ACL injury. Notch width index and 'α angle' are weak indicators in ACL injury prognosis. Ligament impingement may be inferred as an important mechanism in female ACL rupture. Injury prevention strategies, such as prehabilitation programmes, could be introduced in the benefit of young females with stenotic notch.

LEVEL OF EVIDENCE

III.

Evaluation of Posterior Cruciate Ligament and Intercondylar Notch in Subjects With Anterior Cruciate Ligament Tear: A Comparative Flexed-Knee 3D Magnetic Resonance Imaging Study

PURPOSE

To determine if posterior cruciate ligament (PCL) and intercondylar notch (IN) morphometries and volumetrics act as risk factors for anterior cruciate ligament (ACL) tears.

METHODS

A prospective case-controlled magnetic resonance imaging (MRI) study was conducted with subjects presenting noncontact knee injuries. Exclusion criteria were previous surgery, PCL tear, osteoarthritis, tumors, or infectious and inflammatory conditions. All participants underwent a flexed-knee 3-dimensional (3D) magnetic resonance imaging (MRI) to uniformly straighten PCL. MR images were independently reviewed by 2 radiologists and assessed for 2D and 3D measurements (bicondylar width; IN angle, depth, width, and cross-sectional area; PCL width, thickness, and cross-sectional area; and IN and PCL volumes). Clinical profiles were tabulated and subjects were divided into cases (ACL tear) and controls (without ACL tear).

RESULTS

The study was composed of 50 cases versus 52 controls (N = 102), with a mean age of 36.8 years. There was no difference between groups (P > .05) regarding age, gender, body mass index, time from injury, Tegner score, flexion angle, limb side, intensity of injury, or familial or opposite limb history of tear. Agreement between readers ranged from substantial to almost perfect. Subjects with ACL tear presented with lower IN width, lower IN minus PCL widths, lower Notch Width Index, higher PCL/IN width proportion, higher PCL thickness, lower IN depth minus PCL thickness, and higher PCL thickness/IN depth proportion (P < .05). Moreover, higher PCL/IN cross-sectional area proportion, higher PCL volumes (OR = 9.01), and higher PCL/IN volume proportion were also found in cases.

CONCLUSIONS

Our study shows that subjects with ACL tears present not only reduced IN but also larger PCL dimensions. These findings, isolated and combined, and especially PCL volume, might be suggestive as risk factors for ACL tears owing to the reduction of its space inside the IN.

LEVEL OF EVIDENCE

Level III, comparative group.

Outcomes After Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To identify the risk factors predicting unsatisfactory postoperative clinical outcomes after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using multivariate logistic regression.

METHODS

Inclusion criteria were consecutive DB ACL reconstructions from January 2006 to September 2012 with a minimum 3-year follow-up. Exclusion criteria included (1) a delay to surgery from initial injury of more than 4 years (210 weeks); (2) contralateral knee pathology; (3) the lack of postoperative 3-dimensional computed tomography; (4) single-bundle ACL reconstruction; (5) revision ACL reconstruction; (6) meniscus allograft transplantation after total or subtotal meniscectomy; (7) multiple ligament surgeries. According to the overall International Knee Documentation Committee (IKDC) rating at the last follow-up, we sorted all enrolled subjects into superior (IKDC grade A or B) and inferior outcome groups (IKDC grade C or D). Multivariate logistic regression was used to analyze risk factors, including age, gender, body mass index, time from injury to surgery, posterior tibial slope, notch width index, cartilage injury, meniscus injury, and femoral and tibial tunnel positions.

RESULTS

In comparison between the superior outcome group (n = 240) and inferior outcome group (n = 50), anterior (adjusted odds ratio [OR]: 0.902, 95% confidence interval [CI]: 0.846-0.962) or distal (adjusted OR: 1.025, 95% CI: 1.006-1.060) femoral anteromedial tunnel position was a significant risk factor for the inferior outcomes. Partial meniscectomy of medial (adjusted OR: 49.002, 95% CI: 7.047-340.717) or lateral (adjusted OR: 14.974, 95% CI: 2.181-102.790) meniscus and delayed time from injury to surgery (adjusted OR: 1.062, 95% CI: 1.023-1.102) were also a significant predictor.

CONCLUSION

Anterior or distal anteromedial femoral tunnel position, partial meniscectomy of medial or lateral meniscus, and prolonged surgical delay of more than 11.5 weeks from injury were significant risk factors for the inferior clinical outcomes after DB ACL reconstruction.

LEVEL OF EVIDENCE

Level III, retrospective therapeutic case series.

Effects of Notchplasty on Anterior Cruciate Ligament Reconstruction: A Systematic Review

Purpose  Notchplasty is a complementary surgical procedure often performed during anterior cruciate ligament reconstruction (ACLR) with the aim to widen the intercondylar notch and to avoid graft impingement. The aim of this review was to analyze the current literature evidence concerning the effects of notchplasty on clinical outcome after primary ACLR.

Methods  Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, and MEDLINE were used to search English language studies, from January 1990 to July 2015, concerning the effects of the notchplasty on ACLR, using the following keywords: “ACL” OR “anterior cruciate ligament” OR “ACL reconstruction” OR “anterior cruciate ligament reconstruction” AND “notch” OR “notchplasty” OR “intercondylar notch”. Randomized and nonrandomized trials, case series, technical notes, biomechanical studies and radiological study were included.

Results  At the final screening 16 studies were included. Despite widely used, the usefulness of notchplasty during ACLR remains unclear. Some concerns emerged regarding potential harmful effects of notchplasty, mostly related to the knee biomechanics and postoperative blood loss. Notchplasty can be useful in the treatment of arthrofibrosis and in presence of bony spurs of the notch both in primary and revision surgery. However, the level of evidence of available literature is poor and there is a strong need for randomized controlled trials investigating the role of notchplasty on ACLR.

Conclusion  We suggest being aware of potential complications following notchplasty during ACLR before deciding to perform notchplasty in primary ACLR, reserving it for the surgical management of arthrofibrosis, treatment of notch osteophytosis and revision ACLR.

Level of Evidence  Level IV, systematic review of level II-IV studies.

Anterior Cruciate Ligament Injury, Reconstruction, and the Optimization of Outcome

Anterior cruciate ligament reconstruction (ACLR) provides an established surgical intervention to control pathological tibiofemoral translational and rotational movement. ACLR is a safe and reproducible intervention, but there remains an underlying rate of failure to return to preinjury sporting activity levels. Postoperative pathological laxity and graft reinjury remain concerns. Previously, unrecognized meniscal lesions, disruption of the lateral capsule, and extracapsular structures offer potential avenues to treat and to therefore improve kinematic outcome and functional results, following reconstruction. Addressing laterally based injuries may also improve the durability of intraarticular ACLR. Improving the anterior cruciate ligament (ACL) graft replication of the normal ACL attachment points on the femur and the tibia, using either double bundle or anatomical single bundle techniques, improves kinematics, which may benefit outcome and functionality, following reconstruction.

Reliability of 3-Dimensional Computed Tomography for Application of the Bernard Quadrant Method in Femoral Tunnel Position Evaluation After Anatomic Anterior Cruciate Ligament Reconstruction

PURPOSE

To validate whether the Bernard quadrant method, which was developed for application on simple lateral radiography, can be used with 3-dimensional computed tomography (3D CT) to localize the femoral insertion of the reconstructed anterior cruciate ligament (ACL).

METHODS

We analyzed 32 knees with ACL tears that were reconstructed using a metal interference screw for fixation at the femoral tunnel between March 2012 and May 2013. Postoperative lateral radiographs and 3D CT images were obtained 7 days after the operation. By use of the Bernard quadrant method, the location of the femoral tunnel was measured by 2 orthopaedic surgeons by locating the position of the metal interference screw using 3D CT imaging and simple lateral knee radiography. The correlation between the femoral tunnels on the 2 radiographic images was compared using the MedCalc statistical analysis program.

RESULTS

On the 3D CT image, the position of the femoral insertion of the ACL as measured by the position of the metal screw head was 36.3% ± 6.0% in the x-coordinate and 39.6% ± 9.1% in the y-coordinate compared with 37.6% ± 5.8% and 41.0% ± 11.6%, respectively, on the simple radiograph. The Pearson correlation coefficients between 3D CT and simple radiography were 0.840 for the x-coordinate and 0.858 for the y-coordinate. Intraobserver reliability and interobserver reliability for both coordinates were greater than 0.9 on 3D CT.

CONCLUSIONS

Application of the Bernard quadrant method on 3D CT showed high correlation to the originally described method using lateral radiographs and can be used reliably for localizing the reconstructed ACL.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Intercondylar Notch Stenosis of Knee Osteoarthritis and Relationship between Stenosis and Osteoarthritis Complicated with Anterior Cruciate Ligament Injury: A Study in MRI

The aim of this study was to research whether the patients with knee osteoarthritis (OA) exist intercondylar notch stenosis and the relationship between stenosis and OA complicated with anterior cruciate ligament (ACL) injury from magnetic resonance imaging (MRI).A total of 79 cases of moderate-severe OA patients and 71 cases of healthy people were collected; among these OA patients, 38 were OA complicated with ACL injury and 41 were simple OA. The intercondylar notch was divided into A, U, and W types according to the notch shape in the axial sequence of MRI. Measurement of the notch width index (NWI) in the sequences of axial (NWI-1), coronal (NWI-2), and ACL attachment point at femoral (NWI-A) was done. The differences of NWI in different groups and different sequences were compared and the NWI cut-off values in different sequences were resolved by a receiver operating characteristic (ROC) curve which could be used as indicators for intercondylar notch narrowing were calculated.The proportion of type A in moderate-severe OA group was larger than healthy group, and similar to OA complicated with ACL injury and simple OA groups (P <0.05). The NWI values of the moderate-severe OA group in three sequences were smaller than the healthy group, and similar to OA complicated with ACL injury and simple OA groups (P <0.001). The cut-off values of ROC curve were NWI-1 <0.266, NWI-2 <0.247, and NWI-A <0.253 in the moderate-severe OA group, and NWI-1 <0.263, NWI-2 <0.246, and NWI-A <0.253 in the OA complicated with ACL injury group. The intercondylar notch of moderate-severe OA patients exist significant stenosis. Type A is one of the variables that predispose a notch to stenosis. Intercondylar notch stenosis and type A are risk factors for moderate-severe OA patients complicated with ACL injury.

Intercondylar notch dysplasia in open-physis anterior cruciate ligament injuries: A case-control study

BACKGROUND

The incidence of anterior cruciate ligament (ACL) tears in children is rising steadily due to a variety of factors including growing participation in sports. A narrow intercondylar notch is an intrinsic risk factor that is well documented in adults but rarely investigated in children. The objective of this study was to evaluate the potential association between a narrow intercondylar notch and ACL tears in children.

HYPOTHESIS

A narrow intercondylar notch is associated with ACL tears.

MATERIAL AND METHODS

In a paediatric case-control study, we compared intercondylar notch morphology as assessed by magnetic resonance imaging (MRI) in 49 patients with ACL tears (33 males and 16 females with a mean age of 13.6 years) and 50 controls with normal knees (18 boys and 32 girls with a mean age of 13.8 years). In each participant, posterior tibial slope was measured, as well as the notch width index (NWI) (width of the intercondylar notch over bicondylar width at the same level). In addition, to evaluate anterior impingement, the angle formed by Blumensaat's line and the axis of the tibia (α angle) was measured with the knee extended.

RESULTS

The NWI was significantly lower in the cases than in the controls (0.244±0.02 and 0.263±0.02, respectively; P<0.05). The α angle was also significantly smaller in the cases (138.74°±4.6° vs. 141.30°±7.9° in the controls; P<0.05).

DISCUSSION

ACL tears are associated with a small NWI in children. A narrow intercondylar notch is an established risk factor for ACL tears and should be sought routinely to determine whether notch-plasty should be performed during the ACL reconstruction procedure in order to decrease the risk of recurrent ACL tears.

LEVEL OF EVIDENCE

III, case-control study.

Femoral intercondylar notch width size: a comparison between siblings with and without anterior cruciate ligament injuries

PURPOSE

Anterior cruciate ligament (ACL) injuries in siblings are commonly observed in the clinic. One, possibly genetic, factor contributing to the pathogenesis of sibling injuries may be narrow intercondylar notches, which are well recognized as predisposing to ACL injury. This study aimed primarily to: (1) assess the incidence of ACL injuries in siblings within an existing study cohort, (2) compare intercondylar notch width size in injured compared to matched uninjured control siblings and (3) compare the number of injured versus control sibling pairs sharing a narrow notch.

METHODS

Twenty-four ACL-injured siblings from 10 families were matched for age, gender, family composition and sports activity, with 24 uninjured siblings from another 10 families. Intercondylar radiographs were taken to calculate anterior and posterior notch width indices (NWI). Notch size and the number of narrow notches in sibling pairs were compared between groups.

RESULTS

Thirteen of 72 ACL-study participants had siblings with torn ACLs. Mean anterior NWI was 0.18 and 0.24 (p < 0.001), and mean posterior NWI was 0.26 and 0.3 (p = 0.006) for injured and uninjured siblings, respectively. Sixty percent of injured sibling pairs shared a narrow notch, while no uninjured sibling pairs did so (p = 0.003).

CONCLUSION

This study showed that siblings (and often sibling pairs) with injuries do have significantly narrower notches than those without. This could partly explain the prevalence of ACL injuries in siblings. To reduce ACL-injury rates, we advise that siblings of ACL-injured athletes with narrow notches, be radiologically screened, and if necessary, cautioned and counselled regarding preventative training.

LEVEL OF EVIDENCE

Case-control study, Level III.

Effect of Arthroscopic Stabilization on In Vivo Glenohumeral Joint Motion and Clinical Outcomes in Patients With Anterior Instability

BACKGROUND

Glenohumeral joint (GHJ) dislocations are common, and the resulting shoulder instability is often treated with arthroscopic stabilization. These procedures result in favorable clinical outcomes, but abnormal GHJ motion may persist, which may place patients at risk for developing osteoarthritis. However, the effects of shoulder instability and arthroscopic stabilization on GHJ motion are not well understood.

HYPOTHESIS

GHJ motion is significantly influenced by anterior instability and arthroscopic stabilization, but postsurgical measures of GHJ motion are not different from those of control subjects.

STUDY DESIGN

Controlled laboratory study.

METHODS

In vivo GHJ motion was measured by applying a computed tomographic model-based tracking technique to biplane radiographic images acquired during an apprehension test in healthy control subjects (n = 11) and anterior instability patients (n = 11). Patients were tested before surgery and at 6 months after surgery. Control subjects were tested once. Shoulder strength, active range of motion (ROM), and the Western Ontario Shoulder Instability (WOSI) index were also measured.

RESULTS

Before surgery, the humerus of the instability patients during the apprehension test was located significantly more anteriorly on the glenoid (7.9% of glenoid width; 2.1 mm) compared with that of the controls (P = .03), but arthroscopic stabilization moved this joint contact location posteriorly on the glenoid (4.7% of glenoid width; 1.1 mm; P = .03). After surgery, GHJ excursion during the apprehension test was significantly lower (14.7% of glenoid width; 3.6 mm) compared with presurgical values (19.4% of glenoid width; 4.7 mm; P = .01) and with that of the controls (22.4% of glenoid width; 5.7 mm; P = .01). The external and internal rotation strength of patients was significantly lower than that of the controls before surgery (P < .05), but differences in strength did not persist after surgery (P > .17). External rotation ROM in patients was significantly lower than that in control subjects both before and after arthroscopic stabilization (P < .01). The WOSI score improved significantly, from 48.3 ± 13.1 presurgery to 86.3 ± 16.5 after surgery (P = .0002).

CONCLUSION

In patients with anterior instability, arthroscopic stabilization significantly improves measures of strength, ROM, and clinical outcome. However, GHJ excursion is not fully restored to levels seen in the control subjects.

CLINICAL RELEVANCE

Although arthroscopic stabilization satisfactorily restores most clinical outcome measures, GHJ excursion and external rotation ROM remain compromised compared with healthy control subjects and may contribute to the development of osteoarthritis in patients with anterior instability.

An Evaluation of the Association Between Radiographic Intercondylar Notch Narrowing and Anterior Cruciate Ligament Injury in Men: The Notch Angle Is a Better Parameter Than Notch Width

PURPOSE

To evaluate the association of anterior cruciate ligament (ACL) injuries with the intercondylar notch angle and notch width in male patients. The secondary purpose was to evaluate the association of these injuries with other novel morphologic parameters.

METHODS

Male patients undergoing primary ACL reconstruction between 2010 and 2013 for injury through noncontact mechanisms with preoperative magnetic resonance imaging were compared with an age-matched control group of male patients (patients who underwent knee operations other than ACL reconstruction) regarding the following magnetic resonance imaging-assessed parameters: intercondylar notch angle, width, and depth; condylar width; medial/lateral condylar widths; medial/lateral posterior tibial plateau slopes; anterior sagittal tibial slope (corresponding to the level of the tibial ACL footprint); coronal tibial slope; and angle between the Blumensaat line and anterior tibial slope.

RESULTS

In both the coronal and axial planes, patients with ACL injury had a significantly lower intercondylar notch angle (P < .001 and P = .008, respectively) than the control group, but there were no significant between-group differences for intercondylar notch width (P = .9 and P = .97, respectively). In the sagittal plane, patients with ACL injury had significantly higher medial (P < .001) and lateral (P = .02) posterior tibial slopes, a significantly lower anterior tibial slope (P = .01), and a significantly higher angle between the Blumensaat line and anterior tibial slope (P = .02) than the control group.

CONCLUSIONS

Narrowing of the intercondylar notch may be associated with ACL injury in male patients. However, the intercondylar notch angle may be a better parameter to evaluate notch narrowing and its potential association with ACL injuries compared with the notch width. The association between the angle formed by the Blumensaat line and anterior tibial slope and ACL injuries in male patients needs more investigation. This study further suggests that increased posterior tibial slope may be associated with ACL injury in male patients.

LEVEL OF EVIDENCE

Level III, case-control study.

Differences in glenohumeral joint morphology between patients with anterior shoulder instability and healthy, uninjured volunteers

BACKGROUND

Traumatic glenohumeral joint (GHJ) dislocations are common, resulting in significant shoulder disability and pain. Previous research indicates that bony morphology is associated with an increased risk of injury in other joints (eg, the knee), but the extent to which bony morphology is associated with traumatic GHJ dislocation is unknown. This study assessed GHJ morphology in patients with anterior GHJ instability and in a control population of healthy volunteers.

METHODS

Bilateral computed tomography scans were used to measure GHJ morphology in both shoulders of 11 patients with instability and 11 control subjects. Specific outcome measures included the glenoid radius of curvature (ROC) in the anterior/posterior (A/P) and superior/inferior (S/I) directions, humeral head ROC, A/P and S/I conformity index, and A/P and S/I stability angle.

RESULTS

Compared with the control subjects, the glenoid of the instability the injured shoulder in patients with instability was flatter (ie, higher ROC) in the A/P (P = .001) and S/I (P = .01) directions and this finding was also true for uninjured, contralateral shoulder (A/P: P = .01, S/I: P = .03). No differences in GHJ morphology were detected between the instability patients' injured and contralateral shoulders (P > .07). Similarly, no differences in GHJ morphology were detected between the control subjects' dominant and nondominant shoulders (P > .51).

CONCLUSIONS

There are significant differences in GHJ morphology between healthy control subjects and both shoulders (injured and uninjured, contralateral) of patients diagnosed with anterior instability after GHJ dislocation. These findings are important clinically because they suggest that glenoid morphology may influence the risk of GHJ dislocation.

Magnetic resonance evaluation of the knee in children and adolescents with achondroplasia

BACKGROUND

Achondroplasia is the most common form of skeletal dysplasia. Although the radiographic features are well described, MRI features of the knee in achondroplasia have not been reported.

OBJECTIVE

To describe common MRI characteristics of the knee joint in symptomatic children and adolescents with achondroplasia.

MATERIALS AND METHODS

We retrospectively evaluated 10 knee MRI examinations in 8 children and young adults (age range 11-20 years, mean 16.3 years) with achondroplasia. We measured modified Insall-Salvati index, knee flexion angle, anterior cruciate ligament (ACL)-Blumensaat line angle, ACL-tibial angle, posterior cruciate ligament (PCL) angle, intercondylar notch width index, and intercondylar notch depth index. We compared our findings with an age- and gender-matched control group of 20 children (age range 15-18 years; mean 16 years) with normal knee MRIs.

RESULTS

All 10 knees in the achondroplasia group had discoid lateral meniscus; 8 meniscal tears were identified. Patella baja was present in half of the study cases. Greater knee flexion and increased ACL-Blumensaat line and PCL angles were seen in all achondroplasia knees. ACL-tibial angle was similar in the study and in the control group. Children with achondroplasia had deeper A-shape femoral notches that extended more anteriorly than those seen in the control group. MRI findings were confirmed in all seven knees with arthroscopic correlation.

CONCLUSION

Discoid lateral meniscus, often with tear, is a consistent feature in knee MRIs of symptomatic children and adolescents with achondroplasia. Other findings include patella baja, knee flexion, deep A-shape intercondylar notch, increased ACL-Blumensaat line angle and taut PCL.

Intercondylar notch dimensions and graft failure after single- and double-bundle anterior cruciate ligament reconstruction

PURPOSE

The objective of this study was to evaluate the dimensions of the femoral intercondylar notch intraoperatively and to determine whether a small intercondylar notch increases the risk of graft failure after individualized anatomic single- or double-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

A retrospective review of prospectively collected data was performed. One hundred and thirty-seven primary single- or double-bundle ACL reconstructions with at least 2-year follow-up were included in this study. Of these, 116 subjects had intraoperative notch measurements recorded. All operations were performed anatomically using a three-portal technique by the senior author. Intraoperative notch measurements (width at the base, middle, and top and height) were taken using a standard, commercially available arthroscopic ruler. Graft failure was defined as patient report of instability, pathologic laxity on clinical exam, or an MRI or arthroscopic diagnosis of rupture or absence of the ACL graft.

RESULTS

Graft failure at 2-year follow-up in the overall population was 13.9 % (19/137). Graft failure was reported to occur from contact or non-contact trauma, failure of the graft to incorporate, or hardware failure. The dimensions of the intercondylar notch and the graft type used did not influence the risk of graft failure.

CONCLUSIONS

Smaller intercondylar notch dimensions do not appear to be a risk factor for higher rates of graft failure after anatomic and individualized ACL reconstruction. Based on these data, the use of notchplasty is not supported in conjunction with individualized anatomic single- or double-bundle ACL reconstruction.

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.

Effect of Notchplasty in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

BACKGROUND

The effects of notchplasty on the clinical outcome after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction remain unclear.

HYPOTHESIS

Anatomic ACL reconstruction with notchplasty would result in less risk of loss of extension and would provide adequate space for better graft healing, leading to better knee stability compared with anatomic ACL reconstruction without notchplasty.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 137 patients who underwent anatomic double-bundle ACL reconstruction were included. Seventy-three patients without notchplasty were classified as the control group, and 64 patients with 2-mm notchplasty were classified as the notchplasty group. The following evaluation methods were used: loss of extension, patient's subjective feeling of limited extension and pain at passive full extension, muscle strength, manual laxity tests, KT-1000 arthrometer measurement, patellofemoral joint findings, Tegner score, Lysholm score, subjective scores, and time to return to sports. Tearing of the reconstructed ACL and additional synovectomy were recorded. Both tibial and femoral tunnel positions were measured using 2-view radiographs: a Rosenberg and a lateral view.

RESULTS

Loss of extension was larger in the notchplasty group compared with controls (at 6 months: 0.8° vs 1.4°, P = .012; at 2 years: 0.4° vs 0.9°, P = .0053). The number of patients with a feeling of limited extension was also larger in the notchplasty group (at 6 months: 13 patients graded 1+ [somewhat limited] and 2 patients graded 2+ [very limited] vs 18 graded 1+ and 6 graded 2+, P = .015; at 2 years: 2 graded 1+ and 0 graded 2+ vs 4 graded 1+ and 5 graded 2+, P = .011). Six patients in the notchplasty group required additional synovectomy because of the prolonged loss of extension, whereas no patient in the control group required additional synovectomy. There were no differences between groups regarding muscle strength, patellofemoral findings, Lysholm score, Tegner score, subjective scores, or time to return to sports. The KT-1000 arthrometer measurement was better in the notchplasty group (1.2 vs 0.4 mm, P = .0017). However, 6 patients in the notchplasty group showed an overconstrained knee (KT-1000 measurement ≤-2 mm), compared with only 1 patient in the control group. There were no differences between groups in the other manual laxity tests or the tunnel positions.

CONCLUSION

In anatomic double-bundle ACL reconstruction, anterior stability was improved and there were no harmful effects on patellofemoral joint findings by 2-mm notchplasty; however, notchplasty likely caused overconstrained knee, leading to a need for additional synovectomy in some patients. In contrast, anatomic double-bundle ACL reconstruction without notchplasty did not increase the incidence of loss of extension or of graft failure.